Biomedical Journal (Dec 2012)
Study of conjunctival flora in patients after peripheral blood stem cell transplantation and its correlation with tear secretion
Abstract
Background: Human tear film plays an important role in protecting the ocular surface against various pathogens. Dry eye, the major ocular complication of peripheral blood stem cell transplantation (PBSCT), may predispose bacterial colonization to the conjunctiva, and increase the risk of infectious keratitis. The aim of this study is to investigate the conjunctival bacterial flora in patients receiving PBSCT and to stratify the severity of dry eye for comparison. Methods: This cross-sectional study encompassed patients who received PBSCT from 2002 to 2008 in our hospital. At least 1 year after PBSCT, patients were re-evaluated for ocular surface status, and bacterial culture of the conjunctival sac was performed. The eyes of patients were divided into three groups in accordance to the result of the Schirmer Ia test. In the control group, we enrolled dry-eye patients with underlying disease other than hematopoietic stem cell transplantation of which the age range was similar to the study group. Results: Thirty-six patients with 72 eyes were included in our study. The first group (n=36) was defined as having Schirmer Ia test result of 0-5 mm, and the culture of conjunctival sac were positive in 8 eyes (22%). The second group (n=20) was defined as having Schirmer Ia result between 6 and 9 mm, and 4 of which were positive for bacterial culture (20%). In the third group (n=16) with Schirmer Ia result of ≧10mm, flora in patients receiving PBSCT were coagulase-negative Staphylococci, Staphylococcus aureus and Corynebacterium sp. The bacterial colonization rate in the post-PBSCT group was not higher than the control group (22.2% vs. 30.8%), and coagulase-negative Staphylococci was the most common flora in the control group. Conclusion: Despite not having statistical significance, there seems to be a positive correlation between the colonization rate and the severity of dry eye. However, bacterial profile isolated in post-PBSCT patients is not significantly different from other dry eye patients.
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