GRAM NEGATIVE OBLIGATE ANAEROBES
Bacteroides fragilis: Normal GI flora, opportunistic in abdominal trauma
Fusobacterium Fusiform: Normal oral flora (also oral GI oral). Causes
gingivitis from poor oral hygiene or immunocompromised. Elaborates
hemolysins and other exotoxins.
OTHER GRAM NEGATIVE GENUS/SPECIES TO KNOW:
Brucella melitensis: coccobacilli. Fever from direct contact with infected meat
(mostly butchers get it).
Pasturella multocida: coccobacilli; normal flora in cats and dogs. Causes infection
from bites/scratches.
Francisella tularensis: Deerfly fever or rabbit fever; insect vector or infected
animals. Causes local ulceration on hand.
Legionella pneumophila: rods; causes pneumonia and Pontiac Fever.
Mycoplasma pneumoniae: these are the smallest bacteria, and lack a cell wall, so
their shape varies. Causes pneumonia.
Ureaplasma urealyticum; mycoplasmas from the urogenital tract. Normal flora,
opportunistic, causes fever and inflammation, esp. around pregnancy period. 1
SPIROCHETES
Treponema (“turning thread”) pallidum: Syphillis
Has specialized flagella: axial filament: Causes invasive motility (instead of
adhesins). Obligate pathogen
HPR: Obligate path, human reservoir.
MOT/POE: sexual contact/ conjunctiva in birth canal
TROPISM: CNS and blood vessels
INC: 10-90 days (chancre) 2-18 months (stage 2)
VFs/IA: Molecular mimicry (coats itself with our fibronectin protein to hide from
PMNs)
Px: 1° = chancre: local mucosal lesion, slow healing, on genitals/cervix.
2° = gummas: local/regional necrotic lesions on mucosal OR skin; rash
3° = tertiary = CNS tropic; brain abscesses; no treatment
NOTE: All infant’s eyes are treated for Gonorrhea, Treponema, and Chlamydia.
Leptospira interrogans: Found in immunocompromised, esp. pregnant women who
eat unpasteurized cheese.
Borellia hermsii: Relapsing fever; has a tic vector
Helicobacter pylori: gastritis and stomach ulcers. 2
RICKETTSIAE: These are the bridge between bacteria and viruses.
Non-culturable; Obligate pathogens
OBLIGATE INTRACELLULAR PARASITES (except Rochalimea and Ehrlichia)
Arthropod-borne infections (except Chlamydia) “zoonoses”
Angiotrophic (likes blood vessels, causes FEVERS)
Rickettsia rickettsii:
Rocky Mountain Spotted Fever; rash; Endotoxic shock.
Transmitted by tic
Rochalimea quintana: Trench fever and Cat Scratch fever; rash; Endotoxic shock.
Nodular rash in immunocompromised.
Transmitted by flea
Ehrlichia canis: Ehrlichiosis; fever, rash, Endotoxic shock
Transmitted by flea/tic on dogs
Coxiella burnetti: Q fever; acute hepatitis/endocarditis, NO RASH
Transmitted by tick or droplet nuclei
Chlamydia trachomatis: Disease = Trachoma (1° cause of preventable blindness).
from going through STD-infected birth canal. Also LGV and PID.
Chlamydia psittaci: Parrot fever; pneumonia 3
Chlamydia pneumoniae: pneumonia by aerosol or droplet nuclei.