Microbial and vaginal determinants influencing Mycoplasma hominis and Ureaplasma urealyticum genital colonization in a population of female patients.

Mycoplasma hominis and Ureaplasma urealyticum are associated with chorioamnionitis, preterm delivery and pelvic inflammatory disease. The aim of this study was to evaluate the possible risk factors of co-colonization by M. hominis in patients already colonized by U. urealyticum and compare demographic parameters, vaginal pH and microbiota of women colonized by U. urealyticum or M. hominis. A total of 452 patients positive for U. urealyticum or M. hominis were analysed, 421 (93.1%) of whom were positive for U. urealyticum and 31 (6.9%) for M. hominis. Patients positive for M. hominis compared to patients positive for U. urealyticum were more frequently colonized by Gardnerella vaginalis (71% vs 18.5%; p 0.0001), less frequently by lactobacilli (16.1% vs 61.5%; p 0.0001), and more frequently had a pH value higher than 4.5 (96.8% vs 57%; p 0.0001), all conditions associated to bacterial vaginosis (BV). Logistic regression analysis showed that only G. vaginalis colonization and pH higher than 4.5 were independently related to M. hominis colonization (respectively p 0.0001 and p 0.016). Thus, in women colonized by U. urealyticum, BV is an independent risk factor for M. hominis co-colonization.

Rapid identification of bacterial and fungal pathogens from positive blood cultures by MALDI-TOF MS.

Sepsis is a syndrome characterized by a systemic inflammatory response due to severe infection. Early detection of causal agents and appropriate antimicrobial treatment reduce mortality. Conventional microbiological methods often do not provide time critical results for an optimal early management. We used an in-house protocol based on Tween 80 to process 109 positive blood cultures for bacteria and yeast identification by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS), and results were compared to standard reference or automated methods. MALDI-TOF MS correctly identified 91.7% of the isolates. Correct identification was obtained for 57/62 (91.9%) aerobic/facultative anaerobic Gram-positive isolates, 53 (85.5%) at species level, and 4 (6.4%) at the genus level; 32/32 (100%) aerobic/facultative anaerobic Gram-negative isolates, 31 (96.9%) at species level, and 1 (3.1%) at the genus level; 7/7 (100%) obligate anaerobes, all at the genus level; 3/7 (42.8%) fungi, all at genus level. Overall, the median identification time of MALDI-TOF MS vs reference standard methods was significantly shorter: median (interquartile range) 7.1h (4.7-10.2) vs 48.1h (32.5-50.0), p<0.0001. MALDI-TOF MS is a valuable tool for rapid identification of pathogens in septic patients. An in-house protocol based on Tween 80 can be used to process positive blood cultures.