Emergence, spread and characteristics of Neisseria gonorrhoeae isolates with in vitro decreased susceptibility and resistance to extended-spectrum cephalosporins in Sweden

Daniel Golparian (1) , Bengt Hellmark (1) , Hans Fredlund (1) , Magnus Unemo (1)

1 Department of Laboratory Medicine, Microbiology, Örebro University Hospital

Neisseria gonorrhoeae has developed resistance to most therapeutic antimicrobials introduced. Most worrying, treatment failures with oral ESCs are reported, especially from WHO Western Pacific Region (WPR), and the susceptibility to all ESCs (oral and injectable), the last remaining treatment options in many settings, is decreasing globally. Objectives To examine the emergence, spread, and characteristics of N. gonorrhoeae isolates with decreased susceptibility and resistance to ESCs in Sweden. Methods All available Swedish isolates during 1998-2009, with exposure of infection in many countries worldwide, displaying a “decreased susceptibility” to cefixime and/or ceftriaxone (MIC³0.032 mg/L; n=331) were examined using antibiograms, full-length porB gene sequencing, Neisseria gonorrhoeae multi-antigen sequence typing (NG-MAST), and sequencing of ESC resistance determinants (penA, mtrR and porB [penB alteration]). Results Based on the EUCAST breakpoints, 30 (9.1%) and one (0.3%) of the strains displayed in vitro resistance to cefixime and ceftriaxone, respectively. penA mosaic alleles and penA A501 alteration were detected in 24% and 11%, respectively, of the isolates, and in increasing prevalence over the years. Moreover, among these isolates 38 NG-MAST STs were detected, with ST1407 (n=29), ST1103 (n=9) and ST3378 (n=8) being most prevalent. Conclusions The proportions of N. gonorrhoeae isolates with decreased susceptibility and resistance to ESCs have substantially increased over the years in Sweden. Both penA mosaic allele and penA A501 alteration, together with mtrR and penB, are important for the decreased susceptibility and resistance to ESCs. At least one gonococcal penA mosaic strain (ST1407), including its evolving subtypes, with decreased susceptibility/resistance to ESCs circulates worldwide.

Mots clés: ANTIMICROBIAL RESISTANCE; GONOCOCCI; GONORRHOEA; STD; SURVEILLANCE

Daniel Golparian, Bengt Hellmark, Hans Fredlund, Magnus Unemo. Emergence, spread and characteristics of Neisseria gonorrhoeae isolates with in vitro decreased susceptibility and resistance to extended-spectrum cephalosporins in Sweden. Sexually Transmitted Infections, 2010, 86 (6), pp.454. ⟨10.1136/sti.2010.045377⟩. ⟨hal-00576101⟩