Gonorrhoea antimicrobial resistance: is UK antibiotic stewarding policy shows “some success”

A widely circulated press release from the Society of General Microbiology’s (SGM) Annual Conference 2014 (April 14th – 17th) reports that Health for England’s Gonorrhoea Resistance Action Plan, according to representative, Dr Catherine Ison, “has shown some success in delaying the onset of treatment failure to the oral antibiotic cefixime”.  At issue here is the policy of switching to intra-muscular ceftriaxone with azithromycin as the first line treatment for gonorrhoea in the face of alarming evidence of an increase in gonococcal resistance to oral cefixime – a policy that aims to delay the emergence of cefixime resistance, and so “steward” our last remaining antibiotic defences against the infection (STI/blogs/Ison & Lowndes).

So the reprieve continues, we are to assume – in the absence from the press-release of even a head-line figure in support of Ison’s bare claim to “some success”.  If we turn to the Gonococcal Resistance to Antimicrobials Surveillance Programme’s last report (GRASP 2012: published October 2013) we find that the prevalence of GUM isolates exhibiting decreased susceptibility to cefixime (MIC ≥0.125 mg/L) declined significantly in MSM from 17% in 2011 to 7% in 2012, and in females from 3% in 2011 to 1.6% in 2012 (though isolates from heterosexual men show little change in cefixime MICs), following alarming increases in resistance from 2007-2010. In June 2013, Ison & Lowndes (I&L) (STI/blogs/Ison & Lowndes) noted a “striking association” between this decline in resistance and the change in UK prescribing practice referred to above, though “causality cannot be attributed to this observation” (Ison: Doctor’s Channel).  (Any argument for causality would, as a minimum, require precise information regarding the timing of the policy change – which is conspicuously absent from the I&L paper).  The SGM press-release appears to indicate a continuation of the same downward trend, and presumably offers further endorsement for the policy adopted at some point in 2011.

The SGM devoted a Report to sexually transmitted infections in 2013 (SGM – 2013). Anti-microbial resistance (most urgently, at present, in gonorrhoea) heads the list of three research challenges.  Recommendations include investment in research to track the impact of new interventions (e.g. optimizing the use of existing antibiotics), and extending lessons learned on gonorrhoea to understand treatment failure in chlamydia and mycoplasma genitalium – as well, of course, as initiating a drug development strategy that addresses the current problems of market failure.  Interestingly, however, the second challenge, that of rapid diagnosis of bacterial STIs, is also highly relevant to the problem of stewarding antibiotic defences.  The future development of enhanced diagnostic point-of-care tests based on genomic rapid sequencing techniques could enable a more “tailored” response to infection, based on profiling antibiotic susceptibility in the individual case, which would facilitate switching back to “abandoned” antibiotics where the their resistance profile disappears from the local population.

Needless to say, the development of new antibiotics (potentially Cempra’s solithromycin or AstraZeneca’s AZD0914), and of rapid sequencing-based diagnostic techniques, are in the future.  Meantime, the reprieve achieved through stewarding of cephalosporins may, says Ison, be short-lived.

 

 

 

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