Cultures were carried out and considered positive if showing growth of one or more microorganisms. This study was based on 613 positive bacterial isolates that were submitted to antibiotic susceptibility tests. In order to verify the differences between the proportions of microorganisms susceptible to lomefloxacin and ciprofloxacin, a test for two proportions, whose populations were not independent, was used as proposed by McNemar. A total of 613 bacterial isolates was examined in this study. As in previous studies, many of our cultures showed no microbial growth.
Some antimicrobial drugs are subject to restricted use.
For instance, cephalothin is highly effective against Gram-positive cocci, but can be obtained only in specially formulated prescriptions and in cases of demonstrated need. Its circumscribed use is intended to prevent the development of resistant strains. According to several studies, the development of resistance of ocular bacteria to many aminoglycosides has limited their usefulness. It is known that the susceptibility of anaerobic bacteria is greater to third-generation quinolones, such as lomefloxacin. The use of an antibiotic as a prophylactic drug prior to ocular surgery has the objective of eliminating most, if not all, microorganisms present in the conjunctiva.