title: Neisseria gonorrhoeae and extended-spectrum cephalosporins in California: surveillance and molecular detection of mosaic penA.
abstract: BACKGROUND
  The spread of Neisseria gonorrhoeae strains with mosaic penA alleles and reduced susceptibility to extended-spectrum cephalosporins is a major public health problem. While much work has been performed internationally, little is known about the genetics or molecular epidemiology of N. gonorrhoeae isolates with reduced susceptibility to extended-spectrum cephalosporins in the United States. The majority of N. gonorrhoeae infections are diagnosed without a live culture. Molecular tools capable of detecting markers of extended-spectrum cephalosporin resistance are needed.
  
  
  METHODS
  Urethral N. gonorrhoeae isolates were collected from 684 men at public health clinics in California in 2011. Minimum inhibitory concentrations (MICs) to ceftriaxone, cefixime, cefpodoxime and azithromycin were determined by Etest and categorized according to the U.S. Centers for Disease Control 2010 alert value breakpoints. 684 isolates were screened for mosaic penA alleles using real-time PCR (RTPCR) and 59 reactive isolates were subjected to DNA sequencing of their penA alleles and Neisseria gonorrhoeae multi-antigen sequence typing (NG-MAST). To increase the specificity of the screening RTPCR in detecting isolates with alert value extended-spectrum cephalosporin MICs, the primers were modified to selectively amplify the mosaic XXXIV penA allele.
  
  
  RESULTS
  Three mosaic penA alleles were detected including two previously described alleles (XXXIV, XXXVIII) and one novel allele (LA-A). Of the 29 isolates with an alert value extended-spectrum cephalosporin MIC, all possessed the mosaic XXXIV penA allele and 18 were sequence type 1407, an internationally successful strain associated with multi-drug resistance. The modified RTPCR detected the mosaic XXXIV penA allele in urethral isolates and urine specimens and displayed no amplification of the other penA alleles detected in this study.
  
  
  CONCLUSIONS
  N. gonorrhoeae isolates with mosaic penA alleles and reduced susceptibility to extended-spectrum cephalosporins are currently circulating in California. Isolates with the same NG-MAST ST, penA allele and extended-spectrum cephalosporin MICs have caused treatment failures elsewhere. The RTPCR assay presented here may be useful for the detection of N. gonorrheoae isolates and clinical specimens with reduced extended-spectrum cephalosporin MICs in settings where antimicrobial susceptibility testing is unavailable. In an era of increasing antimicrobial resistance and decreasing culture capacity, molecular assays capable of detecting extended-spectrum cephalosporin of resistance are essential to public health.
authors.affiliation: San Francisco Department of Public Health, 101 Grove St, Rm, 419, San Francisco, CA 94102, USA. severin.gose@sfdph.org.
authors.forename: Severin
authors.initials: S
authors.lastname: Gose
authors.forename: Duylinh
authors.initials: D
authors.lastname: Nguyen
authors.forename: Daniella
authors.initials: D
authors.lastname: Lowenberg
authors.forename: Michael
authors.initials: M
authors.lastname: Samuel
authors.forename: Heidi
authors.initials: H
authors.lastname: Bauer
authors.forename: Mark
authors.initials: M
authors.lastname: Pandori
mesh_terms: D000328:Adult; D000483:Alleles; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002140:California / Q000453:epidemiology; D002352:Carrier Proteins / Q000235:genetics*; D002443:Ceftriaxone / Q000494:pharmacology / Q000627:therapeutic use; D002511:Cephalosporins / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D005838:Genotype; D006069:Gonorrhea / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology*; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D017720:Molecular Epidemiology; D009344:Neisseria gonorrhoeae / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D046929:Serine-Type D-Ala-D-Ala Carboxypeptidase; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D002352:Carrier Proteins; D002511:Cephalosporins; D002443:Ceftriaxone; D046929:Serine-Type D-Ala-D-Ala Carboxypeptidase; C586047:penicillin-binding protein 2, Neisseria gonorrhoeae