A retrospective study of microbiologic samples from oral mucosal lesions.

This report describes findings in microbial samples from 271 patients with lesions of the oral mucous membranes. Analyses were made on the basis of direct microscopy and cultivation on nonselective and selective media incubated under aerobic and anaerobic conditions. Growth of bacteria was semiquantitatively determined according to a five-grade scale. Among the 134 samples for direct microscopy, fungi in yeast as well as hyphae phase, were identified in 39 cases. Among the cultivated samples, Candida albicans was detected in 107 cases, of which 71 were full-denture wearers. Staphylococcus aureus, coliform bacteria and Klebsiella were the most frequently isolated "nonoral" bacteria. In some cases also Streptococcus pyogenes, Haemophilus influenzae, Pseudomonas or other gram-negative aerobic bacteria were found. In 84 cases the bacteria mentioned were registered as single "nonoral" infection, and in 63 cases combinations of "nonoral" species occurred. In 51 of these 63 cases C. albicans was also involved. In 31 cases a significant quantitative increase of one or more oral bacterial species was registered. In 93 cases there was no indication of a microbial cause of the lesion. On the basis of these microbial findings, it might be presupposed that in the majority of cases microorganisms were of primary or secondary pathogenic importance to the lesions.