Background: Mycoplasma hominis (Mh) and Ureaplasma spp. (Uspp) are possible pathogens associated with urogenital infections. This study assessed performance of MYCOPLASMA IST3, a new in vitro diagnostic test designed to detect, identify, enumerate and test the susceptibility of Mh and/or Uspp to relevant agents (Levofloxacin, Moxifloxacin, Tetracycline, Erythromycin, Telithromycin and Clindamycin).
Materials/methods: 516 vaginal/cervical or urethral swabs, semen and urines were included. For detection/identification, performance was expressed as the positive (PPA) and negative agreements (NPA) between MYCOPLASMA IST3 and sample status defined using A7 agar and PCR. For indicative enumeration, performance was expressed as the agreement between MYCOPLASMA IST3 and A7 agar results. For Antimicrobial Susceptibility Testing (AST) application, Category Agreement (CA, %) Major Error rate (ME, %) and Very Major Error counts (VME, #) were calculated comparing MYCOPLASMA IST3 category (S or R) to Broth Micro Dilution Minimum Inhibitory Concentration (MIC) results interpreted using CLSI M43-A interpretive breakpoints.
Results: 312 samples were negative, 109 grew viable Uspp, 73 grew Mh and 22 grew both, 38% of the positive samples were contrived (spiked) samples. Regarding the detection/identification application, MYCOPLASMA IST3 had a PPA of 98.5% (129/131) and 92.6% (88/95) and a NPA of 99.7% (384/385) and 99.0% (410/414) with A7 agar for Uspp and Mh, respectively. Among the 22 mixed samples, MYCOPLASMA IST3 recovered both species for 18 samples while only the Uspp was recovered for the remaining samples. Indicative enumeration results were in agreement between MYCOPLASMA IST3 and A7 agar in 84.6% (99/117) and 83.7% (72/86) of the cases for Uspp and Mh, respectively. MYCOPLASMA IST3 AST application produced CA ranging from 96.0% to 100.0% and ME rates from 0.0% to 4.2% (Table). Three VMEs were observed (1 Uspp with tetracycline, 1 Mh with tetracycline, 1 Mh with Moxifloxacin), 2 of them originated from isolates with MIC within ± 1 doubling dilution from the CLSI breakpoint value.
Conclusions: MYCOPLASMA IST3 is an accurate aid in the diagnosis of urogenital infections related to Uspp or Mh, providing clinicians with valuable information to guide treatment.
Table: MYCOPLASMA IST3 Antimicrobial Susceptibility Testing performance.