Study of the relationship between antibiotic resistance markers and virulence markers in NDM-positive Klebsiella pneumoniae strains circulating in various waters and human loci

Abstract

Introduction. The propagation of multi-resistance to antibiotics among hospital isolates of Klebsiella pneumoniae (K. pneumoniae) is a subject of growing concern worldwide. At present, growing data of association between resistance and hypervirulence in clinical isolates of K. pneumoniae emerges. However, the occurrence of these pathogens in the environment remains an open question. The aim of this study was to evaluate and compare antibiotic resistance determinants occurrence in Klebsiella pneumoniae isolates from water sources (environmental and sewage), human sources (practically healthy people and patients with inflaammatory bowel disease (IBD), and extraintestinal infections (ExII)). Materials and methods. The PCR assay of carbapenemase genes IMP, NDM, VIM, KPC, OXA-48 was performed with the commercial “Amplisense” kits according to the manufacturer's instructions. The assay was used to evaluate the occurrence of antibiotic-resistance genes in 223 isolates of Klebsiella pneumoniae from various sources: 42 isolates from sewage, 19 isolates from surface water sources, 30 isolates from biological material (blood, urine, surgical wounds, bronchoalveolar lavage) of patients with extraintestinal infections (ExII), 69 isolates from patients with inflammatory bowel diseases (IBD), and 63 isolates from faeces of practically healthy people. Results. The ExII group revealed various antibiotic resistance genes. The most prevalent gene was OXA (30% had this gene only, other 26,6% had also KPC or NDM). NDM as the only resistance gene was observed in 23,3% of ExII isolates. KPC gene was observed in 3,3% of ExII group. Two isolates from IBD group contained NDM gene along with VIM gene. Only NDM gene was found in all the other groups of Klebsiella pneumoniae isolates (13-28% isolates in every group, no statistical difference). NDM was shown to be associated with virulence genes iutA and rmpA that are responsible for iron consumption and hypermucoid phenotype. Conclusion. The most abundant resistance genes in the studied Klebsiella pneumoniae isolates were NDM (13.5%) and OXA (8%). At the same time, NDM was the only gene found in all groups (11-28%). NDM metallobeta-lactamase gene was associated with rmpA and iutA genes, giving an example of the connection between virulence and resistance properties. A significant amount of resistant isolates from healthy donors and surface waters indicates the need for additional study of the role of NDM positive isolates in pathogenicity of Klebsiella pneumoniae.