UPCII M Microbiologia Teórica 30 2º Ano 2013/2014

Sumário G. Controlo da Infeção em Medicina Dentária Capítulo XXV. Antibióticos e Medicina Dentária Mecanismos de ação das principais classes de antibióticos sobre as células microbianas Resistências a agentes antimicrobianos Alternativas aos antibióticos T30 MJC 10-12-2013

Antibióticos Agentes antimicrobianos vs antimicóticos vs antivirais Primeiros eram de origem microbiana  Hoje há totalmente sintéticos Quinolonas (1960) Oxazolidinonas (2000) Sulfanolamidas (1930) T30 MJC 10-12-2013

Classificação de antibióticos: Actividade Bacteriocida Bacteriostática Espectro de acção Largo Estreito Mecanismo de acção Alvo atingido Síntese proteíca Síntese de ácidos nucleicos Síntese de Peptidoglicano Anti-metabolito Síntese de Membranas T30 MJC 10-12-2013

Tabela resumo dos antibióticos usados em Medicina Dentária T30 MJC 10-12-2013

Inibidores de parede celular Inibidores das transpeptidases Beta lactâmicos Penicilina, cefalosporinas, etc. D-Ala-D-Ala Glicopéptidos Vancomicina, teicoplanina T30 MJC 10-12-2013

Inibidores de síntese proteica Unidade 30S Aminoglicosídeos Tetraciclina Unidade 50S Macrólidos Cloramfenicol Oxazolidinonas tRNA Mucopirocina Factores de alongamento Ácido Fusídico T30 MJC 10-12-2013

Inibidores da síntese de ácidos nucleicos DNA girase e topoisomerase IV Ácido nalidixico Fluoroquinolonas Novobiocina Subunidade Beta da RNA polimerase Rifampina DNA Metronidazole T30 MJC 10-12-2013

Antimetabolitos Dihidrofolato redutase Dihidropteroato sintetase Trimetoprina Dihidropteroato sintetase Sulfonamidas Síntese de ácido micólico Isoniazida T30 MJC 10-12-2013

Inibidores de síntese membranar Polimixinas T30 MJC 10-12-2013

Uso de antibióticos em medicina dentária Infecções periapicais Infecções odontogénicas que extravasam os tecídos do dente (celulite, abcesso) Periodontite Antibioterapia Profilática (Cada vez menos usada só em casos muito especiais) Os mais receitados são: Betalactâmicos Penicilina, Cefalosporinas Clindamicina Tetraciclina Metronidazole T30 MJC 10-12-2013

Resistências a antibióticos Interacções medicamentosas Resistência a antibióticos Não se sabe muito a nível de medicina dentária Sabe-se que genes de resistência a tetraciclina são comuns Bombas de efluxo, proteção ribossomal, inativação enzimática ou modificações do ribossoma Há associação com resistências a penicilina, eritromicina e vancomicina? Não demostrado na cavidade oral mas há elementos transponíveis que têm todas estas resistências. Como pode ser transmitida a resistência? T30 MJC 10-12-2013

What do we know about resistance in the oral biofilm? Oral bacteria carry resistance genes Resistance genes are more prevalent in hosts with oral dysbiosis Link between: resistance genes  resistant phenotype  recurrent infections. ? Evidence on antibiotic resistance within the oral biofilm has been gathered So we know from the literature that: there are resistance genes in some oral bacteria, that those resistance genes are more prevalent in the biofilm of hosts with some oral dysbiosis (eg periodontal disease) That there is, as expected, a relationship between the identification of these resistance genes, a resistant biofilm phenotype and recurrent infections. MJC - CRB, UCP 02-04-2017

Antibiotic prescription by dentists Between 7-11% of antibiotics are prescribed by dentists; A questionnaire applied to 130 dentists: 71 women - 59 men; mean age 32,6 years old 76.2% general dental practitioners 70.0% graduated after 2000; 58,1% without formal update on antibiotic prescription I should now say that I am a Microbiologist working in a department within a dental school and was approached by a student interested in finding out how antibiotic prescription by dentists affects this system. So Isabel started to look at the antibiotic prescription by dentists. She found out that depending on which country you are looking at dentists prescribe between 7-11% of the antibiotics. She also found out that the information for Portugal was not published and therefore Isabel devised and applied a questionnaire to sample prescription patterns of Portuguese dentists. She was able to collect 130 answers representing 71 women and 59 men, with a mean age of 32,6 YO and of which 76.2%) were general practitioners. The majority of the responders graduated after 2000 and about half hadn´t received any formal update on antibiotic prescription since graduation. MJC - CRB, UCP 02-04-2017

Empirical prescription practice Results amoxicillin/clavulanic acid is the first therapeutic option regardless of the treatment or prophylaxis discrepancies between the clinical guidelines and prescription practice Dentists are concerned with bacterial resistance spreading Empirical prescription practice The analysis of the questionnaires revealed essentially that: 1 - amoxicillin/clavulanic acid is usually the first therapeutic option regardless of the problem being treated 2 - there are discrepancies between the clinical guidelines and clinical prescription practice both therapeutic and prophylatic 3 – When asked dentists reported to be concerned with antibacterial resistance spreading. These results suggest that the prescriptions patterns are largely based on empirical knowledge and not on updated scientific evidence and guidelines. MJC - CRB, UCP 02-04-2017

Take-home message Antibiotic prescription by dentists Resistance Spreading Better surveillance and data to support EB guidelines The main conclusion of this preliminary work is that antibiotic prescription by dentists has the potential to impact resistance spreading and therefore we need to improve the information on prescription patterns and above all to generate the knowledge of the oral system to support evidence based guidelines and reinforce their application. Thank you for listening and thank you to these people for doing the work. MJC - CRB, UCP 02-04-2017

Medidas para evitar a propagação de espécies resistentes Restrição do uso profilático a circunstâncias cientificamente comprovadas com necessárias e eficazes. Encontrar alternativas ao uso dos antibióticos Quais? Biomiméticos Terapia fotodinâmica Bacteriófagos Outras substâncias tipo BCWH T30 MJC 10-12-2013

Bibliografia Capítulo 16 Capítulo 36 T30 MJC 10-12-2013