ABSTRACT
BACKGROUND: This study aimed to investigate the prevalence of penicillinase-producing Neisseria gonorrhoeae (PPNG) and their blaTEM-135 gene variant in 2007 and 2012 in Nanjing, China. In addition, molecular epidemiological typing of all isolates was performed to elucidate the genetic relationships of the PPNG strains. METHODS: A total of 199 and 77 N. gonorrhoeae isolates were collected at the National Center for STD Control in 2007 and 2012, respectively. Nitrocefin tests were performed to identify PPNG. Mismatch amplification mutation assay was used to identify blaTEM-135. All isolates were genotyped using N. gonorrhoeae multiantigen sequence typing (NG-MAST), and additionally, porB-based phylogenetic analysis was performed for the PPNG isolates. RESULTS: The total prevalence of PPNG isolates was 41% (114/276) and 58% (66/114) of these PPNG isolates possessed bla(TEM-135). In 2007, 45% (90/199) produced ß-lactamase, and of those PPNG, 58% (52/90) possessed bla(TEM-135). In 2012, 31% (24/77) were PPNG, and 58% (14/24) of those isolates contained bla(TEM-135). There were 162 NG-MAST STs among the 276 isolates, and 89 of those were novel STs. A strong association between specific NG-MAST STs and bla(TEM-135) was found, and the porB-based phylogenetic analysis showed a distant evolutionary relationship between isolates in 2007 and isolates in 2012. CONCLUSIONS: A high prevalence of PPNG and blaTEM-135 was found in Nanjing, China. bla(TEM-135) might be a precursor in the evolution into an extended-spectrum ß-lactamase that can degrade ceftriaxone, which stresses the need to continuously monitor PPNG, blaTEM-135, and additional evolving blaTEM gene variants.
Subject(s)
Gonorrhea/epidemiology , Neisseria gonorrhoeae/isolation & purification , Penicillinase/pharmacology , China/epidemiology , Drug Resistance, Microbial/genetics , Female , Genetic Variation , Gonorrhea/genetics , Gonorrhea/microbiology , Humans , Male , Microbial Sensitivity Tests , Molecular Typing , Neisseria gonorrhoeae/genetics , Phylogeny , Population Surveillance , SerotypingABSTRACT
OBJECTIVE: To investigate the antimicrobial susceptibility,auxotype, and plasmid profile of Neisseria gonorrhoeae isolates in China and to provide evidence for the development of treatment guideline and policy for control. METHODS: Agar dilution was used to detect antimicrobial susceptibility. The auxotype was determined by GC genetic medium. The plasmid was extracted by alkaline cleavage and electrophoresed. RESULTS: A total of 4,976 gonococcal isolates were tested in the last 8 years. The resistant rate for penicillin was 71.60% with PPNG being 15.54%. Tetracycline-resistant (TRNG) isolates accounted for 93.02% with 10.48% high level tetracycline-resistant. The resistant rate for ciprofloxacin was also relatively high (31.78%). The resistant rates for spectinomycin and ceftriaxone were 0.36% and 0.46%. The predominant auxotypes of gonococcal isolates were proto and pro(-) during 1995 - 1996 in Nanjing, accounted for 46.4% and 47.53%, 48.4% and 50.22%, respectively. There were 8 strains harboring 4.2, 5.4, 39.5 kb plasmids and 2 harboring 4.2, 4.9, 5.4, 39.5 kb plasmids in 10 PPNG strains; 2 harboring no plasmid, 28 harboring 4.2, 4.9, 5.4, 39.5 kb plasmids in 30 non-PPNG strains. The 5.4 kb plasmid of PPNG could be digested with restriction endonuclease BamHI while the 5.4 kb plasmid of non-PPNG could not. CONCLUSION: The gonococcal isolates were highly resistant to penicillin, tetracycline, and ciprofloxacin, while were still sensitive to spectinomycin and ceftriaxone. No significant auxotyping change was found in terms of predominant gonococcal strains in the last two years in Nanjing while 5.4 kb plasmid might be the most prevalent resistant plasmid in Nanjing.
