Comparison of the pathogenic potential of Klebsiella pneumoniae isolates from human intestinal microbiota, surface waters, and sewage

Abstract

Introduction. Klebsiella pneumoniae, an opportunistic pathogen responsible for nosocomial and community-acquired infections, is present in soil and water. Still, the virulent potential of K. pneumoniae isolates from the environment is mostly unknown. Since isolates with multiple antibiotic resistance are currently considered to be the main threat of environmental pollution, the bulk of ecological studies of K. pneumoniae are devoted to the identification of just such isolates (mainly producers of beta-lactamases). Material and methods. In this study, 42 isolates of K. pneumoniae isolated from wastewater, 19 from surface water sources, and 63 isolates from the intestinal microbiota of conventionally healthy cases were analyzed by PCR for the presence of potential virulence genes (ybts, kfu, rmpA, mrkD, K2 , alls, magA, iutA). Results. As a result of the analysis, a statistically significant heterogeneity of the studied samples was revealed. Isolates from wastewater showed the highest proportion and spectrum of virulent genes (8 out of 8). Isolates from surface sources were statistically indistinguishable from isolates isolated from the intestinal microbiota of “conventionally healthy” people, while pathogenic determinants were also detected in these groups. Conclusion. K. pneumoniae isolates from surface sources did not statistically differ from isolates from feces of “practically healthy” ones, although some of the virulent genes were also detected in these isolates. Wastewater can serve as a reservoir for highly virulent K. pneumoniae, to a greater extent than the intestines of healthy people, and can serve as a risk to public health. Additional studies with larger samples and a more comprehensive range of virulent traits are needed to predict the spread of hypervirulent strains.