PCR analysis of the presence of virulent genes E. coli isolates from external environmental in comparison with isolates from feces of healthy people and patients with inflammatory bowel diseases

Introduction. Pathogenic Escherichia coli presents a real threat to human health. One of the ways of transmission of these isolates is via environmental water sources. Therefore, evaluation of pathogenic potential of E. coli population in water is of great interest. 

Purpose of the study was to compare E. coli isolates from wells, sewers, water pools and surface waters with two control groups — “non-pathogenic” isolates from feces of healthy people and “potentially pathogenic” from feces of people with inflammatory bowel diseases (IBD). 

Materials and methods. PCR-assay was used to detect potential virulence genes. 19 E. coli virulence genes were analyzed: 11 toxins, 5 adhesion and invasion proteins and 2 diarrhogenic serotypes. The PCR identification of carbapenemase genes and various E. coli pathotypes was performed with the commercial “Amplisense” kits according to the manufacturer’s instruction. The assay was performed on 47 E. coli isolates from water environmental sources (WES), 44 isolates from feces of “practically healthy” people, 43 isolates from feces from IBD patients. 

Results. Isolates from WES were found to be similar to the group of isolates from healthy people. Only 2 types of virulence E. coli were detected in these groups – toxins CNF1 and 2 and invasin einv. IBD group of isolates demonstrated striking difference from the others. Only IBD isolates demonstrated such genes as adhesion regulator aggR, invasive antigen ipaH, hemolysin hly and antibiotic resistance gene NDM. CNF1 gene was found in IBD group significantly more often, than in two other groups. The only pathotype detected in the samples analyzed, enteroaggregative, was limited to the IBD group, too. 

Limitations. To compare the pathogenetic potential of E. coli from human feces and environment, 134 isolates were tested for 19 pathogenic genetic determinants, which is a representative selection. Within the analysis, we were unable to compare bacterial pathogenic potential from various environmental sources (surface waters and sewage, treatment facilities etc.) due to the uneven representation of these objects in the selection. It will be the subject of our future studies.

Conclusion. Pathogenic potential of E. coli isolates from environmental water sources was close to that from healthy human feces.

Contribution:
Pay G.V. — research concept and design, experimental work, statistical processing, text writing, editing.
Rakitina D.V. — performing experimental work, writing a text, editing.
Pankova M.N., Fedez Z.E. — collection and processing of material, isolation of isolates and sowing of crops.
Maniya T.R., Zagainova A.V., Yudin S.M. — editing.
All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.

Conflict of interest. The authors declare no conflict of interest.

Acknowledgement. The research was carried out within the framework of the research work “Development of technologies for cryopreservation and archiving of biological samples of human microecological resources (code“Cryobank”)” No. АААА-А18-118020590091-2, “Development of unified methods, including sampling, for the determination of microbiological and parasitological contamination of wastewater” (code “Wastewater”) No.  АААА-А21-121011190012-3.

Received: March 1, 2022 / Accepted: April 21, 2022 / Published: May 31, 2022