Pharyngeal Chlamydia and gonorrhea: a hidden problem

Antimicrobial resistance determinants in the oropharyngeal microbiome of 'men having sex with men' attending an sexually transmitted infection clinic

BACKGROUND

'Men having sex with men' (MSM) represent a key population with a significant prevalence of pharyngeal Neisseria gonorrhoeae (NG) infections and a high rate of antimicrobial resistance genes in the pharyngeal microbiome. As NG can acquire antibiotic resistance genes from other commensal oropharyngeal bacteria, monitoring the prevalence of these resistance determinants is critical to curtail the spread of NG-resistant strains.

PURPOSE AND RESEARCH DESIGN

Here, we assessed the distribution of five resistance genes (pen (A), mtr (R), gyr (A), par (C), msr (D)) in the oropharynx of 164 MSM, attending an Outpatient clinic for STI screening.

RESULTS

The most frequently detected resistance gene was msr (D) (88.4%), followed by gyr (A) (67.1%). The distribution of resistance genes was not influenced by pharyngeal gonorrhea nor by the HIV status, whereas a younger age was associated with mtr (R) presence (p = .008). Subjects using mouthwash exhibited significantly lower levels of mtr (R) (p = .0005). Smoking habit was associated with a higher prevalence of par (C) (p = .02). A noteworthy association was observed between the presence of msr (D) gene and the use of antibiotics (p = .014).

CONCLUSIONS

Our findings reveal an enrichment of antimicrobial resistance genes in the oropharynx of MSM. These insights could aid in the development of screening programs and antimicrobial stewardship initiatives targeting populations at heightened risk of pharyngeal gonorrhea.

Non-pathogenic Neisseria species of the oropharynx as a reservoir of antimicrobial resistance: a cross-sectional study

Commensal Neisseria species of the oropharynx represent a significant reservoir of antimicrobial resistance determinants that can be transferred to Neisseria gonorrhoeae. This aspect is particularly crucial in 'men having sex with men' (MSM), a key population in which pharyngeal co-colonization by N. gonorrhoeae and non-pathogenic Neisseria species is frequent and associated with the emergence of antimicrobial resistance. Here, we explored the antimicrobial susceptibility of a large panel of non-pathogenic Neisseria species isolated from the oropharynx of two populations: a group of MSM attending a 'sexually transmitted infection' clinic in Bologna (Italy) (n=108) and a group of males representing a 'general population' (n=119). We collected 246 strains, mainly belonging to N. subflava (60%) and N. flavescens (28%) species. Their antimicrobial susceptibility was evaluated assessing the minimum inhibitory concentrations (MICs) for azithromycin, ciprofloxacin, cefotaxime, and ceftriaxone using E-test strips. Overall, commensal Neisseria spp. showed high rates of resistance to azithromycin (90%; median MICs: 4.0 mg/L), and ciprofloxacin (58%; median MICs: 0.12 mg/L), whereas resistance to cephalosporins was far less common (<15%). Neisseria strains from MSM were found to have significantly higher MICs for azithromycin (p=0.0001) and ciprofloxacin (p<0.0001) compared to those from the general population. However, there was no significant difference in cephalosporin MICs between the two groups. The surveillance of the antimicrobial resistance of non-pathogenic Neisseria spp. could be instrumental in predicting the risk of the spread of multi-drug resistant gonorrhea. This information could be an early predictor of an excessive use of antimicrobials, paving the way to innovative screening and prevention policies.

Anal and Oral Sex Behaviors Among Young Black Men Who Have Vaginal Sex: Evidence of the Need for Extragenital Testing for Chlamydia and Gonorrhea

BACKGROUND

Unprotected oral and anal sex may result in extragenital sexually transmitted infections. The purposes of this study were to describe sexual behaviors, barrier use, and chlamydia/gonorrhea (Ct/GC) positivity among young Black men who have sex with women, and to examine the potential influence of extragenital infections on genital infections.

METHODS

Young Black men who had vaginal sex were screened for Ct/GC in New Orleans, LA, from August 14, 2019, to February 29, 2020. Audio/computer-assisted self-interviews were used to collect data on demographics and sexual behaviors. χ2 /Fisher exact or t test/Wilcoxon rank tests were used to assess differences in behaviors by Ct/GC positivity.

RESULTS

Among 373 men studied, 619 female partnerships were reported in the past 2 months. Vaginal sex was reported in all partnerships per study protocol, receiving fellatio in 42.7%, performing cunnilingus in 35.7%, and penile-anal sex in 5.9%. Although 31.4% of the men consistently used condoms for vaginal sex with all partners, consistent barrier use was low during cunnilingus (0.5%) and fellatio (5.1%). Urethral infection rates among all men in the sample were 12.6% for Ct and 1.6% for GC. There was no significant difference in Ct/GC rates between those using and not using condoms consistently during vaginal sex ( P = 0.38).

CONCLUSIONS

Unprotected oral sex with female partners was common. The high rate of genital infection among men who used condoms consistently for vaginal sex suggests that oral infections could be serving as a reservoir of genital infection. Testing at all sites of exposure for youth who engage in heterosexual sex is merited.

Meningococcal Carriage in 'Men Having Sex With Men' With Pharyngeal Gonorrhoea

We assessed the characteristics of Neisseria meningitidis pharyngeal carriage in a cohort of ‘men having sex with men’, including patients with pharyngeal Neisseria gonorrhoeae infection. In the period 2017-2019, among all the oropharyngeal samples tested for gonorrhoea from MSM attending a STI Clinic in Bologna (Italy), we randomly selected 244 N. gonorrhoeae-positive samples and 403 negatives (n=647). Pharyngeal specimens were tested for N. meningitidis presence, by the detection of sodC gene. N. meningitidis-positive samples were further grouped by PCR tests for the major invasive genogroups (i.e., A, B, C, W, and Y). A molecular assay, targeting capsule transporter gene, was used to determine meningococcal capsular status. Overall, 75.8% (491/647) of samples tested positive for sodC gene, indicating a pharyngeal meningococcal carriage. Meningococcal colonisation was significantly more frequent in younger subjects (P=0.009), with no association with HIV infection. Non-groupable meningococci represented most of pharyngeal carriages (about 71%). The commonest N. meningitidis serogroup was B (23.6%), followed by C (2.1%), Y (1.8%) and W (1.1%). Meningococci were often characterized by the genetic potential of capsule production. Interestingly, a negative association between N. meningitidis and N. gonorrhoeae was found: pharyngeal gonorrhoea was significantly more present in patients without meningococcal carriage (P=0.03). Although preliminary, our data added knowledge on the epidemiology of meningococcal carriage in MSM communities at high risk of gonococcal infections, gaining new insights into the interactions/dynamics between N. meningitidis and N. gonorrhoeae.

[Gonococcal pharyngitis]

A description of a clinical case of oligosymptomatic pharyngitis associated with Neisseria gonorrhoeae is presented. On the example of oligosymptomatic localized gonococcal pharyngitis in a sexually active young man, included in the risk group for extragenital forms of sexually transmitted infections, an advantage has been shown molecular biological diagnostic method. Study of the spectrum of microflora of the oropharynx and urethra with assessment sensitivity to antibacterial drugs of representatives of the genus Neisseria isolated during mixed infection oropharynx, demonstrated that non-pathogenic Neisseria species are resistant to cephalosporins III-IV generations. Unrecognized forms of oropharyngeal gonococcal infection, as a consequence of the complications of clinical and diagnostic identification when patients refer to an otolaryngologist or dermatovenerologist, can serve a reservoir of resistant N. gonorrhoeae and a source of intractable gonococcal infection.

Evidence supporting the standardisation of extragenital gonorrhoea and chlamydia screenings for women

OBJECTIVE

Current guidelines for women do not include extragenital screening for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) and do not mention anal sex behaviour. The objective of this cross-sectional study was to determine the number of potentially missed CT and NG cases by relying on urogenital screening and self-reported anal sex behaviour among women.

METHODS

Demographic and clinical data of 4658 women attending a community health centre in Los Angeles, California, USA from 2015 to 2018 were examined. CT and NG were detected using nucleic acid amplification test (APTIMA Combo 2, Hologic Gen-Probe, San Diego, California). Demographic and behavioural factors were also examined to assess potentially missed NG/CT cases. Multivariable regression analyses were used to determine whether reported anal sex behaviour predicts NG/CT rectal infection.

RESULTS

A total of 193 NG cases and 552 CT cases were identified; however, 53.9% of NG cases and 25.5% of CT cases were identified exclusively through extragenital screening. Of all positive cases of rectal CT, 87.0% did not report anal sex without a condom and 91.3% did not report any anal sex with their last sexual partner. Of all positive cases of rectal NG, 78.9% did not report anal sex without a condom and 76.3% did not report any anal sex with their last sexual partner. Anal sex with last partner was not predictive of NG/CT rectal infection.

CONCLUSIONS

Relying solely on urogenital screening and reported behaviour misses NG/CT cases. Extragenital NG/CT screening should be conducted in all women regardless of reported anal sex behaviour.

Mosaic structure of the penA gene in the oropharynx of men who have sex with men negative for gonorrhoea

The oropharynx represents a crucial site for the emergence of multi-drug resistance in Neisseria gonorrhoeae. The mosaic penA alleles, associated with decreased susceptibility to cephalosporins, have emerged by DNA recombination with partial penA genes, particularly those from commensal pharyngeal Neisseria species. Here, we investigated the prevalence of the mosaic structure of the penA gene in the oropharynx of men who have sex with men testing negative for pharyngeal gonorrhoea. From January 2016 to June 2018, 351 gonorrhoea-negative men who have sex with men attending a sexually transmitted infection clinic in Italy were enrolled. Pharyngeal swabs underwent a real-time polymerase chain reaction (PCR) for the detection of the mosaic penA gene. In case of positivity, PCR products were sequenced and searched against several sequences of Neisseria strains. Overall, 31 patients (8.8%) were found positive for the presence of the mosaic penA gene. The positivity was significantly associated with previous cases of pharyngeal gonorrhoea (relative risk [RR]: 3.56, 95% confidence interval 1.44–8.80) and with recent exposure to beta-lactams (RR: 4.29, 95% confidence interval 2.20–8.38). All penA-positive samples showed a high relatedness (90–99%) with mosaic-positive Neisseria strains. Our data underline that commensal Neisseria species of the oropharynx may be a significant reservoir for genetic material conferring antimicrobial resistance in N. gonorrhoeae.

Pharyngeal microbiome alterations during Neisseria gonorrhoeae infection

Pharyngeal gonorrhoea is a common sexually transmitted infection among ‘men having sex with other men’ (MSM). Neisseria gonorrhoeae (NG) pharyngeal infections are usually characterized by the absence of symptoms, acting as an important reservoir for their further spread. To the best of our knowledge, no information about the composition of the pharyngeal microbiome during an ongoing NG infection is currently available. Therefore, in this study, we characterized the pharyngeal bacterial community profiles associated with NG infection in a well-selected cohort of HIV-negative MSM reporting unsafe oral intercourse. A total of 70 pharyngeal swabs were considered, comparing non-infected subjects (n = 45) versus patients with pharyngeal gonorrhoea (n = 25) whose microbiota composition was analyzed from pharyngeal swabs through sequencing of hypervariable V3-V4 regions of the 16S rRNA gene. The pharyngeal microbiome of all subjects was dominated by Prevotellaceae, Veillonellaceae and Streptococcaceae families. Patients with pharyngeal gonorrhoea harboured a pharyngeal microbiome quite similar to negative subjects. Nevertheless, when looking to less-represented bacterial species (relative abundance approximately 1% or less), an imbalance between aerobe and anaerobe microorganisms was observed in NG-infected patients. In particular, the pharyngeal microbiome of NG-positive individuals was richer in several anaerobes (e.g. Treponema, Parvimonas, Peptococcus, Catonella, Filifactor) and poorer in various aerobe genera (i.e. Pseudomonas, Escherichia), compared to non-infected controls. No significant differences were noticed in the distribution of commensal Neisseria species of the oropharynx between NG-positive and negative subjects. Metabolic variations induced by changes in the microbiome abundance were assessed by a functional prediction of the bacterial metabolic pathways: a more abundant involvement of D-glutamine and D-glutamate metabolism, carbohydrate metabolism, as well as a greater activation of the energy metabolism was observed in patients with pharyngeal gonorrhoea compared to non-infected individuals. Information about the bacterial composition of the pharyngeal microbiome in case of gonorrhoea could shed light on the pathogenesis of the infection and open new perspectives for the prevention and control of this condition.