Análise de polimorfismos dos genes TNFα, IL1β, IL6 e IL10 de pacientes internados em unidade hospitalar com infecção bacteriana no sangue

Abstract

Klebsiella pneumoniae is one of the most commonly identified pathogens causing nosocomial infection in hospitalized patients, as it has intrinsic resistance and several virulence factors. Infections caused by these bacteria can result in septicemia and septic shock, which is triggered by lipopolysaccharides (LPS) present in the bacterial wall, stimulating neutrophils, macrophages, endothelial cells and muscles to an exacerbated production of proinflammatory cytokines such as TNFα, IL1, IL6 and IL8. However, modulation of this exacerbated response can be achieved by IL10. The objective of this work was to identify the polymorphisms in immunity genes related to the susceptibility of patients to develop bacterial infections and which virulence factors are present in these pathogens. We analyzed 100 patients for TNFα-308 G / A, IL1β-511 C / T, IL6 -174 G / C and IL10 -1082G/A polymorphisms, all by PCR. The 41 strains of K. pneumoniae from blood cultures were investigated for the presence of virulence genes by specific PCR, and determinations of Type Sequences were performed by MLST. Capsule production was quantified by determination of uronic acid concentration. Statistical analysis was performed by Williams G test, 95% OddsRatio (OR), Trend test (Cochran-Armitage) and Tukey test. Quantitative and qualitative variables were analyzed by the t-student test. Our results reveal that homozygotes for allele A in IL10 -1082G/A have a fourfold higher risk of developing bacterial infection compared with heterozygous patients for this polymorphism. In addition, we emphasize that 99.6% of K. pneumoniae are hypervirulent because they have at least five virulence genes. In conclusion, our findings revealed that IL10 -1082G/A polymorphism and clinical features can be used as markers for the development of bacterial infection.