Study of resistance, virulence and epidemiological profile of Escherichia coli isolated from environment

Abstract

Bacterial resistance is a frequent problem in the hospital environment. Increased resistance among members of the Enterobacteriaceae family has resulted in the emergence of multidrug-resistant species, which represent an important public health problem. Among the enterobacteria, the most commonly reported in hospital infections are Escherichia coli, which belongs to the commensal microbiota and may act as an opportunistic pathogen, especially in immunocompromised patients. Different classes of antimicrobials can be used to treat infections caused by this pathogen, including the ²-lactams, quinolones and fluoroquinolones, tetracyclines, aminoglycosides, folate pathway inhibitors, phenicols and polymyxins. Several virulence factors are correlated to the pathogenicity of this bacterium, including toxins and hemolysins. The objective of this research project is to characterize 100 Escherichia coli isolates obtained from the environment regarding antimicrobial resistance, virulence, clonal relationship and epidemiology. Among the 100 isolates, 64 isolates were classified as Multidrug-Resistant (MDR), presenting non-susceptibility mainly to ampicillin (89%), streptomycin (75%), cefazoline and cefuroxime (67%), trimethoprim + sulfamethoxazole, sulfonamide and trimethoprim (52%). Seven isolates have already been characterized for resistance genes, plasmid typing and virulence. The resistance genes blaCMY, blaOXA-1-like, blaSHV, tetA, tetB were detected in all isolates, followed by the sul1 (4), sul2 (3), aadA (3), sul2, aac(6 ')-Ib (2) and floR (1). According to the plasmid typing, IncF, IncY and ColE-like were detected in all isolates, followed by IncFIB (6), IncFIA (1), IncFIC (1), IncHI1 (1) and IncN (1). Among the virulence genes, the ipaH gene was the most prevalent, being detected in four isolates, followed by the stx2 gene (n = 1). Thus, these isolates were classified into two different pathotypes, being EIEC and STEC, respectively. Two isolates did not present any of the virulence genes investigated. MLST analysis was performed on six of the seven previously characterized isolates, and six different STs (ST10/CC10, ST942, ST1684, ST2600, ST6658 and ST8067) were detected. Two isolates from the soil were characterized by the whole genome sequencing, which presented several genes of resistance, virulence and plasmids. (AU)