Morphological identification of Streptococcus mutans and Streptococcus sobrinus in SB-20M culture medium has efficiency comparable to proteomic identification by the MALDI-TOF mass spectrometry technique.

OBJECTIVES: The objective of this study was to evaluate the efficiency of SB-20 M culture medium to perform differential morphological identification of S. mutans and S. sobrinus compared to biochemical identification and to proteomic identification by the MALDI-TOF mass spectrometry technique. MATERIAL AND METHODS: Unstimulated saliva samples from 266 dental students were seeded on SB-20 M culture medium by the wooden spatula technique. After incubation, S. mutans and S. sobrinus colonies were identified by stereomicroscopy based on their differential morphological characteristics. Following these procedures, 135 colonies with characteristic morphology of S. mutans (89 colonies) and S. sobrinus (46 colonies) were randomly selected, submitted to biochemical identification (biotyping) and proteomic identification by the MALDI-TOF mass spectrometry technique. The results were compared using the Kappa test, with a 5% significance level. RESULTS: All (100%) S. mutans colonies were correctly identified after culture in SB-20 M medium compared to biotyping and proteomic identification. For S. sobrinus, morphological identification in SB-20 M medium was correct for 43 colonies (93.5%) compared to biotyping and proteomic identification. However, there was no statistically significant difference when comparing the capacity to identify S. mutans and S. sobrinus of the three techniques (p < 0.001; K = 0.951). CONCLUSIONS: It was concluded that the SB-20 M culture medium for morphological identification of S. mutans and S. sobrinus was highly reliable, being comparable to the MALDI-TOF mass spectrometry technique. CLINICAL RELEVANCE: The efficiency evaluation of identification methods of S. mutans and S. sobrinus is clinically relevant in order to determine caries risk and activity of patients.

Evaluation of Chair-Side Assays in High Microbiological Caries-Risk Subjects

The aim of this study was to evaluate the commercial chair-side assays Saliva-Check Mutans and ClinproTM Cario L-PopTM in high microbiological caries-risk dental students compared with conventional semi-quantitative colony counting culture-based technique as the reference method. Saliva samples from 93 subjects of both sexes aged 18-26 years were seeded (Köhler and Bratthall method) on plates containing SB-20M culture medium method and 12 subjects with high caries risk were selected. These 12 individuals were subjected to determination of caries risk using two commercial rapid detection chair-side assays (Saliva-Check Mutans and ClinproTM Cario L-PopTM) according to the manufacturers' instructions. The results were analyzed by the Kappa correlation test using SAS statistical software. There was a perfect agreement (Kappa=1) among the three caries risk evaluation methods - chair-side assays and semi-quantitative CFU count (control) - in all subjects. The results suggest that the commercial chair-side assays evaluated in this study may be practical and useful to identify high microbiological caries-risk subjects.

Resumo O objetivo do estudo foi avaliar os testes comerciais de consultório Saliva-Check Mutans e ClinproTM Cario L-PopTM, em estudantes de Odontologia de alto risco à cárie, comparado à técnica convencional semi-quantitativa baseada em contagem de colônias, como método de referência. Amostras de saliva de 93 estudantes de ambos os sexos, entre 18 e 26 anos de idade, foram semeadas em placas contendo meio de cultura SB-20M e 12 pacientes de alto risco à cárie foram selecionados. Estes 12 indivíduos foram submetidos à determinação de risco à cárie por dois testes comerciais de rápida detecção (Saliva-Check Mutans e ClinproTM Cario L-PopTM), seguindo as instruções dos fabricantes. Os resultados foram analisados pelo teste de correlação Kappa, por meio do software estatístico SAS. Houve uma concordância perfeita (Kappa=1) entre os três métodos de avaliação de risco á cárie - testes comerciais e contagem semi-quantitativa de UFC (controle) - em todos os pacientes. O resultado sugere que os testes comerciais de consultório avaliados neste estudo podem ser práticos e úteis para identificar indivíduos de alto risco microbiológico à cárie.

Evaluation of Chair-Side Assays in High Microbiological Caries-Risk Subjects.

The aim of this study was to evaluate the commercial chair-side assays Saliva-Check Mutans and ClinproTM Cario L-PopTM in high microbiological caries-risk dental students compared with conventional semi-quantitative colony counting culture-based technique as the reference method. Saliva samples from 93 subjects of both sexes aged 18-26 years were seeded (Köhler and Bratthall method) on plates containing SB-20M culture medium method and 12 subjects with high caries risk were selected. These 12 individuals were subjected to determination of caries risk using two commercial rapid detection chair-side assays (Saliva-Check Mutans and ClinproTM Cario L-PopTM) according to the manufacturers' instructions. The results were analyzed by the Kappa correlation test using SAS statistical software. There was a perfect agreement (Kappa=1) among the three caries risk evaluation methods - chair-side assays and semi-quantitative CFU count (control) - in all subjects. The results suggest that the commercial chair-side assays evaluated in this study may be practical and useful to identify high microbiological caries-risk subjects.

Mutans streptococci remained viable on toothbrush bristles, in vivo, for 44 h.

BACKGROUND: Toothbrushes harbor a high number of cariogenic microorganisms. AIM: To investigate the viability of mutans streptococci (MS) on toothbrushes bristles and the production of extracellular polysaccharide (ECP) related to drying time. DESIGN: Twenty children were submitted to brushing without dentifrice. Toothbrushes were kept at room temperature from 0 to 48 h and then submitted to microbiological processing. The number of MS colonies/biofilms was expressed according to scores: 0=no colonies were detected; 1=1 to 50; 2=51 to 100; 3=over 100. The amount of ECP was evaluated according to scores: 0=absence; 1=ECP recovering until 50% of the surface; 2=ECP recovering more than 50% of the surface. Data were analyzed by Wilcoxon test (α=5%). RESULTS: At the periods of 0 to 16 h, the toothbrushes had intense bacterial contamination (score 3). From the 18-h, there was a statistically significant decrease in the MS viability (P=0.0078), with predominance of score 1 on periods of 20 to 44 h. The most detected ECP amount was at 0- and 12-h period (P<0.05) with reduction until 32-h period. CONCLUSIONS: Mutans streptococci remained viable on toothbrushes bristles, in vivo, for 44 h.

Recovery of mutans streptococci on MSB, SB-20 and SB-20M agar media.

OBJECTIVE: The recovery of mutans streptococci in saliva and dental biofilm samples depends, in part, on the culture medium used. In this study, we compared (i) the culture media Sucrose-Bacitracin agar (SB-20), Modified SB-20 (SB-20M) and Mitis Salivarius Bacitracin agar (MSB) in the count of colony forming units (cfu) of mutans streptococci and (ii) in the morphological and biochemical differentiation between Streptococcus mutans and Streptococcus sobrinus. DESIGN: Samples of non-stimulated saliva from 20 children were plated on SB-20, SB-20M and MSB, and incubated in microaerophilia at 37°C for 72h. Identification of microorganisms was based on analysis of colony morphology under stereomicroscopy. The biochemical identification of colonies was done by biochemical tests using sugar fermentation, resistance to bacitracin and hydrogen peroxide production. RESULTS: There was no significant difference (p>0.05) in the number of cfu of mutans streptococci recovered on SB-20 and SB-20M agar. Comparing the media, SB-20 and SB-20M yielded a larger number of mutans streptococci colonies (p<0.05) and were more effective than MSB in the identification of S. sobrinus (p<0.05), but not of S. mutans (p>0.05). CONCLUSION: There was no significant difference between SB-20 and SB-20M culture media in the count of mutans streptococci, demonstrating that the replacement of sucrose by coarse granular cane sugar did not alter the efficacy of the medium. Compared with MSB, SB-20 and SB-20M allowed counting a larger number of mutans streptococci colonies and a more effective morphological identification of S. sobrinus.

Morphological differentiation between S. mutans and S. sobrinus on modified SB-20 culture medium.

Due to the major role of Streptococcus mutans and Streptococcus sobrinus in the etiology of dental caries, it is important to use culture media that allow for differentiating these bacterial species. The aim of this study was to evaluate the suitability of a modified SB-20 culture medium (SB-20M) for the isolation and morphological differentiation of S. mutans and S. sobrinus, compared to biochemical identification (biotyping). Saliva samples were collected using the spatula method from 145 children, seeded on plates containing the SB-20M, in which sucrose was replaced by coarse granular cane sugar, and incubated in microaerophilia at 37°C during 72 h. Identification of the microorganisms was performed under stereomicroscopy based on colony morphology of 4904 colonies. The morphological identification was examined by biochemical tests of 94 randomly selected colonies with the macroscopic characteristic of S. mutans and S. sobrinus using sugar fermentation, resistance to bacitracin and production of hydrogen peroxide. There was no statistically significant difference (p>0.05) between morphological identification in the SB-20M medium and biochemical identification (biotyping). Biotyping confirmed that S. mutans and S. sobrinus colonies were correctly characterized in the SB-20M in 95.8% and 95.5% of the cases, respectively. Of the mutans streptococci detected in the children 98% were S. mutans and 2% S. sobrinus. The SB-20M medium is reliable for detection and direct morphological identification of S. mutans and S. sobrinus.

Antimicrobial efficacy of chemical disinfectants on contaminated full metal crowns.

Prosthetic restorations that have been tried in the patient's mouth are potential sources of infection. In order to avoid cross-infection, protocols for infection control should be established in dental office and laboratory. This study evaluated the antimicrobial efficacy of disinfectants on full metal crowns contaminated with microorganisms. Full crowns cast in a Ni-Cr alloy were assigned to one control group (n=6) and 5 experimental groups (n=18). The crowns were placed in flat-bottom glass balloons and were autoclaved. A microbial suspension of each type of strain - S. aureus, P. aeruginosa, S. mutans, E. faecalis and C. albicans- was aseptically added to each experimental group, the crowns being allowed for contamination during 30 min. The contaminated specimens were placed into recipients with the chemical disinfectants (1% and 2% sodium hypochlorite and 2% glutaraldehyde) for 5, 10 and 15 min. Thereafter, the crowns were placed into tubes containing different broths and incubated at 35ºC. The control specimens were contaminated, immersed in distilled water for 20 min and cultured in Thioglycollate broth at 35ºC. Microbial growth assay was performed by qualitative visual examination after 48 h, 7 and 12 days. Microbial growth was noticed only in the control group. In the experimental groups, turbidity of the broths was not observed, regardless of the strains and immersion intervals, thus indicating absence of microbial growth. In conclusion, all chemical disinfectants were effective in preventing microbial growth onto full metal crowns.

Antimicrobial efficacy of chemical disinfectants on contaminated full metal crowns

Prosthetic restorations that have been tried in the patient's mouth are potential sources of infection. In order to avoid cross-infection, protocols for infection control should be established in dental office and laboratory. This study evaluated the antimicrobial efficacy of disinfectants on full metal crowns contaminated with microorganisms. Full crowns cast in a Ni-Cr alloy were assigned to one control group (n=6) and 5 experimental groups (n=18). The crowns were placed in flat-bottom glass balloons and were autoclaved. A microbial suspension of each type of strain - S. aureus, P. aeruginosa, S. mutans, E. faecalis and C. albicans- was aseptically added to each experimental group, the crowns being allowed for contamination during 30 min. The contaminated specimens were placed into recipients with the chemical disinfectants (1 percent and 2 percent sodium hypochlorite and 2 percent glutaraldehyde) for 5, 10 and 15 min. Thereafter, the crowns were placed into tubes containing different broths and incubated at 35ºC. The control specimens were contaminated, immersed in distilled water for 20 min and cultured in Thioglycollate broth at 35ºC. Microbial growth assay was performed by qualitative visual examination after 48 h, 7 and 12 days. Microbial growth was noticed only in the control group. In the experimental groups, turbidity of the broths was not observed, regardless of the strains and immersion intervals, thus indicating absence of microbial growth. In conclusion, all chemical disinfectants were effective in preventing microbial growth onto full metal crowns.

Restaurações protéticas provadas na cavidade bucal dos pacientes são fontes potenciais de infecção. Para evitar infecção cruzada, protocolos de controle de infecção devem ser estabelecidos no consultório e laboratório odontológicos. Este estudo avaliou a eficácia antimicrobiana de desinfetantes químicos em coroas metálicas contaminadas com microorganismos. Coroas totais fundidas com liga de Ni-Cr foram divididas em grupo controle (n=6) e 5 grupos experimentais (n=18). As coroas foram colocadas em balões de vidro e esterilizadas em autoclave. A suspensão microbiana de cada tipo de cepa (S. aureus, P. aeruginosa, S. mutans, E. faecalis e C. albicans) foi assepticamente adicionada a cada grupo experimental, e as coroas foram deixadas contaminar por 30 min. Os corpos-de-prova contaminados foram colocados em recipientes com os desinfetantes químicos (hipoclorito de sódio 1 por cento e 2 por cento e glutaraldeído) por 5, 10 e 15 min. A seguir, as coroas foram colocadas em tubos contendo diferentes meios de cultura e incubadas a 35ºC. Os corpos-de-prova do grupo controle foram contaminados, imersos em água destilada por 20 min e a seguir colocados em tubos de ensaio com meio de cultura Thioglycollate e incubados a 35ºC. A análise do crescimento microbiano foi realizada pelo exame visual qualitativo após 48 h, 7 e 12 dias. Houve crescimento microbiano apenas no grupo controle. No grupo experimental não foi observada turvação dos meios de cultura, independentemente das cepas e períodos de imersão. Conclui-se que todos desinfetantes químicos foram eficazes para prevenir o crescimento microbiano.

Viability of Streptococcus mutans toothbrush bristles.

PURPOSE: Employing microbial culture, the purpose of this study was to assess in vitro the viability of Streptococcus mutans on toothbrush bristles relative to the drying time. METHODS: Forty-five toothbrushes were soaked in a suspension containing S. mutans (ATCC 25175) in a 1,720.000 cfu/mL concentration (0.5 McFarland scale) for 4 minutes, rinsed in sterile tap water, and assigned to 9 groups. Group 1 toothbrushes were immediately incubated in CaSaB CaSaB (bacitracin sucrose broth-selective enrichment broth) culture medium for 4 days. Toothbrushes from groups 2 to 9 were kept at room temperature for 4, 8, 12, 24, 36, 48, 60, and 72 hours, respectively, and subsequently incubated in CaSaB culture medium. RESULTS: It was observed that micro-organisms were present on toothbrushes of groups 1 to 3, ranging from 50 to 100+ cfu. From the 12-hour drying period on, there was no growth of S. mutans. Regarding the S. mutans cfu, the results were expressed in scores and submitted to the Kruskal Wallis statistical test. It was observed that groups 1 to 3 were similar to each other (P>.05) and differed significantly (P<.001) from other groups, which, in turn, behaved similarly (P>0.05). From the 12-hour drying period on, there was a statistically significant decrease in the number of S. mutans cfu (P<.01). CONCLUSION: It may be concluded that Streptococcus mutans remained viable on the toothbrushes' bristles for up to 8 hours.