Objective: To obtain data beneficial for future treatment by observing the circumstances relating to microorganisms isolated in external ocular infections and drug sensitivity, along with changes in drug-resistant bacteria.
Subjects and methods: For an eight-year period from April 1998 to March 2006, the cultivation and identification of secretions from conjunctival sac and drug sensitivity tests were conducted at JA Gifu Koseiren Chuno General Hospital involving 3,876 patients (1,809 males and 2,067 females; average age: 44.2 +/- 29.3 years old, ranging from 0-99 years old) diagnosed with external ocular infections by the Department of Ophthalmology. Sensitivity test results were evaluated based on the US CLSI standards.
Results: Of the 5,002 samples, 3,447 tested positive for cultures (isolation rate: 68.9%). A total of 4,537 strains were isolated. In descending order, the microorganisms isolated were 1,706 strains of coagulase negative Staphylococcus (CNS), including Staphylococcus epidermidis (37.6%), 936 strains of Corynebacterium spp. (20.6%), 635 strains of Staphylococcus aureus (14.0%), 412 strains of Haemophilus influenzae (9.1%), and 246 strains of Streptococcus pneumoniae (5.4%). CNS, Corynebacterium and S. aureus were isolated in relatively large numbers in patients of all ages. H. influenzae and S. pneumoniae were common in children six and under and from winter to spring. At the sametime, resistant bacteria (PRSP or PISP: 166 strains; 2000 onward, BLNAR: 192 strains; and BLPACR: 6 strains) were detected more frequently than sensitive bacteria. H. influenzae was hypersensitive to cefotaxime (CTX) and levofloxacin. Almost no toleration of CTX was observed in S. pneumoniae.
Discussion and conclusion: There are distinctions in the isolated bacteria according to age and season, and the use of drugs that are appropriate to the antibiograms of each facility should be considered.