Microbiology 16 - Atypical Bacteria

Growth Environment for Rickettsia + franz

obligate intracellular

growth environment for chlamydiaceae

obligate intracellular

growth environment for mycoplasma + spirochaetale

free living

Rickettsiaceaem Anaplasmatacaeae (Ehrlichia) , and Coxiella general characteristics

gram-neg
LPS is only weakly endotoxic

There is NO LPS in this bacteria

Ehrlichia

Diseases attributed to Rickettsiaceae, Ehrlichia, and Coxiella are spread by

insect vectors

Diseases attributed to Rickettsiaceae, Ehrlichia, and Coxiella present w/

rapid onset of fever, chills, headache and possible rash

intracellular location of Rickettsiaceae

host cell cytoplasm

Rickettsiaceae diseases

Rocky mountain spotted fever, epidemic typhus, endemic typhus

intracellular location of ehrlichia

membrane-bound vacuoles

ehrlichia associated diseases

sennetsu fever

intracellular location of coxiella

membrane-bound vacuoles

coxiella associated disease

Q fever

Rickettsia rickettsii vector

hard ticks (i.e. Dermacentor)

R. Rickettsii reservoir

rodents and pets

Rocky Mountain Spotted Fever characteristics

quick onset
maculopapular rash to petechia on HAND, ankles, and wrist
Doxycycline treatment

Rickettsia prowazekii primary reservoir

humans

Diseases associated with Rickettsia prowazekii

Epidemic typhus
Recrudescent typhus
Sporadic typhus

Epidemic typhus

pediculus humanus (body louse) vector
crowded squalid conditions
high fever, head/muscle/joint aches
often rash

recrudescent typhus (Brill-Zinsser dz)

gradual onset
reactivation of epidemic dz years after initial diagnosis
less than 1/2 cases get rash

sporadic typhus

flying squirrels may harbor the bacterium
spread by fleas that feed on squirrels + humans

Ehrlichia Chaffeensis reservoir

white-tailed deer and pets

how is ehrlichia chaffeensis transmitted

Lone star ticks (Ambylomma)

This bacterium causes monocytic ehrlichiosis, replicates in monocytes and macrophages

Ehrlichia chaffeensis

Morulae are diagostic but detected in few specimens of this disease

Ehrlichia chaffeensis

Coxiella Burnetii characteristics

multiply in phagosomes and reservoir is livestock

Coxiella burnetii transmission

by aerosol (inhalation) or ticks

phase I antigen is infectious in this bacteria

coxiella burnetii

Acute Q-fever is associatd with these sxs

fever, headache, chills, muscle pain
can present w/ respiratory sxs too

Chronic fever is associated with these sxs

heart, liver and pulmonary dz

This bacteria was initially thought to be a virus, lacks ATP and peptidoglycan, and lacks a distinctive developmental cycle

Chlamydiaceae

Elementary body of Chlamydia characteristics

infectious
Hemagglutinin present
induces endocytosis
metabolically inactive

Reticulate body of Chlamydia characteristics

non-infectious
hemagluttinin absent
doesn't induce endocytosis
metabolically active

most common bacterial STD w/ human only host; grows in non-ciliatd epithelial cells which comprise mucous membranes of urogenital tract, respiratory tract, and conjunctiva

Chlamydia trachomatis

Serovar A, B, Ba, C asociated with this disease;
leading cause of preventable infectious blindness

Trachoma

Serovar D-K associated with this disease

Urogenital tract disease

Serovar L1, L2, L2a, L2b, L3 associated with this disease; late stages may involve ulcers and genital elephantiasis

Lymphogranuloma venereum

inclusion conjunctivitis

adult typically follows genital infection; newborns can acquire during birth

smallest free living bacteria w/ no cell walls, sterol cell membranes and fried egg colony morphology

mycoplasma/ureaplasma

transmission of mycoplasma pneumoniae

respiratory droplets; binds to respiratory epithelium via P1 adhesion

Atypical "walking" pneumonia characteristics

persistent hack, non-productive
pharyngitis, bronchitis, bronchopneumonia
common in young adults

this group of bacteria has helical morphology with axial filaments

spirochetes

Treponema Pallidum characteristics

thin spirochete
microaerophilic
visualized by dark-field/fluoresence
disease: syphillis

Primary syphillis charactertistics

initial chancre develops at innoculate site
papule -> painless ulcer
Chancre - source for microscopic specimen
Contagious (not easy to culture)
spontaneous resolution in 2-6 weeks

Secondary syphillis characteristics

disseminated disease, 1-3 months later
flu-like sxs
disseminated maculopapular rash
wart-like condylomata lata
heals spontaneously to become clinically inactive

Latent syphillis

2/3 of untreated secondary cases will have persistent treponemes w/o symptoms

Late (tertiary) syphillis

1/3 untreated caes
may affect almost any organ
granulomatous lesions of bone, skin, other tissue
aortititis
CNS inflammation
blindness

non-treponemal test for syphillis

detects antibodies against damaged human mitochondrial antigens
NOT present in tertiary
Cheap + quick using VDRL and RPR

Treponemal tests for syphillis

detects antibodies against bacterium
more specific
used to confirm VDRL or RPR w/ FTA and MHA-TP

This syphillis progression does not require both tests to be positive in order to diagnose

tertiary syphillis

Borrelia characteristics

microaerophilic spirochetes
difficult to culture

Relapsing fever is associated with which species

B Recurrentis

Lyme disease is associated with which species

B. burgdorferi

Characteristics of borrelia burgdorferi

tick vector Ixodes
reservoirs in mice and deer

Early presentation characteristics of lyme disease

erhythema migrans
headache, fever, chills
malaise, general fatigue

phase 1 - late signs of lyme disease

neurologic and cardiac dysfunction

phase 2 - late signs of lyme disease

joint pain and arthritis

Characteristics of borrelia recurrentis

arthropod vectors
antigen variation
fever cycling

Epidemic (louse borne) relapsing fever in B. recurrentis characteristics

human reservoir

Endemic (tick-borne) relapsing fever characteristics

caused by several species
Zoonosis, disease of rodents
trans-ovarian tarnsmission in ticks

Leptospira interrogans characteristics

thin spirochetes with hooked ends
transmission through animal urine
Leptospirosis