淋病奈瑟菌临床菌株porB基因分型及其突变与耐药相关性研究

摘要

了解淋病奈瑟菌临床菌株porB基因型及其产物120和121位氨基酸突变与耐药的相关性.采用多重PCR(mPCR)检测淋病奈瑟菌临床菌株porB基因型,扩增产物测序后分析其编码蛋白的120和121位氨基酸突变情况,二倍平皿稀释法检测临床菌株对青霉素和四环素的耐药性.184株淋病奈瑟菌临床菌株中,99.5％ (183/184)检出porB基因,其中61株(33.3％)为porB1A基因型,122株(66.7％)为porB1B基因型.122株porB1B基因型菌株中,117株(95.9％)porB基因120和/或121位氨基酸发生突变,5株(4.1％)porB1B及所有porB1A基因型菌株porB基因120和/或121位氨基酸未突变.117株porB基因120和/或121位氨基酸突变的porB1B基因型菌株中,97.4％ (114/117)和95.7％ (112/117)分别对青霉素和四环素耐药,2.6％菌株(3/117)对青霉素和四环素敏感.61株porB1A基因型菌株中,仅有2株(3.3％)对青霉素和四环素耐药.研究中采用的mPCR能快速、准确地对淋病奈瑟菌临床菌株porB基因进行分型,这些菌株主要携带porB1B基因且该基因型菌株对青霉素和四环素耐药率显著高于porB1A基因型(P＜0.01),该耐药性与porB1B基因120和/或121位氨基酸突变密切相关.%The aim of this study is to understand the genotypes of Neisseria gonorrhoeae porB and the correlation of its mutation at the site of 120 and/or 121 amino acid in its product and drug resistance. The porB genotypes were tested and determined adopting a multiple PCR (mPCR) and the mutation at the site of 120 and/or 121 amino acid in porB sequence were detected by sequencing the porB amplification products. Doubling plate dilution was used to detect drug resistance against penicillin and tetracycline of the clinical isolates. Of the 184 N. gonorrhoeae isolates, 183 ( 183/ 184, 99.5% ) were detected as positive for porB, among them 61 (33. 3% ) were porBIA and 122 (66.7% ) were porBlB. Among the 122 porBIB genotype isolates, 117 (95. 9% ) had the mutation at the site of 120 and/or 121 a-mino acid in porB; 5 (4. 1% ) of porBIB and/or porBIA genotype isolates had no the mutation at the site of 120 and/ or 121 amino acid. Among 117 porBIB genotype isolates with the 120 and/or 121 site amino acid mutation, 97.4% (114/117) and 95.7% (112/117) of the isolates were found respectively to resist penicillin and tetracycline, only 2.6% of the isolates (3/117) were sensitive to the two antibiotics. And among 61 porBIA genotype isolates only two (3.3% ) resisted penicillin and tetracycline. The mPCR used in this study could rapidly and accurately identify the porB genotypes of N. gonorrhoeae isolates. The N. gonorrhoeae isolates tested in this study mainly carried porB1B, and the genotype carrying isolates had significantly higher penicillin and tetracycline resistance than theporB1A genotype carrying isolates (P <0. 01). The high drug resistance of porB1B genotype carrying isolates was allied with the 120 and/or 121 ami no acid site mutation.