The effect of short local treatment with ofloxacin on the selection of fluoroquinolone-resistant coagulase-negative staphylococci

The objective of a prospective randomized study carried out by C.N. Ta et al. (United States), it was determined whether a three-day local treatment with ofloxacin would facilitate the selection of coagulase-negative staphylococcus strains resistant to fluoroquinolones in the conjunctival cavity.

The study included patients awaiting elective eye surgery. Patients in the study group (n = 70) received local treatment with ofloxacin (0.3% eye drops) 4 times a day for 3 days, patients in the control group (n = 89) n have not received treatment. The clinical material was taken from the conjunctival cavity at the start of the study and after 3 days.

At the start of the study, coagulase-negative staphylococci were isolated from 48 patients (69%) in the study group and 53 patients (60%) in the control group; 11 of 48 strains obtained from patients in the study group and 12 of 53 strains obtained from patients in the control group showed resistance to ofloxacin (p greater than 0.9999).

With repeated sampling of clinical material after 3 days, a significant decrease in the frequency of excretion of coagulase-negative staphylococci was observed in patients receiving treatment compared to the control group (18 vs 48 strains, respectively; p = 0.0003). Five of the 17 strains obtained from patients in the study group and 9 of the 48 strains obtained from patients in the control group were resistant to ofloxacin (p = 0.5649).

The absence of significant differences in the number of coagulase-negative staphylococcus strains resistant to ofloxacin in the study group compared to post-treatment control allowed us to conclude that the local use of ofloxacin in the scheme below above does not lead to the selection of coagulase-negative staphylococcus strains resistant to fluoroquinolones in coagulase.