OBJECTIVES: The aim was to study the oral carriage of Enterococcus and Escherichia coli isolates and their content in antimicrobial-resistance and virulence genes in patients with fixed appliances and in healthy volunteers. STUDY DESIGN: Samples from supragingival plaques/tooth surfaces/fixed orthodontic appliances were taken in patients with fixed appliances (n = 46) and in healthy volunteers (n = 55). Samples were seeded on specific media for enterococcal and E. coli recovery, and 1 isolate of each type per sample was selected. Antimicrobial susceptibility and the presence of genes encoding antimicrobial resistance, bacteriocins, and virulence factors were checked by polymerase chain reaction. RESULTS: Enterococci or E. coli were not recovered from healthy volunteers. Nevertheless, 10 isolates (5 E. faecium, 3 E. faecalis, and 2 E. coli) were obtained from 19.5% of patients with fixed appliances, and poor oral hygiene was evidenced in all of the these patients. Percentages of antimicrobial resistance and the resistance genes detected among the enterococci were: erythromycin: 100%, erm(B); kanamycin: 75%, aph(3')-IIIa; tetracycline: 50%, tet(L) with/without tet(M); streptomycin: 37%, ant(6)-Ia; chloramphenicol: 12%, catA. One E. coli isolate showed a phenotype of multiresistance containing 5 resistance genes and class 1 and 2 integrons. All enterococci produced gelatinase, and 4 isolates contained genes encoding enterocins L50A/B and P. The esp virulence gene was found in 1 multiresistant E. faecalis isolate. CONCLUSIONS: Poor or improper oral hygiene in individuals with fixed appliances favors the oral carriage of antimicrobial-resistant E. coli and enterococci. Additional investigations are needed to assess its implication in human health.
OBJECTIVES: The aim was to study the oral carriage of Enterococcus and Escherichia coli isolates and their content in antimicrobial-resistance and virulence genes in patients with fixed appliances and in healthy volunteers. STUDY DESIGN: Samples from supragingival plaques/tooth surfaces/fixed orthodontic appliances were taken in patients with fixed appliances (n = 46) and in healthy volunteers (n = 55). Samples were seeded on specific media for enterococcal and E. coli recovery, and 1 isolate of each type per sample was selected. Antimicrobial susceptibility and the presence of genes encoding antimicrobial resistance, bacteriocins, and virulence factors were checked by polymerase chain reaction. RESULTS: Enterococci or E. coli were not recovered from healthy volunteers. Nevertheless, 10 isolates (5 E. faecium, 3 E. faecalis, and 2 E. coli) were obtained from 19.5% of patients with fixed appliances, and poor oral hygiene was evidenced in all of the these patients. Percentages of antimicrobial resistance and the resistance genes detected among the enterococci were: erythromycin: 100%, erm(B); kanamycin: 75%, aph(3')-IIIa; tetracycline: 50%, tet(L) with/without tet(M); streptomycin: 37%, ant(6)-Ia; chloramphenicol: 12%, catA. One E. coli isolate showed a phenotype of multiresistance containing 5 resistance genes and class 1 and 2 integrons. All enterococci produced gelatinase, and 4 isolates contained genes encoding enterocins L50A/B and P. The esp virulence gene was found in 1 multiresistant E. faecalis isolate. CONCLUSIONS: Poor or improper oral hygiene in individuals with fixed appliances favors the oral carriage of antimicrobial-resistant E. coli and enterococci. Additional investigations are needed to assess its implication in human health.