Analysis of the qualitative and quantitative community composition of bacteria isolated from the purulent focus in patients with chronic osteomyelitis over a three year period

Introduction Annual microbiological monitoring of the leading causative agents of osteomyelitis and their antibiotic sensitivity is essential for identifying drugs that have lost the effectiveness. An increase in microbial associations requires different approaches to antibiotic therapy. Analysis of the composition of associations with a priority pathogen to be identified to avoid administration of ineffective drugs and optimize treatment. The purpose was to monitor qualitative and quantitative community composition of microorganisms isolated from the osteomyelitic focus in patients with chronic osteomyelitis over a three-year period. Material and methods The object of the study were strains of gram-negative and gram-positive bacteria isolated during primary inoculation as part of associations of bacteria from wounds and fistulas of patients who were treated in the clinic of infection osteology at the Kurgan Ilizarov Centre between 2018 and 2020. Standard bacteriological methods were used to isolate pure cultures. Bacteria were identified using bacteriological analyzer. Results and discussion Two-component microbial associations isolated in patients with chronic osteomyelitis included P. aeruginosa + S. aureus, Enterobacteriacae + S. aureus, S. aureus + CoNS. The strains of S. aureus and P. aeruginosa were most common pathogens identified in mixed cultures. Inoculations of S. aureus + Enterococcus sp. increased and P. aeruginosa + Enterococcus sp. associations showed a two-fold decrease in 2020 compared to 2018. Three- and four-component associations of bacteria increased with the spectrum of combinations being diverse among the isolated mix cultures over a three-year period. Bacteria of the Enterobacteriacae and S. aureus family were most common in three-component associations. Four-component associations were represented by mix cultures of gram-positive and gram-negative bacteria including NFGOB and S. aureus. Conclusion An increased frequency of isolated microbial associations necessitates an annual analysis of changes in the qualitative and quantitative composition to identify the spectrum of the most common microflora of the osteomyelitic focus and correct antibiotic therapy.