Genotyping of dominant outer membrane porinIgene of Neisseria gonorrhoeae isolates and analysis of me site mutation of PIB gene
Objective To analyze the dominant genotypes of outer membrane porinⅠ( PⅠ) gene in the isolates of Neisseria gonorrhoeae from Zhejiang area and the correlation among the genetic site mutation and drug resistance, and to determine the distribution of PⅠA and PⅠB genes in the isolates and their dominant genotypes. Methods The entire PⅠgene of 34 N. gonorrhoeae isolates were amplified using high fidelity PCR. The target amplification fragments were sequenced after T-A cloning. The mutadon sites G120 and A121 were analyzed. Results All the 11 PⅠA+ isolates were belonging to serovarsⅠA6. Of the 22 PⅠB+ isolates, 6 (26.1%), 5(21.7%), 2(8.7%), 9(39.1%) and 1(4.3%) strains were identified as serovarsⅠB3,ⅠB3/ 6,ⅠB3/6-ⅠB2 andⅠB2-ⅠB4 chimera, respectively. The sensitivity of the PCR was as high as 10 ng DNA template. 23.0%(26/113) and 77.0% (87/113) of the 113 N. gonorrhoeae isolates carry PⅠA and PⅠB genes. In the 23 sequenced PⅠB+ isolates, one strain(4.3%) had no mutation at the G120 and A121 sites, while 3 strains(13.0%) showed G120 or A121 mutation, 2 strains(8.7%) displayed G120 mutation but lack of A121, and 17 strains(73.9%) exhibited the double site mutation. All the 22 PⅠB+ isolates with mutation at G120 and/or A121 sites were resistant to penicillin and tetracycline. Conclusion The N. gonorrhoeae strains prevalent in the local area are mainly taking PⅠB gene.ⅠA6 is the dominant serovars of the PⅠA + N.gonorrhoeae isolates.ⅠB3/6-ⅠB2 chimeric,ⅠB3 andⅠB3/6 serovars are common in the PⅠB+ N. gonorrhoeae isolates and most of the isolates are the drug resistant G120 and/or A121 mutants.