Which Bacteroides species is noted for 'pitting' of the agar and is sensitive to penicillin 2-unit disks?

Bacteroides ureolyticus is specifically recognized for causing pitting of the agar when cultured. This characteristic is significant in microbiological identification, as the pitting can indicate the organism's enzymatic activity. Furthermore, B. ureolyticus's sensitivity to penicillin, evidenced by the 2-unit disks, distinguishes it from other Bacteroides species which typically exhibit resistance to this antibiotic. Identifying the pitting trait alongside the antibiotic sensitivity provides crucial information for the correct identification of this species in clinical microbiology settings. Other Bacteroides species do not share this specific sensitivity to penicillin or the same level of pitting, making this species unique in those regards.