Clonally Related Neisseria gonorrhoeae Isolates with Decreased Susceptibility to the Extended-Spectrum Cephalosporin Cefotaxime in Amsterdam, the Netherlands

Abstract

ABSTRACTFrom 2006 to 2008,Neisseria gonorrhoeaeisolates were identified with decreased susceptibility to the extended-spectrum cephalosporin (ESC) cefotaxime among visitors of the Amsterdam sexually transmitted infections (STI) clinic, the Netherlands. Spread, clonality, and characteristics of 202 isolates were examined using antibiograms, conventionalpenAmosaic gene PCR, andN. gonorrhoeaemultiple-locus variable-number tandem repeat analysis (NG-MLVA). A strictly defined subset was further characterized byN. gonorrhoeaemultiantigen sequence typing (NG-MAST) and sequencing of ESC resistance determinants (penA,mtrR, andporB1b). Seventy-fourN. gonorrhoeaeisolates with a cefotaxime MIC of >0.125 μg/ml (group A), 54 with a cefotaxime MIC of 0.125 μg/ml (group B), and a control group of 74 with a cefotaxime MIC of <0.125 μg/ml (group C) were included. Fifty-three clonally relatedpenAmosaic-positive isolates (penicillin-binding protein 2 type XXXIV) were identified in group A (n= 47 isolates; 64%) and B (n= 6 isolates; 11%). The 53penAmosaic-positive isolates were predominantly NG-MAST ST1407 (87%) and contained anmtrRpromoter A deletion (98%) andporB1balterations G101K/A102N. All were assigned to the same NG-MLVA cluster that comprised in total 56 isolates. A correlation was found between decreased cefotaxime susceptibility and ST1407 that was highly prevalent among visitors of the Amsterdam STI clinic. The rapid spread of this strain, which also has been identified in many other countries, might be facilitated by high-risk sexual behavior and should be monitored closely to identify potential treatment failure. Quality-assured surveillance of ESC susceptibility on the national and international levels and exploration of new drugs and/or strategies for treatment of gonorrhea are crucial.