Expression of CD14⁺CD282⁺, CD14⁺CD284⁺, CD14⁺HLA-DR⁺, CD14⁺CD11b⁺ receptors and sIgA level in premature infants with <i>K. pneumoniae</i>

Abstract

K. pneumoniae is one of the leading microorganisms causing nosocomial infections among premature newborns. The ineffectiveness of immune defense, morphofunctional immaturity, length of hospitalization and invasive procedures create the prerequisites for the implementation of the infectious process in a hospital setting. The question of the reasons for the development of infection, the etiological agent of which colonizes the intestines, remains open. Purpose of the study: to evaluate the expression of CD14+CD282+, CD14+CD284+, CD14+HLA-DR+, and CD14+CD11b+ receptors on blood monocytes and the level of sIgA in coprofiltrates in premature infants with intestinal colonization by K. pneumonia with different genetic profiles. We examined 11 children with the uge gene (group 1), 20 newborns with the uge + fim genes (group 2), and 12 children with the kfu + uge + fim genes. Microbiological examination of feces included identification and antibiotic sensitivity of microorganisms. Detection of the uge, fim and kfu genes in K. pneumoniae strains was carried out by PCR. The expression level of monocyte activation markers was determined by flow cytometry. Gestational age and anthropometric parameters did not differ between newborns. Children identified with the fim gene in combination with other genes were more often discharged home with K. pneumoniae than with the uge gene. In these children, a decrease in the level of expression of CD14+CD282+, CD14+CD284+, CD14+CD11b+, CD14+HLA-DR+ receptors at birth and upon reaching postconceptional age, and a low sIgA content in coprofiltrates during 24 days of life were recorded. Thus, a decrease in the expression of CD14+CD282+, CD14+CD284+, CD14+CD282+ and CD14+HLA-DR+ receptors by blood monocytes and insufficiency of sIgA production in the large intestine determine a long period of colonization of K. pneumoniae strains with the presence of the fim gene in combination with other genes (from 15 to 180 days), as well as the possibility of Klebsiella infection occurring in subsequent periods of the child’s life. Much more often, children with the combination of genes uge + fim and kfu + uge + fim were discharged from the hospital with a diagnosis of anemia; only in these groups of children was the development of bronchopulmonary dysplasia recorded.

Keywords

• premature newborns
• morbidity structure
• k. pneumoniae virulence genes
• intestinal colonization
• functional activity of monocytes
• siga