Avaliação do perfil de susceptibilidade de bacilos Gram-negativos isolados de cultura de vigilância ao imipenem e polimixina B

Abstract

Introduction: The ascendancy of bacteria resistant to last-line antibiotics has threatened the treatment of healthcare-related infections (HAIs), constituting a worldwide health problem. In this context, the implementation of surveillance cultures is useful in monitoring and preventing the spread of multidrug-resistant drugs in the hospital environment. Objectives: Determine the susceptibility profile to imipenem and polymyxin B of Gram-negative bacteria isolated from surveillance culture samples from ICU patients. Methodology and Results: During the study, 48 strains classified as members of the Enterobacteriaceae family and non-fermenting Gram-negative bacilli were isolated. The profile of sensitivity to antibacterial agents, production of β-lactamases was evaluated and the minimum inhibitory concentration (MIC) compared to imipenem and polymyxin B was determined. A high profile of resistance was observed in the antibiogram in the groups analyzed, followed by the high production of ESBL with emphasis on the Enterobacteriaceae family 26 (54.16%). Phenotypic resistance to carbapenems was detected in 5 (16.1%) of Enterobacteria and 14 (82.35%) of Gram-negative non-fermenting sugar bacilli (BNF). Of the strains resistant to the carbapenems tested, 17 (89,4%) were identified as producing metalo-β-lactamase. About the susceptibility profile drawn from the MIC determination, 18 (94.7%) of the tested samples showed resistance to imipenem with MICs between ≥ 32 - ≥ 512 µg / mL. For Polymyxin B, resistance was observed in 6 (33.33%) of the samples, while 3 (16.6%) presented intermediate sensitivity. Discussion: The high index of samples resistant to carbapenems is consistent with the antibiotic therapy used in ICUs, since the empirical use of these drugs increases the selective pressure in these environments, leading to high levels of resistance, conducting the appearance of strains producing carbapenemases and other β- lactamases, endangering HAI therapy. Conclusion: The identification of strains resistant to antibacterial agents used as the last options in the treatment of infections caused by resistant microorganisms in this work showed a serious global health problem in the fight against bacterial infections.