Features of the microbial landscape of patients' wounds at different periods of existence

Yarets Y.I.

State Institution «Republican Research Center for Radiation Medicine and Human Ecology», Gomel, Belarus

Aim: to analyze the results of a microbiological diagnostics of wound swabs in patients with wounds of different duration.

Material and methods. The results of bacteriological swabs of 405 wound samples from acute wounds (AW, up to 3 weeks, n=176) and chronic wounds (CW, more than 3 weeks, n=229) were analyzed.

Results. Differences were found between the groups in the frequency of obtaining negative swabs (in AW – 24.7% [18.6; 30.9] cases), detection of monocultures (in AW – 50.9% [45.3; 56.5] cases) and microbial associations (in CW – 42.0% [35.4; 48.6]). Gram(+) bacteria – 73.1% and 62.1% (Staphylococcus spp., E. faecalis, Streptococcus gr. viridans) were dominant in wounds; Gram(-) bacteria (23.8% in AW and 33.6% in CW), represented by Enterobacterales, Pseudomonas and Acinetobacter, in CW were characterized by a wider species diversity. Only Gram(+) bacteria were found in AW up to 1 day of the existence; a change in the qualitative composition of microflora was manifested starting from the 10th day of the existence of wounds in the form of the appearance of Enterobacterales, Pseudomonas and Acinetobacter. The prevalence of methicillin-resistant S. aureus and coagulase-negative staphylococci strains was 52% and 54% for AW, 42% and 72% for CW, respectively. E. faecalis showed a high level of resistance to aminoglycosides and fluoroquinolones in all the wounds (>50% of isolates). Gram(+) bacteria were completely susceptible to vancomycin, teicoplanin, linezolid, and tigecycline. The sensitivity of A. baumannii and P. aeruginosa to carbapenems in all cases was high – 69% and 74%, to colistin – 100%. The sensitivity to aminoglycosides – amikacin, tobramycin in P. aeruginosa was 76% and 78%, in A. baumannii – 48% and 59%, respectively. K. pneumoniae showed complete sensitivity to carbapenems. Other Enterobacteriaceae were less resistant than K. pneumoniae.

Conclusion. The results of a microbiological diagnostics of wound swabs made it possible to determine the qualitative structure of microflora and its differences depending on the duration of wound existence. The data obtained are the basis for further research, allowing to establish priority pathogens that disrupt the process of wound healing and are the cause of the formation of chronic wounds.