Increased resistance rates of extended-spectrum β-lactamase-producing Enterobacterales isolated from blood cultures in Brazil

This study aimed to identify and evaluate the antimicrobial susceptibility profile of extended-spectrum β-lactamase (ESBL)-producing Enterobacterales isolated from blood cultures of patients with suspected sepsis. This retrospective cross-sectional epidemiological study was performed for four years (2015 to 2018) by accessing the medical records of patients diagnosed with bloodstream infections in two tertiary public hospitals in Brazil. Culture results and susceptibility tests of bacterial strains isolated from blood samples were analyzed. During four years, 2,263 blood culture exams were performed, and Enterobacterales were isolated in 694 (30.7%) samples. The disk approximation test detected ESBL production in 171 (24.6%) of the 694 isolated Enterobacterales (p<0.05), with 125 (73.1%) corresponding to Klebsiella spp., 28 (16.2%) to Escherichia coli, eight (4.6%) to Enterobacter spp., five (2.9%) to Serratia spp., three (1.7%) to Proteus spp., and two (1.2%) to Citrobacter spp. All tested antibiotics demonstrated low susceptibility (2.9% to 26.9%). The classes of monobactams, cephalosporins, and penicillin showed high resistance indices. The evaluated Enterobacterales isolates exhibited expressive antimicrobial resistance to drugs commonly used as empirical treatment in bloodstream infections. The findings reinforce the relevance of assessing the bacterial antimicrobial susceptibility profile, as it drives antibiotic therapy, potentially detecting multiresistance cases.