Comparative Activity of Lipoglycopeptide Antibiotics Against Gram-Positive Bacteria

Lipoglycopeptide antibiotics are semi-synthetic derivatives of glycopeptides and are characterized by a pronounced bactericidal activity against gram-positive pathogens. The aim of the study was comparative assessment of the sensitivity of gram-positive clinical isolates to lipoglycopeptide antibiotics (telavancin, dalbavancin, oritavancin). The following isolates were included in the work: methicillin-resistant Staphylococcus aureus (MRSA, n=780), methicillin-resistant coagulase-negative Staphylococcus spp. (MRCoNS, n=163), and vancomycin-resistant Enterococcus faecium (VREf, n=93). Serial dilutions were used to assess sensitivity with the addition of 0.002% polysorbate 80 to the medium. Lipoglycopeptides showed more pronounced antibacterial activity against MRSA compared to vancomycin, teicoplanin, and daptomycin, and had a MIC₅₀/MIC₉₀ (µg/ml): for telavancin — 0.06 /0.125, for dalbavancin — 0.016/0.06, and for oritavancin — 0.06/0.125. A trend towards an increase in the MIC of lipoglycopeptides and daptomycin was established in MRSA with the MIC of 2 µg/ml for vancomycin, the proportion of which was 13%. For MRCoNS, MIC₅₀ and MIC₉₀ of lipoglycopeptides did not exceed 0.06 µg/ml and 0.125 µg/ml, respectively. Oritavancin showed strong activity against VREf at MIC range of 0.03 µg/ml to 0.5 µg/ml, and at MIC₉₀ of 0.25 µg/ml. Thus, lipoglycopeptide antibiotics are a plausible alternative to vancomycin and daptomycin; they are characterized by pronounced activity and can be used to treat severe forms of staphylococcal infections.