Isolation of bacteria from cervical lymph nodes in patients with oral cancer

Thirty patients with oral mucosal cancer were studied in relation to oral mucosal damage and bacterial translocation to the regional lymph nodes in the neck. All 30 patients (gingiva 11, tongue 13, cheek mucosa four, oral floor two) underwent extensive, clean-contaminated, head-and-neck surgery (including neck dissection) with free flap reconstruction. A total of 153 lymph nodes was harvested for microbial and histological examination. Viable bacteria were isolated from 70 lymph nodes (45.8%) from 25 patients (83.3%). Bacterial cells in the nodes were detected by scanning electron microscopy. Bacterial translocation was found more often in metastatic nodes (75.0%) than in uninvolved nodes (40.3%) (p = 0.015; chi2 test). Gingival carcinoma yielded 56.4% of bacterial growth in the regional lymph nodes compared to tongue (40.3%), oral floor (40.0%) and cheek mucosa (37.5%). As the gingival carcinoma group includes more T4 cases (11/11; 100%) than the other three groups (7/19; 36.8%), bacterial translocation in uninvolved nodes could be caused by the size and invasion of the primary oral tumor. Oral streptococci (Streptococcus intermedius, Strep. constellatus, Strep. oralis, Strep. mitis, Strep. sanguis, Strep. salivarius) were the most common isolates. Aerobic enteric bacteria (Enterococcus, Escherichia, Klebsiella etc.) were also found in the lymph nodes. Among the anaerobic bacteria, Peptostreptococcus spp. were isolated from 12 patients. Damaged oral mucosa in patients with oral cancer might allow the new bacterial colonization on the surface and subsequently drain the bacteria into the regional lymph nodes as well as the general circulation.