• Diagnosis
• gonorrhoea
• pharynx
• surveillance
• treatment

The incidence of sexually transmitted infections is cyclical and is subject to complex interactions between adaptations of their causative microbes, medication, cultural patterns, demography and economics. While STIs have their most severe impact upon those disadvantaged by socio-economic deprivation, STIs may also flourish during periods of economic growth and societal transformation. While the recent decline in gonorrhoea incidence in many Western countries preceded the worldwide economic recession, the current search for cost-savings in sexual health may leave us less able to recognise and manage the inevitable future resurgence of gonorrhoea.

Pharyngeal infection, as a potential asymptomatic reservoir that sustains the community prevalence of gonorrhoea, is a particular area for concern, especially for high-risk groups such as men who have sex with men (MSM) and commercial sex workers (CSW). Orogenital sex also appears to be practised increasingly in heterosexual couples of all ages. Certainly, the current predominance of HSV-1 as a cause of primary genital herpes supports an increase in oral sex. Among teenagers, oral sex may precede and substitute for genital penetrative intercourse at their sexual debut. It obviates the risk of pregnancy. Moreover, teaching about safer sexual practises may misleadingly suggest that it is safe from the risk of HIV and other STIs, and does not require condom use. In MSM, pharyngeal gonorrhoea is commonly associated with younger age and number of recent insertive oral sex partners but is not influenced by whether or not ejaculation occurs.1 Recent studies indicate that most cases2 3 occurred without evidence of concomitant anogenital infection and were associated with both fellatio and insertive oro-anal sex (‘rimming’). In CSW in Singapore4 and Tel Aviv,5 a high prevalence of pharyngeal gonorrhoea was found to be associated with significantly lower consistent condom use for oral as compared with vaginal sex.

Pharyngeal gonorrhoea is clinically silent with less than 10% of infected persons presenting with symptoms of sore throat and associated dysphagia. Clinical complications are rare, although the pharynx is well recognised as a source of disseminated gonococcal infection. What remains uncertain is whether the isolation of gonococci in throat swabs represents a self-limiting colonisation in most individuals and, if so, how long this lasts, in addition to which organism and host factors predispose to longer-term oropharyngeal infection and persistent transmission risk. Transmission from the pharynx to MSM who only report being recipients of fellatio appears to be as equally efficient as unprotected insertive anal sex.2

Both CDC and European guidelines recommend at least annual screening for pharyngeal gonorrhoea in at-risk groups.6 7 The diagnosis of extragenital gonorrhoea has until recently been reliant on operator-dependent pharyngeal swab sampling and culture on selective media. The poor sensitivity of such tests has been shown in several recent studies.8 In the USA, Nucleic Acid Amplification Tests have not yet been approved by the FDA for the diagnosis of extragenital gonorrhoea but may be offered for such purposes after internal validation of the method by a verification study. In studies that used a rotating gold standard requiring at least two comparator NAATS to be positive, the sensitivity of culture was shown to vary between 41 and 65%.9–11 Both SDA (Becton Dickenson) and AC2 (Aptima Combo 2, Genprobe) have substantially higher sensitivities with specificities of 94–99%. Ampiclor PCR (Roche) also had a higher sensitivity but has a substantially lower specificity. In the UK, it is now recommended that a combination of NAATs tests should supplant culture for the routine diagnosis and follow-up of pharyngeal gonorrhoea, mirroring what is already happening in the routine diagnosis of urogenital infections.12 However, retention of culture facilities remains important for antimicrobial sensitivity testing and surveillance.

It has been long recognised that there is a lower treatment success rate for pharyngeal gonorrhoea, especially with single dosage regimens. Third-generation cephalosporins are currently the mainstay of gonorrhoea treatment; however, treatment failures with both oral cefixime and ceftibuten have been reported. Multiple chromosomal abnormalities are associated with the raised MICs to these agents, and many of these strains also show resistance to other antimicrobial agents.13 IM ceftriaxone is the recommended first-line treatment for pharyngeal gonorrhoea in US and European guidelines, but treatment failures were recently reported in which two different pen A mutations were identified in gonococcal isolates.14 Azithromycin resistance in gonorrhoea is also becoming more common15; recommended treatment dosages are twice those used for chlamydia infections. Concurrent gonococcal infections, especially in non-genital sites, are likely to be overlooked in national screening programmes, and suboptimal treatment regimens may favour the selection of resistant strains. A test of cure after treatment of pharyngeal gonorrhoea is essential, but the optimal timing of NAATs tests for this purpose needs to be determined.

It is inevitable that there will be a resurgence in gonorrhoea, and this may occur just as public sector healthcare budgets worldwide are under increased pressure. Potential cost-savings may be sought in expenditure on health education campaigns, condoms and other preventive activities, less comprehensive STI testing, rationalisation of diagnostic testing modalities with reduced availability of culture and efforts to reduce drug treatment budgets.

The pharynx is increasingly likely to be a source of persistent easily transmissible infection and a site from which multiply resistant gonococcal isolates can emerge. We need to provide consistent messages that cover both STIs and HIV when discussing oral sex and condom usage. Sexual history taking should routinely include questions about orogenital contact and relevant sampling undertaken in at-risk individuals. Further information is required about which populations have a sufficiently high prevalence of infection for routine oropharyngeal testing to be cost-effective.

The continued evolution of gonococcal antimicrobial resistance remains of worldwide concern and surveillance is essential. Reduced vigilance could easily allow the emergence and onward spread of gonorrhoea with multiple antibiotic resistance leading to increased patient morbidity and total healthcare expenditure. Moreover, the consequences would disproportionately affect socio-economically deprived communities, thereby widening healthcare gaps during the recovery from the global recession.