Abstract
Background: :
The positive rate of bacterial culture in examination of corneal ulcer in our institute is 31% (in this study, five of 16 cases). The bacterial culture examination takes from one week to ten days. With a low detection rate and late prognosis, treatment selection has been difficult for clinicians. PCR was designed to identify pathogen DNA information directly.
Purpose: :
To design a Polymerase Chain Reaction (PCR) test to identify the causative pathogens in corneal ulcer.
Methods: :
Sixteen specimens were obtained from corneal lesion sites with sterile swabs. A nested PCR were designed for the 16s rDNA region to detect bacterial pathogens. The first pair of PCR primer amplified a broad range of bacterial pathogens, then nested primers specifically targeted at Staphylococcus sp., Streptocuccus sp., Pseudomonas sp., Moraxella sp., Serratia sp., and Acinetobactor sp. Amplified DNA products were analyzed by sequencing analysis, then compared with results obtained by smears and bacterial and fungal culture.
Results: :
Fifteen of 16 specimens were PCR positive. The PCR negative specimen was fungal positive in culture. When sequencing data was compared with organism culture, Pseudomonas sp. was detected in two samples though both smears and culture were negative.
Conclusions: :
PCR is promising to provide early diagnosis, as bacterial pathogens can be identified within 48 hours. The combination of PCR with organism culture and smear tests increased bacterial pathogen detection.
Keywords: cornea: basic science • bacterial disease • microbial pathogenesis: experimental studies