Biological characteristics of the enteroaggregative <i>escherichia coli </i>ont:h30 18-726 (no. B-8857) strain isolated from a patient with ulcerative colitis and a new method of pcr identification

Abstract

The aim of the work is to assess biological properties of the enteroaggregativeEscherichia coli(EAgEC) strain isolated from the colon mucosa biopsy material from a patient with ulcerative colitis, and to develop a new method for PCR identification ofE. colistrains. Materials and methods.The study involved 46 patients with a verified ulcerative colitis. Isolation of 87E. colistrains was carried out by using colon biopsy material obtained during a standard endoscopic procedure. The description of the biochemical bacterial properties was combined with the molecular genetic detection of virulence determinants and presence of antibiotic resistance mechanisms. Using the “AmpliSense®Escherichiose — FL” reagent kit, a screening for the presence of diarrheagenicE. colistrains was performed, which revealed the presence of a single strain of EAgEC. The methodological approach to creating a new method for strain identification was based on the search for a unique genetic sequence within the glutamate decarboxylase(gad)gene. Results.E. coli18-726 can be described biochemically typical to its species. The studied strain was characterized by a multiple resistance phenotype (MDR) to antibiotics, as well as a lack of sensitivity to five bacteriophages. TheE. coli18-726 strain had a unique sequence of the gene encoding the O-antigen, which differed from 188 known O-antigens (ONT) and, by the identity of the nucleotide sequence of the gene encoding the synthesis of the H-antigen, the strain belonged to the H30 serovar. Thus, the antigenic formula of strain EAgEC 18-726 was expressed as ONT:H30. TheE. coli18-726 strain contained a significant spectrum of genes that enable properties of virulence(iss, capU, aggA, aggB, aggC, aggD, aap, aar)and resistance to antibiotics(blaCTX-M-15, blaTEM-1B, aadA1, aadA5, mph(A), catB3). A new method for identifying EAgEC in chronic bowel disease is based on the polymerase chain reaction method using primers for a specific region of bacterial glutamate decarboxylase(gad)gene.Conclusion.1) The biochemical, antigenic and molecular genetic properties ofE. coliONT:H30 18-726 strain (No. B-8857) isolated from a patient with histomorphologically diagnosed ulcerative colitis were analyzed. 2) A method for PCR identification of EAgEC strains based on the detection of a specific region within the bacterial genomic glutamate decarboxylase gene has been created and patented.