Bacterial Infections-II

Question 1

Lyme’s Disease: organism, gram morphology, reservoir, transmission, endemicity, clinical

Answer 1

Borrelia Burgdorferi
Spirochete, GN-like
Rats
Ixodes ticks
NE and upper MW
Bulls eye rash, disseminate to CNS, myocarditis, arthritis

Question 2

Bubonic plague

Answer 2

Yersinia pestis
GN bipolar staining (safety pin)
Rodents/prairie dogs reservoir 
Fleas transmit 
West, North NM/AZ
Septicemia (DIC, subcutaneous hemorrhage), pneumonic form that can spread via human transmission

Question 3

Tularemia

Answer 3

Franciscella tularensis
GN coccobacillus
Rabbits, small mammals reservoir
Transmitted by animal carcasses, ticks, deer flies
South central states
Ulceroglandular, pneumonic form, BT agent

Question 4

Rocky Mountain Spotted Fever

Answer 4

Rickettsia ricketsii
GN coccobacillus
Mammals reservoir
Transmitted by American dog ticks
Most states, especially south central/Atlantic
Centripetal rash progressing petechial hemorrhage

Question 5

Cat scratch fever

Answer 5

Bartonella henselae 
GNR
Cats/kittens are the reservoir
Scratches are the transmission
Widespread
Cutaneous lesions, fever

Question 6

Anthrax

Answer 6

Bacillus anthracis 
GPR
Livestock/soil reservoir
Animals carcasses and soil transmission
Rural areas
Cutaneous eschar, inhalational anthrax with flu like symptoms that rapidly progress to pulmonary hemorrhage and death, vaccine for livestock, agent of BT

Question 7

Gas gangrene

Answer 7

Clostridium perringens
GPR
GI, microbiota, soil reservoir
Transmission through the spoil
Sporadic cases
Necrotizing fasciitis, myonecrosis, gas production (crepitus)
Cellulitis progressing rapidly to hemorrhagic, bullous lesions, severe pain at site, tachycardia/fever/shock signs of septicemia

Question 8

Syphillis

Answer 8

Treponema pallidum 
GN spirochete
Human reservoir
STD 
Regional outbreaks
Primary ulcer, secondary maculopapular rash, tertiary CV and CNS complications

Question 9

Leprosy

Answer 9

Mycobacterium leprae 
Acid-fast
Humans, armadillos are reservoirs
Transmission is respiratory
Brazil, India, SE Asia, Africa
Tuberculoid leprosy, lepromatous leprosy

Question 10

Zoonoses infections

Answer 10

Lyme disease, plague, tularemia, RMSF, cat scratch fever

Question 11

Soil contaminants

Answer 11

Anthrax
Gas gangrene

*both are GP spore forming rods

Question 12

Person-to-person

Answer 12

Syphillis

Leprosy

Question 13

Diagnosis of Lyme’s disease

2 tier testing for Lyme’s disease

Answer 13

Biopsy/culture

Serology and western blot confirmation

Question 14

Treatment for Lyme’s disease

Answer 14

Doxycillin, amoxicillin

Question 15

Bubonic plague diagnosis

Answer 15

Lymph node biopsy, geisma blood smear

Question 16

Bubonic plague and tularemia treatment

Answer 16

Streptomycin or gentamicin

Question 17

Pathogenesis of Rickettsia rickettsii

Answer 17

Obligate intracellular parasite- can only live in cells
Infects endothelial cells- vasculitis
Perivascular lymphocytic infiltration
Swollen endothelial cells- increase vascular permeability, hypotension, thrombosis, petechial lesions

Question 18

Diagnosis of RMSF

Answer 18

Serology (rising titers) and PCR

Unculturable** because it is obligate intracellular

Question 19

Treatment of RMSF

Answer 19

Doxycycline

Question 20

Anthrax virulence

Answer 20

Anthrax toxin- A2B toxin: edema/lethal factor

B is binding part, A is enzymatic part

Question 21

Anthrax treatment

Answer 21

Ciprofloxacin, doxycycline- protein synthesis inhibition slows toxin production
Vaccine used to control disease in livestock to limit human spread

Question 22

Clostridium perfringens

Answer 22

Anaerobic- severe wounds with necrosis and disrupted blood flow provide an ideal environment for anaerobes
Infection is often polymicrobial- C. Histolyticum, C. Novyi , C. Septicum
Virulence by powerful toxin production–>massive tissue necrosis

Question 23

Gas gangrene treatment

Answer 23

Surgical debridement
Penicillin +Clindamycin or tetracycline (protein synthesis slows production of toxin)
Hyperbaric oxygen

Question 24

Secondary syphillis

Answer 24

Fever, malaise
Generalized lymphadenopathy (primary is regionalized)
Maculopapular rash of palms/soles
Condyloma lata- wart like lesions
All skin lesions are teeming with spirochetes

Question 25

Latent syphillis–>tertiary syphillis

Answer 25

Asymptomatic but seroreactive
Slow, inflammatory tissue damage: gummas (granulomas in skin, liver, bone, testes), CV (aortic aneurysm), CNS (dementia, ataxia, vision loss, headache, seizure)

Question 26

Neurovascular granulomas in dermis
Dermal nerves swollen
Bacilli are few or absent

Answer 26

Tuberculoid leprosy- small number of flat, pale-colored skin lesions with well demarcated borders, Mycobacterial proliferation contained in granulomas
WHO: paucibacillary leprosy

Question 27

Hansen’s disease

Answer 27

Waxy cell wall (mycolic acid)- acid fast: resists decolonization with acid alcohol
Obligate intracellular bacterium (unculturable)
Slow-growing- chronic progression
Infects Schwann cells: peripheral nerve damage= patchy anesthesia, peripheral neuropathy, peripheral nerve hypertrophy
Respiratory transmission

AKA leprosy** by mycobacterium leprae

Question 28

Lepromatous leprosy

Answer 28

Widespread skin lesions of bumps and rashes
Mycobacterial proliferation is poorly contained- skin biopsy shows numerous acid fast bacilli, WHO: multibacillary leprosy
Progressively disfiguring

Question 29

What determines the extent of leprosy?

Answer 29

Cell mediated immunity
Tuberculoid pole- cell mediated response, granuloma formation, few organisms, IFN-gamma, TNF, IL-6/2
Lepromatous pole: humoral response, foamy macrophages, many organisms, IL-4,10

Both cause nerve damage*

Question 30

Leprosy treatment

Answer 30

Multi-drug therapy: rifampin/dapsone/clofazimine