Comparative profile of ocular surface microbiome in vernal keratoconjunctivitis patients and healthy subjects

Purpose To compare ocular surface microbiome and its antibiotic sensitivity in vernal keratoconjunctivitis (VKC) with normal ocular surface. Methods In this case-control study, thirty patients each with clinical diagnosis of VKC and age-matched controls with normal ocular surface were enrolled. Tear film samples were collected from each group and subjected to microbial evaluation with microscopy, conventional culture methods, and polymerase chain reaction (PCR). Microbial diversity and antibiotic sensitivity patterns were analyzed. Results Most patients (67%) belonged to severe grades (3 and 4) of VKC, and allergic history could be elicited in 20%. On culture, bacteria were isolated in 50% of VKC patients and 47% of control group. Staphylococcus species were identified in 70% VKC group and 57% control group. S. aureus growth was seen in 52% and 21% of VKC patients and controls, respectively. S. pneumoniae was isolated only in controls (29%) (p<0.05). Confluent colonies (>= 10 colonies/mu l) were seen in 70% of VKC patients and 14% of controls (p<0.05). Fluoroquinolone resistance was more among higher grades of VKC (50%) (p<0.01) and was observed in 46% of VKC patients and 23% of control group (p<0.01). Both groups were negative for HSV-1 DNA and fungal growth. Conclusion Staphylococcus, the most common ocular surface flora, was predominant in VKC patients. Microbial analysis revealed similar microbial diversity in both groups. However, bacterial load was higher in VKC. Increased fluoroquinolone resistance was observed in VKC patients with more resistance among higher grades. Fungi and HSV-1 were not seen in VKC or normal ocular surface.

Automated summary

This study compared the ocular surface microbiome and antibiotic sensitivity in patients with vernal keratoconjunctivitis (VKC) to those with normal ocular surface. Staphylococcus was found to be the most common ocular surface flora in VKC patients, with higher bacterial load in VKC compared to controls. Increased fluoroquinolone resistance was observed in VKC patients, especially among those with severe grades. Neither fungi nor HSV-1 were detected in VKC or normal ocular surface.