A novel FexA variant from a canine Staphylococcus pseudintermedius isolate that does not confer florfenicol resistance

Abstract

Transposon Tn558 integrated in the chromosomal radC gene was detected for the first time in Staphylococus pseudintermedius. It carried a novel fexA variant (fexAv) that confers only chloramphenicol resistance. The exporter FexAv exhibited two amino acid substitutions, Gly33Ala and Ala37Val, both of which seem to be important for substrate recognition. Sitedirected mutagenesis that reverted the mutated base pairs to those present in the original fexA gene restored the chloramphenicol-plus-florfenicol resistance phenotype. Copyright © 2013, American Society for Microbiology. All Rights Reserved.