University:
American Career College
Course:
NURS115 | Intermediate Medical
Academic year:

2020
Views:

129

Pages:

8
Author:

Damari Cantrell

Genital Mycoplasmas Mycoplasma genitalium Mycoplasma hominis Ureaplasma Species  Introduction • To date, eight species of mycoplasmas and ureaplasmas have been identified in the genital tract. • Six species are classified in the genus Mycoplasma. • M. genitalium has the smallest genome of any mycoplasma (580 kb) and is closely related to M. pneumoniae. The Human Genital Ureaplasmas and Mycoplasmas Species Ureaplasma urealyticum Ureaplasma parvum Mycoplasma hominis M. genitalium M. fermentans M. penetrans M. spermatophilum M. primatum Substrate Utilization Urea Urea Arginine Glucose Glucose and arginine Glucose and arginine Arginine Arginine pH for Growth 6.0-6.5 6.0-6.5 6.5-8.0 7.0-7.5 7.0-8.0 7.0-8.0 7.0-8.0 7.0-8.0  The Human Genital Ureaplasmas and Mycoplasmas • Mycoplasmas and Ureaplasmas are : Small size (0.2 or 0.3 μm)  Small genome (580 to 1170 kb)  No cell wall Requirement for a highly enriched medium containing animal serum The generation times in broth culture are 1 or 2 hours, but M. genitalium grows very slowly, (doubling time : 12 hours or more).  CULTIVATION AND DETECTION • Mycoplasma medium for isolation contains: ◦ peptones, yeast extract, and 20% serum • M. hominis grows readily on both agar plates and broth cultures but M. genitalium grows slowly. • Strains from specimens can not be directly cultured on agar but require tissue culture enrichment. • M. hominis forms microscopically visible colonies in 2 to 5 days. • Growth in broth is usually detected by identifying the alkaline products of arginine hydrolysis with a pH indicator.  Con . . . • M. fermentans is isolated best on mycoplasma agar or broth under anaerobic or microaerophilic conditions. • Overall, diagnosis of mycoplasmal and ureaplasmal infections by culture is slow and difficult. • PCR methods are the assays of choice. Scale bar = 100 μm Light micrograph of Mycoplasma genitalium strain G37 on H agar after 14 days of incubation  SUSCEPTIBILITY TO ANTIMICROBIAL AGENTS • Mycoplasmas in general are susceptible to tetracyclines and quinolones. • Because they have no cell wall, they are not susceptible to penicillins or cephalosporins. • M. genitalium and M. pneumoniae are highly susceptible to macrolides. • M. hominis is intrinsically resistant to erythromycin and other macrolides but moderately susceptible to lincomycin. • Ureaplasmas show limited susceptibility to erythromycin and other macrolides but are resistant to lincomycin.