Discovery of seven novel mutations of gyrB, parC and parE in Salmonella Typhi and Paratyphi strains from Jiangsu Province of China

• Published in: Scientific reports Vol. 10; no. 1; p. 7359
• Main Authors: Qian, Huimin, Cheng, Siyun, Liu, Guoye, Tan, Zhongming, Dong, Chen, Bao, Jinfeng, Hong, Jie, Jin, Dazhi, Bao, Changjun, Gu, Bing
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 30.04.2020; Nature Publishing Group
• Subjects: 631/326/107; 631/326/22; 631/326/41; Anti-Bacterial Agents - pharmacology; Antibiotics; Antimicrobial agents; Antimicrobial resistance; Bacterial Proteins - genetics; China; Ciprofloxacin; Ciprofloxacin - pharmacology; DNA Gyrase - genetics; Drug Resistance, Bacterial - genetics; Genotypes; Humanities and Social Sciences; Microbial Sensitivity Tests; multidisciplinary; Mutation; Mutation - genetics; Nalidixic acid; Nalidixic Acid - pharmacology; Public health; Quinolones; Quinolones - pharmacology; Salmonella; Salmonella paratyphi A - drug effects; Salmonella paratyphi A - genetics; Salmonella Typhi; Salmonella typhi - drug effects; Salmonella typhi - genetics; Science; Science (multidisciplinary); China; Jiangsu China
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-020-64346-0

Objective: To investigate the prevalence of Salmonella Typhi and Paratyphi resistance to quinolones and characterize the underlying mechanism in Jiangsu Province of China. Methods: Antimicrobial susceptibility testing was performed using Kirby-Bauer disc diffusion system. Quinolone resistance-determining region (QRDR), plasmid-mediated quinolone resistance (PMQR) determinant genes were detected by PCR and sequencing. Results: Out of 239 Salmonella isolates, 164 were S . Typhi and 75 were S . Paratyphi. 128 (53.6%) Salmonella isolates were resistant to nalidixic acid; 11 (4.6%) isolates to ciprofloxacin and 66 (27.6%) isolates were intermediate to ciprofloxacin. QRDR were present in 69  S . Typhi isolates, among which mutation at codon 83 ( n  = 45) and 133 ( n  = 61) predominated. In S . Paratyphi, the most common mutations were detected in gyrA at codon 83( n  = 24) and parC : T57S ( n  = 8). Seven mutations were first reported in Salmonella isolates including gyrB : S426G, parC : D79G and parE : [S498T, E543K, V560G, I444S, Y434S]. PMQR genes including qnrD1 , qnrA1 , qnrB4 , aac (6 ′ )-Ib-cr4 and qnrS1 were detected in 1, 2, 3, 7 and 9 isolates, relatively. Conclusions: High resistance to quinolones in Salmonella remains a serious problem in Jiangsu, China. The presence of the novel mutations increases the complexity of quinolone-resistant genotypes and poses a threat to public health. Subject terms: Salmonella Typhi, Salmonella Paratyphi, antimicrobial resistance, QRDR, PMQR.