Comparação entre teste bioquímico clássico e o método da reação em cadeia da polimerase (PCR) para identificação de estirpes de Enterococcus Faecalis isoladas da cavidade oral / Comparison between biochemist classic test and the Polymerase Chain Reaction (PCR) for identification of Enterococcus faecalis from the oral cavity

Introdução: O gênero Enterococcus são habitantes normais do trato gastrintestinal e em menor proporção da vagina e uretra masculina. Tornaram-se importantes agentes de doenças humanas devido principalmente à sua elevada resistência aos agentes antimicrobianos e seus inúmeros fatores de virulência. Objetivo: comparar dois métodos laboratoriais utilizados na identificação de 60 estirpes de Enterococcus coletados da cavidade bucal. Foi realizada a identificação das linhagens por um esquema bioquímico clássico baseado nas características fenotípicas e pela técnica da Reação em Cadeia da Polimerase (PCR). Assim, colônias com características de isolamento próprias de Enterococcus sobre a superfície do M-Enterococcus ágar, foram submetidas aos seguintes testes bioquímicos: produção de catalase, hidrólise da esculina, tolerância ao cloreto de sódio a 6,5 por cento, fermentação do manitol, fermentação da arabinose, fermentação do sorbitol, desaminação da arginina, verificação da motilidade e produção de pigmento. Resultados e Discussão: os resultados dos testes foram interpretados e comparados com características fenotípicas de identificação de Enterococcus. A técnica de PCR foi realizada nessa mesma população de microrganismos. Pode-se observar que os testes bioquímicos clássicos identificaram todas as estirpes isoladas como sendo da espécie E. faecalis, enquanto a técnica de PCR revelou que 10 estirpes não pertenciam a espécie pesquisada. A análise estatística pelo método de Fisher revelou diferença significante entre a série bioquímica e o método da PCR (p<0,05). Conclusões: a coleção de linhagens de Enterococcus isoladas foram identificadas como E. faecalis através de um esquema bioquímico tradicional, baseando-se em suas características fenotípicas. Pela técnica da PCR 10 estirpes da coleção não foram identificadas como E. faecalis, revelando diferenças em suas características genotípicas.

Introduction: The genus Enterococcus are normal inhabitants of the gastro intestinal tract and to a lesser extent the vagina and male urethra. They become important agents of human diseases mainly due to its high resistance to antimicrobial agents and its many virulence factors Objective: The aim of this study was to compare two laboratory methods used to identify 60 strains of Enterococcus collected from the oral cavity. The strains were identified through a conventional biochemical scheme based on phenotypic properties and by the Polymerase Chain Reaction (PCR) technique. Colonies with insulation characteristics pertaining to Enterococcus on the surface of M-Enterococcus agar, were subjected to the following biochemical tests: production of catalase, esculin hydrolysis, 6.5 per cent sodium chloride tolerance, mannitol fermentation, arabinose fermentation, sorbitol fermentation, arginine deamination, motility assay and pigment production. Results and Discussion: The results were interpreted and compared with phenotypic identification of Enterococcus. The PCR technique was performed in this same population of microorganisms. The conventional biochemical tests identified all the isolates as being E. faecalis, while the PCR technique showed that 10 strains did not belong to the species studied. After statistical analysis using the Fisher's method, the research showed, in a significant way, that the conventional biochemical tests were more efficient for the identification of E. faecalis compared to the PCR(p <0.05). Conclusions: the collection of strains of Enterococcus isolates were identified as E. faecalis through a traditional biochemical scheme, based on the phenotypic characteristics. By PCR test collection of 10 strains were not identified as E. faecalis revealing differences in their genotypic characteristics.

Evaluation of peri-implant microbiota using the polymerase chain reaction in completely edentulous patients before and after placement of implant-supported prostheses submitted to immediate load.

PURPOSE: To evaluate, by means of the polymerase chain reaction (PCR), the presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia in the mandibular arch of completely edentulous subjects before implant placement and 4 and 6 months after the placement of mandibular implant-supported fixed prostheses. MATERIALS AND METHODS: Fifteen patients had bacterial plaque collected with sterile paper points before implant placement (ie, when they were completely edentulous) and at 3 sites on the peri-implant sulci displaying the largest probing depths after placement of 5 implants. RESULTS: For the edentulous arch, A actinomycetemcomitans was detected in 13.3% of subjects, P intermedia was detected in 46.7% of subjects, and there was no detection of P gingivalis. After 4 and 6 months of implant placement, A actinomycetemcomitans was detected in 60% and 73.3% respectively; P intermedia in 46.7% and 53.3% respectively; and P gingivalis in 46.7% and 53.3%, respectively. DISCUSSION: Future diagnosis should not be restricted to distinguishing individuals at risk of peri-implant disease. Such individuals should be identified by the employment of microbiologic methods and knowledge of the multifactorial nature of the host response to the action of microorganisms. CONCLUSIONS: The longer the implants were in the oral cavity, the higher the occurrence of A. actinomycetemcomitans, P. gingivalis, and P. intermedia in the peri-implant sulci of completely edentulous patients rehabilitated with mandibular implant-supported fixed prostheses was, without any clinical or radiographic evidence indicating peri-implant disease in the studied period.