PATHOGENIC POTENTIAL OF ESKAPE GROUP BACTERIA ISOLATED FROM WOUNDS: CHARACTERIZATION OF PHENOTYPIC AND GENOTYPIC MARKERS AND POSSIBILITY OF THEIR PRACTICAL APPLICATION
Authors:   Republican Research Center for Radiation Medicine and Human Ecology, Gomel, Belarus, Yarets Yu. I. 
Published: September 2022

Backgroud. Evaluation of the biological properties of isolates obtained from the clinical samples of patients will increase the informative value of the microbiological study and optimize the interpretation of the culture results in order to substantiate further wound treatment tactics. Aim. To analyze the phenotypic and genotypic properties of ESKAPE bacteria and to determine the possibility of practical use of the parameters characterizing the bioprofile of the isolate when interpreting the results of microbiological culture of the wound swabs. Material and methods. Pheno- and genotypic markers of the pathogenic potential of ESKAPE isolates were analyzed: Enterococcus faecalis (n=93), Staphylococcus aureus (n=177), Klebsiella pneumoniae (n=7), Acinetobacter baumannii (n=32), Pseudomonas aeruginosa (n=45), Enterobacterales (Proteus mirabilis, n=26). Microorganisms were isolated from the wound swabs of patients with acute and chronic wounds, who were admitted to the burn department of the Gomel City Clinical Hospital No. 1 for specialized medical care during the period 2012-2020. Integumentary tissue defects were represented by post-traumatic wounds (mechanical trauma, thermal burns), postnecrotic wounds (after purulent-inflammatory diseases of the skin and underlying tissues), trophic ulcers (on the stumps of the lower extremities after prolonged wearing of the prosthesis; neurotrophic ulcers after mechanical trauma to peripheral nerves); pressure ulcers stage III after prolonged tissue compression. When describing the isolates, the duration of the wounds and the presence of clinical signs of infectious inflammation were taken into account. Results. The relationship between the clinical state of the wound (no signs of inflammation, critical colonization, infection) and the bioprofile of the isolate obtained from the wound swabs was determined. Potentially pathogenic S. aureus, possessing colonization, invasive and cytotoxic properties, was found in wounds with a minimum duration of up to 4 days, but the absence of clinical manifestations of infection suggested contamination. Biofilm formation, persistent properties, genetic markers of pathogenicity in S. aureus and E. faecalis in combination with pathological changes in fine-grained granulations in the wound indicated colonization. The inflammatory status of the wounds (critical colonization and infection according to NERDS&STONEES criteria) from which P. aeruginosa and A. baumannii were isolated, the presence of genetic virulence markers, and antibiotic resistance indicated the clinical significance of these isolates as etiological agents of the infectious process. P. mirabilis isolated from critically colonized and infected wounds did not have the full range of virulence markers in all cases, especially in associations. K. pneumoniae was isolated only from the wounds showing signs of inflammation and demonstrated various combinations of genetic determinants of virulence, variability in capsular polysaccharide overproduction and biofilm formation. Conclusion. An algorithm has been developed for interpreting the results of microbiological culture of wound swabs with the use of pheno- and genotypic markers, which are recommended for determining the leading pathogen that colonizes the wound and disrupts the healing process. The algorithm allows assessing the etiological significance of mixed cultures isolated from critically colonized and infected wounds, which will determine the further tactics of treating patients.