Spectrophotometric Analysis of Streptococcus mutans Growth and Biofilm Formation in Saliva and Histatin-5 Relate to pH and Viscosity

ABSTRACT Objective: To analyze the ability of saliva in controlling the growth and the biofilm formation of Streptococcus mutans (S. mutans) as well as the effect of histatin-5 anti-biofilm relate to pH and saliva viscosity. Material and Methods: The S. mutans biofilm assayed by crystal violet 1% and its growth measured by spectrophotometer. The saliva viscosity was analyzed by viscometer, and pH of saliva was measured by pH meter. Results: Based on the optical density values, growth of S. mutans in saliva ranged <300 CFU/mL (0.1 nm) at concentrations of 25%, 12.5% and 6.25% for 24 hours. Whereas at the 48 h and 72 h period of incubation shown an increase in growth of S. mutans ranged 300-600 CFU/mL (0.2-0.36 nm). The inhibitory biofilm formation of S. mutans in saliva was significantly higher at concentrations of 12.5% and 6.25% at 24 h incubation times on a moderate scale, whereas the histatin-5 was effective to inhibit S. mutans biofilm on the 50 and 25 ppm. The saliva possessed a higher inhibitory of biofilm S. mutans than histatin-5 and good level viscosity (0.91-0.92 cP). Conclusion: The saliva was able to control the growth of S. mutans, and histatin-5 can inhibit the biofilm formation S. mutans. Furthermore, the saliva was also able to respond to the pH change with good viscosity of saliva.

Characterization and distribution of viridans group streptococci isolated from infectious endophthalmitis and keratitis / Caracterização e distribuição de estreptococos do grupo viridans isolados de endoftalmite infecciosa e ceratite

ABSTRACT Purpose: The aims of this study were to characterize alpha-hemolytic streptococci among isolates from cases of infectious endophthalmitis and keratitis and to determine their distributions. Methods: The sample included 27 and 35 nonduplicated isolates of alpha-hemolytic streptococci recovered from patients with infectious endophthalmitis (2002-2013) and keratitis (2008-2013), respectively. Isolates were identified by the optochin susceptibility and bile solubility tests, using a biochemical identification system. The minimum inhibitory concentration was determined by the broth microdilution method. Molecular identification was performed by analyses of three constitutive genes and the complementary multilocus sequence. The molecular epidemiology of Streptococcus pneumoniae was investigated using multilocus sequence typing, and the presence of the capsular polysaccharide-encoding gene was assessed using conventional polymerase chain reaction. Outcomes were evaluated using the patients' medical records. Results: Phenotypic tests differentiated S. pneumoniae from other alpha-hemolytic streptococci, consistent with later molecular identifications. Streptococcus oralis was significantly prevalent among the endophthalmitis isolates, as was S. pneumoniae in the keratitis isolates. High levels of susceptibility to antibiotics were observed, including vancomycin, cephalosporins, and fluoroquinolones. High genetic variability was detected among the 19 S. pneumoniae strains, with 15 predicted to be encapsulated. The medical records of patients with infectious endophthalmitis were reviewed (n=15/27; 56%), and final visual acuity was assessed in 12 cases (44%). Many patients progressed to a final visual acuity state of "no light perception" (6/12; 50%), "light perception" (3/12; 25%), or "hand motion" (1/12; 8%). The medical records of patients with infectious keratitis were also reviewed (n=24/35; 69%), and final visual acuity was assessed in 18 cases (51%). Similarly, most patients progressed to a final visual acuity state of "no light perception" (6/18; 33%), "light perception" (1/18; 6%), or "hand motion" (6/18; 33%). Overall, the majority of patients progressed to a final visual acuity state of "no light perception" (12/30), "light perception" (4/30), or "hand motion" (7/30). Conclusions: The distribution of alpha-hemolytic streptococci in ocular infections suggested the presence of a species-specific tissue tropism. The prognoses of patients with ocular streptococcal infections were highly unfavorable, and antibiotic resistance did not contribute to the unfavorable clinical progressions and poor outcomes.

RESUMO Objetivo: O objetivo deste estudo foi caracterizar os estreptococos alfa-hemolíticos isolados de endoftalmite infecciosa e ceratite e determinar sua distribuição. Métodos: A amostra incluiu 27 e 35 isolados não-duplicados de estreptococos alfa-hemolíticos recuperados de pacientes com endoftalmite infecciosa (2002-2013) e ceratite (2008-2013), respectivamente. Os isolados foram identificados pelos testes de suscetibilidade à optoquina e bile solubilidade, utilizando um sistema de identificação bioquímica. A concentração inibitória mínima foi determinada pelo método de microdiluição em caldo. A identificação molecular foi realizada pela análise de três genes constitutivos e análise complementar de sequências multilocus. A epidemiologia molecular do Streptococcus pneumoniae foi investigada por tipagem de sequência multilocus, e a presença do gene codificador do polissacarídeo capsular foi avaliada por reação em cadeia da polymerase convencional. Os resultados foram avaliados utilizando os prontuários médicos dos pacientes. Resultados: Os testes fenotípicos diferenciaram S. pneumoniae dos outros estreptococos alpha-hemolíticos, consistentes com identificações moleculares posteriores. S. oralis foi significativamente prevalente entre os isolados de endoftalmite, assim como S. pneumoniae nos isolados de ceratite. Foram observados altos níveis de suscetibilidade a antibióticos, incluindo vancomicina, cefalosporinas e fluoroquinolonas. Alta variabilidade genética foi detectada entre as 19 cepas de S. pneumoniae, com 15 previstas para serem encapsuladas. Os prontuários médicos dos pacientes com endoftalmite infecciosa foram revisados (n=15/27; 56%), e a acuidade visual final foi avaliada em 12 casos (44%). Muitos pacientes evoluiram para um estado final de acuidade visual de "sem percepção luminosa" (6/12; 50%), "percepção luminosa" (3/12; 25%) ou "movimentos de mãos" (1/12; 8%). Também foram revisados os prontuários médicos dos pacientes com ceratite infecciosa (n=24/35; 69%), e a acuidade visual final foi avaliada em 18 casos (51%). Da mesma foram, a maioria dos pacientes evoluiu para um estado final de acuidade visual de "sem percepção luminosa" (6/18; 33%), "percepção luminosa" (1/18; 6%) ou "movimentos de mãos" (6/18; 33%). No geral, a maioria dos pacientes evoluiu para um estado final de acuidade visual de "sem percepção luminosa" (12/30), "percepção luminosa" (4/30) ou "movimentos de mãos" (7/30). Conclusões: A distribuição de estreptococos alfa-hemolíticos nas infecções oculares sugeriu a presença de um tropismo de tecido específico da espécie. Os prognósticos dos pacientes com infeções oculares por estreptococos foram altamente desfavoráveis e a resistência a antibióticos contribuiu não para as progressões clínicas des­favoráveis e os maus resultados.

Prevalence of rectovaginal colonization by group B Streptococcus in pregnant women seen at prenatal care program of a health organization / Prevalência de colonização retovaginal por estreptococo do grupo B em gestantes de programa de atendimento pré-natal de instituição de saúde

ABSTRACT Objective To evaluate the prevalence of group B Streptococci in pregnant women of a corporate health program, as well as the epidemiological correlations. Methods This retrospective study used medical records of patients who participated of the prenatal care program at a private hospital in the city of São Paulo (SP), Brazil, from 2015 to 2016. Those who abandoned the program or had incomplete data in their medical records were excluded. Quantitative variables were described by means, standard deviations, median, minimal and maximal values. Parity and socioeconomic status were described by absolute frequency and percentages. We used logistic regression models in the software (SPSS) to analyze correlations of variables according to vaginal-rectal culture, considering a 95%CI and p-values. Variables were age, number of pregnancies, weight gain in pregnancy and gestational age at delivery. Results A total of 347 medical records were included, and after applying the exclusion criteria, 287 medical records composed the final sample. Patients' age ranged between 17 and 44 years. Mean age was 30.6 years, 67 patients had positive result for group B Streptococcus (prevalence of 23.3%; 95%CI: 18.7-28.5). Conclusion Considering the high prevalence of group B Streptococcus in our service, the antibiotic prophylaxis strategy based on rectovaginal culture screening approach seems to be cost-effective.

RESUMO Objetivo Identificar a prevalência de estreptococo do grupo B entre gestantes que frequentaram um programa de saúde corporativa, bem como as correlações com a colonização positiva. Métodos Estudo retrospectivo dos prontuários do pré-natal de um hospital privado em São Paulo, no período de 2015 a 2016. Foram excluídas as mulheres que abandonaram o programa ou apresentavam dados incompletos nos prontuários. As variáveis quantitativas foram descritas por média, desvios padrão, mediana, valores mínimos e máximos. A paridade e a condição socioeconômica foram descritos por frequência absoluta e percentagens. Utilizamos modelos de regressão logística no programa (SPSS) para analisar as correlações de variáveis de acordo com a cultura retovaginal, considerando IC95% e valores de p. As variáveis foram idade, número de gestações, peso ganho na gestação e idade gestacional no parto. Resultados Foram incluídos 347 prontuários e, após a aplicação dos critérios de exclusão, 287 prontuários compuseram a amostra final. A idade dos pacientes variou entre 17 e 44 anos. A média de idade foi de 30,6 anos, e 67 pacientes tiveram resultado positivo para o estreptococo do grupo B (prevalência de 23,3%; IC95%: 18,7-28,5). Conclusão Considerando a alta prevalência de estreptococos do grupo B em nosso serviço, existem evidências de que a estratégia de antibiótico profilaxia baseada na cultura retovaginal é custo-efetiva.

Modeling the Growth of Bacteria Streptococcus sobrinus Using Exponential Regression

Abstract Objective: To build an exponential regression model based on parameter estimation. Material and Methods: We developed a simple mathematical model to simulate the growth of bacteria and the exponential growth is often used to model population growth as such cell growth while the exponential decay is portraying a declining or decreases in the size of the population. An exponential regression method was used to fit the data and estimate growth parameter values Streptococcus sobrinus using statistical software SPSS version 20. Results: Based on the results of the parameter estimates, which is constant are 83.039 and b1 is 0.005 while R-square is 0.952. According to the R-Square results obtained, the model is good and appropriate. Conclusion: The model can be used to find the potential biological parameters, which may be able to predict the treatment outcome. This study helps researchers to understand the specific growth rate(s), which can be used to best grow the organism.

Oral streptococci show diversity in resistance to complement immunity.

PURPOSE: Mechanisms underlying systemic infections by oral species of Mitis (Streptococcus mitis, Streptococcus oralis) and Sanguinis (Streptococcus gordonii, Streptococcus sanguinis) commensal streptococci are poorly understood. This study investigates profiles of susceptibility to complement-mediated host immunity in representative strains of these four species, which were isolated from oral sites or from the bloodstream. METHODOLOGY: Deposition of complement opsonins (C3b/iC3b), and surface binding to C-reactive protein (CRP) and to IgG antibodies were quantified by flow cytometry in 34 strains treated with human serum (HS), and compared to rates of opsonophagocytosis by human PMN mediated by complement (CR1/3) and/or IgG Fc (FcγRII/III) receptors. RESULTS: S. sanguinis strains showed reduced susceptibility to complement opsonization and low binding to CRP and to IgG compared to other species. Surface levels of C3b/iC3b in S. sanguinis strains were 4.5- and 7.8-fold lower than that observed in S. gordonii and Mitis strains, respectively. Diversity in C3b/iC3b deposition was evident among Mitis species, in which C3b/iC3b deposition was significantly associated with CR/FcγR-dependent opsonophagocytosis by PMN (P<0.05). Importantly, S. gordonii and Mitis group strains isolated from systemic infections showed resistance to complement opsonization when compared to oral isolates of the respective species (P<0.05). CONCLUSIONS: This study establishes species-specific profiles of susceptibility to complement immunity in Mitis and Sanguinis streptococci, and indicates that strains associated with systemic infections have increased capacity to evade complement immunity. These findings highlight the need for studies identifying molecular functions involved in complement evasion in oral streptococci.

Microbial species associated with dental caries found in saliva and in situ after use of self-ligating and conventional brackets

Abstract Objectives Enamel demineralization is among the main topics of interest in the orthodontic field. Self-ligating brackets have been regarded as advantageous in this aspect. The aim of this study was to evaluate the break homeostasis in the oral environment and the levels of microorganisms associated with dental caries among the different types of brackets. Material and Methods Twenty patients received two self-ligating brackets: In-Ovation®R, SmartClipTM, and one conventional GeminiTM. Saliva was collected before bonding (S0), 30 (S1) and 60 (S2) days after bonding. One sample of each bracket was removed at 30 and 60 days for the in situ analysis. Checkerboard DNA-DNA Hybridization was employed to evaluate the levels of microbial species as-sociated with dental caries. Data were evaluated by nonparametric Friedman and Wilcoxon tests at 5% significance level. Results The salivary levels of L. casei (p=0.033), S. sobrinus (p=0.011), and S. sanguinis (p=0.004) increased in S1. The in situ analyses showed alteration in S. mutans (p=0.047), whose highest levels were observed to the In-Ovation®R. Conclusions The orthodontic appliances break the salivary homeostasis of microorganisms involved in dental caries. The contamination pattern was different between self-ligating and conventional brackets. The In-Ovation®R presented worse performance considering the levels of cariogenic bacterial species.

Bacteriology of peritonsillar abscess: the changing trend and predisposing factors / Bacteriologia do abscesso peritonsilar: tendência de mudança e fatores predisponentes

Abstract Introduction: Peritonsillar abscess is the most common deep neck infection. The infectious microorganism may be different according to clinical factors. Objective: To identify the major causative pathogen of peritonsillar abscess and investigate the relationship between the causative pathogen, host clinical factors, and hospitalization duration. Methods: This retrospective study included 415 hospitalized patients diagnosed with peritonsillar abscess who were admitted to a tertiary medical center from June 1990 to June 2013. We collected data by chart review and analyzed variables such as demographic characteristics, underlying systemic disease, smoking, alcoholism, betel nut chewing, bacteriology, and hospitalization duration. Results: A total of 168 patients had positive results for pathogen isolation. Streptococcus viridans (28.57%) and Klebsiella pneumoniae (23.21%) were the most common microorganisms identified through pus culturing. The isolation rate of anaerobes increased to 49.35% in the recent 6 years (p = 0.048). Common anaerobes were Prevotella and Fusobacterium spp. The identification of K. pneumoniae increased among elderly patients (age > 65 years) with an odds ratio (OR) of 2.76 (p = 0.03), and decreased in the hot season (mean temperature > 26 °C) (OR = 0.49, p = 0.04). No specific microorganism was associated with prolonged hospital stay. Conclusion: The most common pathogen identified through pus culturing was S. viridans, followed by K. pneumoniae. The identification of anaerobes was shown to increase in recent years. The antibiotics initially selected should be effective against both aerobes and anaerobes. Bacterial identification may be associated with host clinical factors and environmental factors.

Resumo Introdução: O Abscesso Peritonsilar é a infecção cervical profunda mais comum. O microrganismo infeccioso pode ser diferente de acordo com os fatores clínicos. Objetivo: Identificar o principal agente causador do abscesso peritonsilar e investigar a relação entre o patógeno causador, os fatores clínicos do hospedeiro e a duração da hospitalização. Método: Este estudo retrospectivo incluiu 415 pacientes hospitalizados diagnosticados com abscesso peritonsilar que foram internados em um centro médico terciário de junho de 1990 a junho de 2013. Coletamos dados através da análise dos arquivos médicos dos pacientes e analisamos variáveis como características demográficas, doença sistêmica subjacente, tabagismo, alcoolismo, hábito de mascar noz de betel, bacteriologia e duração da hospitalização. Resultados: Um total de 168 pacientes apresentaram resultados positivos para isolamento de patógenos. Streptococcus viridans (28,57%) e Klebsiella pneumoniae (23,21%) foram os microrganismos mais comuns identificados pela cultura da secreção. A taxa de isolamento de anaeróbios aumentou para 49,35% nos últimos 6 anos (p = 0,048). Os anaeróbios comuns foram Prevotella e Fusobacterium spp. A identificação de K. pneumoniae aumentou em pacientes idosos (idade > 65 anos) com razão de chances (Odds Ratio - OR) de 2,76 (p = 0,03) e diminuiu na estação do calor (temperatura média > 26 °C) (OR = 0,49, p = 0,04). Nenhum microrganismo específico foi associado à hospitalização prolongada. Conclusão: O patógeno mais comumente identificado através da cultura de secreção foi S. viridans, seguido por K. pneumoniae. A identificação de anaeróbios mostrou ter aumentado nos últimos anos. Os antibióticos selecionados inicialmente devem ser efetivos contra aeróbios e anaeróbios. A identificação bacteriana pode estar associada a fatores clínicos e fatores ambientais do hospedeiro.

Relevancia de profilaxis antibiótica ante procedimientos dentales generadores de bacteriemias transitorias / Antimicrobial prophylaxis for transient bacteremia during dental procedures

This review examines the evidence about the relationship between dental procedures and the incidence of transient bacteremia. One of the main obstacles was to define "invasive dental procedure" as an indication for antimicrobial prophylaxis for patients with high risk of bacteremia. A search in WorldWideScience and ScienceDirect was performed and 20 articles were selected for review. Two contradictions stood out. There is no concrete evidence that a transient bacteremia arising during a dental procedure may be a risk factor for the appearance of bacterial endocarditis. There is no certainty about the effectiveness of antimicrobial prophylaxis, due to the lack of clinical trials of good quality. There is a similitude between bacteremia resulting from invasive and non-invasive dental procedures. The importance of periodontal health as a preventive measure for bacterial endocarditis among high risk patients is highlighted.

Bacteriology of peritonsillar abscess: the changing trend and predisposing factors.

INTRODUCTION: Peritonsillar abscess is the most common deep neck infection. The infectious microorganism may be different according to clinical factors. OBJECTIVE: To identify the major causative pathogen of peritonsillar abscess and investigate the relationship between the causative pathogen, host clinical factors, and hospitalization duration. METHODS: This retrospective study included 415 hospitalized patients diagnosed with peritonsillar abscess who were admitted to a tertiary medical center from June 1990 to June 2013. We collected data by chart review and analyzed variables such as demographic characteristics, underlying systemic disease, smoking, alcoholism, betel nut chewing, bacteriology, and hospitalization duration. RESULTS: A total of 168 patients had positive results for pathogen isolation. Streptococcus viridans (28.57%) and Klebsiella pneumoniae (23.21%) were the most common microorganisms identified through pus culturing. The isolation rate of anaerobes increased to 49.35% in the recent 6 years (p=0.048). Common anaerobes were Prevotella and Fusobacterium spp. The identification of K. pneumoniae increased among elderly patients (age>65 years) with an odds ratio (OR) of 2.76 (p=0.03), and decreased in the hot season (mean temperature>26°C) (OR=0.49, p=0.04). No specific microorganism was associated with prolonged hospital stay. CONCLUSION: The most common pathogen identified through pus culturing was S. viridans, followed by K. pneumoniae. The identification of anaerobes was shown to increase in recent years. The antibiotics initially selected should be effective against both aerobes and anaerobes. Bacterial identification may be associated with host clinical factors and environmental factors.

Lemierre's syndrome due to intratumoral abscess of the uvula.

Lemierre's syndrome (LS), described in detail in 1936, used to be a life-threatening entity until the advent of antibiotics. Tonsillitis or pharyngitis are the main primary infections and oropharyngeal anaerobic flora is the predominant etiology. However, other primary site infections, as well as other microbiological agents have been reported since the first description. Inflammatory symptoms in the neck and marked findings on physical examination predominate the majority of cases. Nonetheless, the authors report the case of a 54-year-old man with a history of dysphagia followed by cough, purulent expectoration, and fever. The bad condition of his dentition was noteworthy. During the diagnostic work-up, an ulcerated lesion in the uvula and a middle lobe pneumonia were disclosed. Streptococcus viridans was isolated from blood culture. On the fifth day of hospitalization, the patient died after a copious episode of hemoptysis. The autopsy findings depicted an abscess within a squamous cell carcinoma of the uvula, pharyngitis with carotid sheath spreading accompanied by pylephlebitis and thrombosis of the internal jugular vein up to the innominate vein, surrounded by an abscess in the mediastinum. Alveolar hemorrhage and pneumonia were also present. We conclude that the ulcerated carcinoma of the uvula housed an abscess, facilitated by the poor oral hygiene, which triggered LS and the descending mediastinitis. Pulmonary involvement was due to the septic embolism from the internal jugular vein. We would like to highlight the uvula abscess as the primary site of infection in this case of LS with S. viridans as the causative agent.