5-Aminolevulinic acid photoactivated over planktonic and biofilm forms of Enterococcus faecalis as a pharmacological therapy alternative

The purpose of the study was to evaluate the antibacterial effect of protoporphyrin IX (PpIX) generated by the exogenous administration of 5-aminolevulinic acid or δ-ALA and activated with an argon laser over a planktonic and biofilm of Enterococcus faecalis (E. faecalis) as a pharmacological therapy alternative. A planktonic strain of E. faecalis was cultured with a solution of ∂-ALA (40 µg/mL)-thioglycolate solution for 13 min, and a biofilm of E. faecalis was cultured in a δ-ALA (80 µg/mL)-thioglycolate solution for 13 min. Then, both were irradiated with an argon laser. Finally, the antibacterial effect was evaluated by counting the CFU in planktonic form, and a LIVE/DEAD viability cell test. The production and accumulation of PpIX from exogenously administered δ-ALA on E. faecalis in planktonic and biofilm forms was confirmed by spectrofluorometry. The irradiation of PpIX with an argon laser produced an antibacterial effect on E. faecalis in planktonic and biofilm form, even without biofilm disruption, at a concentration of 40 µg/mL and 80 µg/mL of δ-ALA, respectively. The exogenous administration of δ-ALA in combination with laser irradiation on planktonic and biofilm forms of E. faecalis produces an effective antibacterial effect as complement or alternative to pharmacological therapies

Do different strains of E. faecalis have the same behavior towards intracanal medications in in vitro research?

Abstract: The aim of this study was to evaluate the antimicrobial action of different endodontic pastes against Enterococcus faecalis ATCC 29212, isolated from the urinary tract, and compare the action with E. faecalis ATCC 4083, isolated from the root canal. For this purpose, dentin blocks were infected for 21 days with both bacteria at different time-intervals to ensure there would be no cross contamination. After this period, blocks were immersed in the test medications for 7 days, according to the following groups: CH/S, CH/P, CH/CMCP, CH/CHX, CH/DAP and TAP. Images of the samples were captured with a confocal microscope and the percentage of live cells was computed by means of the Bioimage program. The ATCC 29212 strain was shown to be more resistant to CH/SS, Calen, CH/DAP, and TAP than the ATCC 4083 strain. The antimicrobial action of the medications against each strain were divergent concerning the order of susceptibility. The authors concluded that the strains behaved in a different manner: in general, those extracted from the urinary tract were more resistant to the tested medications. Therefore, when E. faecalis must be used for in vitro research in endodontics, we suggest the use of ATCC 4083 strain to obtain results that are closer to the clinical reality.

Estudo preliminar toxicológico, antibacteriano e fitoquímico do extrato etanólico das folhas de Jatropha mollissima (Pohl) Baill. (pinhão-bravo, Euphorbiaceae), coletada no Município de Tauá, Ceará, Nordeste Brasileiro / Toxicological, antibacterial, and phytochemical preliminary study of the ethanolic extract of Jatropha mollissima (Pohl) Baill (pinhão-bravo, Euphorbiaceae) leaves, collected in Tauá, Ceará, Northeastern Brazil

RESUMO A cada dia, cepas bacterianas estão tornando-se resistentes a diversos antibióticos, o que faz necessária a busca de novas substâncias eficazes para o tratamento de doenças. Desta forma, este trabalho reporta o estudo preliminar toxicológico, antibacteriano e fitoquímico do extrato etanólico das folhas de Jatropha mollissima (pinhão-bravo, Euphorbiaceae), coletada no Município de Tauá, Ceará, Nordeste Brasileiro. Inicialmente, realizou-se o teste de toxicidade do extrato contra Artemia salina. Na sequencia, foi realizado o ensaio antibacteriano contra quatro cepas bacterianas Gram-negativas (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Hafnia alvei ATCC 51873, Klebsiella pneumoniae ATCC 13883) e uma cepa Gram-positiva (Enterococcus faecalis ATCC 29212). Finalmente, fez-se a análise fitoquímica preliminar do extrato ativo para detecção das principais classes de metabólitos especiais. Como resultado, o extrato etanólico das folhas de J. mollissima se mostrou tóxico para Artemia salina, pois apresentou CL50 igual a 406,02 μg/mL. Quanto à ação antibacteriana, o extrato se mostrou ativo contra a bactéria Gram-positiva Enterococcus faecalis ATCC 29212, apresentando moderada atividade antibacteriana (halo de inibição igual a 7,03 mm). Evidenciou-se no extrato bioativo a presença de cumarinas, fenóis, taninos, flavonoides (flavonóis e flavanonas), alcaloides e esteroides, ambas as classes reportadas como antimicrobianos. Portanto, esse extrato tem potencial para ser usado na produção de fármacos contra infecções causadas por bactérias Gram-positivas. No entanto, as informações direcionam estudos futuros para o isolamento e identificação dos compostos bioativos, monitorados sob a ação antibacteriana mais expressiva.

ABSTRACT Each day, bacterial strains are becoming more resistant to various antibiotics, which requires the search for new effective substances for the treatment of diseases. Thus, this study reports the toxicological, antibacterial, and phytochemical preliminary study of the ethanolic extracts of Jatropha mollissima (pinhão-bravo, Euphorbiaceae) leaves, collected in Tauá, Ceará, Northeast of Brazil. Initially, we performed the toxicity testing of the extract against Artemia salina. Then, we conducted the antibacterial assay against four Gram-negative bacterial strains (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Hafnia alvei ATCC 51873, Klebsiella pneumoniae ATCC 13883), and one Gram-positive strain (Enterococcus faecalis ATCC 29212). Finally, we carried out the preliminary phytochemical analysis of the active extract to detect the main classes of special metabolites. As a result, the ethanolic extract of J. mollissima leaves was toxic to Artemia salina, because it presented LC50 equal to 406.02 µg/mL. Regarding antibacterial action, the extract was active against the Gram-positive bacteria Enterococcus faecalis ATCC 29212, with moderate antibacterial activity (inhibition zone equal to 7.03 mm). The bioactive extract had the presence of coumarins, phenols, tannins, flavonoids (flavanols and flavonones), alkaloids and steroids, both classes reported as antimicrobials. Therefore, this extract has the potential to be used in the production of drugs against infections caused by Gram-positive bacteria. However, these information require further studies for the isolation and identification of bioactive compounds, monitored under the more expressive antibacterial action.

Antibacterial activity and chemical compounds of leaves and branches of Protium hebetatum / Atividade anti bacteriana e compostos químicos das folhas e ramos de Protium hebetatum

ABSTRACT The extracts and fractions of leaves and branches of Protium hebetatum D. C. Daly (Burseraceae) were investigated for their antibacterial activity and chemical composition. The methanol extract of branches (EMG) was considered active against the Escherichia coli and the Proteus vulgaris, showing an inhibition zone of 13 mm, and was selected for bioassay-guided phytochemical fractionation. From the technique of broth microdilution, the extract was considered a moderate inhibitor against Staphylococcus aureus, Pseudomonas aeruginosa and Enterococcus faecalis, with a minimum inhibitory concentration (MIC) of 1 mg/mL. The dichloromethane fraction was considered a moderate inhibitor against S. aureus (MIC of 1 mg/mL) and a potent inhibitor against E. faecalis (MIC of 0.5 mg/mL). F1, F2, F5 and F6 from chromatographic column of dichloromethane fraction were considered moderate inhibitors against S. aureus (MIC of 1 mg/mL). Through analysis by a gas chromatography mass spectrometry, eighteen compounds were identified, from which thirteen (isoeugenol, p-vinylguaiacol, metoxyeugenol, coumarin, 5-hydroxy-scopoletin, 4,7-dihydroxy-6-metoxicromam-2-one, 4[(1E]-3-hydroxy-1-propenyl)-2-methoxyphenol, piperonal, scoparon, o-guaiacol, spathulenol, seringol and antiarol) are unprecedented in these species. We also identified the triterpenes α-amyrin and β-amyrin, the steroids stigmasterol and sitosterol and the coumarin scopoletin, which was closely linked to the antibacterial activity of the samples.

RESUMO Atividade antibacteriana e compostos químicos de folhas e galhos de Protium hebetatum. Extratos e frações de folhas e galhos de Protium hebetatum D. C. Daly (Burseraceae) foram investigados quanto sua atividade antibacteriana e composição química. O extrato metanólico dos galhos (EMG) foi considerado ativo contra Escherichia coli e Proteus vulgaris, apresentando um halo de inibição de 13 mm, sendo selecionado para um fracionamento fitoquímico biomonitorado. A partir da técnica de microdiluição em caldo o EMG foi considerado um inibidor moderado contra Staphylococcus aureus, Pseudomonas aeruginosa e Enterococcus faecalis, apresentando uma concentração inibitória mínima (CIM) de 1mg/mL. A fração diclorometânica foi considerada inibidora moderada contra S. aureus (CIM de 1 mg/mL) e inibidora potente contra E. faecalis (CIM de 0,5 mg/mL). F1, F2, F5 e F6 provenientes da fração diclorometânica foram consideradas inibidoras moderadas contra S. aureus (CIM de 1 mg/mL). Através da análise por cromatografia gasosa acoplada a espectrometria de massa, foram identificados dezoitos compostos, dos quais treze (isoeugenol, p-vinilguaiacol, metoxieugenol, cumarina, 5-hidroxi-escopoletina, 4,7-dihidroxi-6-metoxicromam-2-ona, 4[(1E]-3-hidroxi-1-propenil)-2-methoxifenol, piperonal, escoparona, o-guaiacol, espatulenol, seringol e antiarol) foram identificados pela primeira vez nesta espécie. Foram também identificados os triterpenos α-amirina e β-amirina, os esteroides estigmasterol e sitosterol e a cumarina escopoletina, que estão intimamente ligados à atividade antibacteriana da espécie.

Characterization, antibiotic susceptibility pattern and detection of beta-lactamases in Enterococci.

One hundred strains of Enterococci obtained from various clinical specimens over a period of six months were speciated of which 56 were E. faecalis and 44 were E. faecium. Antimicrobial susceptibility pattern showed 90% of them were resistant to penicillin and 20% of them were resistant to vancomycin. Comparative evaluation of Beta-lactamase production by iodometric method and cloverleaf method showed that the latter was cost effective and easy to perform for routine use.

Biochemical speciation of enterococci causing human infections.

As Enterococci are now coming up as important nosocomial pathogens, their speciation and antibiotic sensitivity testing is important. 120 isolates of Enterococci from various clinical samples were physiologically and biologically characterised. Speciation on the basis of recommended methods revealed 114(95%) as E. faecalis and 6(5%) as E. faecium. Antibiogram of the 120 isolates showed that 100(83.3%) were sensitive to Ampicillin. Combination of Penicillin and Gentamicin was more effective. E. faecium was more drug resistant.

Resistencia de enterococos a los antimicrobianos en Venezuela / Resistance of enterococcus a the antimicrobials in Venezuela

Se analiza la resistencia de Enterococcus sp., según los datos del Proyecto de Vigilancia a la Resistencia Bacteriana en Venezuela. Se utilizó el método de difusión en agar, siguiendo las normas de eficiencia de la NCCLS, en 1925 cepas durante 1988, 1990, 1992 y 1994. El uso de ampicilina o sulbactam/ampicilina en infecciones simples, y la combinación ampicilina más aminoglicósido en infecciones severas, siguen siendo la primera opción. La utilización de eritromicina (48 por ciento), clindamicina (88 por ciento) y tetraciclinas (62 por ciento), al igual que a nivel mundial, no está justificado, debido a los altos porcentajes de resistencia. Venezuela es el primer país latinoamericano en reportar resistencia a vancomicina y, al contrario de lo que ocurre en otros países, se ha mantenido estable en el período estudiado. La alta resistencia de Enterococcus faecalis a los aminoglicósidos es un problema mundial, pero su detección se realiza mediante pruebas especiales, que escapan a los objetivos del proyecto de vigilancia