Abstract
Purpose: :
To determine the conjunctival and lid biota of normal, healthy children.
Methods: :
Thirty–eight children were enrolled in a clinical trial involving the use of contact lenses on a daily wear schedule. The mean age of the children enrolled in the study was 12.5 ± 1.7 yrs (8–14). At baseline, prior to insertion of contact lenses on eye, the upper bulbar conjunctiva (UBC) and the lower lid (LL) margin of each eye of each child was swabbed with a sterile calcium alginate swab, placed in 2ml of sterile phosphate buffered saline (with 1% hexametaphosphate) and sent for microbiological analysis. All samples were processed within 1 hour of aseptic collection. The swabs were vortexed for 30 seconds at high speed after which they were aseptically removed and discarded. 400µl aliquots of the saline were spread onto 3 chocolate blood agar (CBA) plates and 1 Sabouraud Dextrose agar (SAB) + chloramphenicol. After drying, the plates were incubated at 37°C in different environments. The CBA plates in O2 and CO2 incubated for 48 hrs while the one in ANO2 for 4 days. The SAB + chloramphenicol was incubated in O2 for seven days at 25°C.
Results: :
Of the 76 eyes, micro –organisms were isolated from 37% of eyes from the UBC and 53% of the eyes from the LL region. Gram–positive bacteria were the most frequently seen (33% and 51% of total UB and LL samples). Fungi were seen in 4% of total UB and LL samples. Gram negative bacteria was seen in a single eye and was recovered from the UBC. Of the gram–positive bacteria, S.epidermidis (16% of UB and 28% of LL) and Propionibacterium sp (13% of UB and 26% of LL) were the most frequently isolated species. Streptococcus sp. were identified from 4% of the UB and LL samples.
Conclusions: :
A greater number of conjunctival than lower lid samples did not reveal any growth. When microbial growth was observed, gram – positive bacteria esp. S.epidermidis and Propionibacterium sp. were the most frequent and similar to that reported from adult eyes. Fungus and Streptococcus sp. were seen in only a small percent of cases. As contact lenses are increasingly being considered as an effective means of vision correction in children, especially pre–teens an understanding the nature of the ocular biota in children becomes important to effectively manage lens wear and adverse events if any.
Keywords: conjunctiva • microbial pathogenesis: clinical studies • clinical (human) or epidemiologic studies: prevalence/incidence