NEISSERIA
G (-) diplococci
Aerobic / CO2
Normal Flora: MM
Requires blood media
Virulence Factors
a) Capsule
b) Fimbria
c) Endotoxin: causes severe tissue destruction
d) Beta lactamase resistance
e) Iron
f) Protease
DX: Organism in culture fluid
TX : AB
Prevention:
Neisseria gonorrheoeae
STD : Pus à scarring
5-7 day incubation
Bacteremia à arthritis, meningitis, endocarditis
Neisseria menigitidis
Transmission: Respiratory droplet
3-5 day incubation
Throat à bacteremia à meningitis [50% fatality]
CHLAMYDIA
“Gram neg” spherical bacteria (cell wall is similar to gram neg bacteria)
Obligate intracellular parasites of epithelial cells [require ATP]
Virulence factor: surface peptides resemble heart myosin
2 main ecological groups
Group A: STD> eye and genitourinary
Group B: zoonotic
DX: Isolation, IFA, Ab titer
TX: AB
Chlamydia trachomonas
Chlamydia pneumoniae
Chlamydia psittaci
SPIROCHAETACEAE
G (-) spiral rods
Low O2 requirements
Motile with polar flagella
DX: Lesions, IFA
TX: AB
Treponema pallidum
STD: syphilis
Transmission: Oral > Direct, Indirect; Congentital
Clinical course: 3 stages over a period of months to years
* papulosquamous erosive lesions
* progression to eye, skin, blood, CSF
* Latent à If reoccurs affects bones and Nervous system
Treponema pertenue
Yaws
Transmission: poor hygiene
Incubation: several weeks
Clinical: ulcerative granulomatous à bones
Borrelia burgdorferi
Lyme disease
Transmission: Arthropod vector [Tick]
Incubation: 6-8 weeks
Clinical course: Bullseye rash à arthritis à Nervous
Borrelia recurrentis
Relapsing fever
Transmission: Arthropod vector [Tick, lice]
Incubation: 3-11 days
Clinical course: Rash à fever à organ enlargement
Resolves after fever, reoccurs to create organ damage
Repeats several times, ultimately ends in cardiac failure
Leptospirosis
Zoonotic
Transmission: Direct and Indirect urinated contaminated
Incubation: 1-2 weeks
Clinical course: 2 phases Flu like; Neuropathy/Renal/Blood
Spirillum
Rat bite fever
Incubation 2-3 weeks
Clinical course: fever à lymphadentitisà rash à endocarditis
RICKETSIA
“Gram neg” pleomorphic short rods with very permeable cell membrane
Aerobes, but prefer higher CO2
Obligate intracellular parasites: need exogenous cofactors
Infect vascular endothelial cells
Transmission: Arthropods
Virulence Factor: Endotoxin
DX:
TX: AB
Ricketsia ricketsii [Tick vector]
Causative agent of RMSF: fever, headache, chills à rash
Ricketsia prowazekii [louse vector]
Causative agent of louse-borne typhus fever: fever à maculopapular rash
Ricketsia typhi [Flea vector]
Causative agent of endemic typhus: fever, myalgia à macopapular rash
Ricketsia akari [Mite vector]
Causative agent of rickettsial pox: fever à papulovesicular rash
Ricketsia tsutsugamushi [Mite vector]
Causative agent of scrub typhus: fever à rash
Ehrlichia sp.[Tick vector]
Causative agent of Ehrlichiosis: thrombocytopenia
Coxiella [No arthropod vector, spread by respiratory droplets, inhale tick feces]
Causative agent of Q fever: atypical interstitial pneumonia à cardiac
Bartonella henselae
Causative agent of
cat scratch fever : lymphadenopathy
bacillary angiomatosis: angiomas that resemble Kaposi’s sarcoma
MYCOPLASMAS
Smallest known free living organism; bacteria that lack rigid cell wall = no G stain
Related to Low G + C Gram Positive Bacteria
Pleomorphic, filamentous appearance
DX
TX: AB
Mycoplasma pneumoniae virulence factors à interstitial pneumonia
Mycoplasma hominis [STD] > affect placenta à infertility
Ureaplasma urealyticaum [STD] > UTI