Orientadores: Francisco Carlos Groppo, Pedro Luiz Rosalen / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-06T15:10:53Z (GMT). No. of bitstreams: 1 Baglie_RobertaCristianeCatelli_D.pdf: 1140633 bytes, checksum: 4a8bfaf4ec7f401180e020ef256fbba7 (MD5) Previous issue date: 2006 / Resumo: A endocardite infecciosa (EI) é uma infecção grave das válvulas cardíacas, do endocárdio mural e de septos defeituosos, provocada principalmente pelos Staphylococcus aureus e pelos estreptococos grupo viridans. O objetivo deste trabalho foi verificar a resistência aos antimicrobianos de cepas de Staphylococcus aureus e estreptococos grupo viridans provindas de 100 voluntários, sendo 60 adultos (16 a 75 anos) que foram divididos em três grupos: saudáveis (grupo 1), cardiopatas de baixo risco (grupo 2) e cardiopatas de alto risco (grupo 3) para EI e 40 crianças (6 a 14 anos) que foram divididas em dois grupos: saudáveis (grupo 1) e cardiopatas de alto risco (grupo 2) para EI. Além disso, os voluntários dos grupos 2 e 3 e os responsáveis pelas crianças do grupo 2 responderam a um formulário sobre os riscos da EI e sua profilaxia. Amostras de saliva (diluídas 1: 1000) foram inoculadas em Mitis Salivarius agar e incubadas em microaerofilia durante 48 h. Amostras de pele (swab) foram inoculadas em Sal Manitol agar e incubadas em aerobiose durante 24 h. Após testes bioquímicos, os estreptococos grupo viridans e os Staphylococcus aureus foram identificados e submetidos a testes de susceptibilidade microbiológica empregando-se agentes antimicrobianos. Dos voluntários adultos, foram isoladas 186 cepas, 58 do grupo 1, 62 do grupo 2 e 66 do grupo 3. Dentre os estreptococos a espécie S. mitis foi a mais cQmum. A cepa mais resistente contra as penicilinas (amoxicilina, ampicilina, meticilina e oxaci li na) foi a do S. aureus isolada dos grupos 2 (57,90/0) e 3 (800/0). Considerando os grupos 2 e 3: 21 voluntários (52,5%) tinham conhecimento sobre sua doença, entretanto, somente 12,5% sabiam o significado de EI. Dezessete voluntários (42,5%) sabiam sobre a antibioticoprofilaxia antes de algum procedimento dental e 10 voluntários nomearam a amoxicilina como o principal antibiótico para a profilaxia. Trinta e cinco voluntários não receberam informações dos médicos ou dentistas sobre a importância da saúde oral para prevenir a EI. A maior parte (60%) disse ter visitado.o dentista pela última vez há mais de 1 ano. Trinta e cinco porcento afirmou apresentar algum tipo de doença oral (gengivite, cárie, etc.). Dos voluntários pediátricos, foram isoladas 98 colônias, 51 do grupo 1 e 47 do grupo 2. A espécie mais isolada foi Streptococcus pneumoniae: 23,4% e 25,5% nos grupos 1 e 2, respectivamente. S. aureus corresponderam a 36,2% e 31,9% nos grupos 1e 2, respectivamente. Quatorze responsáveis (700/0) tinham conhecimento sobre a doença de suas crianças; entretanto, somente 15% sabia o significado de "endocardite infecciosa". Onze responsáveis (55%) sabiam sobre a antibioticoprofilaxia antes de algum procedimento dental, e 10 responsávies nomearam a amoxicilina como o principal antibiótico para a profilaxia. Dezesseis responsáveis (80%) não receberam informações dos médicos ou dentistas sobre a importância da saúde oral para prevenir a EI. A maioria (40%) disse que a criança visitou o dentista pela última vez há 6 meses. Concluímos que, de acordo com o perfil de resistência das cepas de estregtococos orais, a amoxicilina é o agente antimicrobiano de primeira escolha para a profilaxia da EI. É clara a necessidade ~ de oferecer informações sobre a EI para os pacientes afetados por doenças cardíacas ou para seus responsáveis / Abstract: The aim of this study was to verify the antimicrobial resistance of Staphy/ococcus aureus and viridans streptococci from 100 volunteers, 60 adults (16 to 75 yearsold), which were divided into three groups: healthy (Group 1), low risk (Group 2) and high risk (Group 3) for infective endocarditis (IE) and 40 children (6 to 14 years-old) which were divided into two groups: healthy (Group 1) and high risk (Group 2) for IE. In addition, volunteers were submitted to a structured formulary about IE risks and prophylaxis. Saliva samples were inoculated on Mitis Salivarius agar and incubated in microaerophilia during 48h. Skin samples were inoculated on Mannito/-Sa/t agar and incubated in aerobiosis during 24h. After biochemical tes~ viridans streptococci and S. aureus were identified and submitted to antimicrobial susceptibility tests agc;linst antimicrobial agents. Considering adults, Streptococcus mitis was the most common strain isolated among streptococci. 186 strains were isolated, being 58 from group 1, 62 from group 2 and 66 from group 3. The most resistant strain against penicillins (amoxicillin, ampicillin, methicillin and oxacillin) a was S. aureusisolated from groups 2 (57.9%) and 3 (80%). Consideringgroups 2 and 3: twenty-one volunteers (52.5%) were aware about their disease however, only 12.5% were aware of the meaning of "infective endocarditis". Seventeen volunteers (42.5%) knew about antibiotic prophylaxis before some dental procedures, and 10 volunteers named amoxicillin as the main antibiotic for prophylaxis. Thirty-five volunteers did not receive information from physicians or a , dentists about importance of ora'l health to prevent IE. The majori~ (60%) reported the last visit to the dentist more than 1 year ago. Thirty-five percent reported some kind of oral disease (gingivitis, caries, etc.). Considering children, 98 strains were isolated, being 51 from group 1 and 47 from group 2. . a Streptococcus pneumoniae was the most common streptococci isolated: 23.4% and 25.5% in groups 1 and 2, respectively. S. aureus corresponded to 36.2% and 31.9% in groups 1 and 2, respectively.' Fourteen guardians (70%) were aware about their child's disease; however, only 15% were aware of the meaning of ~ "'infective endocarditis". Eleven guardians (55%) knew about antibiotic prophylaxis before some dental procedures, and 10 volunteers named amoxicillin as the main antibiotic for prophylaxis. Sixteen guardians (80%) did not received information from physicians or dentists about importance of oral health to prevent IE. The most part (40%) reported the last visit to the dentist at least six months ago. We concluded that the resistant profile of the oral streptococci strains supports amoxicillin as the first choice antimicrobial agent for IE prophylaxis. There was a .: clear need for more information regarding IE among patients affected by cardiac disease or their guardians / Doutorado / Farmacologia, Anestesiologia e Terapeutica / Doutor em Odontologia

Thesis (Ph.D.) -- University of Texas Southwestern Medical Center at Dallas, 2006. / Not embargoed. Vita. Bibliography: 166-185.

A Febre Reumática, complicação tardia de uma infecção de orofaringe causada pelo Streptococcus pyogenes (estreptococo -hemolítico do grupo A de Lancefield), tem como conseqüência a Cardiopatia Reumática, explicada pelo mimetismo molecular entre proteínas cardíacas humanas e a associação de proteínas e carboidratos da membrana do S. pyogenes. A profilaxia secundária com a PGB 1.200.000 UI IM propõe-se a evitar novos surtos, sendo administrada em intervalos de vinte e um dias nos países com alto índice de estreptococcia. A lesão valvar predispõe à Endocardite Infecciosa, que resulta de bacteriemias causadas por focos infecciosos de origem bucal em cerca de 40% dos casos. Os Streptococcus Viridans constituem o grupo mais comumente encontrado nas Endocardites Infecciosas, em especial os Streptococcus sanguinis e Streptococcus oralis. O efeito do uso crônico da PGB não foi estudado com especificidade para essa microbiota. Assim, foi avaliada, qualitativa e quantitativamente, a microbiota bucal de 100 pacientes, aos 7 e 21 dias, após profilaxia secundária para a Febre Reumática com a PGB 1.200.000 UI IM e comparada com a de 100 pacientes portadores de doença arterial coronariana sem antecedentes de Febre Reumática. As espécies avaliadas foram divididas em S. sanguinis, S. oralis e outras espécies de Streptococcus Viridans Foram coletadas amostras de saliva pela mastigação de goma de parafina e transportadas em meio VMGA II S. As culturas foram semeadas em ágar Columbia CNA com 5% de sangue desfibrinado puro de carneiro com acréscimo de penicilina G. e incubadas a 35ºC em estufa de CO2 por 72 horas. As colônias sugestivas de Streptococcus foram submetidas a testes bioquímicos para confirmação de gênero e espécie. A concentração inibitória mínima foi determinada pelo método Etest e interpretada segundo os padrões do Clinical and Laboratory Standards Institute. Não houve diferença quanto à presença do S. sanguinis nos grupos estudados (P=0,40). O S. oralis prevaleceu aos 7 dias de PGB em relação ao grupo controle (P=0,01). Quanto à identificação de outras espécies, houve maior número de cepas nos pacientes do grupo controle quando comparados aos do grupo de estudo aos 7 e 21 dias de PGB (P<0,001). Os números de UFC/ml de S. sanguinis, S. oralis e de outras espécies foram comparados entre os grupos e não houve diferença entre eles (P=0,96; P=0,60 e P=0,77; respectivamente). Quanto às CIM do S. sanguinis e do S. oralis, não houve diferença entre os grupos (P=0,79 e P=0,13; respectivamente). Todos os testes estatísticos foram realizados em um nível de significância de 5%. Concluiu-se que o S. oralis prevaleceu aos 7 dias de PGB 1.200.000 UI IM; os Streptococcus Viridans de outras espécies prevaleceram no grupo controle; o número de UFC/mL de saliva não diferiu nos grupos estudados, a susceptibilidade dos S. sanguinis e S. oralis à penicilina G não foi alterada pela ação da PGB 1.200.000 UI IM a cada 21 dias e, por fim, a PGB não provocou reações de hipersensibilidade em nenhum paciente do estudo / Rheumatic fever is the result of a Streptococcus pyogenes (group A -hemolytic Streptococcus) infection of the upper respiratory tract. Rheumatic heart disease is a rheumatic fever consequence and is elucidated by the molecular mimicry between human cardiac proteins and group A streptococcal proteins and carbohydrates association. The secondary prophylaxis with 1,200,000 U BPG every three weeks is used for prevention of recurrent rheumatic fever in developing countries. Valvar defects are a risk for infective endocarditis which is resulted of bacteriemia caused for oral infectious focuses in 40% of cases. Viridans streptococci are the predominant group recovered in infective endocarditis, specially Streptococcus sanguinis and Streptococcus oralis. The effect of chronic BPG wasnt studied with specificity to these pathogens yet. Therefore, the oral microbiota was evaluated, qualitatively and quantitatively, at 7 and 21 days after secondary prophylaxis with BPG to rheumatic fever (study group), in a hundred patients and in comparison to another hundred patients with coronary heart disease who never acquired rheumatic fever (control group). The species evaluated were divided in S. sanguinis, S. oralis and another Streptococcus species. It was collected samples of chewing-stimulated saliva (1ml) and transported in VMGA II S medium. The samples were cultured in pure and with penicillin G 5% sheep blood Columbia ágar (CNA), incubated for 72 hours in an atmosphere containing 5% CO2 at 35ºC. The strains that were suggestive to Streptococcus were identified by biochemical tests to confirm bacteria species and genus. Minimal inhibitory concentration was determined by Etest method and interpreted in accordance to Clinical and Laboratory Standards Institute. The results showed that there was no difference in S. sanguinis presence in all groups (P=0.40). S. oralis prevailed in 7 days BPG group in comparison to control group (P=0.01). The control group showed the highest number of others species in comparison to 7 and 21 days BPG (P<0.001). CFU/ml numbers of S. sanguinis, S. oralis and other species strains were compared in 7 and 21 days BPG to control group and there was no difference among themselves (P=0.96, P=0.60 and P=0.77; respectively). There was no difference in S. sanguinis and S. oralis MICs among the study and control groups (P=0.79 and P=0.13). All statistic tests were done at 5% significance level. It was concluded that S. oralis prevailed in 7 days BPG group in comparison to control group; other species of Viridans streptococci prevailed in control group. The number of CFU/mL did not differ in both studied groups; the penicillin susceptibility of S. sanguinis and S. oralis did not change by BPG every three weeks and, by the end, it was not observed hypersensitivity reactions to penicillin in neither of the patients of this study

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2005. / Härtill 4 uppsatser.

A Febre Reumática, complicação tardia de uma infecção de orofaringe causada pelo Streptococcus pyogenes (estreptococo -hemolítico do grupo A de Lancefield), tem como conseqüência a Cardiopatia Reumática, explicada pelo mimetismo molecular entre proteínas cardíacas humanas e a associação de proteínas e carboidratos da membrana do S. pyogenes. A profilaxia secundária com a PGB 1.200.000 UI IM propõe-se a evitar novos surtos, sendo administrada em intervalos de vinte e um dias nos países com alto índice de estreptococcia. A lesão valvar predispõe à Endocardite Infecciosa, que resulta de bacteriemias causadas por focos infecciosos de origem bucal em cerca de 40% dos casos. Os Streptococcus Viridans constituem o grupo mais comumente encontrado nas Endocardites Infecciosas, em especial os Streptococcus sanguinis e Streptococcus oralis. O efeito do uso crônico da PGB não foi estudado com especificidade para essa microbiota. Assim, foi avaliada, qualitativa e quantitativamente, a microbiota bucal de 100 pacientes, aos 7 e 21 dias, após profilaxia secundária para a Febre Reumática com a PGB 1.200.000 UI IM e comparada com a de 100 pacientes portadores de doença arterial coronariana sem antecedentes de Febre Reumática. As espécies avaliadas foram divididas em S. sanguinis, S. oralis e outras espécies de Streptococcus Viridans Foram coletadas amostras de saliva pela mastigação de goma de parafina e transportadas em meio VMGA II S. As culturas foram semeadas em ágar Columbia CNA com 5% de sangue desfibrinado puro de carneiro com acréscimo de penicilina G. e incubadas a 35ºC em estufa de CO2 por 72 horas. As colônias sugestivas de Streptococcus foram submetidas a testes bioquímicos para confirmação de gênero e espécie. A concentração inibitória mínima foi determinada pelo método Etest e interpretada segundo os padrões do Clinical and Laboratory Standards Institute. Não houve diferença quanto à presença do S. sanguinis nos grupos estudados (P=0,40). O S. oralis prevaleceu aos 7 dias de PGB em relação ao grupo controle (P=0,01). Quanto à identificação de outras espécies, houve maior número de cepas nos pacientes do grupo controle quando comparados aos do grupo de estudo aos 7 e 21 dias de PGB (P<0,001). Os números de UFC/ml de S. sanguinis, S. oralis e de outras espécies foram comparados entre os grupos e não houve diferença entre eles (P=0,96; P=0,60 e P=0,77; respectivamente). Quanto às CIM do S. sanguinis e do S. oralis, não houve diferença entre os grupos (P=0,79 e P=0,13; respectivamente). Todos os testes estatísticos foram realizados em um nível de significância de 5%. Concluiu-se que o S. oralis prevaleceu aos 7 dias de PGB 1.200.000 UI IM; os Streptococcus Viridans de outras espécies prevaleceram no grupo controle; o número de UFC/mL de saliva não diferiu nos grupos estudados, a susceptibilidade dos S. sanguinis e S. oralis à penicilina G não foi alterada pela ação da PGB 1.200.000 UI IM a cada 21 dias e, por fim, a PGB não provocou reações de hipersensibilidade em nenhum paciente do estudo / Rheumatic fever is the result of a Streptococcus pyogenes (group A -hemolytic Streptococcus) infection of the upper respiratory tract. Rheumatic heart disease is a rheumatic fever consequence and is elucidated by the molecular mimicry between human cardiac proteins and group A streptococcal proteins and carbohydrates association. The secondary prophylaxis with 1,200,000 U BPG every three weeks is used for prevention of recurrent rheumatic fever in developing countries. Valvar defects are a risk for infective endocarditis which is resulted of bacteriemia caused for oral infectious focuses in 40% of cases. Viridans streptococci are the predominant group recovered in infective endocarditis, specially Streptococcus sanguinis and Streptococcus oralis. The effect of chronic BPG wasnt studied with specificity to these pathogens yet. Therefore, the oral microbiota was evaluated, qualitatively and quantitatively, at 7 and 21 days after secondary prophylaxis with BPG to rheumatic fever (study group), in a hundred patients and in comparison to another hundred patients with coronary heart disease who never acquired rheumatic fever (control group). The species evaluated were divided in S. sanguinis, S. oralis and another Streptococcus species. It was collected samples of chewing-stimulated saliva (1ml) and transported in VMGA II S medium. The samples were cultured in pure and with penicillin G 5% sheep blood Columbia ágar (CNA), incubated for 72 hours in an atmosphere containing 5% CO2 at 35ºC. The strains that were suggestive to Streptococcus were identified by biochemical tests to confirm bacteria species and genus. Minimal inhibitory concentration was determined by Etest method and interpreted in accordance to Clinical and Laboratory Standards Institute. The results showed that there was no difference in S. sanguinis presence in all groups (P=0.40). S. oralis prevailed in 7 days BPG group in comparison to control group (P=0.01). The control group showed the highest number of others species in comparison to 7 and 21 days BPG (P<0.001). CFU/ml numbers of S. sanguinis, S. oralis and other species strains were compared in 7 and 21 days BPG to control group and there was no difference among themselves (P=0.96, P=0.60 and P=0.77; respectively). There was no difference in S. sanguinis and S. oralis MICs among the study and control groups (P=0.79 and P=0.13). All statistic tests were done at 5% significance level. It was concluded that S. oralis prevailed in 7 days BPG group in comparison to control group; other species of Viridans streptococci prevailed in control group. The number of CFU/mL did not differ in both studied groups; the penicillin susceptibility of S. sanguinis and S. oralis did not change by BPG every three weeks and, by the end, it was not observed hypersensitivity reactions to penicillin in neither of the patients of this study

>Magister Scientiae - MSc / The continued emergence of bacterial resistance to the antibiotics currently employed to treat several diseases has added to the urgency to discover and develop novel antibiotics. It is well established that natural products have been the source of the most effective antibiotics that are currently being used to treat infectious diseases and they remain a major source for drug production. Natural products derived from marine microorganisms have received much attention in recent years due to their applications in human health. One of the biggest bottlenecks in the drug discovery pipeline is the rediscovery of known compounds. Hence, dereplication strategies such as genome sequencing, genome mining and LCMS/MS among others, are essential for unlocking novel chemistry as it directs compound discovery away from previously described compounds. In this study, the genome of a marine microorganism, Thalassomonas viridans XOM25T was mined and its antimicrobial activity was assessed against a range of microorganisms. Genome sequencing data revealed that T. viridans is a novel bacterium with an average nucleotide identity of 81% to its closest relative T. actiniarum. Furthermore, genome mining data revealed that 20% of the genome was committed to secondary metabolisms and that the pathways were highly novel at a sequence level. To our knowledge, this species has not previously been exploited for its antimicrobial activity. Hence, the aim of this study was to screen for bioactivity and identify the biosynthetic gene/s responsible for the observed bioactivity in T. viridans using a bioassay-and-genome- guided isolation approach to assess the bioactive agent. The bioassay-guided fractionation approach coupled to LCMS/MS led to the identification of a novel antimicrobial protein, TVP1. Bioinformatic analyses showed that TVP1 is a novel antimicrobial protein that is found in the tail region of a prophage in the T. viridans genome. Phage-derived proteins have previously been shown to induce larval settlement in some marine invertebrates. Since the mechanism of action of TVP1 remains unknown, it remains a speculation whether it may offer a similar function. More research is required to determine the biotechnological application and the role of TVP1 in its host and natural environment.

Im Rahmen der Untersuchung wurde bei 27 Patienten, die klinische Zeichen der Karies, aber keine pulpitischen Symptome zeigten, kariöses Dentin mit Hilfe eines sterilen Exkavators entnommen. Das durchschnittliche Alter der Patienten beträgt 41 Jahre und der Durchschnittswert des DMF-T-Index 12,5. Die Untersuchungsgruppe bestand zu 55,5 % aus männlichen Probanden sowie zu 44 % aus Rauchern. Nach Isolierung von 107 Reinkulturen aus den Patientenproben erfolgte die Identifizierung der oralen Streptokokken mittels eines mikrobiologischen Standardtests (RapidID-32Strep der Firma BioMérieux) und MALDI-TOF-MS-Analyse. Parallel wurden speziesspezifische PCRs der Dentinproben für S. sanguinis, S. constellatus, S. intermedius, S. anginosus, S. mutans, S. salivarius, S. oralis, S. mitis, S. gordonii und S. parasanguinis durchgeführt. Mittels MALDI-TOF-MS-Analyse konnten insgesamt sechs verschiedene Spezies oraler Streptokokken in den Dentinproben nachgewiesen werden. Am häufigsten kamen Vertreter der Mitis-Gruppe vor (in 89 % der Dentinproben), gefolgt von S. gordonii und S. sanguinis (zu 52 % und 26 % vertreten). Die MALDI-TOF-MS-Methode erwies sich als geeignetere der mit Kultivierung verbundenen Nachweismethoden. Ihre Ergebnisse wurden durch selektive PCRs einzelner Subkulturen und DNA-Sequenzierung bestätigt. Mittels der speziesspezifischen PCRs der Dentinspäne wurden zehn verschiedene Spezies oraler Streptokokken identifiziert. Vertreter der Mutans-Gruppe wurden so zu durchschnittlich 44 %, S. salivarius zu 37 % nachgewiesen. Es zeigte sich ein signifikantes Vorkommen von S. anginosus in Proben, die ebenfalls S. mutans enthielten (p= 0,00213). Alle drei Verfahren sind zur Untersuchung klinischer Proben geeignet, wobei die MALDI-TOF-MS-Analyse die genaueste Differenzierung auf Speziesebene ermöglicht. Die Non-Mutans-Streptokokken S. oralis, S. gordonii und S. anginosus scheinen die Mikroflora von kariösem Dentin zu dominieren. Sie übertrafen in der vorliegenden Arbeit in ihrem Vorkommen S. mutans in mehr als der Hälfte der untersuchten Proben. Diese Beobachtung stützt die erweiterte ökologische Plaquehypothese.

Streptococcus sanguinis, an abundant and benign inhabitant of the oral cavity, is an important etiologic agent of infective endocarditis, particularly in people with pre-disposing cardiac valvular damage. Although commonly isolated from patients with IE, little is known about the factors that make any particular S. sanguinis isolate more virulent than another or, indeed, whether significant differences in virulence exist among isolates. To investigate the virulence of multiple isolates, a variation of the Bar-seq (barcode sequencing) method was employed. A conserved chromosomal site was identified for subsequent insertion of a barcode identifier, unique for each strain. Barcode insertion did not affect growth in vitro or in a rabbit model of endocarditis. Pooling of these strains and inoculation into rabbits demonstrated that all strains were capable of causing disease; however, virulence varied widely among strains. Genomic comparisons of the more virulent strains versus less virulent strains failed to conclusively identify any single gene responsible for virulence. Given this result, we continued our examination of the manganese transport system SsaACB, which is present in every strain of S. sanguinis examined. Although its contribution to virulence has not been confirmed in any strain other than SK36, it has been shown to be required for virulence in multiple species of streptococci, making it a candidate for emerging targeted therapies. In S. sanguinis strain SK36, previous studies have confirmed that loss of the manganese transport protein SsaB is tantamount to loss of virulence. Moreover, ssaB-deficient mutants are deficient for serum growth—a phenotype we have previously found to be associated with virulence. Our in vitro studies of manganese transporter-deficient strain SK36 supported this, but also revealed the emergence of suppressor mutants. In each suppressor mutant that was isolated, mutations were identified that mapped to a common gene, SSA_0696. Deletion of SSA_0696 resulted in restored in vitro growth in the ssaACB-deficient background, unearthing a novel mechanism for bacterial growth under manganese limitation. Fortunately, the suppressor mutant phenotype was not maintained in vivo; however, the combined results of these experiments suggest the efficacy of future therapeutics may require consideration of virulence at the species level and the incorporation of multiple targets.

Im Rahmen der Untersuchung wurde bei 27 Patienten, die klinische Zeichen der Karies, aber keine pulpitischen Symptome zeigten, kariöses Dentin mit Hilfe eines sterilen Exkavators entnommen. Das durchschnittliche Alter der Patienten beträgt 41 Jahre und der Durchschnittswert des DMF-T-Index 12,5. Die Untersuchungsgruppe bestand zu 55,5 % aus männlichen Probanden sowie zu 44 % aus Rauchern. Nach Isolierung von 107 Reinkulturen aus den Patientenproben erfolgte die Identifizierung der oralen Streptokokken mittels eines mikrobiologischen Standardtests (RapidID-32Strep der Firma BioMérieux) und MALDI-TOF-MS-Analyse. Parallel wurden speziesspezifische PCRs der Dentinproben für S. sanguinis, S. constellatus, S. intermedius, S. anginosus, S. mutans, S. salivarius, S. oralis, S. mitis, S. gordonii und S. parasanguinis durchgeführt. Mittels MALDI-TOF-MS-Analyse konnten insgesamt sechs verschiedene Spezies oraler Streptokokken in den Dentinproben nachgewiesen werden. Am häufigsten kamen Vertreter der Mitis-Gruppe vor (in 89 % der Dentinproben), gefolgt von S. gordonii und S. sanguinis (zu 52 % und 26 % vertreten). Die MALDI-TOF-MS-Methode erwies sich als geeignetere der mit Kultivierung verbundenen Nachweismethoden. Ihre Ergebnisse wurden durch selektive PCRs einzelner Subkulturen und DNA-Sequenzierung bestätigt. Mittels der speziesspezifischen PCRs der Dentinspäne wurden zehn verschiedene Spezies oraler Streptokokken identifiziert. Vertreter der Mutans-Gruppe wurden so zu durchschnittlich 44 %, S. salivarius zu 37 % nachgewiesen. Es zeigte sich ein signifikantes Vorkommen von S. anginosus in Proben, die ebenfalls S. mutans enthielten (p= 0,00213). Alle drei Verfahren sind zur Untersuchung klinischer Proben geeignet, wobei die MALDI-TOF-MS-Analyse die genaueste Differenzierung auf Speziesebene ermöglicht. Die Non-Mutans-Streptokokken S. oralis, S. gordonii und S. anginosus scheinen die Mikroflora von kariösem Dentin zu dominieren. Sie übertrafen in der vorliegenden Arbeit in ihrem Vorkommen S. mutans in mehr als der Hälfte der untersuchten Proben. Diese Beobachtung stützt die erweiterte ökologische Plaquehypothese.