P5.094 Evaluation of Gentamicin Susceptibility of Neisseria Gonorrhoeae Isolates in Argentina

Abstract

Introduction The effective treatment of infection by Neisseria gonorrhoeae (Ng) is critical for the individual patient management and essential in the control of gonorrhoea. The emergence of decreased susceptibility to third generation cephalosporins and its association with treatment failure in many regions of the world can quickly make them unsuitable as first-line therapy. Thus it becomes necessary to consider alternatives for future therapeutics. The aminoglycoside gentamicin, was chosen as an alternative treatment after the emergence of penicillinase-producers strains in Africa. This responds to its low cost, also due to the fact that it can be administered in a single dose of 240 mg and because studies showed cure rates of > 95%. Despite some treatment failure reports, gentamicin has proven successful in the treatment of gonococcal urethritis for many years. In Argentina, no susceptibility data are available. Materials and Methods: Retrospective study of a total of 355 Ng isolates derived to our laboratory for susceptibility studies in 2011 from 13 provinces. MIC to gentamicin was determined by agar dilution method according to CLSI. We used Ng ATCC 49226 as control for dilutions of antibiotics, using the interpretation criteria reported in bibliography. Results: Gentamicin susceptibility showed that 99.7% of Argentine isolates were in a narrow range of MIC (4-8 μg/ml) with 74.6% showing an MIC of 8 μg/ml. The MIC range was 4-16 μg/ml, MIC 50 and MIC 90 agreed 8 μg/ml. A 74.6% (265/355) isolates included in this study showed resistance to one or more of the following antibiotics: penicillin (36.3%), tetracycline (43.9%) and ciprofloxacin (48.4%). Conclusions: The Argentine gonococcal population susceptibility to gentamicin is similar to that reported by other regions of the world. In vitro studies of regular assessment would be needed to ensure the effectiveness of gentamicin as alternative drug for the treatment of gonorrhoea.