Analysis of the bacterial content of symptomatic and asymptomatic primary endodontic infections and susceptibility os specific bacteria to antimicrobial agents

Author(s)

Augusto Rodrigues Lima

• Document type: Master's Dissertation
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2017-02-22

Examining board members

Brenda Paula Figueiredo de Almeida Gomes; Alexandre Augusto Záia; Francisco Montagner

• Advisor: Brenda Paula Figueiredo de Almeida Gomes

Abstract

Teeth with pulp necrosis presenting symptomatology and periapical bone destruction tend to be colonized by a more complex anaerobic microbiota compared to the asymptomatic cases. Black pigmented bacteria (BPB), including Prevotella and Porphyromonas spp, and Fusobacterium spp. have been frequently isolated/ detected in symptomatic cases. However, due to the indiscrimated use of antimicrobial agents, resistance to them has been developed. Thus, the aims of this study were: a) to investigate the composition of the microbiota of symptomatic (ie the presence of periapical abscess) and asymptomatic teeth with pulp necrosis by checkerboard; b) to determine the antimicrobial susceptibility of BPB and Fusobacterium spp., identified by sequencing, in front of the most commonly used antimicrobial agents in the dental clinics; and c) to correlate the clinical findings with the microbial date. Patients in need of endodontic therapy due to pulp necrosis with the presence of symptomatology (n = 10) or asymptomatic (n = 10), were selected. Samples for microbiological analysis were collected from 20 root canals, as well as from the dental abscess (n = 10). Part of the microbial samples were processed by checkerboard, and another part was diluted, plated and incubated, and the isolated microorganisms identified by genetic sequencing. The antimicrobial susceptibility of BPB and Fusobacterium spp was determined by the E-test method using the antibiotics: benzylpenicillin, amoxicillin, amoxicillin + clavulanic acid, erythromycin, azithromycin, clindamycin and metronidazole. In conclusion the microbiota of symptomatic cases is more complex than the asymptomatic cases with apical periododontitis, with a greater number of positive and negative associations between the microorganisms. The majority of the selected bacteria showed some resistance to all antimicrobial agents tested (AU)

• FAPESP's process: 14/27366-8 - Analysis of the bacterial and the antimicrobial susceptibility of selected bacteria against antimicrobial agentes
• Grantee: Augusto Rodrigues Lima
• Support Opportunities: Scholarships in Brazil - Master