Caracterização molecular e fenotípica de Escherichia coli e Klebsiella pneumoniae associadas à endocardite infecciosa no Rio de Janeiro, Brasil

Abstract

Infective Endocarditis (IE) is a disease caused by microorganisms that affects the heart tissue, specifically in the mitral, tricuspid and aorta native valves, but mainly prosthetic valves and electronic cardiac devices such as pacemakers and defibrillators. Endocarditis is an infection that presents high rates of mortality and morbidity wich rate varies between 30% and 71%. Occurrence of Endocarditis by gram-positive is more frequent and Staphylococci aureus is the main etiological agent involved in the development of infection. However, IE by gram-negative bacilli has been observed, such as Escherichia coli and Klebsiella pneumoniae. The aim of this study was to characterize molecularly and phenotypically Escherichia coli and Klebsiella pneumonia strains associated with ID isolated of two patients from hospitals in Rio de Janeiro, from the University Hospital Pedro Ernesto (HUPE) and Hospital of the public network Order Terceira do Carmo, respectively. As a molecular methodology, total genome sequencing (WGS) and gMLST were utilized. For phenotypic tests, qualitative biofilm formation in glass slides, quantitative biofilm formation in polystyrene surface and adherence in Vero (renal cells) and HEp-2 (larynx carcinoma) cell lines were performed. Phenotypic tests were realized for detection of antibiotic resistance. From sequencing it was possible to observe the presence of resistance genes in the strain of E. coli for strA, Aada5, strB, Sul1, Sul2 and drfA17 genes. K. pneumoniae strains presented the genes of resistance to fosA, oqxA, oqxB, blaTEM-1B and blaSHV-1. Resistance profile observed for E. coli was Trimetropim, Trimetropim/Sulfamethoxazole and Ampicillin, and all K. pneumoniae strains were resistant to Ampicillin, Phosphomycin and Nitrofurantoin. E. coli strain has genes iutA, allS, fimH, OmpA and Irp2 and all K. pneumoniae strains have the genes mrkD, urea, uge, pgaC, fimC, OmpA and hgpA. gMLST showed that the strain E. coli belongs to the group ST 69 and K.pneumoniae belongs to the group ST 76. As for the phenotypic tests, the E.coli strain showed a strong biofilm formation while K. pneumoniae strains showed moderate biofilm formation in both susfaces. All strains were able to adhere to Vero and HEp-2 cell lines. We can conclude that the strains don´t posses hipervirulente genes, but they are apt to form biofilm and interact with eukaryotic cells of different lineages. The results highlighting important mechanisms of pathogenesis that could help in the understanding of IE caused by E. coli and K. pneumoniae.