Characterization of PMQR in Enterobacterales recovered from diseased companion animals in Argentina

NUSKE EZEQUIEL; RUMI, VALERIA; MAS, JAVIER; GUTKIND GABRIEL; DI CONZA JOSÉ

Chicago

Congreso; ASM Microbe 2020; 2020

Classical high-level resistance to fluoroquinolones is conferred by the mutation of the topoisomerase genes. However, this resistance is only transmissible vertically within the same clone. Plasmid-Mediated Quinolone Resistance (PMQR) genes provide lower resistance levels but can be easily transferred horizontally, making them of epidemiological importance. The study of resistance markers that protect the DNA gyrase (such as Qnr peptides) by site blocking acquires renewed interest in light of the development of new antibiotics, such as gepotidacin, that target this structure. PMQR genes include peptides (qnr genes), hydrolyzing enzymes (aac(6?)-Ib-cr) and efflux pumps (qepA and oqxAB) which provide resistance to multiple antibiotics families. The aim of this study was to evaluate PMQR prevalence in Enterobacterales from veterinary patients (cats and dogs). Stored isolates (collected in Buenos Aires from 2014 to 2018) were sampled from two different strata: Isolates resistant to cefotaxime (CTX) (ESBL/AmpC group: n=107) and susceptible to CTX (Naïve group: n=103). Bacterial identification was done by MALDI-TOF MS. Susceptibility was phenotypically tested by agar disk diffusion test. PMQR detection was performed by PCR, using specific primers for qnrA, qnrB, qnrC, qnrD, qnrE, qnrS, qnrVC, aac(6?)-Ib, qepA, oqxA, and oqxB. Allele typing was done by sequencing.Phenotypically, significant differences between resistance rates of quinolones and other non-β-lactam antibiotics were found between these groups with exception of nitrofurantoin (p