Eye infection in a young patient caused by Corynebacterium bovis: Microbiological methods and 16S rRNA sequencing

Case Report A !4-month-old boy presented with a ?-week history of purulent conjunctivitis. Ocular specimens were cultured for 2 days at 37°C with 6% CO, on Columbia agar with 5% sheep blood. Bacteriological analysis showed grampositive rods growing as small, greywhite colonies I mm in diameter. These rods were considered lipophilic because they grew on trypticase soy agar (bioMCrieux. Geneva, Switzerland) supplemented with 1 c/c Tween 80 but grew poorly when Tween was omitted. The organism was catalase positive and grew on triple-sugar-iron agar. When it was tested with the API Coryne system (bioMCrieux) after 22 h of incubation at 37°C. we obtained a biocode, 4101104. which identified the isolate as Con~ebacterium 1~o~~i.s with a 99.5% probability and a T value of 0.82. The biochemical characteristics of this strain compared with other C. bovis strains, Corvnebacteriwn ureal~ticum, and Corynebacteriurn ,jeikeium are summarized in Table 1. In order to confirm these results, a 16s rDNA analysis was performed. The 16s rRNA gene was amplified using primers BAK1 I w ( I), corresponding to nucleotides 8 to 27 of the Escherichirl coli 16s rRNA gene, and UNIR (2), corresponding to nucleotides I 5 10 to 1492 of the same gene, followed by direct sequencing of the amplicon using six additional internal primers ( I ,3). To establish the closest species. a database search of GenBank was performed with the Blast program. Our I ,433-nucleotide sequence (GenBank accession number AY 168882) showed 99.8% similarity with the published C. bol3i.s isolate 99-0033 16s rDNA sequence (AFS37590) (4), followed by