Babb J L, Cummins C S
Infect Immun. 1978 Mar;19(3):1088-91. doi: 10.1128/iai.19.3.1088-1091.1978.
Capsules were detected by the India ink method in cultures of Bacteroides fragilis, B. vulgatus, B. thetaiotaomicron, and B. ovatus. No capsules were found in the five strains of B. distasonis examined.