Análise fenotípica e genotípica dos aspectos da virulência e da resistência ao telurito de potássio de amostras bacterianas isoladas de hemocultura de pacientes pediátricos

Abstract

Bloodstream infections (BSI) are serious adverse events, especially for vulnerable patients. Data obtained from pediatric ICUs indicate cases of BSI mainly due to coagulase-negative Staphylococcus aureus, Klebsiella pneumoniae complex, Serratia spp., and P. aeruginosa. This study aimed to correlate 59 bacterial isolates recovered from blood cultures from 43 patients with resistance to antimicrobials and K2TeO3, in addition to virulence factors, in hospitalized pediatric patients. Out of the total, 20 patients were neutropenic and 23 were not. Data analysis showed that short-term catheters were more susceptible to IPCS than long-term catheters. The most frequent species identified by the MALDI-TOF MS system were SCN (44.2%), K. pneumoniae (25.6%), and E. coli (18.6%). Approximately 75% of the samples showed agreement in identification between the VITEK® 2 System and the MALDI-TOF MS. The most diverse antimicrobial resistance profiles were among the SCN species (17 profiles), K. pneumoniae (4 profiles), and E. coli (3 profiles). Among the SCN resistance profiles, approximately 13 had a marker to classify them as multiresistant (OXA resistance). Assessing the growth in medium containing K2TeO3 (25 g/mL and 112 g/mL), three samples of E. coli and one of K. pneumoniae showed this capacity. Only three Staphylococcus samples were able to grow at a concentration of 112 g/mL. Between SCN and S. aureus, differences were observed in growth in Congo Red medium. The K. pneumoniae samples were able to produce biofilm, and five of them were positive for the wire test. Among the E. coli samples, four harbored virulence genes related to siderophores and one to capsule production. The results showed that the presence of onco-hematologic disease was different for positive blood cultures in neutropenics, where Staphylococcus epidermidis was the main agent identified among gram-positive bacteria and Klebsiella pneumoniae among Gram-negative, which caused more morbimortality. Despite the limited evaluation the pathogenicity/virulence factors and lack of the investigation of antimicrobial resistance genes in the analyzed strains, it is considered that chemotherapy favors translocation processes of intestinal bacteria. K. pneumoniae was the most frequent in cases of IPCS, and probable alterations may result from colonization processes associated with the different hospitalizations of these patients. The evaluation of control fecal cultures could include, in addition to the search for multiresistant strains, the evaluation of pathogenicity and virulence factors through media containing K2TeO3