Molecular Epidemiological Analysis of Acinetobacter baumannii Strains Isolated in Patients with Burn Injury

Recently, there is a steady increase of infections caused by Acinetobacter spp., especially A. baumannii in patients with burn injury. Hospital populations of microorganisms always include highly virulent and antibiotic-resistant strains. The analysis using molecular markers enables to estimate the epidemiologic relation between strains, reveal the presence of hospital strains, and identify the infection source.

The aim of the investigation was to assess the nature of the spread of significant epidemic strains Acinetobacter baumannii in burn patients, and identify a predominant genotype to determine the presence of hospital strains using molecular genetic techniques (polymerase chain reaction (PCR)).

Materials and Methods. By means of PCR we investigated some major virulence factors and antibiotic resistance of 60 of A. baumannii strains being isolated for more than two years from the burn unit patients. The antibiotic resistance of genes and virulence factors of OXA-23, ISAba1, csuE, tonB were studied. The polymorphism of genotypes was evaluated using χ-square test (Raymond M., Rousset F., 1995).

Results. The strains under study were revealed to have a high resistance level to carbapenems, csuE gene was identified in 40% strains, the gene being one of the film formation susceptibility factors of bacteria. tonB gene encoding the bacteria properties enabling to cause bacteremia promptly was isolated in 15% cases. In the genes encoding antibiotic resistance and virulent factors, we revealed a slight genetic differentiation level of strains (total, 9 combined genotypes with three genotypes predominating: A — 50% cases, F and I — 10% cases) that indicates both exogenous nosocomial infection of patients, and the presence of hospital strains in the department.

Conclusion. The study of the genetic structure of A. baumannii strains using PCR analysis of OXA-23, ISAba1, csuE, tonB genes enables to assess efficiently the epidemic relationship between strains, reveal a predominant genotype and identify epidemiologically important properties of the strains.

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Skurikhina Yu.E., Ibragimova T.D., Skurikhina L.A., Turkutyukov V.B. Molecular Epidemiological Analysis of Acinetobacter baumannii Strains Isolated in Patients with Burn Injury. Sovremennye tehnologii v medicine 2016; 8(1): 134, https://doi.org/10.17691/stm2016.8.1.18