PAENIBACILLUS LAUTUS : A NEW FOE IN ENDOGENOUS ENDOPHTHALMITIS.

Purpose: The objective of this study was to discuss the diagnosis and management of a rare case of endogenous endophthalmitis caused by Paenibacillus lautus mimicking granulomatous uveitis in a child, highlighting the use of 16S rRNA gene amplicon sequencing as an accurate method to identify rare pathogens.

Methods: A retrospective chart review of the clinical presentation, microbiologic workup-including microscopy, culture, antibiotic susceptibility, and polymerase chain reaction for pathogen DNA of clinical samples-and the clinical management of the case were recorded.

Results: A 13-year-old adolescent boy presented with decreased vision in the right eye for 1 month. On examination, he had uveitis with hypopyon and complicated cataract. The patient underwent an anterior chamber tap followed by vitrectomy and lensectomy. The culture of the vitreous aspirate grew Gram-variable bacilli that could not be identified using conventional microbiological techniques. However, polymerase chain reaction-based sequencing of the 16S rRNA gene was performed, and the bacterium was identified as P. lautus . The patient subsequently developed rhegmatogenous retinal detachment, for which he underwent endolaser photocoagulation and oil tamponade. Four months later, silicone oil was removed, and an intraocular lens was implanted. At a 6-week follow-up, the retina remained well attached, and intraocular pressure was maintained.

Conclusion: P. lautus can cause endogenous endophthalmitis and mimic granulomatous uveitis. Techniques such as 16S rRNA gene sequencing can significantly facilitate etiologic diagnosis in cases where conventional methods fail.