Use of DNA microarray analysis in diagnosis of bacterial and fungal endophthalmitis

Tsutomu Sakai1, Kenichi Kohzaki1, Akira Watanabe1, Hiroshi Tsuneoka1, Mitsunobu Shimadzu21Department of Ophthalmology, Jikei University School of Medicine, 2Mitsubishi Chemical Medience Corporation, Tokyo, JapanBackground: To examine the utility of DNA microarray analysis for identifying causative microorganisms in endophthalmitis.Methods: Thirteen samples of vitreous fluid (VF) were obtained from 13 patients during vitrectomy. Vitreous fluids from three patients with suspected endophthalmitis and ten controls without infection were subjected to testing for the presence of bacteria and fungi in culture tests, polymerase chain reaction (PCR) analysis, and DNA microarray analysis.Results: No control sample was positive for bacteria or fungi in the culture test, PCR, or microarray analysis. Specimens from two patients (Cases 1 and 2) with suspected endophthalmitis were positive for bacteria in PCR, and a specimen from one patient (Case 3) was positive for fungi in PCR. Klebsiella pneumonia (Case 1), Streptococcus agalactiae (Case 2), and Candida parapsilosis (Case 3) in the PCR-positive specimens were identified by DNA microarray analysis within 24 hours. Culture results were also positive for K. pneumonia in Case 1, S. agalactiae in Case 2, and C. parapsilosis in Case 3, but required 3 to 4 days to obtain.Conclusions: Microarray analysis is complementary to routine cultures for identifying causative microorganisms and is likely to be a useful tool in patients with suspected endophthalmitis who require rapid diagnosis and early antibiotic treatment.Keywords: DNA microarray, endophthalmitis, microorganism, vitreous flui