The oropharynx of men using HIV pre-exposure prophylaxis is enriched with antibiotic resistance genes: A cross-sectional observational metagenomic study

Macrolide resistance is pervasive in oral streptococci in the Belgian general population: a cross-sectional survey

Background. Commensal streptococci are common inhabitants of the oral microbiome and regulate its structure and function in beneficial ways for human health. They can, however, also be opportunistic pathogens and act as a reservoir of resistance genes that can be passed on to other bacteria, including pathogens. Little is known about the prevalence of these commensals in parents and their children and their antimicrobial susceptibilities in the Belgian general population.Gap Statement. The macrolide susceptibility of commensal oral Streptococci in Belgium is unknown.Methods. We assessed the prevalence and azithromycin susceptibility of commensal streptococcal species in the parents (n=38) and children (n=50) of 35 families in Belgium.Results. The most frequently detected taxonomic grouping was Streptococcus mitis/oralis, which was detected in 78/181 (43.1%) of the children's isolates and 66/128 (51.6%) of the parents' isolates. Of the 311 isolates collected in this study, 282 isolates (90.7%) had an azithromycin MIC value greater than the breakpoint of 0.25 mg l-1 and 146 isolates (46.9%) had azithromycin MICs greater than 2 mg l-1. There was no difference in the azithromycin MIC distribution of all streptococcal isolates between children and parents. All individuals were colonized by streptococci with azithromycin MICs greater than 0.25 mg l-1, and 87.5% of individuals had streptococci with MICs greater than 2 mg l-1.Interpretation. The most prevalent species identified in both age groups was S. mitis/oralis. All individuals harboured streptococci with macrolide resistance. This highlights the need for additional antimicrobial stewardship initiatives to reduce the consumption of macrolides in the general population.

Antimicrobial Resistance of Neisseria gonorrhoeae Isolates among Men Who Have Sex with Men in Lower Silesia, Poland

Neisseria gonorrhoeae (NG) has developed resistance to nearly all antibiotics used for its treatment. However, very limited data are available regarding the antimicrobial resistance of NG isolates among MSM in Poland. The aim of this study was to evaluate the susceptibility of Neisseria gonorrhoeae isolates in this key population. We investigated the antimicrobial susceptibility of NG isolates to six antimicrobials (ceftriaxone, cefixime, azithromycin, ciprofloxacin, tetracycline, and benzylpenicillin). Minimum inhibitory concentrations (MICs; mg/L) were determined using Etests on gonococcal isolates. One hundred high-risk MSM were included in the study (25 HIV-positive and 75 HIV-negative using pre-exposure prophylaxis for HIV). The rate of NG infection was 28%. All NG isolates were susceptible to cefixime and ceftriaxone. Susceptibility to azithromycin was found in 69.2% (18/26) of the NG isolates and resistance in 30.8% (8/26) of NG isolates. Susceptibility to tetracycline was found in 50% (13/26) of the isolates and resistance in 50% (13/26) of the isolates. We observed gonorrhea to be more prevalent in patients with a higher number of oral sexual contacts. Increasing azithromycin resistance is especially concerning for future treatment options, especially if ceftriaxone/cefixime resistance starts to develop and for people with beta-lactam antibiotics allergies. Doxy-PEP might lose its partial efficacy for NG soon.

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.

Lack of Association between Antimicrobial Consumption and Antimicrobial Resistance in a HIV Preexposure Prophylaxis Population: A Cross-Sectional Study

BACKGROUND

In antibiotic naïve populations, there is a strong association between the use of an antimicrobial and resistance to this antimicrobial. Less evidence is available as to whether this relationship is weakened in populations highly exposed to antimicrobials. Individuals taking HIV preexposure prophylaxis (PrEP) have a high intake of antimicrobials. We previously found that there was no difference in the prevalence of pheno- and genotypic antimicrobial resistance between two groups of PrEP clients who had, and had not, taken antimicrobials in the prior 6 months. Both groups did, however, have a higher prevalence of resistance than a sample of the general population.

METHODS

In the current study, we used zero-inflated negative binomial regression models to evaluate if there was an individual level association between the consumption of antimicrobials and 1. the minimum inhibitory susceptibilities of oral Neisseria subflava and 2. the abundance of antimicrobial resistance genes in the oropharynges of these individuals.

RESULTS

We found no evidence of an association between the consumption of antimicrobials and the minimum inhibitory susceptibilities of oral Neisseria subflava or the abundance of antimicrobial resistance genes in these individuals.

CONCLUSIONS

We conclude that in high-antimicrobial-consumption populations, the association between antimicrobial consumption and resistance may be attenuated. This conclusion would not apply to lower-consumption populations.

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.

Effect on the Resistome of Dual vs Monotherapy for the Treatment of Neisseria gonorrhoeae: Results From a Randomized Controlled Trial (ResistAZM Trial)

Background

No randomized controlled trial (RCT) has compared the impact on the resistome of ceftriaxone (CRO) plus azithromycin (AZM) vs CRO for the treatment of Neisseria gonorrhoea (NG).

Methods

This was an open-label, single-center, RCT comparing the effect on the resistome of CRO plus AZM vs CRO for the treatment of NG. Men who have sex with men (MSM) with genital, anorectal, or pharyngeal NG infection were randomized into the CRO/AZM and CRO arms. Oral rinse and anorectal samples were taken for culture and resistome profiling at 2 visits (baseline and day 14). The primary outcome was the ratio of mean macrolide resistance determinants in anorectal samples from day 14 between arms.

Results

Twenty individuals were randomized into the CRO/AZM arm and 22 into the CRO arm. We found no significant difference in the mean macrolide resistance determinants in the day 14 anorectal samples between arms (ratio, 1.05; 95% CI, 0.55-1.83; P = .102). The prevalence of baseline macrolide resistance was high (CRO/AZM arm = 95.00%; CRO arm = 90.91%).

Conclusions

We could not demonstrate a significant effect of dual CRO/AZM therapy on the resistome compared with CRO alone, likely due to a high baseline resistance to AZM. Interventions to prevent the emergence of antimicrobial resistance in MSM are needed.

Correlates of Neisseria gonorrhoeae antimicrobial resistance: cross-sectional results from an open cohort sentinel surveillance network in Québec, Canada, 2016-2019

OBJECTIVES

To examine correlates of Neisseria gonorrhoeae antimicrobial resistance (AMR) to first-line antimicrobials (azithromycin, cefixime and ceftriaxone).

DESIGN AND SETTING

The sentinel surveillance network is an open cohort of gonococcal infection cases from Québec, Canada. Cross-sectional results are reported herein.

PARTICIPANTS

Between 1 January 2016 and 31 December 2019, data from 886 individuals accounting for 941 gonorrhoea cases were included.

METHODS

Epidemiological and clinical data were collected using an auto-administered questionnaire, direct case interviews and chart reviews. Antimicrobial susceptibility testing was performed using the agar dilution method. Generalised estimating equations were used for regression.

RESULTS

The prevalence of azithromycin resistance with a minimal inhibitory concentration (MIC) of ≥2 mg/L was 21.3%. In 2016, men who have sex with men were more likely to be infected with an azithromycin-resistant N. gonorrhoeae isolate (adjusted prevalence ratio (aPR)=4.73, 95% CI 1.48 to 15.19) or with an isolate with increased third-generation cephalosporin (3GC) MIC (aPR=5.32, 95% CI 1.17 to 24.11 for cefixime (MIC≥0.06 mg/L) and aPR=4.38, 95% CI 1.53 to 12.54 for ceftriaxone (MIC≥0.03 mg/L)). However, these associations were not maintained between 2017 and 2019, with increased MIC observed in men who have sex exclusively with women and women. Overall, azithromycin resistance was significantly more likely in cases who self-reported HIV infection (aPR=1.65, 95% CI 1.00 to 2.71). Cefixime increased MIC were more likely in individuals 25-34 years old (aPR=2.23, 95% CI 1.18 to 4.21). Cefixime and ceftriaxone increased MIC were both more likely in cases who reported ≥5 sexual partners (cefixime: aPR=2.10, 95% CI 1.34 to 3.27 and ceftriaxone: aPR=1.62, 95% CI 1.14 to 2.30).

CONCLUSION

Significant correlates of N. gonorrhoeae AMR to first-line antimicrobials were observed. Antimicrobial stewardship may be particularly important for 3GC. Active monitoring and interventions are critical for 3GC non-susceptible strains, especially considering the very low prevalence in Québec.