Characterization of <i>Pseudomonas aeruginosa</i> isolated from positive samples of hemocultures and cerebrospinal fluid of children

Abstract

Introduction. Infections of the bloodstream and central nervous system (CNS) caused by Pseudomonas aeruginosa are associated with a serious patient conditions and are often accompanied by high mortality.Aim. Molecular genetic characterization of P. aeruginosa isolated from positive samples of blood cultures and cerebrospinal fluid of patients under 18 years of age from intensive care units of hospitals.Materials and methods. We conducted a retrospective study of bacteremia and CNS infection cases associated with P. aeruginosa from 2014 to 2021. 24 clinical isolates of P. aeruginosa from positive blood cultures and CSF were analyzed. MICs of antibiotics were determined by serial microdilution in broth. Identification of the genes of carbapenemase was carried out using real-time PCR. Virulence genes were determined by PCR. Population diversity was assessed by MLST.Results. More than 70% of isolates showed resistance to carbapenem antibiotics. The phenotype of multiple drug resistance had 25% of the isolates. Extreme resistance was shown by 54% of isolates. The detection rate of metallo-β-lactamases (MBL) was 54%. Based on PCR data, 33% of the strains were found to have the ExoU type, and 67% had the ExoS type. According to MLST, 16 genotypes were identified. The structure was dominated by two sequence types ST654 (29%) and ST235 (12.5%). The structure of patients was dominated by children with surgical pathology — 16 cases, and there were eight somatic patients. Fatal outcome was observed in 28% of cases with bacteremia and CNS infection associated with P. aeruginosa.Conclusion. P. aeruginosa isolates from positive blood cultures and CSF samples are highly resistant to antibiotics; virulence genes were found in all isolates. Strains of high epidemic risk prevailed in the studied sample. More than a quarter of the described clinical cases had an unfavorable outcome.