[Genetic determinants of secreted lysozyme inhibitors and enterobacteria anti-lysozyme phenotype].

AIM: Determination of interconnection of genetic determinants of secreted lysozyme inhibitors with enterobacteria anti-lysozyme phenotype.

MATERIALS AND

METHODS

50 cultures of non-hemolytic Escherichia coli, Klebsiella pneumoniae isolated from feces of patients with stage I - II intestine dysbiosis and Salmonella enterica isolated from patients with acute intestinal infections (AII) and reconvalescent salmonella carriers served as material for the study. Isolation of matrix DNA of the studied strains for PCR was carried out by DNA-Express kit (Lytex Co., Russia). PCR screening of secreted lysozyme inhibitors genes ivyC and pli was performed based on Syntol Co. (Russia) primers and reagents. Amplicon detection was carried out by agarose gel electrophoresis method. Detection of general anti-lysozyme activity (ALA) was performed by plate method, secreted and sorption ALA components - photometrically by O.V. Bukharin et al. (1999) and V.Yu.Sokolov and A.P.Luda (1987) methods, respectively.

RESULTS

Screening of chromosome localization genes - ivyC in escherichiae and klebsiellae and pliC in salmonellae by PCR method showed their ubiquitous spread among the studied cultures. The search for homologues of pliC gene that are characteristic for K. pneumoniae virulence plasmid revealed positive result in 19 +/- 5.5% of cases. The lowest level of ALA wa noted in carriers of only ivyC gene accounting for an average of 2.8 +/- 0.6 microg/mlxOD, while all enterobacteria with pliC gene had average ALA value of 4 +/- 0.3 microg/mlxOD.

CONCLUSION

Anti-lysozyme activity of enterobacteria is part of the general mechanism of microorganism lysozyme resistance and is determined by the presence of secreted lysozyme inhibitor genes. Application of molecular-genetic approach in the form of the developed experimental test-system based on PCR method allowed to detect secreted lysozyme inhibitor genes in screening mode. High level of secretory ALA is coupled with the presence of pliC gene, while in ivyC gene carriers lower values of the attribute were detected.