Plasmid-mediated PER-1 extended-spectrum betalactamase in Providencia retgeri from Bulgaria

A multiresistant Providencia rettgeri strain was isolated from the urine of a 38-year-old female cancer patient during an episode of febrile neutropenia that followed a course of postoperative adjuvant chemotherapy. The strain was resistant to beta-lactams (except cephamycins and carbapenems), aminoglycosides, fluoroquinolones, chloramphenicol, tetracycline, trimethoprim and sulfonamides. Clavulanic acid restored activity of oxyiminocephalosporins, suggesting the production of an extended-spectrum beta-lactamase (ESBL). PCR and sequencing with primers specific for known ESBL genes identified blaPER-1. The PER-1 determinant was transferable by conjugation and cotransferred with blaTEM-1 (ampicillin resistance), aac(6')-Ib ( amikacintobramycin-kanamycin resistance), gentamicin, chloramphenicol, trimethoprim and sulfonamide resistance determinants. Plasmid-mediated quinolone resistance determinants (qnr and aac(6')-Ib-cr) were not detected. This is the first description of plasmid-mediated PER-1 enzyme in Enterobacteriaceae in Bulgaria. Since PER-1-positive Gram-negative pathogens have been increasingly isolated in Turkey and Europe, and given the potential for further dissemination, nationwide early recognition and rapid identification of PER-1-producing bacteria should be considered to avoid further spread of this resistance determinant.