Mosaic-Like Structure of Penicillin-Binding Protein 2 Gene ( penA ) in Clinical Isolates of Neisseria gonorrhoeae with Reduced Susceptibility to Cefixime

Abstract

Neisseria gonorrhoeae strains with reduced susceptibility to cefixime (MICs, 0.25 to 0.5 g/ml) were isolated from male urethritis patients in Tokyo, Japan, in 2000 and 2001. The resistance to cephems including cefixime and penicillin was transferred to a susceptible recipient, N. gonorrhoeae ATCC 19424, by transformation of the penicillin-binding protein 2 gene (penA) that had been amplified by PCR from a strain with reduced susceptibility to cefixime (MIC, 0.5 g/ml). The sequences of penA in the strains with reduced susceptibilities to cefixime were different from those of other susceptible isolates and did not correspond to the reported N. gonorrhoeae penA gene sequences. Some regions in the transpeptidase-encoding domain in this penA gene were similar to those in the penA genes of Neisseria perflava (N. sicca), Neisseria cinerea, Neisseria flavescens, and Neisseria meningitidis. These results showed that a mosaic-like structure in the penA gene conferred reductions in the levels of susceptibility of N. gonorrhoeae to cephems and penicillin in a manner similar to that found for N. meningitidis and Streptococcus pneumoniae.

Multiplex Real-Time PCR Assay with High-Resolution Melting Analysis for Characterization of Antimicrobial Resistance in Neisseria gonorrhoeae

“…share with gonococcus high sequence similarity for some of the targets (e.g., 23S rRNA and 16S rRNA genes). Moreover, the N. gonorrhoeae mosaic penA allele is thought to be the result of horizontal gene transfer of the commensal orthologues (36,37). Therefore, in order to assess the level of cross-reactivity for all nine genetic targets included in our multiplex real-time PCR platform, a panel of 10 different nongonococcal Neisseria species (overall, 19 strains) was tested.…”

Nucleic Acid Amplification Testing for Neisseria gonorrhoeae

“…38 There have been several studies investigating the use of molecular techniques for identifying N. gonorrhoeae antibiotic resistance, and they have examined genes including the penicillin-binding protein and gyrase A genes 39,40 Nonetheless, such an approach is not yet a plausible alternative to phenotypic methods of sensitivity testing, because many genetic mechanisms of resistance have not as yet been identified. However, in our opinion, the inability of NAATs to provide antibiotic resistance data should not be a reason to exclude them as screening methods for N. gonorrhoeae detection.…”

Population structure of Neisseria gonorrhoeae based on whole genome data and its relationship with antibiotic resistance

“…Different "mosaic" penA alleles are thought to have developed from recombination with portions of DNA transferred horizontally from commensal Neisseria and/or N. meningitidis and underly decreased susceptibility or resistance to cephalosporins by preventing their binding action on the encoded mosaic PBP2 (Ameyama et al, 2002). The mosaic penA XXXIV (Ohnishi, 2011;Grad 2014;Unemo & Shafer, 2014) had the best positive predictive value of all the known resistance determinants we searched for within our dataset, being present in 6/7 of the strains resistant to cefixime.…”