Monitoring of the most common gram-positive microflora and its antibiotic sensitivity in persons with chronic osteomyelitis over a three-year period

Abstract

Purpose To study the most common gram-positive microflora and its antibiotic sensitivity in chronic osteomyelitis over a three-year period. Materials and methods The microbiological study included 5,226 clinical isolates of gram-positive microorganisms belonging to 6 taxa (S. aureus, S. epidermidis, S. saprophyticus, Enterococcus sp., Streptococcus sp., Corynebacterium sp.), detected in the period from 2017 to 2019 in primary cultures from wounds and fistulas of 5,116 patients with chronic osteomyelitis who were treated in the purulent department of our bone infection clinic. Results and its discussion According to our study, S. aureus strains are most common g gram-positive microflora in chronic osteomyelitis, taking the first place in terms of occurrence over a three-year period. The rate of isolation of methicillin-resistant strains of S. aureus (MRSA) over three years was 17.3 ± 1.9 %. In 2019, the occurrence of S. epidermidis strains increased by 28 % compared to 2017, while the number of isolated MRSE remained within 57.2 ± 1.8 %. The analysis of antibiotic patterns showed a tendency to an increase in the number of multi-resistant strains of Staphylococcus sp. Monitoring of the gram-positive microflora in chronic osteomyelitis revealed an insignificant isolation of the bacteria of the genus Enterococcus and Streptococcus (9– 10 % of cases). The most effective against Enterococcus strains were glycopeptides and aminopenicillins, the least effective against strains of Enterococcus were quinolones and aminoglycosides. The most effective drugs against Streptococcus sp. were levofloxacin and clindamycin. The occurrence of bacteria of the genus Corynebacterium sp. was within 3–4 %. The least effective drugs against Corynebacterium sp. were clindamycin, gentamicin, and ciprofloxacin. The strains were susceptible to tetracycline drugs, penicillins, macrolides and rifampicin. Conclusions Considering that gram-positive microorganisms are primary pathogens in the etiology of chronic osteomyelitis, microbiological monitoring of the leading pathogens of the disease and their resistance enables to identify ineffective antibacterial drugs, optimize treatment, and thereby reduce the rate of poor outcomes in the management of the disease.

Keywords

• chronic osteomyelitis
• antibiotics
• resistance
• gram-positive microflora