GENETIC DETERMINANTS OF PATHOGENICITYOF OPPORTUNISTIC ENTEROBACTERIAISOLATED FROM CHILDREN WITH ACUTEINTESTINAL INFECTIONS

Aim. Detection of nucleotide sequences of
genes controlling synthesis of pathogenicity
factors in clinical strains of opportunistic enterobacteria
isolated from children with acute
intestinal infections (AII), as well as their association
with resistance to antibiotics and the
course of the infectious process. Materials and
methods. 175 clinical strains obtained from
children with AII undergoing treatment in
Irkutsk state infectious diseases hospital (2007-2010) were studied. Primers to a number of genes
detected in Escherichia coli pathogenicity islands,
cont rolling type S and type 1 adhesion;
formation of hemolysins; iron-regulatory protein
synthesis; capsule formation were used in
the study. PCR products analysis was performed
by agar gel electrophoresis. Results. Genetic
determinants of pathogenicity were detected in
bacteria genera Klebsiella, Citrobacter, Enterobacter,
Proteus, Kluyvera, Morganella, Pantoea,
Serra tia. Fragments of hlyA and hlyB genes
(hemolysin production) were detected more
frequently; less frequently - sfaA, sfaG, fimA
(adhesion), as well as irp-2 gene (synthesis of
iron-regulatory protein). The largest set of genetic
determinants of pathogenicity was noted
in clinical strains of Klebsiella spp. Cultures with
DNA fragments specific to genes of E. coli
pathogenicity clusters were obtained predominately
from children aged up to 3 years, had
multiple antibiotic resistance and were isolated
significantly more frequently in severe forms of
AII when compared with strains in which these
determinants were not detected. Conclusion. The
studies performed showed that clinical strains
of opportunistic bacteria isolated from patients
with AII have a certain pathogenic potential, as
evidenced by the presence of genetic pathogenicity
markers in them.

opportunistic Enterobacteriaceae, acute intestinal infections, pathogenicity islands, PCR, primers