Interação de cepas de Escherichia coli uropatogênica (UPEC) pertencentes aos grupos clonais ST131, ST648 e ST405 com células cultivadas in vitro e com o modelo in vivo Caenorhabditis elegans

Abstract

Urinary tract infections (UTIs) are among the most common extraintestinal infections. The main etiological agent is the bacterial species Escherichia coli. E. coli originating from UTIs is called uropathogenic E. coli (UPEC) and can colonize the bladder and kidneys by ascending the ureters. UPEC isolates express specific virulence properties such as type 1 and P fimbriae, which participate in adhesion to uroepithelial cells and allow subsequent invasion. The indiscriminate use of antimicrobials has resulted in the worldwide dissemination of resistance among bacteria, becoming a public health concern. In this context, strains from clonal groups ST131, ST648 and ST405 are associated with resistance and a high virulence potential. The aim of this study was to analyze the microbiological characteristics related to the virulence of E. coli strains ST131, ST648 and ST405, derived from urine cultures of patients with urinary tract infection treated at hospitals in the city of Rio de Janeiro. Assays were performed to evaluate the percentage of invasion into cells of the Vero and U937 cell lines, an intracellular persistence assay in the Vero cell line, an infection assay in Caenorhabditis elegans and an adhesion assay in Vero with sample processing for scanning electron microscopy. The data were correlated with previous genetic data, more precisely, with the genetic profile of fimbriae and adhesins. The present study demonstrated that only strains of the ST131 and ST648 groups showed the ability to invade Vero. In the U937 cell line, only one strain ST648 and one strain ST405 demonstrated the ability to invade. Strains of all ST groups were able to persist inside Vero cells, with different rates. ST131 strains were able to kill C. elegans from day one. Scanning electron microscopy confirmed that these strains have invasive potential. These data showed that strains from the ST131 and ST648 clonal groups, in addition to having a virulence profile focused on establishing themselves on the cell surface, also demonstrated the ability to establish themselves in the intracellular environment. These strains have the ability to invade and persist in different periods of infection, characterizing the pathogenic potential of multidrug-resistant strains.