Sensitivity of antibiotic resistant coagulase-negative staphylococci to antiseptic piсloxydin in eye drops Vitabact

Background. Coagulase-negative staphylococci (CNS), primarily Staphylococcus epidermidis, predominate in the normal microflora of the eye. However, due to irrational antibiotic therapy, resistant strains are widely distributed among CNS. Aim. To study the sensitivity of the antibiotic resistant CNS isolates to picloxydine, an antiseptic. Methods. The species, sensitivity to antibiotics and picloxydine were determined for 39 isolates of bacteria obtained from the conjunctival swabs. The cells’ morphology under the antiseptic’s influence was studied by electron microscopy. Results. 33 isolates of S. epidermidis (17 sensitive or resistant to drugs of no more than 2 classes of antibiotics and 16 MDR), 2 S. haemolyticus (1 resistant to 2 classes of antibiotics and 1 MDR), 3 S. hominis (1 sensitive and 2 MDR), 1 S. caprae (MDR) were characterized. In in vitro tests, picloxydine showed high efficiency in suppressing the growth of staphylococci regardless of their sensitivity to antibiotics, as well as bactericidal activity at concentrations of 15.6–31.2 µg/ml, close to those of chlorhexidine. At these concentrations, the antiseptic had a destructive effect on the surface structures of bacterial cells. Conclusion. The picloxydine antiseptic is equally effective against antibiotic- sensitive and antibiotic-resistant coagulase-negative staphylococci.