Effect of Photodynamic Therapy on Microorganisms Responsible for Dental Caries: A Systematic Review and Meta-Analysis.

The aim of this study was to perform a systematic review of the literature followed by a meta-analysis about the efficacy of photodynamic therapy (PDT) on the microorganisms responsible for dental caries. The research question and the keywords were constructed according to the PICO strategy. The article search was done in Embase, Lilacs, Scielo, Medline, Scopus, Cochrane Library, Web of Science, Science Direct, and Pubmed databases. Randomized clinical trials and in vitro studies were selected in the review. The study was conducted according the PRISMA guideline for systematic review. A total of 34 articles were included in the qualitative analysis and four articles were divided into two subgroups to perform the meta-analysis. Few studies have achieved an effective microbial reduction in microorganisms associated with the pathogenesis of dental caries. The results highlight that there is no consensus about the study protocols for PDT against cariogenic microorganisms, although the results showed the PDT could be a good alternative for the treatment of dental caries.

Selection of an appropriate empiric antibiotic regimen in hematogenous vertebral osteomyelitis.

BACKGROUND: Empiric antibiotic therapy for suspected hematogenous vertebral osteomyelitis (HVO) should be initiated immediately in seriously ill patients and may be required in those with negative microbiological results. The aim of this study was to inform the appropriate selection of empiric antibiotic regimens for the treatment of suspected HVO by analyzing antimicrobial susceptibility of isolated bacteria from microbiologically proven HVO. METHOD: We conducted a retrospective chart review of adult patients with microbiologically proven HVO in five tertiary-care hospitals over a 7-year period. The appropriateness of empiric antibiotic regimens was assessed based on the antibiotic susceptibility profiles of isolated bacteria. RESULTS: In total, 358 cases of microbiologically proven HVO were identified. The main causative pathogens identified were methicillin-susceptible Staphylococcus aureus (33.5%), followed by methicillin-resistant S. aureus (MRSA) (24.9%), Enterobacteriaceae (19.3%), and Streptococcus species (11.7%). Extended spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae and anaerobes accounted for only 1.7% and 1.4%, respectively, of the causative pathogens. Overall, 73.5% of isolated pathogens were susceptible to levofloxacin plus rifampicin, 71.2% to levofloxacin plus clindamycin, and 64.5% to amoxicillin-clavulanate plus ciprofloxacin. The susceptibility to these oral combinations was lower in cases of healthcare-associated HVO (52.6%, 49.6%, and 37.6%, respectively) than in cases of community-acquired HVO (85.8%, 84.0%, and 80.4%, respectively). Vancomycin combined with ciprofloxacin, ceftriaxone, ceftazidime, or cefepime was similarly appropriate (susceptibility rates of 93.0%, 94.1%, 95.8%, and 95.8%, respectively). CONCLUSIONS: Based on our susceptibility data, vancomycin combined with a broad-spectrum cephalosporin or fluoroquinolone may be appropriate for empiric treatment of HVO. Fluoroquinolone-based oral combinations may be not appropriate due to frequent resistance to these agents, especially in cases of healthcare-associated HVO.

Bloodstream infections in hospitalized adults with dengue fever: Clinical characteristics and recommended empirical therapy.

BACKGROUND: Dengue is an important mosquito-borne tropical viral disease and dual infection, though rare, has been regarded as a risk factor for severe disease and mortality. However, few studies focused on bloodstream infections (BSIs) and empirical antibiotic therapy rarely addressed. METHODS: Dengue patients with concurrent or subsequent BSIs between July 1 and December 31, 2015 were included. Clinical information, laboratory data, and drug susceptibility data were collected. RESULTS: Totally 80 patients, with an in-hospital mortality rate of 32.5%, were included and categorized into three groups. 32 patients in Group I (BSI onset within 48 h after admission), 32 in Group II (between 48 h and one week), and 16 in Group III (more than one week). Patients in Group I were older (mean age: 75.6 vs. 72.6 or 69.6 years; P = 0.01) and had a higher Charlson comorbidity index (3.1 vs. 1.8 or 1.9; P = 0.02) than those in Group II or III. Streptococcus species (28.9%, 11/38) and Escherichia coli (23.7%, 9/38) were major pathogens in Group I. Enterobacteriaceae (38.2%, 13/34) isolates predominated in Group II. Fatal patients more often received inappropriate empirical antibiotic than the survivors (61.5% vs. 35.2%; P = 0.03). According to susceptibility data, pathogens in Group I and II shared similar susceptibility profiles, and levofloxacin, cefepime, or piperacillin/tazobactam, can be empirically prescribed for those hospitalized within one week. CONCLUSIONS: BSI pathogens vary among dengue patients. For adults with dengue and suspected BSI hospitalized within one week, empirical antimicrobial agents are recommended.

Effects of green tea on miRNA and microbiome of oral epithelium.

Consumption of green tea (GT) extracts or purified catechins has shown the ability to prevent oral and other cancers and inhibit cancer progression in rodent models, but the evidence for this in humans is mixed. Working with humans, we sought to understand the source of variable responses to GT by examining its effects on oral epithelium. Lingual epithelial RNA and lingual and gingival microbiota were measured before and after 4 weeks of exposure in tobacco smokers, whom are at high risk of oral cancer. GT consumption had on average inconsistent effects on miRNA expression in the oral epithelium. Only analysis that examined paired miRNAs, showing changed and coordinated expression with GT exposure, provided evidence for a GT effect on miRNAs, identifying miRNAs co-expressed with two hubs, miR-181a-5p and 301a-3p. An examination of the microbiome on cancer prone lingual mucosa, in contrast, showed clear shifts in the relative abundance of Streptococcus and Staphylococcus, and other genera after GT exposure. These data support the idea that tea consumption can consistently change oral bacteria in humans, which may affect carcinogenesis, but argue that GT effects on oral epithelial miRNA expression in humans vary between individuals.

Persistence of antimicrobial resistance in respiratory streptococci.

OBJECTIVES: To assess whether persistence of antimicrobial resistance (i.e. non-susceptible resistance status) after treatment with penicillins or cephalosporins versus macrolides or tetracyclines differs and to compare the results obtained using routinely collected data with findings reported in prospective studies. METHODS: Routinely collected microbiological data from 14 voluntary participating laboratories (2005) containing information on resistance status and individual antimicrobial consumption patterns (mid 2004-2005) were analysed using a generalised estimating equation (GEE) approach. The link function was adjusted to acknowledge that the proportion of resistant isolates in the population not treated with antibiotics [baseline resistance (BR)] is not necessarily zero. To optimise the comparability of this study with prospective studies, the analysis was repeated after removal of 14 isolates from patients who did not survive 2005. RESULTS: BR estimates were unstable and their confidence intervals were wide, which called for a sensitivity analysis using an adjusted GEE model with three different BR estimates. All models indicated that the proportion of susceptible isolates differed by treatment group and increased significantly over time, with this increase being independent of treatment group. Persistence of resistance after exposure to macrolides or tetracyclines was approximately three times as long as after exposure to penicillins or cephalosporins. CONCLUSIONS: Resistance following treatment with macrolides or tetracyclines persists longer than following treatment with penicillins or cephalosporins, which confirms the findings from prospective studies and suggests the use of routinely collected data as a valuable alternative to determine such differences in persistence of resistance.

The relationship of the lipoprotein SsaB, manganese and superoxide dismutase in Streptococcus sanguinis virulence for endocarditis.

Streptococcus sanguinis colonizes teeth and is an important cause of infective endocarditis. Our prior work showed that the lipoprotein SsaB is critical for S. sanguinis virulence for endocarditis and belongs to the LraI family of conserved metal transporters. In this study, we demonstrated that an ssaB mutant accumulates less manganese and iron than its parent. A mutant lacking the manganese-dependent superoxide dismutase, SodA, was significantly less virulent than wild-type in a rabbit model of endocarditis, but significantly more virulent than the ssaB mutant. Neither the ssaB nor the sodA mutation affected sensitivity to phagocytic killing or efficiency of heart valve colonization. Animal virulence results for all strains could be reproduced by growing bacteria in serum under physiological levels of O(2). SodA activity was reduced, but not eliminated in the ssaB mutant in serum and in rabbits. Growth of the ssaB mutant in serum was restored upon addition of Mn(2+) or removal of O(2). Antioxidant supplementation experiments suggested that superoxide and hydroxyl radicals were together responsible for the ssaB mutant's growth defect. We conclude that manganese accumulation mediated by the SsaB transport system imparts virulence by enabling cell growth in oxygen through SodA-dependent and independent mechanisms.

In vitro anticariogenic effects of Drymocallis rupestris extracts and their quality evaluation by HPLC-DAD-MS³ analysis.

In this study, for the first time, we investigated in vitro inhibitory effects of Drymocallis rupestris extracts and their subfractions obtained with solvents of different polarity (aqueous, 50% ethanolic, diethyl ether, ethyl acetate and n-butanolic) against bacterial viability and caries virulence factors of Streptococcus spp. strains. The diethyl ether subfraction (PRU2) showed bacteriostatic and bactericidal activity against mutans streptococci, with minimum inhibitory concentrations (MICs) in the range of 0.75-1.5 mg/mL and minimum bactericidal concentrations (MBCs) in the range of 1.5-3 mg/mL. Furthermore, PRU2 inhibited biofilm formation by Streptococci in a dose-dependent manner. It was also found that all five D. rupestris preparations exhibited diverse inhibitory effects on de novo synthesis of water-insoluble and water-soluble α-D-glucans by glucosyltransferases of the mutans group streptococci. The phytochemical profile of investigated samples was determined by spectrophotometric and chromatographic (HPLC-DAD-MS³) methods. The high polyphenol (total phenol, phenolic acids, tannins, proantocyanidins, and flavonoids) contents were found which correlated with anticariogenic activity of the analyzed samples. The results demonstrate that D. rupestris extracts and their subfractions could become useful supplements for pharmaceutical products as a new anticariogenic agent in a wide range of oral care products. Further studies are necessary to clarify which phytoconstituents of D. rupestris are responsible for anticaries properties.

Genotyping of erythromycin resistant group C & G streptococci isolated in Chennai, south India.

BACKGROUND & OBJECTIVES: Increasing resistance to erythromycin has been observed worldwide in group C and group G streptococci (GCS/GGS). The information available from India is scanty. The aim of the study was to identify erythromycin resistant GCS/GGS isolates in Chennai, south India, and to compare erythromycin resistant genotypes with emm types. METHODS: One hundred and thirty one GCS/GGS isolates were tested for erythromycin resistance by disc diffusion and agar dilution methods. Erythromycin resistance genotypes [erm(A), erm(B) and mef(A)] were determined by a multiplex PCR. emm types of erythromycin resistant GCS/GGS isolates was also assessed using emm gene sequencing method. RESULTS: Sixteen of the 131 isolates (12.21%) were resistant to erythromycin. Majority of the isolates were GGS (15/16). Eight of the 16 (50%) were S. dysgalactiae subsps. equisimilis. Twelve isolates (75%) were MLS B phenotype and four (25%) were M phenotype. Of the 12 isolates which exhibited MLS B resistance, seven showed cMLS B phenotype and were positive for erm(B) gene. The remaining five were iMLS B phenotype of which three were positive for erm(A) gene and two for erm(B) gene. erm(A) was common among carriers whereas erm(B) was common among clinical isolates. INTERPRETATION & CONCLUSIONS: MLS B was the predominant phenotype and erm(B) was the common genotype in the present study. The emm type stC1400.0 was frequently associated with erythromycin resistant GCS/GGS in our study.

Linezolid as rescue treatment for left-sided infective endocarditis: an observational, retrospective, multicenter study.

The increasing number of resistant bacterial strains in infective endocarditis (IE) emphasizes the need for a constant development of antimicrobials. Linezolid is an oxazolidinone with an effect on Gram-positive cocci. Only a few casuistic reports describe its utilization in the treatment of IE. The objective of this study is to report our experience with linezolid from a large consecutive cohort of IE patients. In a retrospective cohort study, data on 550 consecutive IE patients were collected at two tertiary University Hospitals in Copenhagen, Denmark. The main endpoints were differences in the in-hospital and 12 months post-discharge mortality between IE patients receiving linezolid for a part of the treatment and IE patients receiving conventional treatment. Of the 550 patients enrolled in the study, 38 patients received linezolid treatment and 512 received conventional treatment. Reasons for adding linezolid were antibiotic intolerance (n = 13), nephrotoxicity (n = 5), pharmaceutical interactions (n = 1), inadequate clinical response (n = 14), or inadequate microbial response (n = 5). No significant differences in the cure rate (74 % vs. 71 %, p > 0.05), in-hospital mortality (13 % vs. 14 %, p > 0.05), or post-discharge mortality at 12 months follow-up (26 % vs. 26 %, p > 0.05) were observed. In the current study, we found that linezolid, in general, was well tolerated and associated with the same outcome as in patients with Gram-positive IE treated with other antibiotics.

In vitro inhibitory effects of Polygonum cuspidatum on bacterial viability and virulence factors of Streptococcus mutans and Streptococcus sobrinus.

OBJECTIVES: Polygonum cuspidatum has been used in Korean folk medicine to improve oral hygiene. This study was performed to evaluate the effects of methanol extract from root of P. cuspidatum (MEP) on bacterial viability and the virulence factors of Streptococcus mutans and Streptococcus sobrinus. METHODS: To test the effects of MEP on bacterial viability, we determined the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) against 20 bacterial strains, including S. mutans and S. sobrinus, using a micro-dilution assay. In case of S. mutans and S. sobrinus, the assays for time-kill and bacterial growth rate at sub-MIC concentrations were also performed. To determine effects of the extract on the virulence factors of S. mutans and S. sobrinus, the assays for sucrose-dependent adherence, water-insoluble glucan formation, glycolytic acid production, and acid tolerance were performed at sub-MIC levels. Phytochemical analysis for constituents of MEP was carried out. RESULTS: MEP showed a broad antibacterial range (MIC 0.5-4 mg/ml). The MBC was two to four times higher than the MIC. The time-kill curves showed S. mutans and S. sobrinus were significantly killed after 1h of incubation. At sub-MIC levels, doubling times of S. mutans and S. sobrinus dose-dependently increased up to 211% and 123%, respectively. At sub-MIC levels, MEP also showed inhibitory effects on the virulence factors of S. mutans and S. sobrinus in a dose-dependent fashion. Phytochemical analysis revealed the presence of alkaloids, sterol/terpenes, tannins, flavonoids, and carbohydrates. CONCLUSION: These data indicate that MEP has inhibitory effects on bacterial viability at higher concentrations (> or =MIC) and the virulence factors of S. mutans and S. sobrinus at sub-MIC concentrations, suggesting that it might be useful for the control of dental plaque formation and subsequent dental caries formation.

A third report of "golf ball disease" in an Amazon River dolphin (Inia geoffrensis) associated with Streptococcus iniae.

An Amazon River dolphin (Inia geoffrensis) developed a dermatologic syndrome characterized by the occurrence of slow-growing, nodular, s.c. abscesses. Initial biopsies, cultures, and cytologic analysis of needle aspirates from the abscesses indicated steatitis with probable secondary, gram-negative bacterial infection. Treatment with dietary vitamin E supplement and broad-spectrum antibiotics yielded minimal improvement. Subsequent cultures revealed Streptococcus iniae in addition to several gram-negative bacteria. Vigorous surgical management of the abscesses, including lancing, debridement, and irrigation, combined with antimicrobial therapy specific for Streptococcus and gram-negative organisms, and improvement of the animal's diet and environmental water quality led to gradual recovery. When the animal was ill, it demonstrated an inflammatory leukogram and transient uremia. Streptococcus iniae is a serious pathogen of aquacultured fishes and humans and should be included in the differential diagnosis of chronic dermatopathy in river dolphins. Specific antimicrobial therapy, excellent water quality, surgical management of abscesses, and adherence to sanitary protocols should be observed in cases of suspected S. iniae infection in dolphins.

Celulitis orbitaria en la edad pediátrica. Revisión / Orbital cellulitis in childhood. Review

La celulitis orbitaria comprende dos patologías bien diferenciadas desde un punto de vista anatomoclínico: la forma preseptal y la postseptal. Constituye una enfermedad infecciosa relativamente frecuente en la edad pediátrica que, normalmente, es secundaria a sinusitis. Presentamos una revisión de esta patología haciendo especial hincapié en el cambio etiológico acontecido en la última década tras la vacunación sistemática contra Haemophilus influenzae tipo B. (AU)

Sequential events in the pathogenesis of streptococcal cell wall-induced arthritis and their modulation by bis(5-amidino-2-benzimidazolyl)methane (BABIM).

This report builds on the authors' earlier discovery of bis(5-amidino-2-benzimidazolyl)methane (BABIM) as a strong suppressive agent for streptococcal cell wall fragment-induced arthritis in the Lewis rat. As a synthetic inhibitor of trypsinlike proteases, BABIM opens up a new route to the control of inflammatory joint disease. To gain a deeper insight into the function of the compound, the authors have now studied its influence on the sequential development of the joint changes and the associated lesions in spleen and liver. Bis(5-amidino-2-benzimidazolyl)methane is shown to block acute synovitis, to retard and reduce granuloma formation in spleen and liver, to decrease neutrophilic leukocytosis, and to diminish hemopoietic hyperplasia in the bone, and thus also to mitigate the distinctive osteoclastic and chondroclastic events. The compound does not interfere with the splenic immune response, the temporary rise in hepatocytic mitotic activity, or the organ deposition of streptococcal cell walls.

Mechanisms of platelet aggregation by viridans group streptococci.

The direct aggregation of platelets is thought to be an important event in the pathogenesis of viridans streptococcal endocarditis, but the mechanisms for platelet activation are unknown. We evaluated the processes by which two endocarditis-producing strains of viridans group streptococci activated human platelets in vitro, as measured by platelet cyclooxygenase activity, secretion, and aggregation. Addition of either streptococcal strain to platelets suspended in whole plasma resulted in a mean lag phase of 15.3 min, followed by platelet secretion and brisk aggregation. The lag phase duration was dependent on the platelet donor and appeared to be a function of direct platelet-bacterial interaction. Aggregation was partially inhibited by 20 muM [corrected] indomethacin and blocked completely by 1 mg of apyrase, an extracellular ADP hydrolase, per ml. Neither strain aggregated washed platelets suspended in Tyrode solution alone. However, both strains produced maximal aggregation when the platelet suspension was supplemented with 10% (final concentration) normal plasma. Studies with factor-deficient plasmas demonstrated that exogenous fibrinogen was required for aggregation. One or more additional plasma components were needed, which eluted with a molecular weight of 67,000 to 130,000 on gel permeation chromatography. These cofactors have not been described for other platelet agonists, which suggests that viridans streptococci may aggregate human platelets by a novel mechanism.

Virulence of Streptococcus mutans: an antibiotic-suppressed rat model for studies of pathogenesis.

This investigation describes a simple and effective method of antibiotic suppression of the total indigenous microbiol flora of rats. Specifically, the results of this study demonstrate that: (1) antibiotics which inhibit microbial growth of oral and fecal cultures from individual rats are effective in suppressing the indigenous flora of 95% of these rats when provided as dietary supplements; (2) S mutans 6715 colonized 95% of the antibiotic-suppressed animals while only 50% of the untreated rat pups yielded S mutans following challenge with a single inoculum of this micro-organism; and (3) significant smooth surface caries developed in S mutans-infected rats within 20 days when provided caries-promoting Diet 305, while noninfected, antibiotic-suppppressed offspring remained essentially caries-free.