non-human vertebrate host is reservoir of infection

human contact not essential for microbe's normal lifecycle

human-->human transmission possible

gram- rod

protein capsule covering

bipolar staining "closed safety pin"

bacteria multiplies in fleas foregut --> blockage due to blood clot prevent passage of subsequent blood meals --> regurgitation by 'blocked' flea facilitates transmission

*bubonic plague

incompletely understood

LPS endotoxin important in sepsis

after inoculation, bacilli --> regional lymph node

--> replicates intracellularly infected monocytes disseminate 

1. bubonic plague

2. pneumonic plague

symptoms: fever, chills, myalgia, arthalgias, headache

progression: w/in 24h px @ proximal lymph node, enlarging bubo --> sepsis w/o tx --> multi-organ failure

symptoms: bloody sputum, chest px, dyspnea & cyanosis, death w/in 24h

*likely outcome of terrorist attack

lactose non-fermenter

oxidase & urease both negative

better growth @ 28*C

fluorescence antibody positivity

"hammered copper" growth (48h) & "fried egg" (72h) growth on blood agar plates

very small gram- rod

fastidious

strict aerobe

human acquisition: infected animals (rabbits & squirrels, tick bite); NOT from humans

highly infectious: can be aerosolized

-intracellular w/in macrophages (inhib lys-phag fusion)

-virulent strains encapsulated (antiphagocytic)

Tularemia ("glandular fever", "rabbit/tick/deer-fly fever")

presentation: sudden onset of fever & generalized myalgia/arthralgia

-five different forms (ulceroglandular, oculoglandular, typhoidal, pneumonic, oropharyngeal/gastrointestinal)

rapidly progressing

acute onset (fever, chills, myalgias, headache, sweats)

conjunctivitis w/ periauricular lymphadenitis in hunter w/ recent rabbit handling

often w/ swollen cervical lymph nodes

-consider this pathogen in pts from endemic areas w/ fever, ulcerative lesions & lg lymph node

-bacteria present in gram stain (blood/tissue samples); weakly staining => difficult to differentiate

-require cysteine/cystine for growth

-antigen agglutination test sensitive (Ig against Brucella cross-react)

-unique long-chain saturated/unsaturated fatty acids (GLC)

*easily aerosolized/inoculated in skin 

unencapsulated

gram- rod/coccobacilli

good growth on peptone based medium & w/ C02

resistant to drying => good airborne transmission

*to clear this infection: need both humoral & CMI

-intracellular brucella: suppress respiratory burst/apoptosis

-LPS 'O' antigens: colonies either smooth or rough (only smooth colonies are pathogenic)

Undulant Fever (Brucellosis)

-presentation: fever w/ profuse sweats (esp at night); fever rises then falls then repeats; musculoskeletal signs/symp

-chronic form: mimic miliary TB (supp. lesions in liver, spleen, bone)

fastidious 

slow growth

strict aerobe (req C02)

blood culture: seen directly w/ fluoresceinated antibody

Brucella abortus antigens cross-react w/ Francisella antigens

-3 important species (quintana, bacilliformis, henselae)

-gram- coccobacilli, fastidious, needs high C02

-transmission by: body louse, sand fly, cat scratch, respectively

-no animal model to study virulence

-caused by Bartonella quintana

-sympt: severe headache, fever, weakness & px in long bones

-complications: endocarditis, bacteremia

-Bartonella quintana & Bartonella henselae

-type: vascular proliferative disorder (hemangioma)

-risk factors: I/C & AIDS pts

-affected regions: skin, S/C tissues, bones

-sympt: nodular skin lesions (ulcerate & drain)

-Bartonella henselae

-bite/scratch-->papule-->vesicle; chronic proximal lymphadenopathy w/ occasional suppuration

-dx: PCR on lymph node diopsied or aspirated material 

-Bartonella bacilliformis

-transmitted to human<--sand fly (Andes Mtns.)

-acute febrile phase: bacteria invade RBCs, severe anemia

-symp: muscle/joint px, fever, headache, coma

dx: symptoms & recent proximity to Peru, Ecuador, Colombia

-OF followed by chronic cutaneous skin lesion (Verruga Peruana)

small gram- coccobacilli bipolar-staining

associated w/ animal bite/scratch/lick

1. cellulitis

2. lymphadenitis

3. septicemia in I/C pts

4. septic arthritis (cat bite)

gram- rod

good growth on blood agar

Streptobacillus moniliformis

Spirillum minus

long thin gram- rods (poorly staining)

human acquisition from rat bite or oral/eye/nasal secretions of infected animal

Rat-bite Fever

-abrupt onset: fever, headache, chills, muscle pain & migratory polyarthalgias; maculopapular rash on abdomen

dx: rash, recent rat bite, & migratory polyarthalgias

Identify Streptobacillus moniliformis:

L-form colonies on serum-enriched media

Identify Spirilum minus:

Darkfield or Giemsa smears; difficult to culture

Anthrax (Bacillus anthracis)

Botulism (Clostridium botulinum)

Plague (Yersinia pestis)

Smallpox (Variola major)

Tularemia (Tularemia)

Viral hemorrhagic fevers (Ebola, Marburg - filoviruses & Lassa, Machupo - arenaviruses)

Brucellosis

Melioidosis

Psittacosis

Q fever

Typhus

Viral encephalitits (VEE, WEE, EEE)

food-borne diarrhea (Salmonella, Shigella, EHEC)

water-borne diarrhea (cholera, cryptosporidium)

Glanders 

Clostridium perfringes Epsilon toxin

Staphylococcus aureus enterotoxin B

Ricin