Choice of antibiotics for the treatment of orthopedic infection caused by gram-positive pathogens, based on a 12-year follow-up. Part 2: fluoroquinolones, sulfonamides, tetracyclines, lincosamides, fosfomycin

The aim of the study — to substantiate the choice of a drug for empirical antibacterial therapy based on the analysis of antimicrobial resistance dynamics in leading Gram(+) bacteria isolated from patients with orthopedic infection from 2011 to 2022. Methods. We performed a retrospective study of data on the antimicrobial susceptibility in leading Gram(+) bacteria isolated from patients who were treated from 01.01.2022 to 31.12.2022. Based on the data obtained, we investigated the dynamics and determined the prognosis of resistance in leading Gram(+) pathogens. This article analyzes 5 groups of antibiotics active against Gram(+) microorganisms: fluoroquinolones, sulfonamides, tetracyclines, lincosamides, fosfomycin. Results. More than 75% of MRSA strains and more than 50% of MRSE strains demonstrated resistance to fluoroquinolones. Methicillin-sensitive strains have a lower resistance profile; the proportion of moxifloxacin-resistant MSSA during the entire follow-up period was 2.3%, MSSE — 14.7%. The proportion of ciprofloxacin-resistant E. faecalis strains decreased during the 12-year follow-up from 61.3% in 2011 to 40.4% in 2022. Over the 12-year follow-up period, our center has seen a decrease in the proportion of Staphylococcus spp. strains resistant to co-trimoxazole. At the same time, the drug is more active against S. aureus and methicillin-sensitive strains than against S. epidermidis and MR strains, respectively. The local monitoring data in our center demonstrate the activity of fosfomycin against more than 90% of staphylococci. In general, the average proportion of MRSA strains resistant to this drug was 5.8%, MRSE — 7.7%, and MSSE — 7%. The proportion of clindamycin-resistant MSSA increased from 1.5 to 12% and averaged 4.4%. At the same time, the incidence of clindamycin-resistant MRSA varied between 39-60% with a tendency to decrease to 48% by the end of the follow-up period. Conclusions. None of the broad-spectrum antibiotics can be recommended for use in the initial empirical therapy of orthopedic infection. Fluoroquinolones and co-trimoxazole are active against 30-33%, tetracyclines — against 39% (mainly due to the continued activity of minocycline and tigecycline), clindamycin — against 64% of gram-positive pathogens. Fosfomycin remains active against about 90% of staphylococci. However, to date, there are no criteria for assessing the sensitivity of enterococci to it, and therefore the sensitivity of enterococci to fosfomycin has not been determined.