Study of Conjunctival Flora in Patients after Peripheral Blood Stem Cell Transplantation and its Correlation with Tear Secretion

Abstract

Scientific background of the subjectDry eye occurs in 40-76% of post-peripheral blood stem cell transplantation (PBSCT) patients. The rate of positive conjunctival swab cultures in dry eye patients increases when compared with normal control, and the mean bacterial count is positively correlated with the reduction in goblet cells. What this study adds to the fieldThere is a positive correlation between the colonization rate and the severity of dry eye in post-PBSCT patients.Coagulase-negative Staphylococci is the most common colonizing bacteria of the ocular surface in both the normal population and post-PBSCT patients. The spectrum of conjunctival flora is independent of patient immune status.Background: Dry eye is a major ocular complication of peripheral blood stem cell transplantation (PBSCT) and may predispose bacterial colonization to the conjunctiva. To investigate the conjunctival bacterial flora in patients receiving PBSCT, we encompassed patients who received PBSCT at least 1 year from 2002 to 2008 in this cross-sectional study. Methods: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 culture rates were 22% (8 in 36) in the first group (Schirmer Ia= 0-5 mm), 20% (4 in 20) in the second group (Schirmer Ia= 6-9 mm), and 0% (n=16) in the third group (Schirmer Ia ≧ 10 mm). The 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. Conclusions: In 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. (Biomed J 2012;35:493-99)

Antibiotic susceptibility profiles of ocular and nasal flora in patients undergoing cataract surgery in Taiwan: an observational and cross-sectional study

“…Our culture rate was lower than that obtained from other studies 15–18 but moderately higher than in a previous study conducted at CGMH from 2002 to 2008 (18%). 19 By contrast, the culture rate from nares for S. aureus was consistent with that of previous studies. 20–23 Insufficient rotation of the cotton swab on the conjunctiva, lengthy shipping time and culture conditions may have contributed to the low culture yield, although the specific cause of the low conjunctival culture rate is uncertain.…”

Floral Differences of Conjunctiva in Patients with Renal Diseases

“…Still, it is unclear whether this diversity of bacterial species and a high bacterial growth rate in such a disease come from either the disease itself or its treatment modality. Otherwise, in patients receiving immune suppressive therapy for bone marrow transplantation and AIDS, the bacteria in the conjunctival flora are similar to healthy subjects [21,22].…”

Microbial Keratitis in Patients With Stevens–Johnson Syndrome and Toxic Epidermal Necrolysis: Experience From a Tertiary Centre in Taiwan

“…Our data revealed a 66.7% positive culture rate, which was much higher than that of normal subjects. 34 However, only 1 patient had the same bacteria isolated from the preceding conjunctival culture and from subsequent corneal ulcer. The large disparity between causative microorganisms of keratitis and conjunctival flora may result from chronic use of antibiotics and environmental changes because alteration of normal flora and mixed flora has often been seen in cases of SJS, when compared with controls.…”