Abstract
Abstract: :
Purpose: Staphylococci are the most frequently recovered bacteria from conjunctivae of healthy (asymptomatic) eyes. Bacteria were collected, identified to the species-level and the antibiotic susceptibility profile to most commonly used antibiotics were determined from subjects in the US and India. This comparative study provides a basis to support clinical investigations of new antibiotics in these very different parts of the world. Methods: DNA-based characterization data from Qualicon's Automated RiboPrinter and 16S rRNA gene sequences were combined with phenotypic biochemical and morphological data to identify all bacteria to the species-level. End-point broth dilution MICs were performed according to NCCLS methods. Results: Specimens were collected from the conjunctivae of 189 subjects in the US and 119 subjects in India.In the US studies, 95% of the isolates recovered were gram-positive; staphylococci comprised 75% of the total bacteria recovered. The overall percentage of staphylococcal isolates susceptible to selected antibiotics: a) oxacillin - 77 %, b) moxifloxacin - 98 %, c) ciprofloxacin - 83 %, d) ofloxacin - 81 %, e) tobramycin - 76 %, and f) erythromycin - 54 %. The three most frequent staphylococcal species were S. epidermidis, S. warneri, and S. pasteuri. In the India studies, only 65% of the isolates recovered were gram-positive; staphylococci comprised 60% of the total bacteria recovered. The overall percentage of staphylococcal isolates susceptible to selected antibiotics: a) oxacillin - 89 %, b) moxifloxacin - 100 %, c) ciprofloxacin - 96 %, d) ofloxacin - 95 %, e) tobramycin - 89 %, and f) erythromycin - 68 %. The three most frequent staphylococcal species were S. epidermidis, S. hominis subsp. novobiosepticus, and S. arlettae. The most frequent Gram-negative bacteria recovered was Pseudomonas stutzeri. Conclusion: Bacteria recovered from the conjunctivae of healthy subjects were primarily Gram-positive. However, there was a significantly higher frequency of Gram-negative bacteria recovered in India compared to the US. Acquired resistance to selected antibiotics was generally more frequent in the US, although the actual extent is dependent on the antibiotic structural class and varies greatly even between species of the same genus.
Keywords: 328 bacterial disease • 365 conjunctiva • 319 antibiotics/antifungals/antiparasitics