ABSTRACT
Objective To determine the prevalence of penicillinase-producing Neisseria gonorrhoeae(PPNG) and the distribution of blaTEM-135 gene variants in PPNG at several gonococcal antimicrobial surveillance sites in China, to compare N. gonorrhoeae multi-antigen sequence typing(NG-MAST)types of PPNG and its blaTEM-135 gene variants, and to assess the difference and association in NG-MAST types of blaTEM-135 gene variants among different regions. Methods A total of 572 N. gonorrhoeae isolates were collected at 6 gonococcal antimicrobial surveillance sites from Jiangsu, Shanghai, Zhejiang, Tianjin, Guangdong and Guangxi in 2012. After isolation, purification, and identification, cefalotin paper discs were used for detection of PPNG. DNA was extracted by QIAxtractor DX kits after cultivation of the PPNG strains. Then, mismatch amplification mutation assay (MAMA) PCR was performed to identify blaTEM-135 variants, and NG-MAST analysis to determine N. gonorrhoeae genotypes. Results Among the 572 N. gonorrhoeae strains, 38.1%(218/572) were identified as PPNG, and of the PPNG strains, 52.3% (114/218) were blaTEM-135 variants. The detection rate of PPNG at these surveillance sites from high to low was as follows: 51.7% (45/87, Zhejiang), 45.6%(36/79, Shanghai), 38.0% (78/205, Guangdong), 37.5% (12/32, Guangxi), 31.2% (24/77, Jiangsu) and 25.0%(23/92, Tianjin), and that of blaTEM-135 variants was as follows: 68.9%(31/45, Zhejiang), 58.3%(14/24, Jiangsu), 50.0%(39/78, Guangdong), 47.2%(17/36, Shanghai), 39.1%(9/23, Tianjin)and 33.3%(4/12, Guangxi). NG-MAST analysis showed that the ST2318, ST1768, ST1866, ST1053 and ST8726 types predominated among these bla TEM-135 variants, and a strong correlation was found between blaTEM-135 variants and some NG-MAST types, such as ST1768, ST1053 and ST8726 types. The distribution of NG-MAST types was significantly different between the surveillance site in Tianjin (in the Northern part of China) and the other sites (in the Southern part of China), but highly similar among the surveillance sites in Jiangsu, Zhejiang and Shanghai regions. Conclusions There is a high prevalence of PPNG and its blaTEM-135 variants at several gonococcal antimicrobial surveillance sites in China, with significant differences in NG-MAST genotype distribution of PPNG and its blaTEM-135 variants among different regions.
ABSTRACT
Objective To test the ceftriaxone susceptibility of Neisseria gonorrhoeae (NG) isolates from Nanjing city,and to assess their genotypes by using the NG multi-antigen sequence typing (NG-MAST) method.Methods A total of 204 NG strains isolated in 2007 and 81 in 2012 from Nanjing city were included in this study.The minimum inhibitory concentration (MIC) of ceftriaxone was determined for these strains using an agar dilution method.DNA was extracted by the Qiagen commercial kit from these strains followed by NG-MAST.Results All the isolates were susceptible to ceftriaxone (MIC,≤ 0.25 μg/ml).The MIC of ceftriaxone was ≥ 0.06 μg/ml for 63.2％ of all the NG strains,70.6％ of those isolated in 2007 and 44.4％ of those in 2012,and ≥ 0.125 μg/ml for 31.6 ％ of all the NG strains,39.7％ of those isolated in 2007,11.1％ of those in 2012.Totally,166 genotypes were identified among the 285 isolates,of which,73 had been reported,and 93 were previously unreported.The most prevalent genotype was ST568 (n =13) in NG strains isolated in 2007,followed by ST270 (n =9),ST421 (n =7),ST2288 (n =5),ST1731 (n =4),ST1766 (n =4),ST1866 (n =4),ST1870 (n =4),while ST2318 (n =5),ST1053 (n =4),ST5990 (n =4),ST8726 (n =4) were the common genotypes in 2012.Those isolates with identical or similar genotypes tended to display similar MICs for ceftriaxone.Conclusions The prevalent genotypes of NG are markedly different between 2007 and 2012 in Nanjing region,and there is a strong association between the genotypes and ceftriaxone susceptibility of NG.NG-MAST results may serve as a genetic marker in the surveillance of antibiotic susceptibility in NG.
ABSTRACT
Objective To monitor antibiotic resistance of Neisseria gonorrhoeae in Nanjing City based on analysis of the results from 1999 to 2002. Methods The production of ?-lactamase was determined by paper acidometric method. Minimum inhibitory concentrations (MICs) of penicillin, ceftriaxone, tetracycline, ciprofloxacin and spectinomycin were determined by an agar plate dilution method. Results A total of 417 clinical isolates of Neisseria gonorrhoeae were examined. During the period of 1999-2002, positive rate of PPNG rapidly increased from 8.0% to 31.31% (P