Abstract
Keywords
Introduction
Chlamydia trachomatis (chlamydia) and Neisseria gonorrhoeae (gonorrhoea) are two of the most common bacterial sexually-transmitted infections (STIs) worldwide. 1 In the Philippines, the Quezon City Service Delivery Network recorded 2583 STI cases from January to November 2022, of which 41.65% had gonorrhoea and 24.31% had non-gonococcal infections. 2 Prevalence of symptomatic urethritis was 2.38% among 1007 patients screened in the HIV clinic of the Philippine General Hospital from 2005-2017. 3 The clinical cure rate based on symptom relief was 100%, but the reinfection or relapse rate was 12.5% after at least 6 months from documented clinical cure. 3 The syndromic approach likely underestimates the true prevalence of both diseases. The diagnosis of asymptomatic chlamydia and gonorrhoea relies on nucleic acid amplification tests (NAATs). This study aimed to determine the prevalence of chlamydia and gonorrhoea infections among newly diagnosed Filipinos with human immunodeficiency virus (HIV) and to describe site-specific detection rates using NAAT.
Methods
We conducted a single-center cross-sectional study at a tertiary hospital HIV treatment hub in Metro Manila from August 2018 to March 2019. The study protocol was approved by the University of the Philippines Manila Research Ethics Board (UPMREB 2018-154-01). We enrolled newly-diagnosed people living with HIV, antiretroviral treatment-naïve participants, aged 18 years and older who gave informed consent. Participants with recent antibiotic use with activity against chlamydia or gonorrhoea were excluded. All participants had rectal and pharyngeal specimens collected using the GeneXpert® collection swabs and were instructed to collect a single first stream urine sample. For female participants, a clinician-taken endocervical swab was also collected. All urine, rectal, pharyngeal, endocervical swab samples were transported and processed in the molecular laboratory of the National Institutes of Health. The GeneXpert® test was performed according to manufacturer’s instructions. Results were relayed to the managing physicians for appropriate disposition.
Results
Baseline characteristics.
MSM, Men who have sex with men; STI, Sexually Transmitted Infection; WHO, World Health Organization; IQR, Interquartile range.
Chlamydia and Gonorrhoea disease prevalence according to site of infection (N = 60 each site).
Multisite infections refer to detection in at least two sites.
bAny site positive refers to detection in at least one site.
Discussion
The overall prevalence of genital and extragenital chlamydia or gonorrhoea among our participant group was high at 32%. Since the majority (89.5%) of our participants were asymptomatic, 84.2% rectal chlamydia or gonorrhoea would have been missed if screening was performed using only urine. This is similar to a retrospective analysis of asymptomatic MSM screened for chlamydia and gonorrhoea at a San Francisco STD clinic, where they found that 83.8% of chlamydial and gonococcal infections would have been missed by screening only for urethral infections, compared with only 9.8% of infections missed by screening the rectum and pharynx. 4 Asymptomatic chlamydia and gonorrhoea in pharyngeal and rectal sites were also commonly seen in MSM patients in Thailand, 5 China, 6 Peru, 7 South Africa, 8 and Germany. 9
Our results confirm a high proportion of asymptomatic infection (13.3%) detected using nucleic acid testing when compared to the previously reported prevalence of urethritis of 2.38% in 1007 participants using syndromic approach in participants screened at the same HIV clinic from 2005-2017. 3 Our rates were similar to a review of sexually transmitted co-infections point prevalence of 9.5% for both syphilis and gonorrhoea and 5% for chlamydia, which was greatest at time of HIV diagnosis. 3
Our study has some limitations. The results represent data from one treatment hub and may not be reflective of the true burden of chlamydia and gonorrhoea among people living with HIV in the Philippines.
Recommendations
The prevalence of chlamydia and gonorrhoea among newly diagnosed Filipino people living with HIV was 32%; and is sufficiently high to warrant routine NAAT screening. Since resource limitation is one of the major barriers to the use of molecular diagnostics for chlamydia and gonorrhoea, self-taken pooled specimen from different sites can be used to decrease cost of screening. Diagnostic accuracy of chlamydia and gonorrhoea samples taken from the pharynx, rectum, first catch urine (for MSM) and vulvovaginal swabs (for females), shows no difference with clinician-taken compared with self-taken extragenital samples. 10
Footnotes
Funding
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the This study was supported materially by Macrogen Inc and Cepheid Inc and partially funded by the Philippine Council of Health Research and Development under the Research Fellowship Grant of Dr Jose Carlo Valencia.
Declaration of conflicting interests
The authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Dr Edsel Maurice Salvaña received material support through Macrogen and Cepheid Inc.