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Acinetobacter baumannii is an important opportunistic pathogen that causes serious health-related infections, especially in intensive care units. The present study aimed to investigate the antimicrobial activity of Riparin-B (Rip-B) alone and in association with norfloxacin against multidrug-resistant clinical isolates of A. baumannii. For this, the minimum inhibitory concentrations were determined by the microdilution method. For the evaluation of resistance-modulating activity, MIC values for antibiotics were determined in the presence or absence of subinhibitory concentrations of Rip-B or chlorpromazine (CPZ). The AdeABC-AdeRS efflux system genes from these isolates were detected by PCR. Docking studies were also carried out to evaluate the interaction of Riparin-B and the AdeABC-AdeRS efflux system. The study was conducted from 2017 to 2019. The results showed that Rip-B showed weak intrinsic activity against the strains tested. On the other hand, Rip-B was able to modulate norfloxacin’s response against A. baumannii strains that express efflux pump-mediated resistance. Docking studies provided projections of the interaction between Rip-B and EtBr with the AdeB protein, suggesting that Rip-B acts by competitive inhibition with the drug. Results found by in vitro and in silico assays suggest that Rip‐B, in combination with norfloxacin, has the potential to treat infections caused by multidrug-resistant A. baumanni with efflux pump resistance.

It is well known that the inadequate disposal of polymeric materials causes significant environmental problems. Recycling and the use of biodegradable polymers are among the methods used to minimize these problems. However, the low mechanical performance of the majority of biodegradable polymers hinders the direct substitution of synthetic polymers, such as polyethylene (PE), polypropylene (PP) and polystyrene (PS), by biodegradable ones. Blending synthetic and biodegradable polymers is a way to develop recyclable biodegradable products with a good set of mechanical properties. Therefore, in this work we investigate the influence of extrusion cycles on the degradation of a polypropylene/poly (butylene adipate-co-terephthalate)/thermoplastic starch blend before and after inoculation with Aspergillus sp. and Penicillium sp. fungi degradaded for 30 days. The samples were exposed to the fungi and their mass loss, chemical structure, hydrophilicity, and morphology were observed as a function of inoculation time and processing cycles. Our results indicate that thermo-mechanical degradation favors the deposition of fungi in the samples and enables changes in film morphology and hydrophilicity. Keywords: Fungi degradation, Mechanical recycling, Hydrophilicity

The aim of the present study was to evaluate the effect of commercial sweeteners on root dentin demineralization using a microcosm biofilm model. Bovine dentin specimens with pre-determined surface hardness were randomized into six groups according to the studied sweeteners: sucralose, stevia, saccharin, aspartame. Sucrose was used as a positive control and an untreated group as a negative control. The specimens were submitted to biofilm development from one saliva donor and the cariogenic challenge occurred on subsequent five days, twice a day. At the end, the percentage of surface hardness loss (%SHL) and biomass was determined and submitted to ANOVA followed by Tukey's test. Sucrose presented the highest rate of demineralization, however, all sweeteners tested lead to a statistically higher root demineralization compared to the negative control (p

Riparins are alkamides naturally found in the fruits of Aniba riparia (Nees) Mez, but currently synthetic molecules as Riparin E (Rip-E) can be obtained. Potential biological of Rip-E as schistosomicidal agent against Schistosoma mansoni worms, as well as against Staphylococcus aureus strains has already been described. However, the mechanism of action related to antimicrobial activity of Rip-E against bacterial or fungi species has not yet been reported. This study had as objective to evaluate the Rip-E antimicrobial activity against Gram-positive and Gram-negative bacteria, as well as against yeast species of clinical importance. Minimal inhibitory concentrations of the compound against bacterial and yeast strains were determined by microdilution method. To verify if a possible lethal effect caused by Rip-E were related to plasma membrane damage, microbial cells treated with Rip-E were stained with 7-aminoactinomycin D (7-AAD) and analyzed by flow cytometry. Rip-E showed a bactericide effect against Gram-positive species S. aureus and S. epidermidis, as well as, against Gram-negative species Escherichia coli and Salmonella enterica Typhimurium, but was inactive against Pseudomonas aeruginosa. Moreover, Rip-E showed activity against fungi species Candida albicans and C. tropicalis. S. aureus, E. coli and C. albicans cells treated with Rip-E were marked with 7-aminoactinomycin D (7-AAD) indicating that Rip-E can cause plasma membrane damage, acting as a potential microbicide agent for prevention or treatment of infectious diseases.

Searching for new alternatives to antibiotic treatments is crucial to surmount the multidrug-resistant bacteria. In this work, the antimicrobial activity of synthetic imidazolidines was evaluated as well as their modulating effect on the resistance to fluoroquinolones in a S. aureus strain (SA-1199B), which overexpresses the norA gene that encodes the NorA efflux pump. Results showed weak antimicrobial activity (512 μg mL−1) for two fluorobenzylidene derivatives against this bacterial strain, while the other benzylidene derivatives were inactive. Despite this fact, both fluorinated compounds were able to enhance the activity of norfloxacin and ciprofloxacin against SA-1199B up to 6.4– and 3.2-fold, respectively. In addition, both derivatives potentiated the action of ethidium bromide against this strain, suggesting that the modulating effect probably involves the inhibition of the NorA efflux pump, which is in concordance with the fluorimetic assays and molecular docking analyses performed in this work.

The aim of this study was to investigate intrinsic antimicrobial activity of three monoterpenes nerol, dimethyl octanol and estragole, against bacteria and yeast strains, as well as, investigate if these compounds are able to inhibit the NorA efflux pump related to fluoroquinolone resistance in Staphylococcus aureus. Minimal inhibitory concentrations (MICs) of the monoterpenes against Staphylococcus aureus, Escherichia coli and Candida albicans strains were determined by micro-dilution assay. MICs of the norfloxacin against a S. aureus strain overexpressing the NorA protein were determined in the absence or in the presence of the monoterpenes at subinhibitory concentrations, aiming to verify the ability of this compounds act as efflux pump inhibitors. The monoterpenes were inactive against S. aureus however the nerol was active against E. coli and C. albicans. The addition of the compounds to growth media at sub-inhibitory concentrations enhanced the activity of norfloxacin against S. aureus SA1199-B. This result shows that bioactives tested, especially the nerol, are able to inhibit NorA efflux pump indicating a potential use as adjuvants of norfloxacin for therapy of infections caused by multi-drug resistant S. aureus strains.

Objective. This in vitro study investigated the effect of Fluoride (F), Chlorhexidine (CHX), and their association on the viability of Streptococcus mutans using a biofilm model. Materials and Methods. Biofilms were anaerobically grown on glass slides that were vertically suspended in 24-well plates for 5 days. After 48 h of initial growth, biofilms were treated for the next 72 h, 2x/day with CHX at 0.12% and 2%, F as NaF at 0.08% and 0.4% and their association. Results. CHX treatment decreased the bacteria counts either alone or in association with both F concentrations, when compared with control group and the F treatments alone (p

El objetivo fue asociar el uso de protesis dentales totales y la prevalencia de Candida spp. en ancianos institucionalizados con 60 o mas anos de edad, en una ciudad del Nordeste de Brasil. Se llevo a cabo un estudio del perfil de salud y cuantificacion de Candida spp. por aislamiento con agar Sabouraud. A partir de 181 ancianos institucionalizados, solo 17 (66­84 anos) cumplieron los criterios de inclusion. 47,1 % eran totalmente dependientes y 58,8 % necesito ayuda con la higiene. Los farmacos mas utilizados fueron antihipertensivos. Los resultados mostraron una alta prevalencia de Candida spp. (64,5 %) en las protesis dentales totales de los ancianos institucionalizados y esto tal vez sea un reflejo de la deficiente higiene oral.

Objective: This study aimed to test the calcium hydroxide associated with vehicles Aloe vera, chlorhexidine digluconate (2%) and saline, in inhibiting bacterial growth on Mueller-Hinton agar plates.Methods: The species Staphiloccocus aureus, Streptococcus pyogenes, Escherichia coli and Enterecoccus faecalis were isolated and inoculated in 3 mL of BHI (Brain Heart Infusion). Holes (5 mm diameter) were made in the plates and filled with the test materials. After incubation, readings were taken with a hand lens and a caliper with 0.1 mm accuracy to determine the diameter of the inhibition zone, after 24 and 48 hours. Each experiment was repeated six times, and the average values were obtained.Results: Chlorhexidine digluconate without calcium hydroxide resulted in better inhibition of bacterial growth, followed by the hydroxide pastes evaluated. E. coli strains were the most resistant to the tested compounds, followed by S. pyogenes and S. aureus. There was no statistically significant interaction between the variables.Conclusion: Chlorhexidine digluconate (2%) alone showed the best antimicrobial effectiveness. Aloe vera is a promising vehicle for the calcium hydroxide but more studies should be conducted on herbal medicines in dentistry. Objetivo: Este estudo teve como objetivo testar o hidróxido de cálcio associado com os veículos Aloe vera, digluconato de clorexidina (2%) e solução salina, na inibição do crescimento bacteriano em placas de ágar Mueller-Hinton.Métodos: As espécies Staphiloccocus aureus, Streptococcus pyogenes, Escherichia coli e Enterecoccus faecalis foram isoladas e inoculadas em 3 mL de BHI (Brain Heart Infusion). Orifícios de 5 mm de diâmetro foram feitos nas placas e as substâncias a serem testadas foram inseridas. Após a incubação, as leituras dos halos de inibição foram aferidas com lente de mão e cursor com precisão de 0,1 mm a fim de determinar o diâmetro da zona de inibição, após 24 e 48 horas. Cada experimento foi repetido seis vezes, e os valores médios foram obtidos.Resultados: Digluconato de clorexidina (2%) isolado apresentou melhor inibição do crescimento bacteriano, seguido pelas pastas de hidróxido de cálcio avaliadas. Bactérias E. coli foram as mais resistentes aos compostos testados, seguidas por S. pyogenes e S. aureus. Não houve interação significativa entre as variáveis.Conclusão: Digluconato de clorexidina (2%) isolado apresentou melhor efetividade antimicrobiana. Aloe vera é um veículo promissor para o hidróxido de cálcio, entretanto mais estudos devem ser realizados com medicamentos fitoterápicos na Odontologia.

Summary The gene Ldccys1 enconding a cysteine proteinase of 30 kDa from Leishmania (Leishmania) chagasi , as well as the recombinant cysteine proteinase rLdccys1, obtained by cloning and expression of the Ldccys1 gene in the pHIS vector, were used to evaluate their ability to induce immune protective responses in BALB/c mice against L. (L.) chagasi infection. Mice were immunized subcutaneously with rLdccys1 plus Bacille Calmette Guerin (BCG) or Propionibacterium acnes as adjuvants or intramuscularly with a plasmid carrying the Ldccys1 gene ( Ldccys1 /pcDNA3) and CpG ODN as the adjuvant, followed by a booster with rLdccys1 plus CpG ODN. Two weeks after immunization the animals were challenged with 1 × 10 7 amastigotes of L. (L.) chagasi . Both immunization protocols induced significant protection against L. (L.) chagasi infection as shown by a very low parasite load in the spleen of immunized mice compared to the non-immunized controls. However, DNA immunization was 10-fold more protective than immunization with the recombinant protein. Whereas rLdccys1 induced a significant secretion of IFN-γ and nitric oxide (NO), animals immunized with the Ldccys1 gene increased the production of IgG2a antibodies, IFN-γ and NO. These results indicated that protection triggered by the two immunization protocols was correlated to a predominant Th1 response.

Objective: This study aimed to test the calcium hydroxide associated with vehicles Aloe vera, chlorhexidine digluconate (2%) and saline, in inhibiting bacterial growth on Mueller-Hinton agar plates. Methods: The species Staphiloccocus aureus, Streptococcus pyogenes, Escherichia coli and Enterecoccus faecalis were isolated and inoculated in 3 mL of BHI (Brain Heart Infusion). Holes (5 mm diameter) were made in the plates and filled with the test materials. After incubation, readings were taken with a hand lens and a caliper with 0.1 mm accuracy to determine the diameter of the inhibition zone, after 24 and 48 hours. Each experiment was repeated six times, and the average values were obtained. Results: Chlorhexidine digluconate without calcium hydroxide resulted in better inhibition of bacterial growth, followed by the hydroxide pastes evaluated. E. coli strains were the most resistant to the tested compounds, followed by S. pyogenes and S. aureus. There was no statistically significant interaction between the variables. Conclusion: Chlorhexidine digluconate (2%) alone showed the best antimicrobial effectiveness. Aloe vera is a promising vehicle for the calcium hydroxide but more studies should be conducted on herbal medicines in dentistry.

A 500 bp fragment encoding an isoform of cysteine proteinase from Leishmania (Leishmania) amazonensis was subcloned and expressed in the pHis vector, resulting in a recombinant protein of 24 kDa, rLacys24. In Western blots of L. (L.) amazonensis extracts, antibodies directed to rLacys24 recognized a cysteine proteinase isoform of 30 kDa. Analysis by fluorescence-activated cell sorter showed a significantly higher expression of CD8(+) lymphocytes in animals immunized with rLacys24 plus CFA, whereas a low expression of CD4(+) lymphocytes was observed in these animals. The cytotoxicity of lymphocytes isolated from mice immunized with rLacys24 plus CFA on L. (L.) amazonensis-infected macrophages was significantly higher than that observed in the presence of lymphocytes from control animals. Immunization of BALB/c mice with rLacys24 plus CFA resulted in a low but significant decrease of foot lesions after challenge with L. (L.) amazonensis compared to those exhibited by control mice.

A recombinant protein, rLdccys1, produced by expression of the gene encoding a 30 kDa cysteine proteinase from Leishmania (Leishmania) chagasi, was used to detect specific antibodies in serum by enzyme-linked immunosorbent assays and to test for reactivity in delayed-type hypersensitivity (DTH) responses of dogs from an endemic region of visceral leishmaniasis (VL), Teresina, Piaui State, Brazil. Amastigote or promastigote extracts were also assayed for comparison. The sensitivity for detection of specific antibodies to L. (L.) chagasi using rLdccys1, lysates from L. (L.) chagasi promastigotes and amastigotes was 96%, 68%, and 69%, respectively. No cross-reactivity between rLdccys1 and Chagas disease was observed, and little reactivity was found with sera from dogs with babesiosis and ehrlichiosis. Among 106 sera from symptomatic dogs and 22 from non-infected controls, no false negatives and only two false positive sera were found for rLdccys1. In contrast, amastigote lysates yielded 11 false positives and 13 false negatives, whereas the corresponding numbers for promastigote lysates were 17 and 16. DTH responses were determined after intradermal injection of rLdccys1 or amastigote extract and the induration area was measured at 24, 48 and 72 h after injection. All asymptomatic dogs showed a positive intradermal response to rLdccys1 (>10 mm) which peaked at 48 h, whereas no significant reactivity to the recombinant antigen was found in the symptomatic group. Histological analysis of the intradermal induration showed a predominance of necrotic and hemorrhagic areas in sections from asymptomatic dogs injected with L. (L.) chagasi amastigote extract, whereas a typical granulomatous reaction mediated by mononuclear cells was observed in sections from asymptomatic animals injected with rLdccys1. Grouping data from ELISA and DTH assays with rLdccys1 and L. (L.) chagasi amastigote extracts showed that humoral and cellular responses were inversely correlated during the development of canine VL. Overall, these findings indicate that L. (L.) chagasi recombinant cysteine proteinase is potentially useful for diagnosis of canine VL, as well as for the discrimination of clinical and subclinical forms of the disease.