Abstract

In recent years there has been a rapid increase in bacterial resistance in Brazil and worldwide. Among the mechanisms described, Extended-Spectrum ß-Lactamases (ESBL) are of great importance. The continuous assessment of bacterial resistance have fundamental importance in preventing the occurrence of outbreaks and the spread of resistance, especially in the Amazon due to the relative isolation of cities and difficulties in epidemiological surveillance in the region. In the present work we approach the use of phenotypic and genotypic characterization in Enterobacterial isolates by determining the resistance profile to β-lactam antimicrobials by antibiogram and the search for blaCTX-M, blaTEM, blaSHV genes associated with β-lactam resistance. Thus, 88 samples from outpatients from 14 regions in northern Brazil, belonging to the Brazilian Amazon, were analyzed from 2012 to 2014. Of these, Salmonella Typhi (57/64.77%), Salmonella spp. (26/29.54%), Shigella flexneri (2/2.27%), Shigella dysenterie (1/1.14%), Shigella sonnei (1/1.14%) and diarrhogenic Escherichia coli (1/1.14%). As for the resistance profile, only Escherichia coli showed resistance to first, second, third and fourth generation penicillins and cephalosporins and the aztreonam monobactamide, the other isolates did not show resistance profile according to the Clinical and Laboratory Standards (CLSI) standards. The evaluation of the blaCTX-M, blaTEM and blaSHV genes showed positive results only for the blaCTX-M gene in the Escherichia coli sample, with no amplifications being observed in the other analyzed samples. Although resistance was observed in only one sample, the data suggest the circulation of β-lactam resistance genes in Enterobacteria and, therefore, we suggest that continuous resistance evaluation can prevent the spread of β-lactamase-producing Enterobacteria, evidencing the importance of continuous monitoring and efficient strategies to reduce the spread of these agents by preventing outbreaks by resistant strains.

Keywords: β-lactamases; ESBLs; Antimicrobial resistance; Enterobacteria, PCR