Prevalence of cefixime-resistant Neisseria gonorrhoeae in Melbourne, Australia, 2021-2022.

While ceftriaxone remains the first-line treatment for gonorrhoea, the US CDC recommended cefixime as a second-line treatment in 2021. We tested 1176 Neisseria gonorrhoeae isolates among clients attending the Melbourne Sexual Health Centre in 2021-2022. The prevalence of cefixime resistance was 6.3% (74/1176), azithromycin resistance was 4.9% (58/1176) and ceftriaxone resistance was 0% (0/1176). Cefixime resistance was the highest among women (16.4%, 10/61), followed by men-who-have-sex-with-women (6.4%, 7/109), and men-who-have-sex-with-men (5.8%, 57/982). The prevalence of cefixime-resistant N. gonorrhoeae exceeds the threshold of the 5% resistance level recommended by the World Health Organization; and thus, cefixime treatment would have limited benefits in Australia.

Universal lymphogranuloma venereum (LGV) testing of rectal chlamydia in men who have sex with men and detection of asymptomatic LGV.

BACKGROUND: Lymphogranuloma venereum (LGV) is caused by Chlamydia trachomatis serovars L1-L3. This study determined the positivity for LGV testing before and after introduction of universal LGV testing of positive rectal Chlamydia trachomatis samples in men who have sex with men (MSM). METHODS: From March 2015 to February 2018, MSM with rectal C. trachomatis were not routinely tested for LGV at the Melbourne Sexual Health Centre unless they had HIV or symptoms of proctitis. From February 2018, universal testing for LGV of all positive rectal C. trachomatis specimens in men over the age of 25 years, regardless of symptoms was undertaken. LGV positivity was defined as the detection of LGV-associated C. trachomatis serovars. RESULTS: There were 3429 and 4020 MSM who tested positive for rectal chlamydia in the selective and universal LGV-testing periods, respectively. Of the total 3027 assessable specimens in both periods, 97 (3.2%; 95% CI 2.6% to 3.9%) specimens tested positive for LGV. LGV positivity in the selective testing period was higher than in the universal testing period (6.6% (33/502) vs 2.5% (64/2525), p<0.001). The proportion of LGV cases that were asymptomatic increased from 15.2% (5/33) in the selective testing period to 34.4% (22/64) in the universal testing period (p=0.045). Of the 70 symptomatic LGV cases symptoms included rectal discharge (71.4%, n=45) and rectal pain (60.0%, n=42). CONCLUSION: Universal LGV testing of all positive rectal chlamydia samples in MSM compared with selective testing led to the detection of asymptomatic rectal LGV, which constituted 34% of rectal LGV cases.

Culture obtained from urethral swab of asymptomatic men who screen positive for Neisseria gonorrhoeae by urine nucleic acid amplification testing.

BACKGROUND: In a previous study of men attending Melbourne Sexual Health Centre who had Neisseria gonorrhoeae detected by urine Aptima Combo 2 (AC2) testing, 11% were asymptomatic. This study aimed to determine whether N. gonorrhoeae can be cultured from asymptomatic men screening positive for N. gonorrhoeae by nucleic acid amplification testing (NAAT) of urine. METHODS: Between 1 July 2017 and 31 March 2019, all men attending Melbourne Sexual Health Centre were tested for N. gonorrhoeae by AC2 testing of urine whether urethral symptoms were reported or not. NAAT-positive men were recalled and a urethral swab performed for gonococcal culture using modified Thayer-Martin media with determination of minimum inhibitory concentrations (MICs) by agar dilution. RESULTS: There were 1001 cases (860 individuals) positive for N. gonorrhoeae by urine AC2: 892 (89%) reported urethral symptoms; 109 (11%) did not. Twenty-five asymptomatic cases were excluded because of antibiotic use at or following screening. Of the remaining 84 asymptomatic men, 41 (49%) had a urethral swab performed a median of 5 days after screening. Twenty-one men had urethral discharge at the return visit, 11 of whom reported the discharge at the return visit. Of the 41 men who were swabbed, 31 (76%; 95% CI 60% to 88%) were culture positive for N. gonorrhoeae. Among the 21 men who subsequently developed discharge, 19 (90%; 95% CI 70% to 99%) were culture positive. Among the 20 men who remained asymptomatic, 12 (60%; 95% CI 36% to 81%) were culture positive. MIC profiles were obtained from all isolates. CONCLUSIONS: Gonorrhoea was isolated in most but not all asymptomatic men screening positive for N. gonorrhoeae by urine NAAT. Clinicians should consider performing urethral culture in such men to ensure optimal surveillance for antimicrobial resistance. Isolation of N. gonorrhoeae by culture in men without discharge indicates these are true infections with viable organisms.

Reflex Detection of Ciprofloxacin Resistance in Neisseria gonorrhoeae by Use of the SpeeDx ResistancePlus GC Assay.

Resistance-guided therapy (RGT) for gonorrhea may reduce unnecessary use of broad-spectrum antibiotics. When reflexed from the Aptima Combo 2 assay, the ResistancePlus GC assay demonstrated 94.8% sensitivity and 100.0% specificity for Neisseria gonorrhoeae detection. Of the 379 concordant N. gonorrhoeae-positive samples, 86.8% were found to possess the gyrA S91F mutation, which was highly predictive for ciprofloxacin resistance and stable across 3,144 publicly available N. gonorrhoeae genomes. Our work supports the feasibility of implementing RGT for gonorrhea into routine molecular workflows.

Incidence and duration of incident oropharyngeal gonorrhoea and chlamydia infections among men who have sex with men: prospective cohort study.

OBJECTIVES: This prospective cohort study aimed to determine the natural history and incidence of oropharyngeal gonorrhoea and chlamydia among a cohort of men who have sex with men (MSM) over a 12-week period, and to examine risk factors associated with incident oropharyngeal infections. METHODS: MSM either aged ≥18 years and had a diagnosis of oropharyngeal gonorrhoea by nucleic acid amplification test (NAAT) in the past 3 months or aged 18-35 years who were HIV-negative taking pre-exposure prophylaxis (PrEP) were eligible for this study. Enrolled men were followed up for 12 weeks. Oropharyngeal swabs were collected at week 0 (baseline) and week 12 (end of study). Between these time points, weekly saliva specimens and the number of tongue kissing, penile-oral and insertive rimming partners were collected by post. Oropharyngeal swabs and saliva specimens were tested by NAAT for Neisseria gonorrhoeae and Chlamydia trachomatis. Poisson regression was performed to examine the risk factors (weekly number of partners) associated with incident oropharyngeal gonorrhoea. RESULTS: A total of 100 MSM were recruited. The incidence of oropharyngeal gonorrhoea and chlamydia was 62 (95% CI 37 to 105) and 9 (95% CI 2 to 35)/100 person-years, respectively. The median duration of incident oropharyngeal infection with gonorrhoea was 28 days (IQR=21-36, n=7). The incidence rate ratio (IRR) for oropharyngeal gonorrhoea increased with an increased number of kissing partners (IRR=1.08; 95% CI 1.03 to 1.12) an increased number of penile-oral sex partners (IRR=1.07, 95% CI 1.01 to 1.14) but not with an increased number of insertive rimming partners (IRR=1.11, 95% CI 0.96 to 1.29) or other demographic factors. The IRR and duration of incident oropharyngeal chlamydia were not calculated due to the small number of cases (n=2). CONCLUSIONS: MSM have a high incidence of oropharyngeal gonorrhoea and the median duration of infection was less than 3 months.

Pooling Pharyngeal, Anorectal, and Urogenital Samples for Screening Asymptomatic Men Who Have Sex with Men for Chlamydia trachomatis and Neisseria gonorrhoeae.

Screening for Chlamydia trachomatis and Neisseria gonorrhoeae at the pharyngeal, urogenital, and anorectal sites is recommended for men who have sex with men (MSM). Combining the three individual-site samples into a single pooled sample could result in significant cost savings, provided there is no significant sensitivity reduction. The aim of this study was to examine the sensitivity of pooled samples for detecting chlamydia and gonorrhea in asymptomatic MSM using a nucleic acid amplification test. Asymptomatic MSM who tested positive for chlamydia or gonorrhoea were invited to participate. Paired samples were obtained from participants prior to administration of treatment. To form the pooled sample, the anorectal swab was agitated in the urine specimen transport tube and then discarded. The pharyngeal swab and 2 ml of urine sample were then added to the tube. The difference in sensitivity between testing of pooled samples and individual-site testing was calculated against an expanded gold standard, where an individual is considered positive if either pooled-sample or individual-site testing returns a positive result. All samples were tested using the Aptima Combo 2 assay. A total of 162 MSM were enrolled in the study. Sensitivities of pooled-sample testing were 86% (94/109; 95% confidence interval [CI], 79 to 92%]) for chlamydia and 91% (73/80; 95% CI, 83 to 96%) for gonorrhea. The sensitivity reduction was significant for chlamydia (P = 0.02) but not for gonorrhea (P = 0.34). Pooling caused 22 infections (15 chlamydia and 7 gonorrhoea) to be missed, and the majority were single-site infections (19/22). Pooling urogenital and extragenital samples from asymptomatic MSM reduced the sensitivity of detection by approximately 10% for chlamydia but not for gonorrhea.

Extragenital Mycoplasma genitalium infections among men who have sex with men.

OBJECTIVES: There are limited data on the prevalence of Mycoplasma genitalium (Mgen) coinfection with rectal chlamydia (Chlamydia trachomatis (CT)) and rectal gonorrhoea (Neisseria gonorrhoeae (NG)) infections and few studies examining the prevalence of pharyngeal Mgen in men who have sex with men (MSM). Using transcription-mediated amplification assay, this study aimed to determine the proportion of rectal CT and rectal NG infections in MSM who are coinfected with rectal Mgen, and the proportion of MSM with Mgen detected in the pharynx in order to inform clinical practice. METHODS: This was a cross-sectional study conducted at Melbourne Sexual Health Centre in Australia. Consecutively collected rectal swabs from MSM that tested positive for CT (n=212) or NG (n=212), and consecutively collected pharyngeal samples (n=480) from MSM were tested for Mgen using the Aptima Mycoplasma genitalium Assay (Hologic, San Diego). Samples were linked to demographic data and symptom status. RESULTS: Rectal Mgen was codetected in 27 of 212 rectal CT (13%, 95% CI 9 to 18) and in 29 of 212 rectal NG (14%, 95% CI 9 to 19) samples, with no difference in the proportion positive for Mgen. MSM with rectal CT/Mgen coinfection had more sexual partners than those with rectal CT monoinfection (mean 6 vs 11, p=0.06). MSM with rectal NG/Mgen coinfection were more likely to be HIV-positive than those with rectal NG monoinfection (OR=2.96, 95% CI 1.21 to 7.26, p=0.023). MSM with rectal CT/Mgen coinfection were more likely to be using pre-exposure prophylaxis than MSM with rectal NG/Mgen coinfection (OR 0.25, 95% CI 0.10 to 0.65, p=0.002). Pharyngeal Mgen was uncommon and detected in 8 of 464 samples (2%, 95% CI 1% to 3%). Pharyngeal Mgen was associated with having a rectal STI (OR=10.61, 95% CI 2.30 to 48.87, p=0.002), and there was a borderline association with being HIV-positive (p=0.079). CONCLUSION: These data indicate one in seven MSM treated for rectal CT or rectal NG will have undiagnosed Mgen that is potentially exposed to azithromycin during treatment of these STIs. Rectal Mgen coinfection was associated with specific risk factors which may inform testing practices. Pharyngeal Mgen was uncommon.

Trends and Risk Factors for Antimicrobial-Resistant Neisseria gonorrhoeae, Melbourne, Australia, 2007 to 2018.

Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a major public health problem. Traditionally, AMR surveillance programs for N. gonorrhoeae have focused mainly on laboratory data to describe the prevalence and trends of resistance. However, integrating individual-level risk factors (e.g., sexual orientation or international travel) with laboratory data provides important insights into factors promoting the spread of resistant N. gonorrhoeae Here, over a 12-year period, we assessed the trends and risk factors for resistant N. gonorrhoeae in individuals attending a large publicly funded sexual health center in Melbourne, Australia. A total of 7,588 N. gonorrhoeae isolates were cultured from 5,593 individuals between 1 January 2007 and 31 December 2018. The proportion of isolates with penicillin resistance decreased from 49.5% in 2007 to 18.3% in 2018 (ptrend < 0.001) and from 63.5% in 2007 to 21.1% in 2018 for ciprofloxacin resistance (ptrend < 0.001). In contrast, the proportion of isolates displaying decreased susceptibility to ceftriaxone increased from 0.5% in 2007 to 2.9% in 2018 (ptrend < 0.001), with a significant increase in low-level azithromycin resistance, from 2.5% in 2012 to 8.2% in 2018 (ptrend < 0.001). Multivariate analysis identified risk factors for multidrug-resistant (MDR) N. gonorrhoeae, namely, female sex and country of birth, with MDR isolates more common in individuals born in northeast Asia, further highlighting the importance of this region and international travel as factors in the cross-border transmission of MDR N. gonorrhoeae Future surveillance work should incorporate additional epidemiological and genomic data to provide a comprehensive overview of the emergence and spread of resistant N. gonorrhoeae.

Bacterial Load of Chlamydia trachomatis in the Posterior Oropharynx, Tonsillar Fossae, and Saliva among Men Who Have Sex with Men with Untreated Oropharyngeal Chlamydia.

The aim of this study was to determine whether Chlamydia trachomatis could be detected in saliva and if infection is specific to an anatomical site in the oropharynx. Men who have sex with men (MSM) who were diagnosed with oropharyngeal chlamydia at the Melbourne Sexual Health Centre in 2017-2018 were invited to participate upon returning for treatment. Swabs at the tonsillar fossae and posterior oropharynx and a saliva sample were collected. Throat samples were tested for C. trachomatis by the Aptima Combo 2 assay. The bacterial loads of C. trachomatis in all samples were assessed by quantitative PCR (qPCR) detecting the ompA gene. We calculated the positivity and bacterial load of C. trachomatis for all samples. Forty-two MSM were included. The median age was 28 years (interquartile range [IQR], 24 to 33 years). Thirty-two participants (76.2%; 95% confidence interval [CI], 60.5% to 87.9%) had C. trachomatis detected by qPCR at both the tonsillar fossae and the posterior oropharynx, followed by 9.5% (n = 4; 95% CI, 2.7% to 22.6%) positive at the posterior oropharynx only and 4.8% (n = 2; 95% CI, 0.58% to 16.2%) positive at the tonsillar fossae only. Twenty-nine MSM had C. trachomatis detected in saliva (69.0%; 95% CI, 52.9% to 82.3%). The median C. trachomatis load in saliva was 446 copies/ml (IQR, 204 to 1,390 copies/ml), that in the tonsillar fossae was 893 copies/swab (IQR, 390 to 13,224 copies/ml), and that in the posterior oropharynx was 1,204 copies/swab (IQR, 330 to 16,211). There was no significant difference in C. trachomatis load between the tonsillar fossae and the posterior oropharynx (P = 0.119). Among MSM with oropharyngeal chlamydia, nearly three-quarters had chlamydia DNA detected in saliva, although the viability and implications for transmission are unknown.

Prevalence of genital and oropharyngeal chlamydia and gonorrhoea among female sex workers in Melbourne, Australia, 2015-2017: need for oropharyngeal testing.

OBJECTIVE: The Victorian legislation requires sex workers to have quarterly screening for genital chlamydia and gonorrhoea, but screening for oropharyngeal infection is not mandatory in Victoria, Australia. In 2017, oropharyngeal screening for gonorrhoea and chlamydia was added as part of the routine quarterly screening for sex workers attending the Melbourne Sexual Health Centre (MSHC). The aim of this study was to examine the prevalence of oropharyngeal gonorrhoea and chlamydia among female sex workers (FSW). METHODS: We included females who (1) self-identified as sex workers or were attended MSHC for a sex work certificate and (2) had tested for any STI or HIV, between March 2015 and December 2017. The prevalence of HIV, syphilis, chlamydia and gonorrhoea was calculated. RESULTS: There were 8538 FSW consultations among 2780 individuals during the study period. There was a twofold increase in genital gonorrhoea (from 0.5% (95% CI 0.3% to 0.9%) to 1.1% (95% CI 0.8% to 1.5%); ptrend=0.047) and a 1.5-fold increase in genital chlamydia (from 2.2% (95% CI 1.6% to 2.8%) to 3.2% (95% CI 2.6% to 3.8%); ptrend=0.031) during the period. Overall, the prevalence of HIV (0.2% (95% CI 0.1% to 0.3%)) and syphilis (0.1% (95% CI 0.0% to 0.2%)) remained low and did not change over time. In 2017, the prevalence of oropharyngeal gonorrhoea was 2.0% (95% CI 1.6% to 2.6%) and oropharyngeal chlamydia was 2.1% (95% CI 1.6% to 2.7%). Among FSW who were tested positive for gonorrhoea and chlamydia, 55% (n=41) and 34% (n=45) only tested positive in the oropharynx but not genital for gonorrhoea and chlamydia, respectively. CONCLUSION: The prevalence of oropharyngeal gonorrhoea and chlamydia is similar to the prevalence at genital sites and is often independent of genital infection. It is important to test the oropharynx and genital site for chlamydia and gonorrhoea among FSW.

Should Asymptomatic Men Who Have Sex With Men Be Screened for Oropharyngeal Chlamydia? Clinical Outcomes From a Cross-Sectional Study.

OBJECTIVE: To help inform screening guidelines, we estimated the proportion of asymptomatic men who have sex with men (MSM) with oropharyngeal chlamydia. STUDY DESIGN: An audit of asymptomatic MSM attending a sexual health service from March 2015 to April 2016 was conducted. They each had an oropharyngeal swab that was tested for Chlamydia trachomatis by transcription-mediated nucleic acid amplification. In addition, a random sample of 17 swabs that initially tested positive had confirmatory testing to determine the likelihood of true positivity. RESULTS: We collected 4877 oropharyngeal swabs: 72 (1.5%; 95% confidence interval [CI], 1.2-1.9) were diagnosed positive for chlamydia. Most (n = 56 [78%]; 95% CI, 67-86) only had oropharyngeal chlamydia detected (i.e., no concurrent extraoropharyngeal chlamydia and/or gonorrhea). Of the 17 samples that underwent confirmation, all confirmed positive (100%; 95% CI, 82-100). CONCLUSIONS: Although oropharyngeal chlamydia prevalence was low among asymptomatic MSM, most oropharyngeal chlamydia cases had no chlamydia at other sites, and these cases would have been missed and not treated if routine oropharyngeal chlamydia testing was not done.

Increased Detection of Pharyngeal and Rectal Gonorrhea in Men Who Have Sex With Men After Transition From Culture To Nucleic Acid Amplification Testing.

BACKGROUND: This before-and-after study measured the impact of a change in testing methods from culture to nucleic acid amplification testing (NAAT) on the detection of pharyngeal and rectal gonorrhea in men who have sex with men (MSM) on a sexual health service level, including the effect on subgroups anticipated to have higher rates of gonorrhea. METHODS: In March 2015, Melbourne Sexual Health Centre changed its laboratory method for gonococcal testing from culture to NAAT using the Aptima Combo 2 and Aptima GC tests. We compared the proportion of tests positive for rectal and pharyngeal gonorrhea in MSM using culture in 2014 with those using NAAT in 2015. RESULTS: The proportion of tests positive for rectal gonorrhea by NAAT was double that obtained by culture (8% vs 3.9%; prevalence ratio [PR], 2.0; 95% confidence interval [CI], 1.8-2.4) and 5-fold for pharyngeal gonorrhea (8.3% vs 1.6%; PR, 5.2; 95% CI, 4.2-6.4). Similar increases in test positivity were observed in human immunodeficiency virus (HIV)-positive and HIV-negative men. By NAAT, test positivity for rectal gonorrhea was higher in HIV-positive compared with HIV-negative men (15.4% vs 7.3%; PR, 2.1; 95% CI, 1.7-2.6). Culture and NAAT had similar test positivity for rectal gonorrhea among men who reported contact with gonorrhea (24.9% vs 25.3%, PR 1.0, 95% CI 0.8-1.4) and men who presented with symptoms of proctitis (22.2% vs 27.9%, PR 1.3, 95% CI 0.8-2.0). CONCLUSIONS: A switch from culture to Aptima Combo 2 testing for extragenital gonorrhea in MSM increased detection and was most marked for pharyngeal infections.

Near-to-patient-testing to inform targeted antibiotic use for sexually transmitted infections in a public sexual health clinic: the NEPTUNE cohort study.

Background: Empiric treatment of sexually transmitted infections can cause unnecessary antibiotic use. We determined if near-to-patient-testing (NPT) for Neisseria gonorrhoeae, Chlamydia trachomatis and Mycoplasma genitalium (MG) improved antibiotic-use for a range of clinical presentations. Methods: Clients attending with non-gonococcal urethritis (NGU), proctitis, as STI-contacts, or for an MG-test-of-cure (MG-TOC) between March and December 2021 were recruited. Participants received near-to-patient-testing (NPT-group) for the three STIs using the GeneXpert® System (Cepheid), and concurrent routine-testing by transcription-mediated-amplification (TMA; Aptima, Hologic). Antibiotic-use among NGU or proctitis cases in the NPT-group was compared to clinic-controls undergoing routine-testing only. The proportion in the NPT-group who notified partners <24 hrs of their STI-specific result was calculated. Findings: Among 904 consults by 808 NPT-participants, ≥1 STI was detected in 63/252 (25.0%) with NGU, 22/51 (43.1%) with proctitis, and 167/527 (31.7%) STI-contacts. MG was detected among 35/157 (22.3%) MG-TOC consults. Among NGU and proctitis cases, fewer in the NPT-group received empiric treatment compared to clinic-controls (29.4% [95% CI: 24.3-34.9%] vs 83.8% [95% CI: 79.2-87.8%], p < 0.001), resulting in more NPT-group cases appropriately treated (STI-specific drug/no drug appropriately; 80.9% [95% CI: 76.0-85.1%] vs 33.0% [95% CI: 27.7-38.6%], p < 0.001) and fewer mistreated (incorrect drug/treated but pathogen-negative; 17.8% [13.7-22.6%] vs 61.4% [55.6-66.9%], p < 0.001). Of 167/264 in the NPT-group with an STI who responded regarding partner-notification, 95.2% notified all/some partners; 85.9% notified them <24 hrs of the STI-specific result. Interpretation: Near-to-patient-testing significantly improved antibiotic use and a high proportion of individuals rapidly notified partners of STI-specific results, highlighting the broad benefits of timely diagnostic strategies for STIs in clinical decision making and partner notification. Funding: ARC ITRP Hub-grant; NHMRC.

Economic evaluation alongside a clinical trial of near-to-patient testing for sexually transmitted infections.

BACKGROUND: Current clinical care for common bacterial STIs (Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and Mycoplasma genitalium (MG)) involves empiric antimicrobial therapy when clients are symptomatic, or if asymptomatic, waiting for laboratory testing and recall if indicated. Near-to-patient testing (NPT) can improve pathogen-specific prescribing and reduce unnecessary or inappropriate antibiotic use in treating sexually transmitted infections (STI) by providing same-day delivery of results and treatment. METHODS: We compared the economic cost of NPT to current clinic practice for managing clients with suspected proctitis, non-gonococcal urethritis (NGU), or as an STI contact, from a health provider's perspective. With a microsimulation of 1000 clients, we calculated the cost per client tested and per STI- and pathogen- detected for each testing strategy. Sensitivity analyses were conducted to assess the robustness of the main outcomes. Costs are reported as Australian dollars (2023). RESULTS: In the standard care arm, cost per client tested for proctitis, NGU in men who have sex with men (MSM) and heterosexual men were the highest at $247.96 (95% Prediction Interval (PI): 246.77-249.15), $204.23 (95% PI: 202.70-205.75) and $195.01 (95% PI: 193.81-196.21) respectively. Comparatively, in the NPT arm, it costs $162.36 (95% PI: 161.43-163.28), $158.39 (95% PI: 157.62-159.15) and $149.17 (95% PI: 148.62-149.73), respectively. Using NPT resulted in cost savings of 34.52%, 22.45% and 23.51%, respectively. Among all the testing strategies, substantial difference in cost per client tested between the standard care arm and the NPT arm was observed for contacts of CT or NG, varying from 27.37% to 35.28%. CONCLUSION: We found that NPT is cost-saving compared with standard clinical care for individuals with STI symptoms and sexual contacts of CT, NG, and MG.

Drug susceptibility testing for oxygen-dependent and oxygen-independent resistance phenotypes in trichomonads.

Trichomonas vaginalis is the most prevalent, non-viral sexually transmitted human infection, causing 170 million cases of trichomoniasis annually. Since the 1950s, treatment has relied on 5-nitroimidazoles (5NIs), leading to increasing drug resistance. A similar drug resistance problem is present in the veterinary pathogen, Tritrichomonas foetus. There are currently no agreed standards for defining 5NI resistance, due in part to two distinct oxygen-dependent ("aerobic") and oxygen-independent ("anaerobic") resistance phenotypes. Diagnostic tools to detect 5NI resistance are lacking, and current assays used to phenotypically assess 5NI resistance in vitro are complicated by these two resistance phenotypes. We demonstrate that microaerophilic conditions support sufficient parasite growth to interrogate oxygen-dependent resistance of 5NIs against known resistant and susceptible isolates of T. vaginalis and T. foetus. We further demonstrate that microaerophilic conditions allow sufficient growth for compatibility with existing growth assays, including our TriTOX assay. Adopting microaerophilic conditions eliminates traditional 'by-eye' estimates of minimum inhibitory concentrations and opens up options for increased throughput and automation, scalable to higher-throughput analyses of 5NI resistance. This would further allow the development of quantitative phenotypic standards to benchmark oxygen-dependent or oxygen-independent trichomonad 5NI resistance towards standardised surveillance programs to combat drug resistance.

A comparison of cotton-tipped and nylon flocked swabs for culture of Neisseria gonorrhoeae from oropharyngeal samples.

Our aim was to determine if there was a difference in culture positivity for oropharyngeal gonorrhoea when sampling using a nylon-flocked versus cotton-tipped swab. We collected FLOQSwabs and cotton-tipped swabs from individuals aged ≥ 18 years who had untreated oropharyngeal gonorrhoea detected by NAAT between November 2019-June 2020.Of 78 participants, 32 (41.0%) were culture-positive for N. gonorrhoeae from either swab. Of these 32, 29 (90.6%, 95%CI: 75.0%-98.0%) were positive on both swabs, one (3.1%, 95%CI: 0.0%-16.2%) tested positive on FLOQSwab only and two (6.2%, 95%CI: 0.1%-20.8%) tested positive on cotton-tipped swabs only. There was moderate agreement between the swabs in the amount of bacterial growth (Cohen's Kappa (k)=0.745; 95%CI: 0.622-0.868, p<0.001). Our results showed that the proportion of positive results was comparable using the FLOQSwabs versus the cotton-tipped swabs for oropharyngeal gonorrhoea culture.

Evaluation of ResistancePlus MG FleXible, a 'near-patient' test for the detection of Mycoplasma genitalium and macrolide resistance mutations, using freshly collected clinical samples.

Introduction. Mycoplasma genitalium is a sexually transmitted pathogen with increasing resistance to first- and second-line antimicrobials. The 'near-patient test' ResistancePlus MG FleXible (SpeeDx) detects M. genitalium plus four macrolide resistance mutations (MRMs), facilitating same-day patient follow up.Hypothesis/Gap Statement. This assay has not been assessed on freshly collected samples.Aim. Our goal was to evaluate the performance of the ResistancePlus MG FleXible test against the standard of care open platform test.Methods. ResistancePlus MG FleXible (analysed on the Cepheid GeneXpert platform) was evaluated on freshly collected samples and compared to the standard of care open platform test ResistancePlus MG (SpeeDx) analysed on the LightCycler 480 II (Roche).Results. For 270 valid tests, ResistancePlus MG FleXible yielded a high positive per cent agreement (PPA) of 94.1% [96/102; 95 % confidence interval (CI): 87.6-97.8 %] and negative per cent agreement (NPA) of 95.2% (160/168; 95 % CI: 90.8-97.9%) for M. genitalium detection compared to the reference assay (kappa for test concordance of 0.89; 95 % CI: 0.83-0.95). Performance was similar across different sample types. For the detection of MRMs, ResistancePlus MG FleXible had a PPA of 97.1% (66/68; 95% CI: 89.8-99.6) and NPA of 78.6% (22/28; 95 % CI: 59.0-91.7), with test comparison kappa of 0.79 (95 % CI: 0.65-0.93). Notably, of six discordant results (i.e. determined to be wild type by the reference assay), five were positive for MRMs by Sanger sequencing, indicating that the ResistancePlus MG FleXible assay has an improved performance for mutation detection.Conclusion. ResistancePlus MG FleXible had comparable test performance for M. genitalium detection as the open platform assay, with improved detection of MRMs. The ResistancePlus MG FleXible 'near-patient' assay can deliver a rapid result to expedite appropriate treatment.

Nonclassical Pathogens as Causative Agents of Proctitis in Men who Have Sex With Men.

BACKGROUND: This study aimed to identify enteric and sexually acquired rectal pathogens, other than chlamydia and gonorrhea, associated with symptomatic proctitis in men who have sex with men (MSM). METHODS: Anorectal swab samples were obtained from MSM presenting with rectal symptoms and a clinical diagnosis of proctitis at the Melbourne Sexual Health Centre between January 2017 and March 2019. Samples that tested positive for Neisseria gonorrhoeae and Chlamydia trachomatis were excluded. As a comparison group, anorectal samples were also obtained from MSM not reporting symptoms of proctitis between November 2018 and February 2019. Samples from both groups were tested for 15 viral, bacterial, and protozoal enteric pathogens using polymerase chain reaction. RESULTS: Anorectal samples from 499 men with symptomatic proctitis and 506 asymptomatic men were analyzed. Age, HIV status, and pre-exposure prophylaxis (PrEP) use did not differ between men with proctitis and asymptomatic men. Treponema pallidum was more common in men with proctitis (risk difference [RD], 3.6%; 95% CI, 2.0%-5.2%). Most men with anorectal T. pallidum presented with painful anal primary infections. Shigella spp. was more common among men with proctitis compared with asymptomatic men (RD, 1.8%; 95% CI, 0.1%-3.5%). Most men with Shigella did not report diarrhea. Mycoplasma genitalium was more common in men with proctitis (RD, 4.3%; 95% CI, 1.1%-7.5%). Herpes simplex virus (HSV)-1 (RD, 10.1%; 95% CI, 6.8%-13.3%) and HSV-2 (RD, 7.2%; 95% CI, 4.5%-10.0%) were more common with proctitis. CONCLUSIONS: Testing for T. pallidum, Shigella, and HSV should be considered in MSM presenting with symptomatic proctitis. These data provide support for M. genitalium as a significant cause of proctitis. A comprehensive diagnostic evaluation is required for MSM with proctitis.

Performance of the ResistancePlus MG diagnostic test for Mycoplasma genitalium using samples collected with Hologic Aptima Specimen Collection kits.

Introduction. Mycoplasma genitalium is a sexually transmitted organism with high levels of resistance to the recommended first-line therapy, azithromycin. The ResistancePlus MG test concurrently detects M. genitalium, and the presence of macrolide-resistance mutations (MRM). European, UK and Australian guidelines recommend a diagnostic test that reports MRM to optimize treatment through resistance-guided therapy. Hence, for samples collected for use on other platforms, reflex testing using the ResistancePlus MG test would be beneficial.Aim. To validate the ResistancePlus MG assay using samples collected in Aptima buffer for testing on the Hologic Panther.Methodology. Positive (n=99) and negative (n=229) clinical samples collected in Aptima buffer were extracted on the MagNA Pure 96 (Roche Diagnostics), and tested with the ResistancePlus MG test on the LightCycler 480 II (Roche Diagnostics). Results were compared to matched samples collected using standard sample collection (urine or swab resuspended in PBS), with positive percent agreement (PPA), negative percent agreement (NPA) and Cohen's Kappa statistic.Results. The ResistancePlus MG test had high performance with a 200 µl input volume (PPA/NPA for M. genitalium detection, 92.9 % [95 % confidence interval (CI): 85.5-96.9]/100 % [95 % CI: 97.9-100], MRM detection, 96.9 % [95 % CI: 88.2-99.5]/85.7 % [95 % CI: 66.4-95.3]) and for 1 ml input volume (PPA/NPA for M. genitalium detection, 95.9%/96.6%, MRM detection, 98.4%/90.3%). Samples remained positive after storage at room temperature beyond the manufacturer-recommended storage of <60 days (mean storage time for 1 ml extraction: 129 days).Conclusion. Samples collected using Aptima collection kits are suitable for reflex testing using the ResistancePlus MG test, allowing detection of macrolide resistance.

Risk Factors for Asymptomatic Enteric Pathogen Detection Among Men Who Have Sex With Men.

Improved knowledge of factors that promote outbreaks of enteric pathogens among men who have sex with men (MSM) could enable targeted public health interventions. We detected enteric pathogens in 57 of 519 (11%) asymptomatic MSM, and we found that enteric pathogen detection was associated with both oroanal sex (rimming) and group sex.