Characterization of the molecular mechanisms of quinolone resistance in Yersinia enterocolitica O:3 clinical isolates

Abstract

Our results show that the high level of resistance to nalidixic acid is likely due to an overexpression of an efflux pump plus a mutation in the gyrA gene, whereas decreased susceptibility to ciprofloxacin is only associated with the presence of a mutation in the gyrA gene.

Further Characterization of Three Yersinia enterocolitica Strains with a Nalidixic Acid–Resistant Phenotype Isolated from Humans with Diarrhea

“…These findings suggest that efflux activity in this bacterium contributes to quinolone/FQ resistance, a feature that confirms earlier observations (Capilla et al, 2004).…”

“…Fluoroquinolones (FQ) are used for the treatment of this infection, particularly in immunocompromised individuals (Capilla et al, 2004). In Gram-negative bacteria, three mechanisms of FQ resistance have been described including target gene mutation(s); reduction in drug accumulation; and plasmid-mediated quinolone resistance (PMQR).…”

“…Within these loci, the quinoloneresistance-determining region (QRDR) is a mutational hot spot (Fà brega et al, 2010). Several mutations have already been identified in gyrA in Yersinia enterocolitica, the most common of which lead to amino acid substitutions at Ser-83 and Asp-87, conferring resistance to nalidixic acid (Sánchez-Céspedes et al, 2003;Capilla et al, 2004;Sihvonen et al, 2011).…”

The Challenge of Efflux-Mediated Antibiotic Resistance in Gram-Negative Bacteria

“…It also contains genes for RND pumps. In one study, all 41 nalidixic acid-resistant isolates of Y. enterocolitica showed significant decreases in nalidixic acid MICs in the presence of 20 g/ml PA␤N, suggesting a strong contribution of efflux (330). A Mar homolog was identified in Y. pestis, and its overexpression increased, albeit to a small degree, the MICs of several antibiotics, including tetracycline and rifampin (331), presumably by the increased expression of the AcrB-type pump.…”

Virulence-associated gene pattern of porcine and human Yersinia enterocolitica biotype 4 isolates

“…The 2 chloramphenicol-resistant strains also possessed antibiotic resistance to nalidixic acid. Antibiotic resistance of Y. enterocolitica to nalidixic acid has been described in Switzerland (Fredriksson-Ahomaa et al, 2012), and a substantial increase in nalidixic acid resistance in human clinical isolates has been detected in Spain between 1995 and 2002 (Capilla et al, 2004). MIC50 and the MIC90 of florfenicol were 4 mg/L each for isolates from porcine tonsils and from porcine feces.…”