Preclinical Immunology and Microbiology Review 2023: For USMLE Step 1 and COMLEX-USA Level 1

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PRECLINICAL

IMMUNOLOGY

AND

MICROBIOLOGY

REVIEW

2023

® FOR

USMLE

STEP

1

AND

® COMLEX

USMLE®

USA

and

the

Federation

do

not endorse,

(NBOME),

United

States

of State which

this

Medical

Medical

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Boards

product.

COMLEX

is not affiliated

with

LEVEL

Examination®

(FSMB),

which

are

USA® is a registered Kaplan

and

was

not

is a joint not

1

program

affiliated

trademark involved

in the

with of the

of the Kaplan National

production

National and

Board

were Board

of, and

not

of Medical

involved

of Osteopathic does

not

endorse,

Examiners

in the

production

Medical this

(NBME)

Examiners, product.

and

of, and Inc

PRECLINICAL

IMMUNOLOGY

AND

MICROBIOLOGY

REVIEW

2023

FOR

USMLE®

STEP

COMLEX

USA®

USMLE® and of State COMLEX was

1

United

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USA® is a registered

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premiums, sales

Editors

Immunology

Tiffany Chief

L.

Resident,

University

of

Alley,

DO,

Department

Tennessee

PhD of

Graduate Knoxville,

Pathology

School

of

Medicine

TN

Microbiology

Christopher Professor

and Lake

C.

Director Erie

College

of

Keller,

Microbiology of

Erie,

Osteopathic P

PhD and

Immunology

Medicine

We

want

to

hear

what Please

you email

think. us

What at

do

you

like

[email protected]

or

not

like

about

the

Notes?

Table

PART

I:

of

Contents

IMMUNOLOGY

CHAPTER

1:

The

Immune

CHAPTER

2:

Ontogeny

CHAPTER

3:

Lymphocyte

CHAPTER

4:

Periphery:

Innate

CHAPTER

5:

Secondary

Lymphoid

of

Innate

CHAPTER

6:

System

the

.

.

.

Immune

Secondary

.

Cells

Development

and

Immune

Immune

B and

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Selection

Response

.

Lymphoid

Meets

Adaptive

Activation

7:

Humoral

CHAPTER

8:

Cell

CHAPTER

9:

Immunodiagnostics

CHAPTER

10:

Immunizations

CHAPTER

11:

Primary

CHAPTER

12:

Hypersensitivity

and

CHAPTER

13:

Transplantation

.

.

.

.

.

.

.

I:

APPENDIX

II:

IMMUNOLOGY

ANSWERS

CD

Immunity.

.

EXPLANATIONS

.

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3

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7

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113

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Immunodeficiencies

PRACTICE

AND

.

Immunity

Markers

Cytokines

.

.

CHAPTER

APPENDIX

.

Tissue:

T Lymphocyte

.

.

Tissue:

Response

Mediated

.

.

.

.

Autoimmune

Disease

.

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123

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127

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129

QUESTIONS

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133

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145

PART

II:

MICROBIOLOGY

CHAPTER

1:

General

CHAPTER

2:

Medically

CHAPTER

3:

Bacterial

CHAPTER

4:

Medically

Relevant

Viruses

CHAPTER

5:

Medically

Relevant

Fungi

CHAPTER

6:

Medical

CHAPTER

7:

Clinical

CHAPTER

8:

Comparative

APPENDIX

I:

INDEX

v

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Parasitology

Infectious

.

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. 167

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. 179

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. 247

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. 269

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. 325

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. 341

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. 357

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. 381

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. 393

.

.

Disease

Microbiology

Charts

and

.

.

Tables

QUESTIONS

EXPLANATIONS

.

.

Bacteria

Genetics

PRACTICE

AND

.

Relevant

Reference

MICROBIOLOGY

ANSWERS

Microbiology

.

.

.

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.411

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.443

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.455

PART

IMMUNOLOGY

The

LEARNING

Define

❏

Discriminate

describe

immune

The

system

is

immune

designed

to

of

and

the

immune

acquired

recognize it

distressed,

system

is

immune

Innate

innate

Additionally,

damaged,

adaptive

components

between

manner.

diseased,

the

system

immunity

SYSTEM

coordinated

or

divided

and

recognizes

respond and

to

non

eliminates

self cells

antigen that

in

are

dying.

into

2 complementary

arms:

the

innate

and

the

systems.

Immunity

Innate It

and

IMMUNE

The

System

OBJECTIVES

❏

THE

Immune

immunity

involves

provides

several

•

Anatomic

•

Physiologic

•

Complement

•

Cellular:

•

Inflammation

Innate

and

Are

•

Have

•

present

molecular

patterns

Are

limited

Adaptive

not

the

anti

defense

against

membranes

infectious

and

microbials

following

with

specificity associated

of

agents.

and

normal

flora)

cytokines)

granulocytes

intrinsically

limited

line

mucous

pH,

have

(pathogen

first

(skin,

and

defenses

for

or shared

molecular

characteristics

without

in

previous

microbe patterns

and [PAMPs]

common:

stimulation cellular

structures

and

damage

associated

[DAMPs])

diversity

recognition •

physical

phagocytes

Have

body’s barriers:

(temperature,

immune

•

the

defensive

as

reflected

by

a limited

number

of

pattern

receptors enhanced

in

activity

upon

subsequent

exposure—no

memory

Immunity

The

components

their

effector

of cells.

the

adaptive

immune

response

are

B and

T

lymphocytes

and

a

1

PART

I

|

IMMUNOLOGY

Adaptive

immune

defenses

•

Each

•

As

•

Are

enhanced

•

Are

capable

•

Are

self

The

B and a

of

is

characteristics

specific

for

have

each

repeat

a

particular

extensive

self

common:

antigen

diversity

exposure

distinguishing

in

—immunologic

from

non

memory

self

limiting

of

adaptive

immunity

against

Specificity

is

against •

following

lymphocytes with

defense

•

the

lymphocyte

population,

features

possible

T

have

required,

persistent

Diversity

is

are

designed

to

give

the

individual

the

best

disease.

along

or

with

recurrent

required

to

immunologic

memory,

to

protect

challenge.

protect

against

the

maximum

number

of

potential

pathogens. •

Specialization

of

defense •

The is

•

can

be

ability vital

Self

to

in

I 1

distinguish

1.

the

conserve

versus

in

Characteristics

to

and

(host

return

cells)

to

resources

leukemia

Adaptive

so

or

and

For

the

and

non

a

basal to

self

(pathogens)

resting avoid

state

after

a

uncontrolled

cell

Adaptive

pathogen

associated

For

patterns

specific

antigens

microbial

of

and

(PAMPs)

nonmicrobial

Diversity

Limited

High

Memory

No

Yes

No

No

reactivity

effective

Immunity

molecular

Self

most

lymphoma.

Innate

Specificity

that

challenges.

response.

system

energy

necessary

self

autoimmune

resulting

Innate

is diverse

between an

allows to

proliferation

Table

function against

inhibiting

limitation

challenge

effector

mounted

agents

Components

Anatomic

and

physiologic

barriers

Skin,

mucosa,

flora,

temperature,

normal

Lymph pH,

antimicrobials,

and

nodes,

spleen,

mucosal

associated

lymphoid

tissues

cytokines

Blood

proteins

Complement

Cells

Antibodies

Phagocytes, and

granulocytes

natural

killer

(NK)

B

lymphocytes

T

lymphocytes

and

cells

Function The

innate

stop

an

ologic able

to

and

adaptive

infection.

arms

Once

of

a pathogen

barriers,

the

innate

contain

and

eliminate

immune the

the

immune has response

infection.

broken

response through is immediately

work the

in

collaboration

anatomic activated,

to

and

physi

oftentimes

CHAPTER

When

the

innate

pathogen, immune the

immune

the response

primary

in

an

Once

an

cease.

Antibodies

while

memory

the

infection

has and cells

unable

to

response

antigen

for

through

is

immune

infection

infection

response

adaptive

the

is

specific

of

been

cleared,

residual

both

effector

provide

long

term

and

the

cells

it

response

cells

replication

of

activated

Typically,

immune

effector

the and

manner.

adaptive

action

control

engaged

to

by

takes

1–2

begin

a

the

innate weeks

clearance

after of

the

antibodies.

innate

and

continue

to

immunologic

adaptive provide

immune

responses

protective

protection

immunity,

from

subsequent

infection.

2 4

1 Innate

Induction 3

immune

of

response

Level

Immunological

adaptive Adaptive

response

immune

response

memory

of

microorganism

Antigen’s

threshold

level

to

activate

adaptive

immune

response

Duration Entry

of

infection

of

Pathogen

cleared

microorganism

FFigure igure

The

innate

another;

•

and rather,

they

Phagocytic pattern

•

adaptive

by

and

present

Immune Response

act

Response to an Acute

independently

of

to Infection an

one

by

binding

to

phagocytosis.

antigen

PAMPs

to release

through

facilitate of

various

stimulation

cytokines

that

of trigger

responses.

cytokines

that

enhance

microbicidal

activities

phagocytes. •

Cytokines tiation

•

Antibodies complement

released of

B

by

phagocytes

lymphocytes will

aid

activation

into in

Acute

mechanism.

subsequent

immune

produce

not

feedback

leading

with

of Immune the

do

pathogens

process

specific

lymphocytes

a positive

receptors

lymphocytes of

responses

recognize

cells T

initiation T

work

cells

specific

•

immune

recognition

Phagocytic

I 1 I 1.1 Timeline 1. Timelineof the

the and

and plasma

destruction antibody

T

lymphocytes

cells of

and pathogen

dependent

will isotype

drive

differen

switching. through

cellular

opsonization, cytotoxicity.

of

Infection

1

|

THE

IMMUNE

SYSTEM

PART

I

|

IMMUNOLOGY

Anatomic

and

Physiologic

Barriers

Immune Respons Phagocytes

and

Complement

Granulocytes

Innate

Cytokines

Immune

Antibodies

Response

T

Adaptive

Lymphocytes

B

Lymphocytes

Cytokines

Figure

I 1

Figure I 1 2. Interaction

2. Interaction between

Recall

Question

Which

of

the

immunologic

between Innate and Adaptive Innate and Adaptive

following

is most

response

re

exposure?

A.

Innate

B.

Natural

killer

C.

Innate

immunity

likely

against

immunity,

as

to

the

adaptive

cause

same

immunity

Immune Immune

Responses Responses

a faster infectious

takes

and

stronger

agent

1–2

after

weeks

cells

because

macrophages

recognize

PAMPs

and

DAMPs

D.

Adaptive

E.

Complement

immunity

and

immunological

memory

activation

Answer:

6

D

Ontogeny

LEARNING

❏

the

Immune

Cells

OBJECTIVES

Explain

information

immune

❏

of

Explain

related

to

origin

related

to

antigen

and

function

of

cells

of

the

system

information

recognition

molecules

of

lymphocytes

❏

Answer

questions

about

the

generation

of

receptor

diversity

ORIGIN Hematopoiesis tion

of

involves

the

multipotent

During

blood stem

the

cells.

The

and Once

and

finally,

production,

site

early

the

bone

differentiation,

megakaryocytes of

the

hematopoiesis

where

Figure

it

will

I 2 1.

yolk

sac

Sites

matura

from

during

shifts remain

and

leukocytes)

changes

development, begins,

marrow

and

hematopoiesis

fetal

organogenesis to

development,

(erythrocytes,

embryogenesis

hematopoiesis. spleen,

cells

development.

is to

throughout

of Hematopoiesis

the the

site liver

of and

adulthood.

2

PART

I

|

IMMUNOLOGY

These

multipotent

undergo population

of

common

stem

The

cells

The

common

in

The

(self

cell stem

common

bone

the

or

a

cells

to

lymphoid and

the

of

renewal),

response

lymphocytes

in

One

multipotent

cells

•

found

progenitor

myeloid

•

cells

division.

lymphoid

(potency). and

stem

asymmetric

daughter

while

the

will

myeloid

give

renew

the

either

a

rise

into

to

rise

cell

the

various

growth

gives

cell

gives

cells,

and

to

to

lymphoid

factors.

to

B

lymphocytes,

T

cells.

progenitor

monocytes/macrophages

ability

serve

progenitor

and

cell (NK)

mast

can

differentiate

progenitor

karyocytes/thrombocytes,

other

the

will

myeloid

cytokines

killer

have cells

common

various

natural

marrow

2

rise

to

eosinophils,

dendritic

erythrocytes,

mega

basophils,

neutrophils,

cells.

FUNCTION The

white

functions Cells

of

non

the

blood

cells

of

in

body

once

the myeloid

specific,

immune

from

stereotypic

and

T

cell

the

of

the of

immunity. in

in

bloodstream

the

microscopic

perform branch

lymphoid

Natural immunity.

specialized

is complete.

innate

the

innate

light

have

marrow

megakaryocytes,

members

in

cells

bone

and

lymphocytes at

stem

the

lymphocytes

participate

indistinguishable

2 interdependent

T

roles

but

and

lymphoid in

are

and

specific

B lymphocytes

and

erythrocytes

lymphocytes

lineage

morphologically

•

except

antigen

lymphoid

Although

myeloid differentiation

responses B

focused, the

the their

lineage,

response.

perform

both

killer

cells

are level,

of

the

lineage are

also

almost

they

represent

lineages.

B lymphocytes

remain

within

the

bone

marrow

to

complete

their

development. •

T

lymphocytes

the

Both

B and

specific

leave

T

lymphocytes

antigens;

•

the

bone

marrow

and

undergo

development

within

thymus.

The granular through

the

natural

have

killer lymphocyte non

surface

generation

specific

(NK)

of

these

cell

(the

that binding.

recognizes

membrane

receptors

receptors

third

will

type tumor

of and

be

designed discussed

lymphocyte) virally

to in

is infected

bind

chapter

a large cells

to 4.

CHAPTER

In

2

|

ONTOGENY

T

cell

progenitor

T

stem IL

CELLS

lymphocyte

Thymocyte

Cytotoxic

Lymphoid

IMMUNE

Thymus

Helper

NK

OF THE

B

B progenitor

Lymphocyte

T

Plasma

lymphocyte

cell

cell

7

Multipotent

stem

cell

Dendritic

cell

Monocyte

Granulocyte/ Monocyte GM

CSF,

IL

Macrophage Neutrophil

progenitor

3

IL

IL

5

5 Eosinophil

Eosinophil

progenitor

Myeloid stem

Mast

cell

cell

Basophil

Thrombopoietin

Basophil progenitor

Erythropoieti IL

11

Megakaryocyte

Erythroid

Figure

I 2 Figure

Platelets

progenitor

I2. 2 2.Ontogeny Ontogeny

Erythrocytes

Immune ofof Immune

Cells Cells

9

PART

Table

I 2

Myeloid

1.

I

|

White

Cell

Neutrophil

Blood

Cells

Tissue

or

polymorpho nuclear

IMMUNOLOGY

Most

Location

Physical

abundant

circulating

blood

cell

(PMN)

with

segmented,

lobular lobes)

Lymphocyte

Tissue

Location

Bloodstream, lymphoid

Physical

secondary tissues

small

extracellular

activity

aimed

at

killing

pathogens

pink

granules

dark a

Function

staining

thin

Surface B

Phagocytic nuclei

Description

Large, with

a

and

cytoplasmic

Cell

Function

Granulocyte

(3–5

cell

Lymphoid

Description

rim

nucleus

of

cytoplasm

No

function

until

activated

secondary

lymphoid

Terminally

differentiated

in

the

tissues

markers: lymphocytes

T

CD19,

20,

21

lymphocytes -

CD3

Helper -

T

cells

CD4

CTLs -

Plasma

cell

Bloodstream, lymphoid bone

Natural cell

killer

Bloodstream

secondary tissue

marrow

and

CD8

Small

eccentric

intensely

nucleus,

staining

Golgi

lymphocyte

that

B

secretes

antibodies

apparatus

Lymphocyte

with

cytoplasmic

granules

Surface CD16,

large

Kills

virally

infected

cells

and

tumor

cells

markers: 56

(Continued

1

)

CHAPTER

Table

I 2 1.

Myeloid

White

Cell

Blood

Location

Physical

Circulating

blood

cell

Reside

in

all

Description

Agranulocyte kidney

Macrophage

|

ONTOGENY

OF THE

IMMUNE

CELLS

Cells

Tissue

Monocyte

2

tissues

Function

with shaped

Agranulocyte

a

bean

or

Precursor

of

tissue

macrophage

nucleus

with

cytoplasmic

membrane

cytoplasmic

vacuoles

a

ruffled

•

Phagocyte

•

Professional

and antigen

presenting

antigen

presenting

large

extracellular

large

extracellular

large

extracellular

and cell

vesicles

Dendritic

cell

Reside and

in

epithelial

lymphoid

Agranulocyte

tissue

stellate

with

thin,

•

T cell

activator

•

Phagocyte

•

Professional

cytoplasmic

projections cell

Eosinophil

Circulating

blood

recruited

Mast

cell

into

connective

tissue

respiratory

and

Reside

in

adjacent

cell

most to

nucleus of

GI

Low

the

with and

cytoplasmic

tissues

blood

Granulocyte nucleus

frequency

with and

•

Elimination

pink

of

parasites •

Type

I hypersensitivity

cell

nucleus cytoplasmic

large

small

•

Elimination

blue

of

parasites

granule

Granulocyte blood

bilobed

activator

granules

cytoplasmic

circulating

large

T cell

tracts

vessels

Basophil

Granulocyte

loose

•

with and

large

bilobed

•

Type

•

Elimination

blue

I hypersensitivity

of

parasites

granules •

Type

I hypersensitivity

1

PART

I

|

IMMUNOLOGY

Laboratory

evaluation

of

patients

cell

morphology

and

relative

the

morphology

and

proportions

some

pathologic

band

cells,

Cell

A

lymphocytes

eosinophils

Table

state.

and

I 2

2.

commonly counts of

standard (B

by white

white

lymphocytes,

assessment of

blood blood T

cells cell

of

a blood indicate

differential

lymphocytes,

the

Leukocytes

Evaluated

in

a WBC

NK

cells),

Range

(%)

Differential

Adult

Neutrophils

(PMNs)

Reference

50–70

cells

0–5

Lymphocytes

20–40

Monocytes

5–10

Eosinophils

0–5

Basophils

55

with

transplant

high

alcohol

intake;

immunosup

patients

intracellular

pathogen;

endotoxin

Disease(s) •

Legionnaires ing mental

•

disease

systems

(“atypical

(now

confusion;

Pontiac

pneumonia”):

routinely diarrhea

fever:

associated

decontaminated); (no

pneumonitis;

no

with

pneumonia;

Legionella

in

GI

air

condition

hyponatremia;

tract)

fatalities

Diagnosis •

Urinary

•

DFA

•

Fourfold

antigen (direct

Treatment:

test

(serogroup

fluorescent

increase

antibody)

in

(levofloxacin)

(immunocompromised

Prevention:

routine

GENUS:

on

biopsy,

(+)

by

Dieterle

silver

stain

antibody

fluoroquinolone

rifampin

1)

or

patients);

decontamination

macrolide

drug

of

air

(azithromycin)

must

penetrate

conditioner

with human

cooling

cells.

tanks

KEY

FRANCISELLA

VIGNETTE

Francisella

Francisella

tularensis

•

Hunter atypical

Distinguishing

Features

•

Small

gram

•

Potential

•

Zoonosis

Reservoir: endemic

every

with

ulceroglandular

pneumonia,

•

Arkansas/Missouri

•

Exposure

disease, or

GI

disease

to

rabbits,

ticks

agent

species state

tularensis

rod

biowarfare

many in

negative

CLUES

of of

the

wild U.S.

animals, but

especially highest

in

rabbits, Arkansas

deer, and

and

rodents;

Missouri

21

Pathology

BehavioralScience/Social Sciences

PART

II

|

MICROBIOLOGY

Microbiology Transmission •

•

Tick

bite

ulcer

at

(Dermacentor) bite

site,

Traumatic

→

and

ulceroglandular

regional

disease,

lymph

implantation

while

node

characterized

enlargement

skinning

and

rabbits

→

by

fever,

necrosis

ulceroglandular

disease •

Aerosols

(skinning

•

Ingestion

(of

typhoidal

tularemia.

Pathogenesis: cells);

bite);

facultative

VIGNETTE

Bordetella

•

or

contaminated

pathogen

tularemia tularemia

Diagnosis:

serodiagnosis

Treatment:

streptomycin

(open

(culture

tick

those

atypical

is

against (for

wound

(bioterrorism;

protection vaccine

GENUS:

meat

water)

(localizes

in

contact

with

produces

reticuloendothelial

at

hazardous);

bites;

high

DFA;

glove

rabbit

blood;

Unvaccinated

child

religious

Cough

(immigrant

use

grows

while

on

BCYE

butchering

rabbits;

risk)

BORDETELLA

Genus

family

objections)

with

inspiratory

“whoop”

Features •

Gram

•

Strict

Species

NOTE

negative

Immunity

rods

aerobes

of

Medical

Bordetella

B. pertussis

small

Importance:

Bordetella

pertussis

pertussis

Distinguishing

Features:

small

gram

negative,

aerobic

rods;

encapsulated

organism •

Vaccine is

immunity

primarily

•

Babies

•

Vaccinated

lasts

5–10

yrs

(and Reservoir:

IgA)

born

with

little

humans

immunity

>10

yrs

human

Transmission:

serve

(vaccinated)

respiratory

droplets

as Pathogenesis

reservoir

•

12–20% >2

•

Vaccine

•

Acellular

of wks

afebrile

have

(DTaP

adults

with

•

B.

pertussis

•

Attachment

is

pertussis

to

hemagglutinin;

vaccineDTaP)

•

Toxins –

Components:

immunogens

manufacturer;

pertussis

filamentous (OMP)

21

hemagglutinin;

vary

surface

pathogen

cough nasopharyngeal

ciliated

pertussis damage

Adenylate phagocytosis

•

mucosal

toxin

respiratory cyclase and

(on

epithelial

outer

cells

membrane)

is aids

via in

filamentous attachment

epithelium. toxin:

causes

impairs local

leukocyte

chemotaxis

→

inhibits

edema

by

toxoid; pertactin

–

Tracheal

–

Endotoxin

cytotoxin:

interferes

with

tick

pneumonia)

pertussis

or

•

CLUES

infected

intracellular

ulceroglandular

attenuated

pneumonia

response

pneumonic

Prevention:

→

undercooked,

granulomatous

Disease:

KEY

rabbits)

ciliary

action;

kills

ciliated

cells

live,

CHAPTER

–

Pertussis

toxin

ation

of

with

Gi

(A

and

(inhibiting

transfer

of

lymphocytosis;

component,

negative

signals islet

immune

B

effector

protein

regulator

from

cell

activation

cells

OM of

surface

(decreased

adenylate

to

leading

to

toxin):

ADP

chemotaxis);

RELEVANT

BACTERIA

system:

blocking

increased

MEDICALLY

interferes

mediator

hypoglycemia;

|

ribosyl

cyclase)

intracellular

2

of

histamine

sensitivity

Table

II 2

18.

Stages

of

Whooping

Cough

(Pertussis)

Incubation

Duration

7–10

Symptoms

None

vs.

Results

of

Catarrhal

days

1–2

weeks

Rhinorrhea,

Culture

Paroxysmal

Convalescent

2–4

3–4

weeks

Repetitive

malaise,

sneez

ing,

Bacterial

cough

whoops,

anorexia

vomiting,

leukocytosis

with

weeks

Diminished

longer)

paroxysmal

development

of

complications seizures,

Bacterial

(or

cough,

secondary (pneumonia,

encephalopathy)

Culture

Diagnosis •

Fastidious/delicate: cough

•

Difficult

•

Direct

•

PCR

14

or to

culture

and

days

tests

care,

Prevention:

all

vaccine toxoid);

immunity

middle

GENUS:

DTaP

from

Gengou

media;

either

direct

of

paroxysmal on

stage

on

nasopharyngeal

smear

available

i.e.,

hospitalization

household

immunity

(IgA)

Bordet

(DFA)

serologic

including

or

cultures

from

supportive

pertussis

Lowe

nasopharyngeal

immunofluorescence

Treatment: for

Regan

plates

if

age

1:160

rifampin

cotrimoxazole

KEY

is

antibodies

agar near

factors

S.

agar

human

X

(hemin)

and

V

(NAD)

(BA) aureus

provides

on

BA

both

=

X

“satellite”

and

V

phenomenon

factors

nasopharynx

respiratory

droplets,

shared

toys

for

growth

on

nutrient

CHAPTER

2

|

MEDICALLY

RELEVANT

BACTERIA

Pathogenesis •

Polysaccharide

capsule

important •

Capsule

IgA

important

in

diagnosis;

serotype

protease

b capsule

is polyribitol

phosphate)

most

factor

agglutination); •

(type

virulence

is a

antigen

all

mucosal

isolates

screen

by

colonizing

on

CSF

(e.g.,

latex

particle

quellung. factor.

Diseases •

Meningitis –

Epidemic

–

After

in

unvaccinated

maternal

children

antibody

has

ages

waned

and

3

months

before

to

2

years

immune

response

of

child

is adequate –

Up

to

1990,

(mainly •

Otitis

•

Bronchitis:

•

Pneumonia:

•

Epiglottitis:

media:

Diagnosis:

still

usually

was

rare

blood

Treatment:

or

if

CSF

common

child

cause

age

2,400

•

S.

typhi

•

S.

enteritidis

•

S.

typhimurium

•

S.

choleraesuis

•

S.

paratyphi

•

S.

dublin

Importance serotypes

of

Salmonella.

or

third

present

tract

catheter

generation

cephalosporin

for

CHAPTER

Salmonella

enterica

2

KEY

typhi

|

VIGNETTE

Salmonella Distinguishing

Features

•

Gram

negative

•

Facultative

•

Produces

•

Species

•

Sensitive

rods,

highly

anaerobe,

motile

with

non–lactose

the

Vi

MEDICALLY

CLUES typhi

•

Patient

with

•

Travel

to

•

Gram

(

biochemical

Reservoir:

only;

fecal

stomach

acid

or

predisposes

Pathogenesis

Infection

•

Host

•

Salmonella

S.

S.

in

•

Symptoms: than

•

3:

Prevention: (Ty21a), ViCPS

bladder); sickle

fever),

S.

gas

Widal

test

decreased

cell

disease

typhi

(milder

form:

of

common

Salmonella M

positive

contact.

cells,

then

blood

septicemia

mesenteric

lymph

nodes

(proteins)

have

rose

spots

in

macrophages;

fusion allow

of

it

to

resistant

lysosomes

to

with

withstand

oxygen

killing

cultures

headache,

25%

fever)

replicates

decreased

independent stool

cultures;

(mainly

and of

defensins

85%

Complications

Diagnosis:

Treatment:

of

oxygen

fever,

if

endotoxin

monia,

patient’s

H2S

are

positive

abdominal

pain,

constipation

more

common

diarrhea

(local

biopsy

80%

because

and

week

in

constipation

of

intracellularly killing

and

By

produces

nonlactose

septicemia)

have

survives

•

side

19

signs

dependent

as

(enteric

from

basolateral

patients

phagosomes

(gall

cells

region;

“ruffle”

reach

macrophage

carriers

fever

ileocecal

(transient

1 week:

human

mononuclear

typhoid

membranes

typhi

), encapsulated,

paratyphi)

(trunk/abdomen), •

area

infection

Disease:

blood

At

endemic

reservoirs

from of

begins cell

and

animal

route

Salmonella

fever;

•

•

oral

and

paratyphoid

no

impairment

to

pain

acid

humans

Transmission:

abdominal

reactions •

to

fever,

fermenting

fermenter, with

BACTERIA

capsule

H2S identification

RELEVANT

abscess

the

serum

can

rose can

necrosis

be

if

isolated

sanitation;

detected

polysaccharide

with

perforation

cholecystitis,

typhi

generation

(no

O,

marrow, Vi,

and

(Widal

(attenuated S.

bone to

agglutination

third

vaccines killed

capsular

patches

blood,

antibodies

by

or

3 heat

from

present;

fluoroquinolones

parenteral

Peyer

thrombophlebitis,

pneu

etc.

be

spots

of

damage),

formation,

organisms from

untreated: triggered

and

antigens

S.

typhi

tissue in

test)

cephalosporins

oral longer

urine, H

vaccine used

of in

U.S.),

and

strain

21

parenteral

vaccine)

23

Pathology

BehavioralScience/Social Sciences

PART

II

|

MICROBIOLOGY

Microbiology KEY

VIGNETTE

Salmonella

CLUES enterica

Salmonella

Subspecies

Other

Than

S.

Subspecies

other

than

typhi

(S.

enteritidis,

typhimurium)

typhi

•

Enterocolitis—inflammatory, ingestion

of

handling

pet

•

Septicemia—very

•

Osteomyelitis—sickle

•

Gram lactose

(

poultry

follows products

Distinguishing •

or

fermenter,

Facultative

gram

MacConkey

reptiles

) bacillus,

Features

young

or

cell

motile, produces

negative

rods,

non–lactose

fermenting

on

EMB,

medium

•

Produces

H2S,

motile

(unlike

•

Speciated

with

biochemical

Shigella)

elderly

disease

non− H2S

Vi

reactions

and

serotyped

with

O,

H,

and

antigens

Reservoir:

enteric

tracts

of

humans

and

domestic

animals,

e.g.,

chickens

and

turtles

Transmission: butter,

raw produce,

chicken

eggs);

and

reptile

eggs pets

in

kitchen;

(snakes,

food

borne

outbreaks

(peanut

turtles)

Pathogenesis •

Sensitive

to

stomach

•

Lowered

stomach

•

Endotoxin

•

Invades

in

cell in →

dose

(antacids

wall;

mucosa

shallow

(infectious

acidity

inflammation

•

acid

no

or

105

organisms)

gastrectomy)

increases

risk

exotoxin

ileocecal

region,

increased

PG

invasive →

to

increased

lamina

propria

cAMP

→

→

loose

diarrhea;

ulceration

Spread

to

most

septicemia

common)

not but

common

may

occur

with with

S.

enterica

subsp.

enteritidis

(the

others

Disease(s) •

Enterocolitis/gastroenteritis

(second

Campylobacter): ally •

bloody,

Septicemia and

enterica

Osteomyelitis:

trait)

Treatment: ampicillin, invasive

Prevention:

23

subsp.

subsp.

dublin):

sickle

cell

common

S.

usually

in

myalgia;

to

osteomyelitis

or of

elderly

paratyphi, when

Salmonella

sickle

cell

disease

(not

(>80%)

on

Hektoen

antibiotics

are generation

agar,

H2S

contraindicated

production

for

cephalosporin,

self

limiting

fluoroquinolone,

gastroenteritis; or

TMP

SMX

disease

properly

it

cases

osteomyelitis; in

after occasion

headache subsp.

young 10%

predisposes of

only

enterica

very

complicates

disease

cause

vomiting; pain;

choleraesuis,

agent

bacterial

nausea;

abdominal

arthritis

causal

patients

third

fever;

or

most

incubation;

enterica

common

culture

hour

stools;

endocarditis

is most

Diagnosis:

loose (S.

S.

occurs; •

6–48

cook

foods

and

wash

hands,

particularly

food

handlers

for

CHAPTER

GENUS:

2

KEY

GARDNERELLA

|

MEDICALLY

VIGNETTE

RELEVANT

BACTERIA

CLUES

Gardnerella Gardnerella

vaginalis •

Female

patient

with

thin

vaginal

discharge Distinguishing

Features

•

Gram

variable

•

Facultative

•

Catalase

rod;

Gram

positive

cell

envelope

anaerobe

negative

Reservoir:

has

human

Transmission:

and

oxidase

negative

•

Post

antibiotic

•

Clue

cells

•

Whiff

test

or

menses

vagina

endogenous

(normal

flora

gets

disturbed,

increased

pH)

Pathogenesis •

Polymicrobial

•

Works

infections synergistically

with

Lactobacillus, •

other

Mobiluncus,

Thought

to

flourish

normal

Bacteroides, when

the

flora

organisms

including

Peptostreptococcus

vaginal

pH

increases,

reduction

of

vaginal

Lactobacillus •

Follows

menses

Disease:

bacterial

adherent

fluid)

Diagnosis: smear;

>4.5,

Whiff

Treatment:

antibiotic

vaginosis

pH for

or

(vaginal

clue

cells

add

KOH

test,

metronidazole

Recall

Question

Ulcers

caused

or

by

therapy

Shigella

odor,

increased

(epithelial

cells

to

and

sample

discharge

covered assess

with for

(thin,

bacteria)

“fishy”

gray,

on

amine

vaginal

odor

clindamycin

species

have

which

of

the

following

characteristics?

A.

Are

B.

Have

C.

Invade

D.

Are

deep

granulomatous

the

vascular

borders

structures

shallow

Answer:

GENUS:

BACTEROIDES

Bacteroides

fragilis

Distinguishing reduced

D

Features:

anaerobic

gram

negative

rods;

modified

LPS

with

activity

23

Pathology

BehavioralScience/Social Sciences

PART

II

|

MICROBIOLOGY

Microbiology KEY

VIGNETTE

Bacteroides

•

Reservoir:

CLUES fragilis

Patient

abdominal

surgery,

trauma,

abdominal

surgery

Septicemia,

•

Gram

peritonitis,

(

) bacilli,

the

genus

endogenous or

Bacteroides

from

bowel

is

defects

predominant

(e.g.,

anaerobe

cytotoxic

drug

use,

cancer),

trauma

Pathogenesis:

modified

reduced •

colon;

Transmission:

with

emergency

human

endotoxin

LPS

(missing

activity;

heptose

capsule

is

and

2

keto

3

deoxyoctonate)

has

antiphagocytic

abscess Diseases:

anaerobic

septicemia,

peritonitis

(often

mixed

infections),

and

abdominal

abscess

Diagnosis:

anaerobes

are

identified

by

biochemical

tests

and

gas

chromatography

Treatment •

Metronidazole,

clindamycin,

or

cefoxitin;

abscesses

should

be

surgically

drained •

Antibiotic

resistance

common

aminoglycosides);

Prevention:

7−10%

prophylactic

Distinguishing

Features:

Transmission:

endogenous

Pathogenesis:

Porphyromonas

Disease:

VIGNETTE

•

or

some

biliary

and

resistant

tract

surgery

spp.

negative

has

cephalosporins,

clindamycin

rods,

gingipains:

anaerobic,

act

as

normal

proteases,

oral

adhesins,

flora

degrades

cytokines

disease

gram

negative

rods

isolated

from

abscess

CLUES metronidazole

pallidum

Sexually IV drug

•

Gram

anaerobic,

Treatment: Treponema

GI

now

Fusobacterium

inflammatory

periodontal

Diagnosis: KEY

and

G,

strains

for

Prevotella,

antibodies

all

antibiotics

Porphyromonas,

IgG

(penicillin

of

active using

Primary:

patient

or

neonate

of

SPIROCHETES

female

nontender,

indurated

genital GENUS:

TREPONEMA

chancre

•

Secondary: colored

•

Tertiary:

maculopapular, rash,

copper

condylomata

gummas

in

cardiovascular

Treponema

pallidum

lata

CNS

Distinguishing

and

•

system

Features

Thin cell

•

Spirillar, by

•

dark

Specific

gram

(

) bacteria

field

or

fluorescent

and

nonspecific

spirochete,

not

reliably

seen

on

Gram

(basically

visualized •

Outer

•

Axial

•

Cannot

•

Is

membrane

has

endotoxin

like

lipids

antibody filaments

=

endoflagella

in

clinical

=

periplasmic

serologic culture

lab;

serodiagnosis

tests

Reservoir:

23

stain

envelope)

an

obligate

human

pathogen

genital

(but

tract

not

intracellular)

flagella

a

gram

negative

CHAPTER

Transmission:

transmitted

Pathogenesis: tendency

Table

II 2

sexually

disease to

chronicity

22.

Stages

characterized

of

or

across

the

by

endarteritis

d

to

3

mo

post

resulting

in

lesions;

chancre;

rated

edge;

to

3

mo

later)

patchy

Fluorescent 50%

weeks

and

both

(30%

of

untreated,

years

lata: and

lesions;

highly

lesion

negative

by

nonspecific

and

specific;

positive

flat,

mucous

wartlike membrane

infectious

Positive

(syphilitic

aortitis,

be

alopecia

perianal

Gummas

of

will serology

Serology

palms

None

later)

microscopy

nonspecific

colored)

includes

Condylomata

Latent

indu heals

(copper

diffuse,

soles,

clean,

3−6

Maculopapular rash,

Tertiary

patients

BACTERIA

strong

contagious;

spontaneously

(1

of

RELEVANT

Diagnosis

Nontender

exposure)

Secondary

MEDICALLY

placenta

Clinical

(10

|

Syphilis

Stage

Primary

2

CNS

granulomas),

serology

Serology:

inflammation

(tabes

cific

specific may

be

tests

Nonspe

negative

dorsalis)

Congenital

(babies

of

IV

drug

users)

Stillbirth,

keratitis,

damage,

notched

8th

asymptomatic

or

widespread

nerve

teeth; with

Serology:

most

born

rhinitis

within

should 3

mo

of

revert birth

to if

negative

uninfected

→

desquamating

maculopapular

rash

Diagnosis •

Visualize

organisms

microscopy •

was

Serology

–

by

2 types

Ab

binds

used

to

–

Specific o

those

with

Lyme

disease;

ABS;

most

nation

(MHA

RPR, syphilis;

specific

so

disease

other

to

usually

fluorescent used

diseases treponemal test);

in

Treponema

mammalian of

ART);

field

titer

may

with lab

mitochondrial

antigen very

is

heart, in

decline FTA

in

primary

tertiary

and

ABS

(VDRL),

(more

cow

sensitive

rapid

recombinant

spirochetes: remain

treponemal

widely

(ART),

antibody bind

earlier;

(dark

tests

source

confirm

research test

treponemal

antibodies; positive

found

(VDRL,

reagin

for

screening

cheap

secondary

venereal

tests

reagin) antigen

not

automated

Earliest and

and

treatment;

microscopy

used)

antibody:

(=

tests

early)

or

longer

treponemes;

screening

Examples: (RPR),

of

cardiolipin: and

in

(except with

no

antibody

membranes

o

but

important:

Nontreponemal o

immunofluorescence

standard

plasma

antigen

reagin

test

(ICE)

expensive) these

positive

tests for

(bejel)

and

antibody pallidum

life,

are

more

but

positive

may absorption

be

specific

positive

in in

(FTA

microhemaggluti

TP)

23

Pathology

BehavioralScience/Social Sciences

PART

II

|

MICROBIOLOGY

Microbiology Treatment •

Benzathine lis

•

penicillin

(no

resistance

Jarisch

increased

occur

during

Borrelia

•

Patient

with

•

Larger

erythema

like

symptoms

•

Gram

Northeast,

•

Microaerophilic

•

Difficult

to

•

Later:

neurologic,

penicillin

spirochete

given

24

BP;

hours

of

rigors,

syphilis

antibiotic

treat

leukopenia;

may

disease

to

contacts;

no

vaccine

available

culture

burgdorferi white

footed

Transmission:

seasons

Midwest,

any

first

syphi

late

negative

Ixodes

•

Ixodes

mice

(nymphs)

(deer)

scapularis

(e.g., •

of

secondary and

ticks

and

and

white

nymphs;

tailed

deer

worldwide

but

(adult

in

3

ticks)

main

areas

of

U.S.:

migrans

Spring/summer

during decreased

and

congenital

spirochetes

Reservoir:

influenza

starts and

primary for

Features

Borrelia

burgdorferi

and

•

CLUES

reaction:

treatment

for G

BORRELIA

Genus

VIGNETTE

form)

penicillin

temperature

benzathine

GENUS:

acting

penicillin);

Herxheimer

ment;

Prevention:

KEY

(long to

West

cardiac,

(I.

Wisconsin,

dammini)

in

Northeast

(e.g.,

Connecticut),

Midwest

Minnesota)

Coast •

Ixodes

•

Late

pacificus

on

West

Coast

(e.g.,

California)

arthritis/ spring/early

summer

incidence

arthralgias Pathogenesis:

B.

primarily

the

Disease:

Lyme

Stage days

Stage (days

1: to

heart,

2:

invades

joints,

disease

early 1

to

burgdorferi and

(#1

localized

vector

(3

month)

early

disseminated

and

arthritis

borne

spreads

Target

enously)

hematog

bloodstream

by

in

immune

to complexes

U.S.)

rash like

Swollen

Bell

symptoms

lymph

Secondary

spreads

via

is caused

disease

Flu

weeks)

(organism

CNS;

skin

palsy,

extreme

nodes

annular

skin

headache, fatigue,

Palpitations,

lesions meningitis,

conjunctivitis arrhythmias,

myocarditis,

pericarditis

Stage (months

23

3:

late to

persistent years)

Arthritis

(mostly

complex

mediated

knees),

immune

involve

CHAPTER

Diagnosis:

serodiagnosis

by

ELISA

(negative

early);

Western

blot

2

|

MEDICALLY

RELEVANT

BACTERIA

for

confirmation

Treatment: (even

doxycycline, in

children);

Prevention:

amoxicillin, ceftriaxone

DEET;

Borrelia

avoid

tick

recurrentis Features:

Transmission: hermsii

(and

Pathogenesis:

body

other

species

antigenic

Disease(s):

relapsing

B.

associated

hermsii);

Diagnosis:

cause

louse

for

of

fever

B.

leads

relapsing

antigen)

not

primary for

arthritis

used

in

U.S.

fever

recurrentis;

to

borne

on

return

soft

of

relapsing

camping

seen

flagellar

ceftriaxone

ticks

from

mice

for

B.

Borrelia)

(tick

with

(OspA

or

hermsii

variation

spirochetes

patient

B.

for

doxycycline

vaccine

spirochetes,

human 13

azithromycin/clarithromycin

secondary;

bites;

and

Distinguishing

or

for

in

dark

fever

rural

field

fever/chills

areas

of

in

U.S.

is

caused

mainly

by

Colorado

microscopy

of

blood

smear

when

is febrile

Treatment:

doxycycline;

Recall

Question

Which

of

the

Jarisch

Herxheimer

following

bacteria

in

cell

osteomyelitis

sickle

A.

Escherichia

coli

B.

Salmonella

enterica

C.

Staphylococcus

D.

Yersinia

reaction

is the

most

possible

common

cause

of

disease?

aureus

enterocolitica

Answer:

GENUS:

LEPTOSPIRA

Leptospira

KEY

interrogans

Distinguishing dark

B

Features:

field

spirochetes

microscopy

but

not

with

light;

can

tight be

terminal

cultured

hooks

in

vitro;

or

coils

aerobic);

(seen

on

VIGNETTE

Leptospira

by

Patients

with

influenza

like

symptoms

serology ±

Reservoir:

interrogans

generally •

diagnosed

CLUES

wild

and

domestic

animals

GI

symptoms

(zoonosis) •

Occupational to

water

or

recreational

exposure

aerosols

Transmission •

Contact branes

•

•

In

U.S.,

with or

animal

enters

via

ational

waters

Hawaii

highest

urine

small

dog,

livestock, (jet

skiers)

incidence

in

breaks

water; in

and or

organism

penetrates

mucous

mem

•

Hawaii

•

Spirochetes

epidermis rat

urine

occupational

through exposure

contaminated (sewer

with

terminal

hoo

recre workers)

state

237

Pathology

BehavioralScience/Social Sciences

PART

II

|

MICROBIOLOGY

Microbiology Pathogenesis:

no

Disease: ±

GI

hepatitis

renal

and

2

23.

Comparison

of

Chlamydiaceae,

Typical (S.

Obligate lar

intracellu

ATP?

Normal

Peptidoglycan cell

*Chlamydial

Rickettsiaceae,

or

not

mud

fever);

treated,

can

influenza progress

test);

culture

(blood,

CSF,

urine)

insensitive

doxycycline

for rat

and

short

term

exposure;

vaccination

of

domestic

control

Mycoplasmataceae

with

Typical

Bacteria

Bacteria

no

Chlamydiaceae

Rickettsiaceae

Mycoplasmataceae

Yes

Yes

No

layer envelope?

peptidoglycan

lacks

ATP

No

ATP

Limited

Normal

Modified*

Normal

peptidoglycan

peptidoglycan

peptidoglycan

muramic

acid

and

is

considered

by

FAMILY:

Family

some

as

modified,

by

others

CHLAMYDIACEAE

Features •

Obligate

•

Elementary

•

Not

•

Cannot

•

Cell

Genera

23

or

if

parasite?

Make

in

swamp

disease);

BACTERIA

aureus)

Mostly

G

pets;

UNUSUAL

II

microscopy

doxycycline

livestock

Table

(Weil

(agglutination

field

penicillin

Prevention:

known

of

intracellular

seen

Medical

•

Chlamydia

•

Chlamydophila

•

Chlamydophila

bacteria

body/reticulate on

Gram

make

wall

like to

failure

dark

Treatment:

factors

disease,

symptoms

serodiagnosis labs;

virulence

(swineherd’s

tract

and

Diagnosis: few

or

leptospirosis

disease

in

toxins

body

stain

ATP

lacks

muramic

Importance trachomatis pneumoniae

psittaci

acid

ATP

Normal

No

as

absent.

ATP

peptidoglycan

available

CHAPTER

Chlamydia

KEY

trachomatis

Distinguishing

Obligate

•

Found

intracellular

•

Infective

•

Not

in

bacterium;

cells

as

form:

seen

on

|

metabolically

inactive,

Gram

cannot

make

active,

replicating

extracellular

stain;

ATP reticulate

elementary

peptidoglycan

layer

bodies

•

Sexually

•

Adult:

body

lacks

muramic

acid

MEDICALLY

VIGNETTE

Chlamydia

Features

•

2

•

RELEVANT

BACTERIA

CLUES

trachomatis

active

patient

urethritis,

or

cervicitis,

inclusion

conjunctivitis

Neonate:

inclusion

neonate

PID,

conjunctivitis/

pneumonia Reservoir:

human

genital

tract

and

eyes •

Transmission: eye

sexual

contact

and

contact

at

birth;

trachoma

is

transmitted

by

hand

from

Africa/Asia,

genital

lymphadenopathy

infection surfaces

Immigrant

to

flies.

Pathogenesis: mucosal

and

of

leads

to

nonciliated

columnar

granulomatous

or

cuboidal

response

and

epithelial

cells

of

•

Cytoplasmic

inclusion

bodies

in

scrapings

damage.

Diseases •

STDs –

in

U.S.

Serotypes

D

herpes –

and

(most are

Nongonococcal tility

–

Inclusion

–

Inclusion

resistance

in

conjunctivitis cough)

L1,

ligament

U.S.,

though

overall

and

major

portion

of

infer

(with

NGU

and

pneumonia

eosinophilic

in

reactive

arthritis)

neonates/infants

(stac

infiltrate

venereum

Serotypes at

in

prevalence) PID,

adults

and/or

with

STD in

reinfection)

conjunctivitis

ulcer

bacterial common cervicitis,

to

Lymphogranuloma

–

common more

urethritis,

(no

cato •

K HPV

site

of

2,

3 (prevalent

contact;

(groove

in

swollen

sign);

Africa,

Asia,

lymph

tertiary

South

nodes

includes

America);

(buboes)

ulcers,

painless

around

fistulas,

inguinal

genital

elephan

tiasis •

Trachoma

–

Leading and

–

cause

of

preventable

infectious

blindness:

serotypes

A,

B,

Ba,

C

Follicular

conjunctivitis

eyelashes

leading

leading

to

probes

in

corneal

to

conjunctival

scarring

and

scarring,

and

inturned

blindness

Diagnosis •

NAAT;

DNA

•

Cytoplasmic

inclusions

antibody

stained

•

Cannot

•

Is

•

Serodiagnosis:

Treatment:

Prevention: systemic

U.S.

be

cultured

scrapings

inert

media

on

in

cultures

azithromycin

, iodine

, or

embryonated

fluorescent

eggs

doxycycline

for for

or

Giemsa

PCR

ELISA

or

erythromycin erythromycin

on

or

cultured

DFA,

and

seen

smear

tissue

(rRNA)

infected

neonatal

mothers conjunctivitis

to

prevent to

prevent

neonatal

disease;

pneumonia

23

Pathology

BehavioralScience/Social Sciences

PART

II

|

MICROBIOLOGY

Microbiology KEY

VIGNETTE

CLUES

GENUS:

CHLAMYDOPHILA

Chlamydophila

•

C.

pneumoniae:

pneumonia:

atypical sputum

intracytoplasmic

•

C.

II 2

24.

Diseases

Caused

by

Chlamydophila

Species

with Organism

C. pneumoniae

Distinguishing

Potential

characteristics

atherosclerosis

Reservoir

Human

C. psittaci

inclusions

psittaci:

exposure

Table

atypical to

pneumonia:

association

with

No

glycogen

in

inclusion

bodies

parrots

Transmission

respiratory

Respiratory

tract

droplets

Birds,

parrots,

(major

U.S.

Dust

of

dried

secretions

Pathogenesis

Intracellular

growth;

smooth lial

muscle, cells,

Disease

and

Atypical nia;

dry

Diagnosis

cough

Psittacosis

bronchitis;

and

(ornithosis);

atypical

pneumonia

prominent

hepatitis,

hoarse

and

with

possible GI

CNS

symptoms

sinusitis

Serology

(complement or

Serology,

microimmuno

fluorescence)

Treatment

pneumo

lobe;

sputum,

fixation

growth

coronary

“walking”

ness;

Intracellular

feces

macrophages

single

scant

bird and

endothe

or

artery

infects

turkeys reservoir)

Cold

agglutinin

negative

Macrolides

and

complement

fixation Cold

agglutinin

negative

Doxycycline

tetracycline

Prevention

GENUS:

Table

II

Group

Rocky Spotted

2 25.

Infections

Disease

Mountain

Scrub

Avoid

birds

RICKETTSIA

Caused

by

Rickettsiae

and

Close

Relatives

Bacterium

Arthropod

Vector

Reservoir

R.

rickettsii

Ticks

R.

prowazekii

Human

R.

typhi

Flea

Rodents

Mites

Rodents

Tick

Small

Ticks,

Host

dogs,

Fever

Epidemic

Endemic

None

Typhus

Typhus

Typhus

Orientia

louse

Humans

tsutsugamushi

Ehrlichiosis

24

E.

chaffeensis

A.

phagocytophilum

mammals

rodents

CHAPTER

Genus

2

|

MEDICALLY

RELEVANT

BACTERIA

Features •

Aerobic,

•

Obligate

gram

bacilli

intracellular

dent

Species

negative

(too

bacteria

small

(do

not

to

stain

make

well

with

sufficient

Gram

ATP

stain)

for

indepen

life)

of

Medical

Importance

•

Rickettsia

rickettsii

•

Rickettsia

prowazekii

•

Rickettsia

typhi

•

Orientia

•

Ehrlichia

spp.

•

Coxiella

burnetii

tsutsugamushi

Rickettsia

(formerly

R.

tsutsugamushi)

KEY

rickettsii

Reservoir:

small

wild

Transmission: ovarian

hard

rodents

and

ticks:

larger

wild

Dermacentor

and

(also

domestic

animals

reservoir

hosts

Rickettsia

(dogs)

because

of

VIGNETTE

•

trans

transmission)

rickettsii

Patient and ankles

Pathogenesis: many

invade

organs

Disease:

including

Rocky

•

Prevalent

•

Headache, and

•

cells

brain,

Mountain

on

liver,

spotted

East

Coast

fever

skin,

fever

(OK,

(38.8

lining

C

capillaries, lungs,

causing

kidney,

and

vasculitis GI

[102.0

NC, F]),

SC);

2–12

malaise,

day

tract

incubation

myalgias,

toxicity,

influenza

petechial

like

rash

and

wrists

that and

symptoms begins

moves

on to

trunk

in

(RMSF)

TN,

with

vomiting,

•

East

Coast

•

Spring/summer

•

Outdoor

•

Weil

mountainous

areas

seasons

exposure

Felix

(+)

confusion

Rash and

endothelial

CLUES

(maculopapular wrists

and

( centripetal •

Ankle

•

Diagnosis

→ then

petechial)

spreads

starts

to

the

(by

trunk,

day

6 of

palms,

illness)

soles,

on

and

ankles

face

rash) and

wrist

may

swelling

be

conjunctivitis,

also

confused

and

occur

by

GI

symptoms,

periorbital

swelling,

stiff

neck,

arthralgias

Diagnosis •

Clinical

symptoms

•

Start

•

Serological

(above)

treatment

and

without IFA

test

tick

bite

laboratory most

widely

confirmation used;

fourfold

increase

in

titer

is

diagnostic •

Weil Proteus

Treatment:

Prevention:

Felix

test

(cross

vulgaris)

doxycycline,

tick

protection

is

no

reaction

of

Rickettsia

longer

used

(but

even

in

and

children

prompt

age

removal;

antigens may

200)

immunity

granulomatous

disease

immunocompromised

normal

polymorphonuclear

multiple

listed number.

flora

leukocytes

subcutaneous

are

number that

cell

not

have

the

to

human

do

disease

organisms

scenarios

and

causes

to

SOME

•

7#

Disease

OBJECTIVE

Answer

These

Infectious

causal

with If

it

the

agents,

abbreviation

specifically

at

the “CA.”

says

“species,”

end

of

This you

the means should

description you give

there should

be

may

be

able

to

a list

species.

35

Pathology

BehavioralScience/Social Sciences

PART

II

|

MICROBIOLOGY

Microbiology Table

II

Type

7

1.

Diseases

of

Infection

Skin,

Mucous

Case

Furuncles,

Membranes,

and

Vignette/Key

Neck,

Underlying

Tissues

Clues

face,

axillae,

Common

buttocks

Causal

Agents

Staphylococcus

aureus

carbuncles Inflamed Acne

vulgaris

follicles

from

Inflammation

of

neck

follicles

down

and

Pseudomonas

sebaceous

aeruginosa

Propionibacterium

(hot

tub

folliculitis)

acnes

glands

Impetigo

Vesicular

lesions

SubQ

Initially

vesicular;

lesions;

catalase

Initially

vesicular

bullae;

catalase

granulomas/

erosion;

but

fish

crusted

Streptococcus

pyogenes

organism

with

longer

lasting

Staphylococcus

aureus

organism

preceded

Tropical

honey

negative

positive

Sometimes

ulcers/cellulitis

skin

by

neurologic

enthusiasts;

pain

Herpes

granulomatous

Mycobacterium

lesion

marinum

(fish

tank

granuloma)

Cellulitis

following

contact

with

saltwater

or

Vibrio

vulnificus

oysters

Mycetoma with tract yellow

(swelling

pain,

Solitary

sinus

or

lymphocutaneous

gardeners

or

lesions,

florists,

sphagnum

rose

Sporothrix

moss

schenckii

(rose

gardener

disease)

formation, granules

in

Subcutaneous ders)

exudate)

Jaw

area,

dental

Malignant

pustule

swelling

multiple

shoul

Bacteria:

associated

→

with or

dark

red

→

black

necrosis

Actinomyces,

Madurella,

extraction,

Pustule →

(extremities,

CA

carious

teeth,

Nocardia,

Fungi:

Pseudallescheria,

Actinomyces

Sporothrix

israelii

“lumpy

jaw”

trauma

fluid

filled,

tumor

eschar

like

surrounded

lesion by

Bacillus

anthracis

red

margin

Ecthyma

Cellulitis

gangrenosum

Blue

green

Dermal

pus,

pain,

Red,

raised

Hot

inflamed

Wounds

grape

skin

odor,

heat

and

facial

tissues. of

above)

like

edema, butterfly

extension ing

(as

burns

rapid

spread.

Pseudomonas

septicemia

Pseudomonas

aeruginosa

Streptococcus

pyogenes

(Erysipelas)

rash

Deeper lesions

tissues or

from

wounds

includ

Variety gram

of (–)

bacteria: rods,

S.

aureus,

Clostridium

S. and

pyogenes, anaerobes

surgical

Surgical

wounds

(clean)

Surgical

wounds

(dirty)—list

Trauma—list

Shallow

Staphylococcus

groups

S.

groups

puncture

aureus,

Clostridium,

wound

through

tennis

shoe

aureus

Enterobacteriaceae,

anaerobes

Enterobacteriaceae,

Pseudomonas

Pseudomonas

aeruginosa

sole

Animal

bites

Various

Pasteurella

Human

Dog

Rat

bites,

fist

fights

Eikenella

bites

multocida

corrodens

Capnocytophaga

bites

canimorsus

Streptobacillus

moniliformis

minus

358

Cat

scratches

with

stellate

resulting granulomas

in

lymphadenopathy

Bartonella

hensela

and

Spirillum

CHAPTER

Table

II 7

Type

2.

Ear,

Nose,

Infection

Acute

Throat,

Upper

Respiratory

Case

otitis

media

System

Vignette/Key

Red,

Common

tympanic pain

ruptures

or

membrane,

goes

if

ear

|

CLINICAL

INFECTIOUS

DISEASE

Infections

Clues

bulging

102–103;

7

away

tubes

fever

if are

H. 5

Agents

Streptococcus

drum patent.

Causal

CA

pneumoniae

influenzae

(often

nontypeable,

recurs) Moraxella

catarrhalis

RSV Rhinovirus

Otitis

externa

Ear

pain—list

of

organisms

NF

often

involved

Often

mixed

Staph

aureus

Candida

otitis

Severe

externa

ing

Sinusitis

Sinus

Oral

cavitary

disease

ear

pain

pain;

low

mouth—overgrowth

chetes

and

throat

Inflamed

tonsils/pharynx,

purulent

and

ach

rior

upset;

papules

grade

BUN; WBC when

cold

fever

of

red

and oral

treponemes

spirochetes)

be

Streptococcus

pyogenes

strep)Rash stom

erythrogenic

poste

Coxsackie

indicates

(group presence

exotoxin

A of

A

on

with

Strep

with

severe

type

a

1–2

Epstein

II

virus

day

cells

gradual

Corynebacterium

diphtheriae

(diphtheria)

laryngotracheitis;

ECG;

Barr

rash;

nasopharyngitis

Exudate

A

fever

lymphadenopathy;

abnormal

media

on

may

base

Downey

obstructive

(toxin).

pts

fever,

membranous

from

otitis

rash

like

(+);

and/or neck

pts,

fever,

lymphadenopathy,

heterophile

acute

Candida

abscesses;

pharynx,

looking

fatigue,

onset

IC

develop

with and

aeruginosa

risk:

which

may

Pseudomonas

deficiency

sandpaper

palate

Throat

Low

coating

lymphadenopathy,

White

Common

C

(water)

for

NF)*

organism)

Fusobacterium

increased

AIDS,

vitamin

cervical

white

(from

(water

(normal

under);

infants,

antibiotics,

spiro

NF)*

Pseudomonas

As

of

thick

base

premature

threaten

bacteria

with

red

life

fever

fusiform

mouth

(painful

diabetic;

grade

Painful

Sore

Sore

in

(from

albicans

Proteus

Malignant

infections:

bull elevated

little bleeds

change

in

profusely

dislodged

Rhinitis,

sneezing,

seasonal

peaks

coughing;

list

CA

with

Rhinoviruses

(summer–fall)

Coronaviruses Human Adenovirus,

(winter–spring) metapneumovirus many

others

35

Pathology

BehavioralScience/Social Sciences

PART

II

|

MICROBIOLOGY

Microbiology Table

Type

II

7

3.

Eye

Infections

Infection

Case

Eyelid

Vignette/Key

Bilateral

Clues

eyelid

swelling,

eosinophilia,

fever,

earlier

GI

Stye;

2

Common

>10%

muscle

Causal

Agents

Trichinella

pain;

Sx

CA

Staphylococcus

aureus

Propionibacterium

Unilateral

inflammation

often to

around

at

eye

Mexico,

or

Central

bite

mouth; or

site

acnes

Trypanosoma

cruzi

travel

South

America

Conjunctivitis

Red

neonate

days Red

itchy

eye(s)/pus;

onset

2–5

itchy

eye(s)/pus;

onset

5–10

days

age

(other

groups)

Red

with

itchy

pain,

Red

pink

Neisseria

gonorrhoeae

Chlamydia D–K

Neonate

Conjunctivitis

Bacterial

“sticky

eye(s),

thin

eye,

trachomatis

Staphylococcus

exudate;

Viral

pink

common

pus;

4

CA

S.

aureus,

aureus

eye:

adenovirus

than

A (all

Haemophilus

sion

eye,

pus,

bodies

serotypes

in

Granulomas

Chorioretinitis

Neonate

Retinopathy keratitis

36

with in

baby

Mom

with

or

IV

drug

inclu CA

U.S.

Chlamydia with

serotypes

pink

Strep,

gram

scarring,

eye blind

Chlamydia serotypes

Strep

influenzae,

H.

abuser

2

CA

Toxoplasma,

Treponema syphilis)

aegyptius

trachomatis D

K

(inclusion

conjunctivi

trachomatis A,

B,

Ba,

C

(trachoma)

serotypes

AIDS;

eye)

[+])

tis)

inturned

corneal CA

of

scrapings;

and

lashes, ness;

presence in

(more

bacterial

group

pneumoniae

Red

(serotypes

U.S.)

eye”

photophobia

eye

CMV

pallidum

(congenital

CHAPTER

Table

II 7

Type

4.

Cardiac

back

Case

endocarditis:

Chills,

fever, pain,

Vignette/Key

Developing arthralgia,

acutely

lesions;

myalgia, ill,

drug

CLINICAL

INFECTIOUS

DISEASE

Clues

a

heart

Common

murmur;

IV

Causal

Agents

Staphylococcus

aureus

Staphylococcus

aureus

user

Janeway

emboli

Not

Subacute

endocarditis:

Fever with

|

Symptoms

Infection

Acute

7

with

weight

sweats,

anorexia,

murmur

may

drug

oral

user

hygiene

or

dental

work

Viridans cases

symptoms onset,

weakness,

present;

Poor

vague

insidious

IV

streptococci in

(55%

native

of

hearts)

fatigue, loss,

night

myalgias; have

emboli,

been

long

splinter

hemorrhages

Gram

neg.

oral

endocarditis

(normal

flora)

HACEK

organisms

(Haemophilus

aphrophilus

Actinobacillus

actinomycetem

comitans Cardiobacterium Eikenella Kingella

Biliary GU

IV

or

urinary

manipulation

drug

tract in

user

infection elderly

hominis corrodens kingae)

Enterococcus

faecalis

men

Staph. Aspergillus Candida

epidermidis (branching

2

cough,

≤5

weeks,

nourished,

giant

cell

influenzae

Parainfluenza

Adults

Foul

baby/child;

with

#1

Chlamydophila

rash

CA

sputum,

often

pts,

smelling

follows

burn

CGD,

malnourishment

pneumonia

and

rium

with

huge

of

pneumoniae

Anaerobes,

mixed

infection

capsule,

+,

Salmon

low

fever,

diffuse

dry

infil

Klebsiella

negative currant

post

catalase

+,

colored

Pneumonia

pneumoniae

bacte jelly

sputum

influenza

Staphylococcus

aureus

coagulase

+

sputum

teens/young

cough;

initially

adults;

non

bad

productive

hacking

Mycoplasma

cough

cause

trates

pneumoniae of

pneumonia

(most in

children) Atypical

with

especially

respiratory

bird

patients

to

East,

Legionella

hepatitis

Chlamydophila

cough;

“ground exudate

progressive

winter,

spp.

drinker

honeycomb

cysts,

Far

smoker,

staccato

biopsy:

staining

exposure

heavy

exposure,

with

x ray;

Travel

distress

conditioning yr,

with

glass” silver

air >50

Atypical

AIDS

Pneumocystis

psittaci

jirovecii

with

hypoxia

early

spring,

SARS

CoV

hypoxia

Spring,

pneumonia

or

cough loss,

with

Over

4

55,

corners

region,

HIV+,

or

exposure

immigrant

to

from

rodents

developing

Hantavirus

Mycobacterium

tuberculosis

country

night

calcifying

Dusty

environment

contamination

with

bird

(Missouri

or

bat

chicken

fecal

Histoplasma

capsulatum

Coccidioides

immitis

Blastomyces

dermatitidi

farmers),

lesions yeasts

packed

Desert

sand,

Rotting South

(Bacteroides,

Peptococcus)

formation

Gram

Atypical:

aspiration,

gram

ventilator,

Abscess

362

risk

Pseudomonas

possible

formation,

anaerobic,

Nosocomial,

sweats,

↑

blindness

Streptococcus

CF

aspiration

abscess

facultative

weight

pneumoniae

influenza

pts,

sputum,

Alcoholic,

chronic

Mycoplasma

pertussis

Measles:

hemorrhagic

alcoholics)

influenzae,

pneumoniae,

Fusobacterium,

Acute

(Croup)

Haemophilus

Bordetella

>9

unvaccinated

(including

virus

RSV

years

afebrile;

pneumonia

Neutropenic

Acute

(epiglottitis)

infiltrates Rusty

cough,

Agents

phonation

years

Poorly

productive

barking

hoarse

infant

With

Pneumonia

sharp

stridor,

Wheezy;

>5

diffuse

Most

unvaccinated

Infant

Typical:

Infections

contaminated Carolina

into

SW

phagocytic

cells

U.S.

wood,

North

and

school

common age

CHAPTER

Table

Type

II 7

6.

Genitourinary

Infection

Urethritis

Tract

7

|

CLINICAL

INFECTIOUS

DISEASE

Infections

Case

Vignette/Key

Gram

negative

Clues

Most

diplococci

in

PMNs

in

urethral

Common

Neisseria

Causal

Agents

gonorrhoeae

exudate

Culture

negative,

Urease

positive,

Flagellated

Cystitis

inclusion

no

bodies

cell

wall

protozoan

Frequent

and

with

painful

Chlamydia

corkscrew

urination,

motility

hematuria,

and

fever

trachomatis

Ureaplasma

urealyticum

Trichomonas

vaginalis

#1

E.

coli,

other

Young,

newly

positive

Pyelonephritis

As

Cervicitis

Friable,

sexually

active

individual;

gram

Staphylococcus

above,

with

flank

inflamed

pain

and

cervix

probes

prominent

with

or

fever

E.

mucopurulent

culture

to

coli,

Staphylococcus

Neisseria

distinguish

gonorrhoeae

trachomatis

odor

Adherent

yellowish

amine

odor

cells

discharge,

in

KOH,

clue

pH cells;

>5,

fishy

gram

negative

(virus)

vaginosis)

nerella

staining

parasite)

simplex

(Bacterial

negative

(non

intracellular

Herpes

itching,

(gram

diplococci)

obligate

discharge

enterics,

saprophyticus

Chlamydia

pain,

negative

Proteus

cocci

discharge;

Vaginal

gram

Pseudomonas,

overgrowth

vaginalis

and

of

Gard

anaerobes

dominate

Vulvovaginitis,

pruritis,

consistency

of

Foamy,

purulent

motile

erythema,

cottage

discharge,

trophozoites

discharge:

Candida

spp.

cheese

many

PMNs

microscopically

and

Trichomonas

vaginalis

(corkscrew

motility)

Pelvic tory

inflamma disease

Adnexal nia,

tenderness, vaginal

cervical tory

Genital

lesions

bleeding,

discharge, movement,

mass

on

follows

menses

Genital

warts

deep

fever; possibly

bimanual

dyspareu

tenderness palpable

exam,

Neisseria from

inflamma

onset

gonorrhoeae

trachomatis

or

or

both

or

a

Chlamydia variety

of

other

organisms

often

Human U.S.

papilloma STD),

virus

Treponema

(most pallidum,

common molluscum

contagiosum

Multiple

painful

Nontender, 2–10

Non

indurated,

Genital tiasis

elephan

Initial develop develop,

ulcer

recurring

healing

Herpes

spontane

Treponema

simplex

virus

pallidum

weeks

painful

adenopathy,

Guinea,

coalescing,

indurated

ously

Soft,

vesicular,

slow

painless

to

ulcer,

gram

papule fistulas; tropics,

papule,

pt

negative

heals;

suppurative

with

Haemophilus

ducreyi

heal

from

Caribbean

intracellular

lymph genital microfilariae

or

New

bacilli

nodes

in

granulomatis

(granuloma

ingui

nale)

enlarge

elephantiasis

Klebsiella

and may

Chlamydia Wuchereria

trachomatis or

Brugia

L1–L3 (filarial

nematodes)

bloodstream

36

Pathology

BehavioralScience/Social Sciences

PART

II

|

MICROBIOLOGY

Microbiology Diarrhea

Dysentery •

Abdominal

•

Usually

cramps,

tenesmus,

associated

with

and

invasive

pus

and

bacterial

blood

in

disease

the

in

the

stool colon

Diarrhea •

Refers

•

Most

to

profuse

watery

commonly

mucosal

feces

associated

surfaces

of

with

the

small

increased intestine

secretion in

of

response

to

fluid

across

a toxin

or

the a

viral

infection •

Table

II 7

7.

Diarrhea

by

No

inflammatory

cells,

usually

no

fever

Intoxication

Common Most

Common

Sources

Ham, salad,

potato

Age

Group

Incubation

Infected

Period

All

1–6

Duration Pathogenesis

hours

cream

Heat

stable

enterotoxin

pastries

produced

in

sits

abd