title: Changes in the rates of Neisseria gonorrhoeae antimicrobial resistance are primarily driven by dynamic fluctuations in common gonococcal genotypes.
abstract: To examine how gonococcal genotypes and associated changes over time influence rates of Neisseria gonorrhoeae antimicrobial resistance.
  
  
  
  All available N. gonorrhoeae isolates collected in New South Wales, Australia in the first half of both 2012 and 2014 were genotyped using the Agena MassARRAY iPLEX platform. Genotypic data were compared with phenotypic antimicrobial resistance profiles over time. We focused on penicillin and ciprofloxacin as significant increases in resistance to both antibiotics were observed over this time period.
  
  
  
  Genotyping data were obtained for 760 and 782 isolates in 2012 and 2014, respectively. A total of 162 distinct genotypes were identified in the study, including 36 (22.2%) genotypes present in both years ( persisting genotypes), 54 (33.3%) observed in 2012 only and 72 (44.4%) observed in 2014 only (s ingle-year genotypes). Overall, persisting genotypes comprised 15 of the 20 most common genotypes, 8 of which showed a significant change in proportion from 2012 to 2014. Persisting genotypes also comprised the majority (>70%) of ciprofloxacin- and penicillin-resistant isolates in both years. Significant fluctuations in the most common persisting genotypes accounted for the majority of observed increases in both ciprofloxacin and penicillin resistance. Single-year genotypes contributed to ∼20% of ciprofloxacin and penicillin resistance in each year.
  
  
  
  The results show that the gonococcal genotypes persisting in the study population fluctuated significantly within a 3 year period, with numerous other genotypes appearing or disappearing. It is the net effect of these changes that determines N. gonorrhoeae antimicrobial resistance levels within the population.
authors.affiliation: WHO Collaborating Centre for STD, Microbiology Department, South Eastern Area Laboratory Services, Prince of Wales Hospital, Randwick, New South Wales 2031, Australia.|School of Medical Sciences, Faculty of Medicine, UNSW Australia, Sydney, New South Wales 2052, Australia.
authors.forename: Monica M
authors.initials: MM
authors.lastname: Lahra
authors.affiliation: The University of Queensland, UQ Centre for Clinical Research (UQCCR), Herston, Queensland 4029, Australia.
authors.forename: Ella
authors.initials: E
authors.lastname: Trembizki
authors.affiliation: The University of Queensland, UQ Centre for Clinical Research (UQCCR), Herston, Queensland 4029, Australia.
authors.forename: Cameron
authors.initials: C
authors.lastname: Buckley
authors.affiliation: Kirby Institute, UNSW Australia, Sydney, New South Wales 2052, Australia.|Sydney Sexual Health Centre, Sydney Hospital, Sydney, New South Wales 2000, Australia.
authors.forename: Basil
authors.initials: B
authors.lastname: Donovan
authors.affiliation: Melbourne Sexual Health Centre, Alfred Health, Carlton, Victoria 3053, Australia.|Central Clinical School Monash University, Melbourne, Victoria, Australia.
authors.forename: Marcus
authors.initials: M
authors.lastname: Chen
authors.affiliation: Kirby Institute, UNSW Australia, Sydney, New South Wales 2052, Australia.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Guy
authors.affiliation: WHO Collaborating Centre for STD, Microbiology Department, South Eastern Area Laboratory Services, Prince of Wales Hospital, Randwick, New South Wales 2031, Australia.
authors.forename: Ratan L
authors.initials: RL
authors.lastname: Kundu
authors.affiliation: Kirby Institute, UNSW Australia, Sydney, New South Wales 2052, Australia.
authors.forename: David G
authors.initials: DG
authors.lastname: Regan
authors.affiliation: School of Medical Sciences, Faculty of Medicine, UNSW Australia, Sydney, New South Wales 2052, Australia.|Pathology Queensland Central Laboratory, Brisbane, Queensland 4029, Australia.
authors.forename: David M
authors.initials: DM
authors.lastname: Whiley
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001315:Australia / Q000453:epidemiology; D002443:Ceftriaxone / Q000494:pharmacology; D002939:Ciprofloxacin / Q000494:pharmacology; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D005838:Genotype; D006069:Gonorrhea / Q000453:epidemiology* / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D009344:Neisseria gonorrhoeae / Q000187:drug effects* / Q000235:genetics*; D010403:Penicillin Resistance / Q000235:genetics; D010406:Penicillins / Q000494:pharmacology; D000198:Spectinomycin / Q000494:pharmacology; D013753:Tetracycline Resistance / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D010406:Penicillins; D002939:Ciprofloxacin; D002443:Ceftriaxone; D000198:Spectinomycin