中国东部淋病奈瑟菌分离株中主要的 porB1A 和 porB1B 基因型以及基因突变与耐药性的相关性。
Predominant porB1A and porB1B genotypes and correlation of gene mutations with drug resistance in Neisseria gonorrhoeae isolates in Eastern China.
机构信息
Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of Zhejiang University, Zhejiang 310003, Hangzhou, China.
出版信息
BMC Infect Dis. 2010 Nov 10;10:323. doi: 10.1186/1471-2334-10-323.
BACKGROUND
Variations of porB1A and porB1B genes and their serotypes exist in Neisseria gonorrhoeae isolates from different geographical areas, and some site mutations in the porB1B gene correlate with drug resistance.
METHODS
The β-lactamase production of N. gonorrhoeae isolates was determined by paper acidometric test and nitrocefin discs. The porB1A and porB1B genes of 315 non-penicillinase-producting N. gonorrhoeae (non-PPNG) strains were amplified by PCR for sequencing to determine serotypes and site mutations. A duplex PCR was designed to simultaneously detect both porB1A and porB1B genes. Penicillin and tetracycline resistance was assessed by an in vitro drug sensitivity test.
RESULTS
Of the N. gonorrhoeae isolates, 31.1% tested positive for porB1A and 68.9% for porB1B genes. All the 98 porB1A+ isolates belonging to IA6 serotype with either no mutation at the 120 and 121 sites (88.8%) or a D120G (11.2%) mutation and were no resistance to both penicillin and tetracycline. Among the 217 porB1B+ isolates, 26.7%, 22.6% and 11.5% belonged to IB3, IB3/6 and IB4 serotypes, respectively. Particularly, two novel chimeric serotypes, IB3/6-IB2 and IB2-IB4-IB2, were found in 77 and 8 porB1B+ isolates. Two hundred and twelve (97.7%) of the porB1B+ isolates were presented G120 and/or A121 mutations with 163 (76.9%) at both sites. Interestingly, within the 77 porB1B+ isolates belonging to IB3/6-IB2 serotype, 15 were discovered to possess novel deletions at both A121 and N122 sites. All the replacement mutations at these sites in PorB1B were correlated with resistance and the deletion mutation showed the highest resistance.
CONCLUSION
N. gonorrhoeae isolates circulating in Eastern China include a sole PorB1A serotype (IA6) and five PorB1B serotypes. Multiple mutations in porB1B genes, including novel A121 and N122 deletions, are correlated with high levels of penicillin and tetracycline resistance.
背景
不同地理区域淋病奈瑟菌分离株的 porB1A 和 porB1B 基因及其血清型存在变异，porB1B 基因中的某些位点突变与耐药性相关。
方法
采用纸片酸定量法和硝噻吩纸片法检测淋病奈瑟菌分离株的β-内酰胺酶产生情况。对 315 株非青霉素酶产生淋病奈瑟菌（非青霉素酶产生淋病奈瑟菌）的 porB1A 和 porB1B 基因进行 PCR 扩增和测序，以确定血清型和位点突变。设计了一种双重 PCR 来同时检测 porB1A 和 porB1B 基因。采用体外药敏试验评估青霉素和四环素的耐药性。
结果
315 株淋病奈瑟菌分离株中，31.1%检测出 porB1A 基因阳性，68.9%检测出 porB1B 基因阳性。所有 98 株 porB1A+分离株均属于 IA6 血清型，120 和 121 位点无突变（88.8%）或 D120G 突变（11.2%），对青霉素和四环素均无耐药性。217 株 porB1B+分离株中，IB3、IB3/6 和 IB4 血清型分别占 26.7%、22.6%和 11.5%。特别是，在 77 株和 8 株 porB1B+分离株中发现了两种新的嵌合血清型，IB3/6-IB2 和 IB2-IB4-IB2。212 株（97.7%） porB1B+分离株在 G120 和/或 A121 位点发生突变，其中 163 株（76.9%）在两个位点发生突变。有趣的是，在 77 株属于 IB3/6-IB2 血清型的 porB1B+分离株中，有 15 株在 A121 和 N122 位点同时发生了新的缺失。PorB1B 中这些位点的所有替换突变均与耐药性相关，而缺失突变则显示出最高的耐药性。
结论
中国东部地区流行的淋病奈瑟菌分离株包括一种单一的 PorB1A 血清型（IA6）和五种 PorB1B 血清型。porB1B 基因的多种突变，包括新的 A121 和 N122 缺失，与高水平的青霉素和四环素耐药性相关。
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