An evaluation of gentamicin susceptibility of Neisseria gonorrhoeae isolates in Europe

The emergence of decreased susceptibility to third-generation, extended-spectrum cephalosporins in Neisseria gonorrhoeae and associated treatment failures highlights the need to consider alternatives for future therapeutic use, such as gentamicin. The three laboratories surveying gonococcal antimicrobial susceptibility as part of the European Network for Sexually Transmitted Infections Surveillance compared agar dilution and Etest to determine gentamicin MICs and performed the first survey of gentamicin susceptibility on 1366 gonococcal isolates from 17 European Union/European Economic Area (EU/EAA) countries in 2009. Sentinel surveillance of gentamicin susceptibility showed that 95% of European isolates were within a narrow MIC range (4-8 mg/L), with 79% showing an MIC of 8 mg/L. Most countries showed little variation, but wider MIC ranges were observed in Greece (1-16 mg/L) and France, Norway and Sweden (2-16 mg/L). While MICs for both methods generally differed by just one doubling dilution, they were lower by Etest. This is the first reported evidence that the European gonococcal population susceptibility to gentamicin is similar to that reported in other world regions. Clinical trials to evaluate the therapeutic efficacy of gentamicin may be warranted.