A Gram stain of anaerobic growth from a peritoneal fluid abscess reveals pleomorphic, pale-staining Gram-negative rods. The isolate grows on Bacteroides Bile Esculin (BBE) agar, hydrolyzing esculin (producing black colonies), and is resistant to kanamycin (1000 µg), vancomycin (5 µg), and colistin (10 µg) disks. Which organism group is most likely?