Analysis of in vitro expression of virulence genes related to antibiotic and disinfectant resistance in Escherichia coli as an emerging periodontal pathogen

The collective involvement of virulence markers of <i>Escherichia coli</i> as an emerging pathogen associated with periodontitis remains unexplained. This study aimed to implement an <i>in vitro</i> model of infection using a human epithelial cell line to determine the virulome expression related to the antibiotic and disinfectant resistance genotype and pulse field gel electrophoresis (PFGE) type in <i>E. coli</i> strains isolated from patients with periodontal diseases. We studied 100 strains of <i>E. coli</i> isolated from patients with gingivitis (n = 12), moderate periodontitis (n = 59), and chronic periodontitis (n = 29). The identification of <i>E. coli</i> and antibiotic and disinfectant resistance genes was performed through PCR. To promote the expression of virulence genes in the strains, an <i>in vitro</i> infection model was used in the human epithelial cell line A549. RNA was extracted using the QIAcube robotic equipment and reverse transcription to cDNA was performed using the QuantiTect reverse transcription kit (Qiagen). The determination of virulence gene expression was performed through real-time PCR. Overall, the most frequently expressed adhesion genes among the isolated strains of gingivitis, moderate periodontitis, and chronic periodontitis were <i>fimH</i> (48%), <i>iha</i> (37%), and <i>papA</i> (18%); those for toxins were <i>usp</i> (33%); those for iron acquisition were <i>feoB</i> (84%), <i>fyuA</i> (62%), <i>irp-2</i> (61%), and <i>iroN</i> (35%); those for protectins were <i>traT</i> (50%), <i>KpsMT</i> (35%), and <i>ompT</i> (28%); and those for pathogenicity islands were <i>malX</i> (45%). The most common antibiotic and disinfectant resistance genes among gingivitis, moderate periodontitis, and chronic periodontitis strains were <i>sul-2</i> (43%), <i>bla_SHV</i> (47%), <i>blaTEM</i> (45%), <i>tet(A)</i> (41%), <i>dfrA1</i> (32%), <i>marR-marO</i> (57%), and <i>qacEA1</i> (79%). The findings revealed the existence of a wide distribution of virulome expression profiles related to the antibiotic and disinfectant resistance genotype and PFGE type in periodontal strains of <i>E. coli.</i> These findings may contribute toward improving the prevention and treatment measures for periodontal diseases associated with <i>E. coli.</i>