Influence of oral hygiene in patients with fixed appliances in the oral carriage of antimicrobial-resistant Escherichia coli and Enterococcus isolates.
OBJECTIVE
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.


METHODS
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.
Veterinary Science Department, Center of Studies of Animal and Veterinary Sciences University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.
Patricia
P
Poeta
Gilberto
G
Igrejas
Alexandre
A
Gonçalves
Eugénio
E
Martins
Carlos
C
Araújo
Carlos
C
Carvalho
Jorge
J
Rodrigues
Laura
L
Vinué
Maria
M
López
Carmen
C
Torres
D000293:Adolescent; D000328:Adult; D001426:Bacterial Proteins / Q000032:analysis; D001430:Bacteriocins / Q000032:analysis; D002702:Chloramphenicol Resistance / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics; D004352:Drug Resistance, Microbial; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D016983:Enterococcus / Q000235:genetics / Q000302:isolation & purification*; D013293:Enterococcus faecalis / Q000235:genetics / Q000302:isolation & purification; D016984:Enterococcus faecium / Q000235:genetics / Q000302:isolation & purification; D004917:Erythromycin / Q000494:pharmacology; D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification*; D005260:Female; D006801:Humans; D019868:Kanamycin Kinase / Q000032:analysis; D007613:Kanamycin Resistance / Q000235:genetics; D008297:Male; D008565:Membrane Proteins / Q000032:analysis; D008780:Methyltransferases / Q000032:analysis; D008875:Middle Aged; D009910:Oral Hygiene; D009967:Orthodontic Appliances / Q000382:microbiology*; D013307:Streptomycin / Q000494:pharmacology; D013753:Tetracycline Resistance / Q000235:genetics; D037521:Virulence Factors / Q000032:analysis; D055815:Young Adult
D001426:Bacterial Proteins; D001430:Bacteriocins; D008565:Membrane Proteins; D037521:Virulence Factors; C111937:enterocin L50A; C417717:enterocin P; C116707:enterococcal surface protein, esp; C094988:tetL protein, Enterococcus faecalis; D004917:Erythromycin; D008780:Methyltransferases; D019868:Kanamycin Kinase; D013307:Streptomycin