Oral and maxillofacial infections (OMIs) are polymicrobial conditions in which obligate anaerobes, particularly Fusobacterium spp., play an important pathogenic role. Despite their relevance, the species distribution, ecological context, and antimicrobial susceptibility of Fusobacterium in OMIs remain incompletely understood. This study aimed to characterise their occurrence, co‑isolation patterns, and resistance profiles to improve diagnostic accuracy and guide empirical therapy. Clinical specimens collected between October 2018 and August 2023 from 41 patients were cultured under aerobic and anaerobic conditions. Fusobacterium isolates were identified using MALDI‑TOF MS, and susceptibility was reinterpreted according to EUCAST version 16 (2026). In total, 42 isolates were recovered, predominantly F. nucleatum (66.7%) and F. necrophorum (26.2%), with F. periodonticum, F. gonidiaformans, and F. canifelinum each representing 2.4%. Species distribution varied by specimen type: among 28 stomatognathic samples, F. nucleatum was found in 85.7%, F. necrophorum in 10.7%, and F. periodonticum in 3.6%. Peritonsillar abscesses were dominated by F. necrophorum (80%). All maxillary sinus samples exclusively contained F. nucleatum. Polymicrobial infections occurred in 85.4% of cases, frequently involving Streptococcus spp. (including the S. anginosus group) and members of the Prevotellaceae family, whereas peritonsillar abscesses more often exhibited monomicrobial growth. Isolates showed high susceptibility to β‑lactam/β‑lactamase inhibitor combinations and carbapenems, while metronidazole and clindamycin displayed broader MIC distributions. These findings highlight the importance of assessing the co‑occurrence of Fusobacterium species with other members of the polymicrobial community within OMIs, as understanding these interspecies associations is crucial for selecting effective empirical therapy.
