| Summary: | The <i>Prevotella</i> genus is a normal constituent of the oral microbiota, and is commonly isolated from mechanically treated polymicrobial infections. However, antibiotic treatment is necessary for some patients. This study compared the antibiotic susceptibility and the presence of resistance genes in clinical oral isolates of <i>P. intermedia</i>, <i>P. nigrescens</i>, and <i>P. melaninogenica</i>. Antibiotic susceptibility was assessed using the agar dilution method. PCR confirmed the species and resistance gene frequency in the <i>Prevotella</i> species. The frequencies of species <i>P. intermedia</i>, <i>P. nigrescens</i>, and <i>P. melaninogenica</i> were 30.2%, 45.7%, and 24.1%, respectively. No isolates of <i>P. intermedia</i> were resistant to amoxicillin/clavulanic acid, tetracycline, or clindamycin. <i>P. nigrescens</i> and <i>P. melaninogenica</i> were resistant to amoxicillin/clavulanic acid and tetracycline at frequencies of 40% and 20%, respectively. <i>P. intermedia</i> was resistant to metronidazole at a frequency of 30%, <i>P. nigrescens</i> at 20%, and <i>P. melaninogenica</i> at 40%. <i>P. nigrescens</i> and <i>P. melaninogenica</i> were resistant to 50% and 10% clindamycin, respectively. The gene most frequently detected was <i>tetQ</i>, at 43.3%, followed by <i>tetM</i> at 36.6%, <i>bla<sub>TEM</sub></i> at 26.6%, <i>ermF</i> at 20%, <i>cfxA</i>, <i>cfxA</i><sub>2</sub>, and <i>nimAB</i> at 16.6%, and <i>nimAEFI</i> at 3.3%. <i>P. nigrescens</i> was the species with the highest resistance to antibiotics such as amoxicillin/clavulanic acid, amoxicillin, and clindamycin, in addition to being the species with the largest number of genes compared to <i>P. intermedia</i> and <i>P. melaninogenica.</i>
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