Mycoplasma, Chlamydia, Rickettsia
Terms
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- General characteristics of Mycoplasma
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Pleomorphic, NO CELL WALL
resistant to cell wall antibiotics (penicillins, cephalosporins)
unable to Gram Stain
slow grow, fastidious, aerobes or facultative anaerobes - What are L-forms?
- Cell wall deficient bacteria that arise from environmental stress. They are NOT mycoplasma
- Morphology of Mycoplasma
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many forms: spherical, pear-shaped, filamentous
0.2 to 0.8 um in diameter
stain w/ ACRIDINE ORANGE
Dienes stain for observing colonies
Gliding motility on liquid covered surfaces - Cultivating Mycoplasma
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Very sensitive to desiccation
culture media: beef extract, horse serum, yeast extract w/ nucleic acids.
Horse serum for cholesterol needed for sterols in membrane
1-6 hr generation time
fried egg appearance, very small - Characteristics of Mycoplasma pneumoniae
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Primary atypical pneumonia
upper/lower respiratory pathogen, NOT commensal
walking pneumonia: close contact areas (college, barracks)
Dx formerly from cold agglutinins, now PCR & Serology - Characteristics of Mycoplasma hominis
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Colonizes genital tract of 1/2 healthy adults
Causes upper genitourinary tract infection in females: salpingitis, pyelonephritis, PID, postpartum fever - Characteristics of Ureaplasma urealyticum
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Colonize male/female gential tracts
Hard to know disease role - high carrier state in sexually active
Non-gonococcal urethritis in men and upper genitourinary tract infection in women
Assoc w/ reprod disorders, low birthweight w/ respiratory disease
found in spinal fluid in infants - Characteristics of Chlamydiaceae
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resemble gnr
obligate intracellular parasites (can't make ATP)
prefer columnar epithelia lining mucous membranes
cultivated in susceptible tissue
unique replication cycle - Characteristics of Chlamydia psittaci
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Psittacosis, parrot fever, ornithosis
found in wild birds
treat w/ erythromycin, tetracycline - Characteristics of Chlamydia trachomatis
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3 Disease states:
1- conjunctivitis
2- Lymphogranuloma venereum
3- urethritis, PID, infertility, premature birth, cervical infection
ID'd by Serology, DFA, PCR - Characteristics of Chlamydia pneumoniae
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aka TWAR / a cause of pneumonia
common among students
pharyngitis followed by flu-like lower respiratory symptoms
possible involvement in Coronary artery disease, asthma
ID: serology, HL, PCR - Characteristics of Rickettsiae
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Gram NEGATIVe, obligate intracellular parasites
most can't be cultivated on ordinary media: need hen eggs, lab animals or cell culture
Arthropod vectors, xcept in Q fever
RMSF 90% of rickettsial disease in US - Characteristics of Coxiella burnetti
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Q fever, recovered from urine, feces, milk of animals & ticks.
can form endospore
single organism is pathogenic
Usually manifested as pneumonia
ID: complement fixation
treated by tetracycline - Characteristics of Rickettsia
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systemic disease, fever, rash, chills
ID by serology
RMSP = R. rickettsii
Murine Typhus = R. typhi