Gardnerella vaginalis and Mollicute detection in rectal swabs from men who have sex with men

Abstract

The numbers of rectal sexually transmitted infections are on the rise especially among men who have sex with men. Males from men who have sex with men population are encouraged to send a rectal swab to the laboratory for sexually transmitted infection screening at their visit to the Genitourinary Medicine Clinic. In healthy asymptomatic males, the range of pathogens tested is limited therefore other pathogens may be left untreated allowing infections to persist among sexual partners. Molecular techniques have revolutionarised sexually transmitted infection testing enabling the detection of previously difficult-to-culture pathogens in extra-genital sites and have increased the evidence base for their clinical significance. The present study tests 107 rectal swabs from men who have sex with men negative for Chlamydia trachomatis and Neisseria gonorrhoeae against quantitative polymerase chain reaction (qPCR) assays targeting five common sexually transmitted bacteria which include Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma urealyticum, Ureaplasma parvum and Gardnerella vaginalis. The pathogenic role of these five bacteria in men who have sex with men is currently unknown. Amongst the 107 patients, a positive qPCR was obtained respectively for G. vaginalis 89 (83.2%); U. urealyticum 26 (24.3%); M. hominis 26 (24.3%); M. genitalium 10 (9.3%) and U. parvum 5 (4.7%). Bacterial loads in single and co-infections were compared for each organism. G. vaginalis and M. hominis loads were significantly ( p = 0.007 and p = 0.005, respectively) higher when co-infecting with at least one other organism. Amongst co-infections, the loads of each organism were assessed to determine possible synergies. G. vaginalis and M. hominis displayed a synergistic pattern ( r = 0.51; p = 0.02) which is in keeping with a similar synergy detected previously in the vagina of women with bacterial vaginosis. This study outlines that potential significant infections are being missed in men who have sex with men population; however, further research is warranted to confirm a pathogenesis in the rectal mucosa before routine screening can be introduced to clinical settings.

Mycoplasma Genitalium and Mycoplasma Hominis are prevalent and correlated with HIV risk in MSM: a cross-sectional study in Shenyang, China

“…Similarly, we found a high prevalence of rectal Mh (7.1%), though lower than reports from MSM in Northern Ireland (24.3%) [19]. To our best knowledge, the relationship between Mh and HIV infection in MSM has not been previously reported.…”

Prevalence and antibiotic resistance of rectal Mollicutes in HIV-infected men who have sex with men at the University Hospital of Dresden, Germany

“…In a recent Chinese study on 183 MSM, rectal prevalence of M. hominis detected by multiplex PCR was 7.1% [40], which is comparable with our results using culture (7.3%). Detection rates by PCR were much higher in a study from Ireland on 107 rectal swabs from MSM: 24.3% U. urealyticum, 24.3% M. hominis, and 4.7% U. parvum, respectively [41]. Symptoms in our patients were rare and if present, mainly found in presence of Ureaplasma spec.. Of note, in one of the symptomatic patients only U. urealyticum was detected.…”

Identification and characterization of NanH2 and NanH3, enzymes responsible for sialidase activity in the vaginal bacterium Gardnerella vaginalis

“…4 However, the ability to liberate 9-Oacetylated sialic acids may help nanH2ϩ G. vaginalis strains to colonize niches outside of the vagina. For example, in men, women, and children, G. vaginalis has been reported to be an inhabitant of the distal gastrointestinal tract (anal swabs) (71)(72)(73), where 9-O acetylation of sialic acid reaches high levels (colon, rectum, and anus) (52, 53). Given that 9-O acetylation impedes the activity of many bacterial sialidases (74,75), NanH2-expressing strains of G. vaginalis may have a competitive advantage in the rectum because of an expanded capacity to forage on 9-O-acetylated sialic acids.…”