title: Detection of mutations in the gyrA gene and class I integron from quinolone-resistant Salmonella enterica serovar Choleraesuis isolates in Taiwan.
abstract: The quinolone resistance-determining regions (QRDRs) of the gyrA gene of quinolone-resistant Salmonella enterica serovar Choleraesuis isolates were sequenced. Four types of point mutation, Ser-83-to-Phe (TCC --> TTc), Ser-83-to-Tyr (TCC --> TAC), Asp-87-to-Gly (GAC --> GGC), and Asp-87-to-Asn (GAC --> AAC), were found. PCR-RFLP and MAS-touch down PCR were performed on fifty swine clinical isolates of S. enterica serovar Choleraesuis (NalR) collected during 1997-2002. The analysis indicated seven isolates with point mutations in codon 83, 13 with point mutations in codon 87, and 30 with double mutations in both codons 83 and 87. The MICs of enrofloxacin of the isolates with a single mutation in codon 83 or 87 were <2microg/ml, while the MICs of the isolates with double mutations in both codon 83 and 87 ranged from 2 to 64microg/ml. A class I integron comprised of dhfr, orfF and aad2 was also identified in both human and swine S. enterica serovar Choleraesuis isolates. These results indicate that PCR-RFLP and MAS-touchdown PCR assays can be used for surveillance of gyrA gene mutations, which are important for fluoroquinolone resistance in Salmonella. Isolates with double mutations in gyrA codons 83 and 87 are the major type of quinolone-resistant Salmonella isolated from swine in Taiwan. A surveillance system may be applied to the swine industry to monitor the emergence of fluoroquinolone and/or multi-drug-resistant S. enterica serovar Choleraesuis in Taiwan.
authors.affiliation: Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14850, USA.
authors.forename: Tzu-Ming
authors.initials: TM
authors.lastname: Huang
authors.forename: Yung-Fu
authors.initials: YF
authors.lastname: Chang
authors.forename: Chao-Fu
authors.initials: CF
authors.lastname: Chang
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology; D001483:Base Sequence; D027081:DNA Gyrase / Q000235:genetics*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics; D000077422:Enrofloxacin; D024841:Fluoroquinolones / Q000494:pharmacology; D032023:Integrons / Q000235:genetics; D008969:Molecular Sequence Data; D009268:Nalidixic Acid / Q000494:pharmacology; D017354:Point Mutation; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012150:Polymorphism, Restriction Fragment Length; D015363:Quinolones / Q000494:pharmacology; D012481:Salmonella Infections, Animal / Q000382:microbiology; D019779:Salmonella enterica / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D016415:Sequence Alignment; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology; D013624:Taiwan
chemical_list: D000890:Anti-Infective Agents; D004269:DNA, Bacterial; D024841:Fluoroquinolones; D015363:Quinolones; D009268:Nalidixic Acid; D000077422:Enrofloxacin; D027081:DNA Gyrase