title: Molecular characterization of acquired enrofloxacin resistance in Mycoplasma synoviae field isolates.
abstract: The in vitro activity of enrofloxacin against 73 Mycoplasma synoviae field strains isolated in Israel and Europe was determined by broth microdilution. Decreased susceptibility to enrofloxacin was identified in 59% of strains, with the MICs ranging from 1 to >16 μg/ml. The estimated MIC50 and MIC90 values for enrofloxacin were 2 and 8 μg/ml, respectively. Moreover, this study showed that 92% of recent Israeli field isolates (2009 to 2011) of M. synoviae have MICs of ≥ 2 μg/ml to enrofloxacin. Comparison of the quinolone resistance-determining regions (QRDRs) in M. synoviae isolates revealed a clear correlation between the presence of one of the amino acid substitutions Asp79-Asn, Thr80-Ala/Ile, Ser81-Pro, and Asp84-Asn/Tyr/His of the ParC QRDR and decreased susceptibility to enrofloxacin (MIC, ≥ 1 μg/ml). Amino acid substitutions at positions GyrA 87, GyrB 401/402, and ParE 420/454 were also identified, but there was no clear-cut correlation with susceptibility to enrofloxacin. Comparison of vlhA molecular profiles revealed the presence of 9 different genotypes in the Israeli M. synoviae field isolates and 10 genotypes in the European isolates; only one vlhA genotype (type 4) was identified in both cohorts. Based on results of vlhA molecular typing, several mechanisms for emergence and dissemination of Israeli enrofloxacin-resistant M. synoviae isolates are suggested.
authors.affiliation: Mycoplasma Unit, Department of Avian and Fish Diseases, Kimron Veterinary Institute, Bet Dagan, Israel. innal@moag.gov.il
authors.forename: I
authors.initials: I
authors.lastname: Lysnyansky
authors.forename: I
authors.initials: I
authors.lastname: Gerchman
authors.forename: I
authors.initials: I
authors.lastname: Mikula
authors.forename: F
authors.initials: F
authors.lastname: Gobbo
authors.forename: S
authors.initials: S
authors.lastname: Catania
authors.forename: S
authors.initials: S
authors.lastname: Levisohn
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D027081:DNA Gyrase / Q000235:genetics; D027101:DNA Topoisomerase IV / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D000077422:Enrofloxacin; D005060:Europe; D024841:Fluoroquinolones / Q000494:pharmacology*; D005838:Genotype; D007557:Israel; D037102:Lectins / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D058889:Molecular Typing; D009175:Mycoplasma Infections; D045805:Mycoplasma synoviae / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D015363:Quinolones / Q000494:pharmacology; D017422:Sequence Analysis, DNA
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D024841:Fluoroquinolones; D037102:Lectins; D015363:Quinolones; C406455:VlhA protein, Mycoplasma synoviae; D000077422:Enrofloxacin; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase