Aspectos microbiológicos de Escherichia coli ST 131, ST 648 e ST 405 isoladas de pacientes com infecção do trato urinário

Abstract

Urinary tract infections (UTIs) are among the most frequent extra-intestinal infections. The main etiological agent is the bacterial species Escherichia coli. E. coli from UTI is called uropathogenic E. coli (UPEC) and can colonize the bladder and kidneys as it ascends through the ureters. UPEC isolates express specific virulence properties such as fimbriae type 1 and P fimbriae, which participate in the adhesion to uroepithelial cells and biofilm formation. The biofilm present in human infections makes it difficult to eradicate the disease with antimicrobial therapy, being associated with the antimicrobial resistance and escape of the immune system in the host. The indiscriminate use of antimicrobials has resulted in the worldwide spread of resistance among bacteria becoming a public health concern. In this context, strains of clonal groups ST 131, ST 648 and ST 405 are inserted and they are associated with resistance and a high virulence potential. The objective of the present study was to analyze the microbiological characteristics related to the virulence of strains of E. coli ST 131, ST 648 and ST 405, from urinoculture of patients with urinary tract infection, attended at the Hospital Universitário Pedro Ernesto (HUPE), Fundação Bela Lopes de Oliveira (FBLO) and Hospital Rio-Laranjeiras (HRL), in the city of Rio de Janeiro. The assays were performed to evaluate the adherence pattern to the HEp-2 and Vero cell lines. To evaluate the biofilm formation, qualitative and semi-quantitative biofilm assays were performed on the abiotic surfaces, polystyrene and glass, respectively. The data were correlated with previous genetic data, more precisely, with the genetic profile of fimbriae and adhesins. The present study demonstrated that all the strains adhered to the cells, but with different adherence patterns. The typical pattern of aggregate adherence was observed only in ST 131 strains. ST 648 and ST 405 strains had no typical adherence pattern. In the abiotic surfaces, all the strains were able to form biofilm, exhibiting different intensities. Strains ST 131, ST 648 and ST 405 can form strong biofilm in polystyrene. In this study was possible to verify that the strains of the clonal groups studied have a virulence profile aimed at establishment on cellular surfaces and abiotic surfaces. Such strains have the ability to form structured biofilms, characterizing the pathogenic potential of strains resistant to antimicrobials in the hospital environment.