SYNTHESIS OF A PROTEIN THAT IS IMMUNOCHEMICALLY SIMILAR TO HUMAN LACTOFERRIN BY KLEBSIELLA PNEUMONIAE

Abstract

Nowadays, great importance is attached to the role of iron in infection processes, since pathogenic bacteria produce Fe3+ cholinating compounds with the ability to absorb Fe3+ and remove it from the siderophores of the host. This ability is considered as a pathogenicity factor, enabling the pathogen to propagate in the macroorganism. Many bacterial species are known to increase virulence with iron ions present. Therefore, the sideroform system of bacteria can influence the disease severity by binding Fe3+ ions and reducing their content in tissues. The study purpose was to determine the ability of K. pneumonia to synthesize a protein, immunochemically similar to human lactoferrin (hereinafter — microbial-derived lactoferrin, MdLF), and the resistance of these microorganisms to the damaging effect of human lactoferrin (LF). Methods. The study was conducted on archival strains of K.pneumoniae, formerly isolated from patients with intestinal bacterial overgrowth syndrome (n=140), and from the control group (n=70). The supposed presence of MdLF in the samples was confirmed through an ELISA assay using Hycult Biotech test kits (Netherlands). Results. The ability to synthesize MdLF, which directly depends on the presence of lactoferrin in the culture medium, was revealed in 100% of the strains. MdLF synthesis significantly decreased if LF was present. The patient strains synthesized MdLF less than those taken from the healthy people, but they were more resistant to human lactoferrin, which suggests that the criterion of microbial resistance to LF, taken at 400 ng/ml, should be used as a diagnostic criterion. Klebsiellae bacteria that formed single colonies after beef-extract agar inoculation synthesized MdLF the most and had the highest resistance to LF, which increases their epidemiological importance. Conclusion. The study established the diagnostic value of the human LF — microorganism MdLF system for predicting infectious process development and assessing the epidemiological danger from particular strains.