Abstract
Abstract: :
Purpose: To evaluate the in vitro anti-infective activity of levofloxacin (LEVO), ciprofloxacin (CIP), tobramycin (TOB), trimethoprim (TRI), polymyxin B (PMB) and sulfasoxazole (SULF) using isolates recovered from bacterial conjunctivitis patients. Methods: In this retrospective study, 143 conjunctival isolates {81 Gram positive (GP) and 62 Gram negative (GN)} were tested for susceptibility to LEVO, CIP, TOB, TRI, PMB, and SULF using Kirby-Bauer disk-diffusion methodology with susceptibility breakpoints based on NCCLS guidelines or other appropriate references. Results: Isolates tested included: Streptococcus pneumoniae (STP), methicillin resistant Staphylococcus aureus (MRSA), methicillin susceptible Staphylococcus aureus (MSSA), methicillin resistant Staphylococcus epidermidis (MRSE), methicillin susceptible Staphylococcus epidermidis (MSSE), Haemophilus influenzae (HFLU) and Pseudomonas species. LEVO provided 100% coverage for 5 species including STP, MRSA, MRSE, HFLU and P. aeruginosa (PSAG). PMB/TRI in combination (POLY) was the next most active agent providing 100% coverage for MRSA, MSSA, HFLU and PSAG isolates. CIP provided 100% coverage of MRSA and HFLU. Only the MSSA and Pseudomonas species were 100% susceptible to TOB. SULF demonstrated 100% coverage of MRSA and MSSA, but poorly covered GN isolates, with all PSAG resistant. Conclusion: Broad-spectrum coverage is important since initial antibiotic treatment of most ocular infections is often empiric, with medication generally started prior to identification of the causative organism. Additionally, published data indicate that up to 90% or more of implicated organisms are GP. In the present in vitro analysis, LEVO demonstrated the best broad-spectrum and GP coverage by a single agent, with 94% of tested isolates being susceptible, including 100% of STP and PSAG isolates. Lesser coverage was noted with POLY, TOB and CIP, in which 85% of organisms tested were shown to be susceptible. In Vitro Anti-infective Susceptibility Efficacy (% Tested)
Keywords: 328 bacterial disease • 366 conjunctivitis • 319 antibiotics/antifungals/antiparasitics