Predominant porB1A and porB1B genotypes and correlation of gene mutations with drug resistance in Neisseria gonorrhoeae isolates in Eastern China

Abstract

BackgroundVariations 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.MethodsThe 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.ResultsOf 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.ConclusionN. 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.

C4BP-IgM protein as a therapeutic approach to treat Neisseria gonorrhoeae infections

“…Data obtained from China and Europe approximately a decade ago suggest that about 30% and 70% of gonococcal isolates express PorB1a and PorB1b, respectively (20,21). Based on our data and previous studies (17), if we assume that 90% of PorB1a isolates and about 20% of PorB1b isolates bind C4BP, we expect C4BP-IgM to provide about 45% strain coverage.…”

“…PorB1a strains are frequently associated with disseminated infection, while PorB1b strains usually cause local infections of the genital tract (19). Surveillance data suggest that PorB1a strains are less prevalent than PorB1b strains (20)(21)(22).…”

Genomic Analysis Reveals Antibiotic-Susceptible Clones and Emerging Resistance in Neisseria gonorrhoeae in Saskatchewan, Canada

“…1a and b). As reported previously, isolates with porB1a genotypes (n ϭ 4) were also susceptible to ␤-lactam antibiotics (19). Isolates with mosaic PBP2 type 34.001 (with substitutions I312M, V316T, N512Y, and G545S) and mutations in MtrR (Ϫ35A del) and PorB (G120K;A121N) (n ϭ 24) had significantly (P Ͻ 0.001) higher ranges of ceftriaxone (0.016 to 0.062 mg/liter) (Fig.…”

Plasmid mediated penicillin and tetracycline resistance among Neisseria gonorrhoeae isolates from Kenya

“…Five different patterns of PenB were identified in 23 (63.9%) study isolates: pattern I (G120D); pattern II (A121G, G120D, and -N122); pattern III (A121G, G120N, and -N122); pattern IV (A121S, and N122K) and pattern V (A121G, and -N122) (Table 6 ). These patterns were formed by alterations in PenB that have been associated with reduced drug accumulation and consequently drug resistance in gonococci [ 56 ]. There was no significant increase in both penicillin (Median 8.000, IQR 29, p = 0.6779) and tetracycline (Median 12.0000, IQR 18, p = 0.1203) MICs observed in isolates harboring the above described PenB amino acid changes when compared to the isolates without the PenB alterations (penicillin; Median 2.000, IQR 39.5600, tetracycline; Median 24.0000, IQR 18).…”

“…A previous study by Sun et al, (2010) reported novel PorB deletions at both A121 and N122 positions, and associated these changes with high levels of both chromosomal penicillin (MIC of 4–8 mg/L) and tetracycline (MICs of 4–16 mg/L) resistance [ 56 ]. It is worth noting that the present study identified deletion at only position N122.…”