Bacteriologic findings in patients with ocular infection and antibiotic susceptibility patterns of isolated pathogens

摘要

Objective: Isolation of common bacterial pathogens involved in ocular infection and their in vitro susceptibility to commonly used ocular antibiotics and the trends in antibiotic resistance developed by these pathogens. Patients & Methods: Corneal scrapings were obtained from 318 hospitalized patients through Central laboratory, Imam Khomeini Hospital, Ahwaz, Iran from October 2005 to March 2006.They were inoculated directly onto blood agar and thioglycollate broth and were incubated. The isolates were identified as per standard procedures. Antibiotic susceptibility was determined for all positive cultures and susceptibility of isolated pathogens to commonly used ocular antibiotics was examined. Results: Of the isolats (n=70) Gram positive cocci accounted for 47 (67.2%) of all bacterial isolates gram negative bacilli for 23 (32.8%). Coagulase negative staphylococci (33%) and Pseudomonas sp. (24%) were most common isolated. In susceptibility testing, Gentamicin had coverage against 35 (74.5%) of 47 gram positive cocci and 19 (82.6%) of 23 gram negative isolates. The coverage of Tetracycline, Cephalotin and Ceftriaxon against the gram positive cocci isolates were 61.7%, 55% and 53% respectively. All the gram positive cocci isolats showed resistance to Cefotaxime and Penicillin. Ceftriaxon and Tobramycin had coverage against 17 (73.9%) and 14 (60.8%) of 23 gram negative isolates respectively. The coverage of Vancomycin against coagulase negative staphylococci was 100%. However all the isolates of S. aureus were resistant to Vancomycin. Conclusions: Susceptibility analysis revealed that the most effective antibiotics were Gentamicin (77.1% of 54 isolates) and Ceftriaxon (42% of 42 isolates). Both antibiotics had good coverage against gram-positive cocci which constitute the majority (67.1%) of ocular isolates in this study.