Background: Urinary tract infections (UTI) cause severe losses to the swine industry worldwide and uropathogenic Escherichia coli (UPEC) are the main agent isolated from UTI in sows.
Objective: The aim of this study was to investigate the virulence genes, assess the phylogenetic background, clonal diversity, and the pattern of resistance to antimicrobials in 186 isolates of UPEC isolated from sows in Brazil.
Materials and methods: Urine samples from 300 sows of three herds with clinical signs from São Paulo State (Brazil) were screened for UTI; samples with suggestive results were submitted to bacterial isolation. E. coli strains isolated were characterized using disk diffusion technique, polymerase chain reaction and Single-enzyme amplification fragment length polymorphism (SE-AFLP).
Results: Virulence genes focH and papC were present in 78.5% and 58% of strains, respectively, followed by cnf1 (23.2%), afa (13.4%), sfa (11.3%), iucD (6.9%), and hlyA (1.6%). No clonal relatedness was found by SE-AFLP. A total of 98% of isolates (182/186) were multidrug resistant, and the highest levels of resistance were to sulfonamides, tetracycline, florfenicol, and ampicillin. Isolates were classified in phylogenetic group B1 (34.4%), followed by D (33.9%), E (30.1%) and A (1.6%).
Conclusions: The data obtained suggest that pigs from clinically affected herds may serve as a reservoir of uropathogenic and multidrug-resistant E. coli strains.
Keywords: AFLP; Escherichia coli; Swine; phylogenetic group; porcine; resistance; urinary tract infections; virulence genes.