The structure of ESKAPE pathogens isolated from patients of the neonatal intensive care unit at the National Hospital of Pediatrics in Hanoi, the Socialist Republic of Vietnam

Introduction. The incidence of healthcare-associated infections is a major public health problem worldwide, affecting all countries regardless of their economic status. The main agents of these infections are pathogens belonging to the ESKAPE group. The aim of the study was to explore the structure, molecular and antigenic characteristics of the ESKAPE pathogens isolated from oral and anal mucosa of patients of the neonatal intensive care unit (NICU), and to assess their etiological significance in occurrence of healthcare-associated infections. Materials and methods. Samples from a total of 49 children were tested, including 40 newborns patients of NICU at the National Hospital of Pediatrics in Hanoi. Collection and processing of biomaterial (oropharyngeal swabs, rectal swabs) and isolation of bacterial cultures were performed using conventional bacteriological methods. Mass spectrometry was used for identification of isolates. Klebsiella pneumoniae strains were analyzed using the whole-genome sequencing method. Results. The group of gram-positive ESKAPE pathogens identified in oral mucosa was represented by isolates Enterococcus faecium and Staphylococcus aureus. The isolates of the family Enterobacteriaceae included K. pneumoniae, Escherichia coli, Enterobacter cloacae; the group of nonfermenting gram-negative bacteria was represented by Pseudomonas aeruginosa, Acinetobacter baumannii. The structure of ESKAPE pathogens persistent in anal mucosa was characterized by dominance of Enterococcus spp., E. coli, K. pneumoniae and P. aeruginosa bacteria. The whole-genome sequencing of K. pneumoniae isolates revealed 7 clusters and 8 sequence types. ST14 and ST1741 prevailed, accounting for 25%, respectively, of the total number of the studied strains. The molecular serotyping showed that by the O antigen, strains belonged mainly to serotypes O1v1, O1/ O2v2, O5; by the presence of the capsular antigen to serotypes KL2, KL104, KL60. Conclusion. The analysis of the structure of the ESKAPE pathogens isolated from the oral and anal mucosa of patients of NICU at the National Hospital of Pediatrics in Hanoi identified etiologically significant agents of bacterial infections: S. aureus, K. pneumoniae, E. coli, E. cloacae, P. aeruginosa, A. baumannii. The molecular and genetic analysis of K. pneumoniae strains co-circulating in mucous membranes of several patients of the unit revealed their homology, thus confirming healthcare-associated contamination of children with nosocomial strains.