Chlamydia & Mycoplasma Flashcards
obligate intracellular organism
requires the biochemical resources of a eukaryotic host cell for growth and replication
common host cells for Chlamydia
Non-ciliated, columnar or transitional epithelial cells
Chlamydia life forms
- Elementary body - infectious; extracellular; metabolically inert; resembles GNR
- Reticulate body - noninfectious; intracellular; resembles spore
trachoma
chronic eye infection with Chlamydia
Number one cause of preventable blindness
precursor to trachoma
follicular conjunctivitis
Chronic inflammation causes…
Eyelid to turn inward
Continual abrasion to the cornea from the eyelashes
Scarring and ulceration of the cornea
Secondary infection and blindness
Begins as a lesion that becomes enlarged groin lymph nodes (bubo) leading to draining sinuses, genital hyperplasia and rectal fistulas/strictures
Lymphogranuloma Venereum
Lymphogranuloma Venereum seen primarily in…
Africa, Asia, and South America
Most common sexually transmitted infection in U.S.
chlamydia
Chlamydia in mother causes ———– in infant
conjunctivitis, nasopharyngeal infection and pneumonia
Infants receive prophylactic eye drops (———–) at birth to prevent eye infections due to C. trachomatis and N. gonorrhoeae
erythromycin
sample for Chlamydia ID
Collect infected epithelial cells from genitourinary tract, urethra, or conjunctiva
specimens of choice for Chlamydia
Urethral and endocervical cells
With Chlamydia culture, must keep viable by….
refrigerating specimens and limiting transport time
Advantage - immediate determination if columnar epithelial cells are present
Direct fluorescent antibody for genital tract Chlamydia specimens
Considered the gold standard for detection of C. trachomatis until the development of nucleic acid amplification tests
cell culture – McCoy cell line with cyclohexamide
Chlamydia cell culture has 80% sensitivity due to…
issues with inherent technical complexities
Enzyme immunoassay is based on monoclonal antibodies to Chlaymidia’s…
LPS
Positive result is only preliminary due to potential for false-positive results
Chlamydia immunoassay
Not used to test for Chlamydia in urine or vaginal swabs
immunoassay
NAAT for Chlamydia not approved for…
conjunctival, oropharyngeal and rectal specimens
Used to tx Chlamydia
Need antibiotics that can penetrate cells such as erythromycin, tetracyclines, and fluoroquinolones
bird pathogen
Chlamydophila psittaci
Pneumonia
Severe h/a
Mental status changes
Hepatosplenomegaly
Chlamydophila psittaci
dx is based on serology
1:32 titer indicates acute illness
C. psittaci
C. psittaci BSL
BSL 3
C. psittaci tx
tetracycline
C. psittaci fatal in —–% untreated cases
20
Pneumonia
Bronchitis
Pharyngitis
Sinusitis
90% cases asymptomatic
Chlamydophila pneumoniae
dx based on PCR
sputum NOT an ideal specimen
Chlamydophila pneumoniae
Chlamydophila pneumoniae tx
tetracycline
erythromycin
Smallest known free-living forms (0.3 x 0.8 μm)
no cell wall
Mycoplasma
Ureaplasma
Small colonies embedded in
solid media
Mycoplasma
Ureaplasma
require sterols and fatty acids
Mycoplasma
Ureaplasma
Infections can occur singly or as outbreaks in closed populations such as families or dormitories - more common in young adults
M. pneumoniae CA pneumonia
walking pneumonia; individual does not feel well but not sick enough to stay home
M. pneumoniae
At/post puberty colonization occurs primarily through sexual contact
Can cause PID, BV, urethritis, prostatitis, amnionitis.
M. hominis
U. urealyticum
Indicated in chorioamnionitis, early spontaneous abortions and premature deliveries.
M. hominis
U. urealyticum
Can dry out very quickly, need prompt transport
Avoid cotton swabs with wooden sticks
Mycoplasmas
Mycoplasma specimens
body fluids, tissue, swab of throat, nasopharynx, urethra, cervix/vaginal, tracheal aspirate, and placenta
Media contains beef/soybean protein (sterols)
SP4, Shepard 10B broth or 2SP
Mycoplasmas
M. pneumoniae and M. genitalium require ——– and can take 21 days to appear
M. hominis requires ——– and appear in 2 to 4 days
U. urealyticum requires ——- and appear in 2 to 4 days
glucose
arginine
urea
Production of … after overnight incubation of a urogenital specimen suggests U. urealyticum
an alkaline reaction in media with urea
On subculture, extremely small colonies which require stereomicroscope to see
Look like a bird’s nest
Ureaplasma
Alkaline reaction in media with ——– within 24 to 72 hours is likely M. hominis
arginine
fried egg colony; light edge, dark center
M. hominis
infections are usually self limited and don’t require treatment
M. pneumoniae
Sensi testing reference lab usually recommended for significant infections
M. hominis
Mycoplasma and Ureaplasma intrinsically R to B-lactams because
they don’t have a cell wall
Maybe more prevalent than Neisseria gonorrhoeae
Association with HIV infection
M. genitalum
Treatment of choice is azithromycin but developing increasing resistance
Moxifloxacin can also be used
M. genitalum
Multiply by binary fission in cytoplasm of host cells
Release of mature organism causes lysis of host cells
Rickettsiaceae
Rickettsiaceae
Rickettsia
Ehrlichia
Anaplasma
Cannot be grown on cell-free media but have been grown in the yolk sac of embryonated eggs and several cell lines
Rickettsiaceae
Tick, mite, louse, flea or other insects
Rickettsia
Ehrlichia and Anaplasma are transmitted by…
ticks
3 groups of Rickettsial diseas
spotted fever
typhus
scrub typhus
Rocky Mountain Spotted Fever - most severe of rickettsial infections
Rickettsia rickettsii
Murine Typhus
Rickettsia typhi
Rickettsial Pox
Rickettsia akari
Epidemic Typhus
Rickettsia prowazekii
induce vasculitis in internal organs, including brain, heart, lungs and kidneys
Pneumonitis, CNS manifestations, Myocarditis, DIC, low blood volume and hypotension
R. rickettsii
triad of RMSF sx
Headache, fever, spotted centripetal rash
(due to vascular damage)
Potential bioterrorism organism due to low dose aerosols
R. rickettsii
Rumpel-Leede phenomenon
petechiae after blood pressure taken
RMSF
Only performed in a few specialized labs using embryonated eggs and tissue culture.
R. rickettsii culture
Collect blood, in heparin vials, and skin biopsies for culture early in disease process
RMSF
Upon entry into WBCs, develop in morulae (mulberry-like bodies).
Ehrlichia and Anaplasma
infects monocytes and causes human monocytic ehrlichiosis (HME).
E. chaffeensis
infects neutrophils causing human granulocytic anaplasmosis.
A. phagocytophilum
Rickettsial disease tx
doxycycline or another tetracycline antibiotic
Causes Q (query) fever
Coxiella burnettii
Most common reservoirs are cattle, sheep and goats
Coxiella burnettii
Required to be reported within 7 days and either destroyed or transferred to lab registered to possess agent
Potential for use as a bioweapon
Coxiella burnettii
Shell vial assay with human lung fibroblasts
Coxiella burnettii
Coxiella burnettii culture
can be done in cell-free media but discouraged because lab worker infections can occur
BSL 3 required
