Abstract and Introduction
Abstract
Background Culture is insensitive for the detection of pharyngeal gonorrhoea but isolation is pivotal to antimicrobial resistance surveillance. The aim of this study was to ascertain whether recommendations provided to clinicians (doctors and nurses) on pharyngeal swabbing technique could improve gonorrhoea detection rates and to determine which aspects of swabbing technique are important for optimal isolation.
Methods This study was undertaken at the Melbourne Sexual Health Centre, Australia. Detection rates among clinicians for pharyngeal gonorrhoea were compared before (June 2006–May 2009) and after (June 2009–June 2012) recommendations on swabbing technique were provided. Associations between detection rates and reported swabbing technique obtained via a clinician questionnaire were examined.
Results The overall yield from testing before and after provision of the recommendations among 28 clinicians was 1.6% (134/8586) and 1.8% (264/15 046) respectively (p=0.17). Significantly higher detection rates were seen following the recommendations among clinicians who reported a change in their swabbing technique in response to the recommendations (2.1% vs 1.5%; p=0.004), swabbing a larger surface area (2.0% vs 1.5%; p=0.02), applying more swab pressure (2.5% vs 1.5%; p<0.001) and a change in the anatomical sites they swabbed (2.2% vs 1.5%; p=0.002). The predominant change in sites swabbed was an increase in swabbing of the oropharynx: from a median of 0% to 80% of the time.
Conclusions More thorough swabbing improves the isolation of pharyngeal gonorrhoea using culture. Clinicians should receive training to ensure swabbing is performed with sufficient pressure and that it covers an adequate area that includes the oropharynx.
Introduction
Gonorrhoea is one of the most common bacterial sexually transmitted infections worldwide with high prevalence rates reported among many populations of men who have sex with men (MSM). Rectal gonorrhoea has been shown to facilitate the acquisition of HIV. Pharyngeal gonorrhoea is believed to be an important reservoir for infection with transmission to the urethra via oral sex. Guidelines recommend that MSM should be screened for pharyngeal and rectal gonorrhoea, in addition to other sexually transmitted infections, at least annually, with screening of higher risk men every 3–6 months.
Nucleic acid amplification tests (NAAT) and culture are available for the detection of Neisseria gonorrhoeae. NAAT are highly sensitive but false positive results may occur. Culture is more specific but less sensitive than NAAT, with studies showing the sensitivity of culture to be as low as 50% compared with NAAT for the detection of pharyngeal gonorrhoea. However, culture permits the determination of antibiotic susceptibility and surveillance of antimicrobial resistance to gonorrhoea, a critical role, given the relentless development of gonococcal resistance to antimicrobials including cephalosporins. The load of N gonorrhoeae at the pharynx has been shown to be lower than that seen with rectal gonorrhea, with culture from the pharynx missing lower-load infections.
Pharyngeal gonorrhoea contributes significantly to the epidemiology of gonococcal infection in a number of ways. It is a predominantly asymptomatic infection and therefore will only be detected with screening. Furthermore, it is believed to play a role in the development of antimicrobial resistance via the exchange of genetic material between N. gonorrhoeae and commensal Neisseria species within the pharynx. An additional concern is that many of the antimicrobials used to treat pharyngeal gonorrhoea have reduced penetration of the pharynx.
In a previous study, we found that clinicians who reported inducing a gag reflex more frequently had higher detection rates for pharyngeal gonorrhoea. Our hypothesis was that because of the insensitivity of culture, thorough swabbing was required for optimal isolation of pharyngeal gonorrhoea. The aim of the current study was to ascertain whether recommendations on swabbing technique could lead to improvements in pharyngeal gonorrhoea detection rates and to determine which aspects of swabbing technique are important for optimising yield.