Analysis of the gyrA gene of clinical Yersinia ruckeri isolates with reduced susceptibility to quinolones.
Antimicrobial susceptibility of seven clinical strains of Yersinia ruckeri representative of those isolated between 1994 and 2002 from a fish farm with endemic enteric redmouth disease was studied. All isolates displayed indistinguishable pulsed-field gel electrophoresis restriction patterns, indicating that they represented a single strain. However, considering both inhibition zone diameters (IZD) and MICs, the isolates recovered in 2001-2002 formed a separate cluster with lower levels of susceptibility to all the quinolones tested, especially nalidixic acid (NA) and oxolinic acid (OA), compared with the isolates recovered between 1994 and 1998. Analysis of the PCR product of the quinolone resistance-determining region of the gyrA gene from clinical isolates of Y. ruckeri with reduced susceptibility to OA and NA revealed a single amino acid substitution, Ser-83 to Arg-83 (Escherichia coli numbering). Identical substitution was observed in induced OA-resistant mutant strains, which displayed IZD and MICs of quinolones similar to those of the clinical isolates of Y. ruckeri with reduced susceptibility to these antimicrobial agents. These data indicate in that for Y. ruckeri, the substitution of Ser by Arg at position 83 of the gyrA gene is associated with reduced susceptibility to quinolones.
Gibello
Alicia
A
Departamento Sanidad Animal, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid, Spain.
Porrero
M Concepción
MC
Blanco
M Mar
MM
Vela
Ana I
AI
Liébana
Pilar
P
Moreno
Miguel A
MA
Fernández-Garayzábal
José F
JF
Domínguez
Lucas
L
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology; D027081:DNA Gyrase / Q000737:chemistry / Q000235:genetics*; D024881:Drug Resistance, Bacterial / Q000235:genetics; D005393:Fish Diseases / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009268:Nalidixic Acid / Q000494:pharmacology; D017686:Oncorhynchus mykiss; D010093:Oxolinic Acid / Q000494:pharmacology; D015363:Quinolones / Q000494:pharmacology*; D044124:Yersinia ruckeri / Q000187:drug effects* / Q000235:genetics
D000890:Anti-Infective Agents; D015363:Quinolones; D009268:Nalidixic Acid; D027081:DNA Gyrase; D010093:Oxolinic Acid