Profilaxia antimicrobiana em odontologia – avaliação do uso por profissionais e da resistência bacteriana a antimicrobianos na cavidade oral de pacientes submetidos à cirurgia de terceiros molares

Abstract

The irrational use of antimicrobial drugs has become a global epidemiological problem due to the development of bacterial resistance, with serious consequences for the public health. In the context of dentistry, dentists play an important role in prescribing antibiotics. To date, there is no convincing evidence that results in a clear balance between benefits and possible harm in administering prophylactic antibiotics prior dental procedures. Therefore, there is still a need to improve antibiotic administration and clarify effective measures to disseminate information. The aim of this study was to evaluate the use of antimicrobial prophylaxis by dental professionals in Porto Alegre and the metropolitan region and, subsequently, to detect bacteria resistant to amoxicillin, azithromycin, clindamycin or chlorhexidine in the oral cavity of patients undergoing third molar extraction, and to characterize them for resistance to a wide panel of antimicrobial. Dentists were asked to complete an anonymous online questionnaire about antimicrobial prescribing. The questionnaire was completed by 82 dentists, and 85.3% of whom indicated prophylaxis, mainly using amoxicillin. Many different protocols were observed, and the greatest diversity was found in post-procedure prescriptions. The vast majority of participants (91.5%) agree that guidelines for prescribing antibiotics in dentistry are necessary, and 62.2% believe that the use of antibiotics as prophylactics can have some impact on bacterial resistance. Subsequently, samples were collected from oral cavity of 24 patients, mostly young and healthy, who underwent extraction of third molar. The samples were seeded in culture medium under selection pressure of amoxicillin, azithromycin, clindamycin or chlorhexidine. Microbial growth was observed against all antimicrobials in all patients, and 32 different morphotypes were found. At least one isolate of each morphotype was identified by MALDI-TOF (Matrix Assisted Laser Desorption Ionization – Time of flight) mass spectrometry, and 25 different species and one isolate identified at the genus level were found. Some isolates were chosen at random to be evaluated for their susceptibility to a wide panel of antibiotics, and among 31 isolates belonging to 10 species, 23 resistance patterns were found. Chlorhexidine co-selected for antibiotic resistance, and macrolide resistance was the most prevalent. Furthermore, we detected methicillin-resistant S. epidermidis and S. aureus among the isolates. Finally, we consider that the need for a greater approach to the issue of bacterial resistance and the proper use of antibiotics is remarkable. Many professionals use antibiotics as prophylactis in different dosages without relating to the possibility of selection of resistant bacteria. It was also possible to verify the presence of bacteria resistant to some of the antibiotics most used by the dentists interviewed, as well as to chlorhexidine, which corroborates the need to establish clear and accessible guidelines for the use of antibiotics and other chemicals that may act by co-selecting antibiotic resistance.