Antimicrobial and synergistic effects of lemongrass and geranium essential oils against Streptococcus mutans, Staphylococcus aureus, and Candida spp.

BACKGROUND: The oral cavity harbors more than 700 species of bacteria, which play crucial roles in the development of various oral diseases including caries, endodontic infection, periodontal infection, and diverse oral diseases. AIM: To investigate the antimicrobial action of Cymbopogon Schoenanthus and Pelargonium graveolens essential oils against Streptococcus mutans, Staphylococcus aureus, Candida albicans, Ca. dubliniensis, and Ca. krusei. METHODS: Minimum microbicidal concentration was determined following Clinical and Laboratory Standards Institute documents. The synergistic antimicrobial activity was evaluated using the Broth microdilution checkerboard method, and the antibiofilm activity was evaluated with the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay. Data were analyzed by one-way analysis of variance followed by the Tukey post-hoc test (P ≤ 0.05). RESULTS: C. schoenanthus and P. graveolens essential oils were as effective as 0.12% chlorhexidine against S. mutans and St. aureus monotypic biofilms after 24 h. After 24 h P. graveolens essential oil at 0.25% was more effective than the nystatin group, and C. schoenanthus essential oil at 0.25% was as effective as the nystatin group. CONCLUSION: C. schoenanthus and P. graveolens essential oils are effective against S. mutans, St. aureus, Ca. albicans, Ca. dubliniensis, and Ca. krusei at different concentrations after 5 min and 24 h.

Phytochemical Composition and Antimicrobial and Antibiofilm Effect of Myrciaria cauliflora Hydroethanolic Extract against Staphylococcus aureus and Acinetobacter baumannii.

Staphylococcus aureus and Acinetobacter baumannii are opportunistic pathogens, and both are involved in different oral infections. This work aimed to analyze the phytochemical composition of Myrciaria cauliflora hydroethanolic extract and to evaluate its antimicrobial and antibiofilm action against Staphylococcus aureus (ATCC 6538) and Acinetobacter baumannii (ATCC 19606; multi-resistant clinical strains 58004, 50098, 566006, and H557). Myrciaria cauliflora hydroethanolic extract was prepared, and the content of soluble solids, flavonoids, and phenols was quantified. High-performance liquid chromatography (HPLC) was performed later. The minimum inhibitory concentration was determined using the broth microdilution method according to the Clinical and Laboratory Standards Institute, standard M7-A6, and subsequently, its minimum bactericidal concentration was determined. Then, the most effective concentrations were analyzed against biofilms. Statistical analysis was performed using the ANOVA method with Tukey's test. The soluble solids content in the prepared hydroethanolic extract of M. cauliflora was 2.22%. Additionally, the total flavonoid content, measured using the quercetin standard curve, was 0.040 mg/mL. Furthermore, the total phenol content, determined using the gallic acid standard curve, was 0.729 mg/mL. HPLC analysis presented peaks of gallic acid (11.80 m), p-coumaric acid (12.09 m), cinnamic acid derivative (19.02 m), and ellagic acid (29.83 m). The extract demonstrated antimicrobial and antibiofilm action against all tested strains. However, the most effective antibacterial concentration against all the tested bacteria was 5.55 mg/mL. Therefore, these chemical components justify that M. cauliflora hydroethanolic extract is effective in reducing biofilm formation in S. aureus (standard strain) and A. baumannii (standard and clinical strains).

Artemisia vulgaris Induces Tumor-Selective Ferroptosis and Necroptosis via Lysosomal Ca2+ Signaling.

OBJECTIVE: To evaluate the chemical composition and effects of Artemisia vulgaris (AV) hydroalcoholic extract (HEAV) on breast cancer cells (MCF-7 and SKBR-3), chronic myeloid leukemia (K562) and NIH/3T3 fibroblasts. METHODS: Phytochemical analysis of HEAV was done by high-performance liquid chromatography-mass (HPLC) spectrometry. Viability and cell death studies were performed using trypan blue and Annexin/FITC-7AAD, respectively. Ferrostatin-1 (Fer-1) and necrostatin-1 (Nec-1) were used to assess the mode of HEAV-induced cell death and acetoxymethylester (BAPTA-AM) was used to verify the involvement of cytosolic calcium in this event. Cytosolic calcium measurements were made using Fura-2-AM. RESULTS: HEAV decreased the viability of MCF-7, SKBR-3 and K562 cells (P<0.05). The viability of HEAV-treated K562 cells was reduced compared to HEAV-exposed fibroblasts (P<0.05). Treatment of K562 cells with HEAV induced cell death primarily by late apoptosis and necrosis in assays using annexin V-FITC/7-AAD (P<0.05). The use of Nec-1 and Fer-1 increased the viability of K562 cells treated with HEAV relative to cells exposed to HEAV alone (P<0.01). HEAV-induced Ca2+ release mainly from lysosomes in K562 cells (P<0.01). Furthermore, BAPTA-AM, an intracellular Ca2+ chelator, decreased the number of non-viable cells treated with HEAV (P<0.05). CONCLUSIONS: HEAV is cytotoxic and activates several modalities of cell death, which are partially dependent on lysosomal release of Ca2+. These effects may be related to artemisinin and caffeoylquinic acids, the main compounds identified in HEAV.

Synergistic Antibiofilm Action of Cinnamomum verum and Brazilian Green Propolis Hydroethanolic Extracts against Multidrug-Resistant Strains of Acinetobacter baumannii and Pseudomonas aeruginosa and Their Biocompatibility on Human Keratinocytes.

The accumulated dental biofilm can be a source of oral bacteria that are aspirated into the lower respiratory tract causing ventilator-associated pneumonia in hospitalized patients. The aim of this study was to evaluate the synergistic antibiofilm action of the produced and phytochemically characterized extracts of Cinnamomum verum and Brazilian green propolis (BGP) hydroethanolic extracts against multidrug-resistant clinical strains of Acinetobacter baumannii and Pseudomonas aeruginosa, in addition to their biocompatibility on human keratinocyte cell lines (HaCaT). For this, High-performance liquid chromatography analysis of the plant extracts was performed; then the minimum inhibitory and minimum bactericidal concentrations of the extracts were determined; and antibiofilm activity was evaluated with MTT assay to prevent biofilm formation and to reduce the mature biofilms. The cytotoxicity of the extracts was verified using the MTT colorimetric test, evaluating the cellular enzymatic activity. The data were analyzed with one-way ANOVA and Tukey's tests as well as Kruskal-Wallis and Dunn's tests, considering a significance level of 5%. It was possible to identify the cinnamic aldehyde in C. verum and p-coumaric, caffeic, and caffeoylquinic acids as well as flavonoids such as kaempferol and kaempferide and Artepillin-C in BGP. The combined extracts were effective in preventing biofilm formation and reducing the mature biofilms of A. baumannii and P. aeruginosa. Moreover, both extracts were biocompatible in different concentrations. Therefore, C. verum and BGP hydroethanolic extracts have bactericidal and antibiofilm action against multidrug resistant strains of A. baumannii and P. aeruginosa. In addition, the combined extracts were capable of expressively inhibiting the formation of A. baumannii and P. aeruginosa biofilms (prophylactic effect) acting similarly to 0.12% chlorhexidine gluconate.

Effects of Calendula officinalis and Capsicum annum glycolic extracts on planktonic cells and biofilms of multidrug-resistant strains of Klebsiella pneumoniae and Pseudomonas aeruginosa.

Empirical knowledge of natural plant extracts is increasingly proving to be a promising field. The effect of Calendula officinalis L. (CO) and Capsicum annum (CA) glycolic extracts (GlExt) have potential that should be further developed in microbial tests. The effect of CO-GlExt and CA-GlExt was evaluated on eight multidrug-resistant clinical strains of Klebsiella pneumoniae and Pseudomonas aeruginosa, as well as collection strains for each bacterial. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extract were determined in comparison with 0.12% chlorhexidine. The tests were performed on single species biofilms, at 5 min and 24 h, using the MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) assay. The MIC and MBC of the extract ranged from 1.56 to 50 mg mL-1 for all strains evaluated. Analysis of the MTT assay revealed a strong antimicrobial potential of CA-GlExt, comparable to chlorhexidine. The findings suggest that CA-GlExt is effective against multidrug-resistant strains of K. pneumoniae and P. aeruginosa in planktonic state and biofilms.

Antimicrobial action of four herbal plants over mixed-species biofilms of Candida albicans with four different microorganisms.

This study aimed to evaluate the antimicrobial effect of four herbal plants glycolic extracts over mixed-species biofilm composed of Candida albicans (C. albicans) and another pathogenic bacterium as alternative therapy to be investigated. Four plants extract of Pfaffia paniculata roots; Hamamelis virginiana leaf, Stryphnodendron barbatiman tree bark and Gymnema sylvestre stem and leaves were tested over multi-species biofilm of C. albicans (ATCC 18804) and Streptococcus mutans (ATCC 35688), Staphylococcus aureus (ATCC 6538), Enterococcus faecalis (ATCC 4083) or Pseudomonas aeruginosa (ATCC 15442) for 5 min and 24 h and colony forming units per millilitre was calculated. The data were analysed using Kruskal-Wallis with Dunn's test (p ≤ 0.05). All tested extracts showed antimicrobial action over the mixed-species biofilms after 24 h. Some extracts eliminated totally the biofilms. The glycolic extract of P. paniculata, H. virginiana, S. barbatiman and G. sylvestre are effective over mixed-species biofilms and may be indicated as endodontic irrigant or intracanal medication.

Extratos hidroetanólicos de canela (Cinnamomum verum) e romã (Punica granatum L) promovem ação antibacteriana frente cepas resistentes a antibióticos de Acinetobacter baumannii e Pseudomonas aeruginosa / Cinnamon (Cinnamomum verum) and pomegranate (Punica granatum L) hydroethanolic extracts promote antibacterial action against antibiotic-resistant strains of Acinetobacter baumannii and Pseudomonas aeruginosa

A resistência bacteriana tem aumentado progressivamente no mundo, assim, há necessidade de novas opções de tratamentos. A fitoterapia tem ganhado notoriedade para combater infecções, principalmente as causadas por bactérias resistentes aos antibacterianos disponíveis. Diante do exposto, o presente estudo teve como objetivo preparar e analisar a composição fitoquímica e a ação antibacteriana dos extratos hidroetanólicos de canela (EHC) e romã (EHR) isolados e associados frente culturas planctônicas e biofilmes de cepas padrão e clínicas de Acinetobacter baumannii e Pseudomonas aeruginosa, além disso, analisar a ação citotóxica dos extratos em queratinócitos humanos (HaCat). Para isso, os EHC e EHR foram preparados e quantificado o teor de sólidos solúveis. Posteriormente, foi quantificado o teor de flavonoides e fenóis totais, análise antioxidante por meio da redução do radical 2,2'-difenil-1-picrilhidrazila (DPPH), e a fitoquímica por cromatografia líquida (HPLC). Em relação a ação antibacteriana dos extratos, foi aplicado o teste de microdiluição em caldo (CLSI ­ M7-A9) e a ação sinérgica realizada por meio do ensaio de checkerboard. As concentrações mais efetivas foram analisadas sobre biofilmes em formação (prevenção) e biofilmes formados (tratamento de 24 h), e quantificada a viabilidade por meio do teste colorimétrico MTT. Para avaliar a citotoxidade, os tratamentos foram aplicados sobre cultura celular de HaCat por 24 h e analisados por meio do teste colorimétrico MTT. A análise estatística foi realizada com 5% de significância (p<0.05), analisados pelo método ANOVA complementado pelo Teste de Tukey. Os resultados demonstraram que os EHC e EHR possuem ação antioxidante e presença de fitocompostos. Os extratos apresentaram ação antibacteriana para todas as cepas avaliadas, quando os mesmos foram associados, obteve-se concentrações sinérgicas para as cepas clínicas de A. baumannii. Em relação a ação antibiofilme, o EHC inibiu a formação em 95% e EHR em 96% do biofilme de #Ab 1, enquanto a cepa #Pa 2 teve 92% e 93% de inibição quando em contato com EHC e EHR, respectivamente. Após tratamento de 24 h em biofilmes formados, as reduções da viabilidade foram de 72% para as cepas #Ab 2 e #Ab 3 quando em contato com o EHC, já EHR inibiu em 83% a viabilidade da cepa #Ab ATCC. Para P. aeruginosa (#Pa 2), as reduções da viabilidade foram de 84% e 88,5% quando tratados com EHC e EHR, respectivamente. A avaliação da citotoxicidade em HaCat demonstrou que após tratamentos com diferentes concentrações dos extratos a viabilidade celular se manteve acima de 70% em todos os grupos. Diante disso, conclui-se que os EHC e EHR apresentam importante ação antioxidante e antibacteriana, tanto em culturas planctônicas quanto em biofilmes, e não apresentaram efeitos citotóxicos na faixa de concentração testada. (AU)

Bacterial resistance has progressively increased in the world, thus, there is a need for new treatment options. Phytotherapy has gained notoriety for fighting infections, mainly those caused by bacteria resistant to available antibacterials. In view of the above, the present study aimed to prepare and analyze the phytochemical composition and antimicrobial action of hydroethanolic extracts of cinnamon (EHC) and pomegranate (EHR) isolated and associated against planktonic cultures and biofilms of standard and clinical strains of Acinetobacter baumannii and Pseudomonas aeruginosa, in addition, analyze the cytotoxic action of the extracts on human keratinocytes (HaCat). For this, the EHC and EHR were prepared and the soluble solids content was quantified. Subsequently, the content of flavonoids and total phenols, antioxidant analysis through the reduction of the radical 2,2'-diphenyl1-picrylhydrazyl (DPPH), and phytochemistry by liquid chromatography (HPLC) were quantified. Regarding the antimicrobial action of the extracts, the broth microdilution test (CLSI ­ M7-A9) was applied and the synergistic action was performed through the checkerboard test. The most effective concentrations were analyzed on forming biofilms (prevention) and formed biofilms (24 h treatment), and viability was quantified using the MTT colorimetric test. To evaluate the cytotoxicity, the treatments were applied on HaCat cell culture for 24 h and analyzed using the MTT colorimetric test. Statistical analysis was performed with 5% significance (p<0.05), analyzed by the ANOVA method complemented by the Tukey test. The results showed that the EHC and EHR have antioxidant action and presence of phytocompounds. The extracts showed antibacterial action for all evaluated strains, when they were associated, synergistic concentrations were obtained for the clinical strains of A. baumannii. Regarding the antibiofilm action, EHC inhibited formation by 95% and EHR by 96% of the #Ab 1 biofilm, while the #Pa 2 strain had 92% and 93% inhibition when in contact with EHC and EHR, respectively. After 24 h treatment in formed biofilms, viability reductions were 72% for strains #Ab 2 and #Ab 3 when in contact with EHC, whereas EHR inhibited the viability of strain #Ab ATCC by 83%. For P. aeruginosa (#Pa 2), viability reductions were 84% and 88.5% when treated with EHC and EHR, respectively. The evaluation of cytotoxicity in HaCat showed that after treatments with different concentrations of extracts, cell viability remained above 70% in all groups. Therefore, it is concluded that EHC and EHR have important antioxidant and antibacterial action, both in planktonic cultures and in biofilms, and did not show cytotoxic effects in the tested concentration range. (AU)

Antimicrobial and Antibiofilm Effect of Brazilian Green Propolis Aqueous Extract against Dental Anaerobic Bacteria.

Green propolis may represent a promising therapeutic alternative against dental anaerobic pathogens because of its antimicrobial action. This study aimed to evaluate the antimicrobial and antibiofilm actions of Brazilian green propolis aqueous extract (BGP-AqExt) against dental anaerobic bacteria. The minimum inhibitory concentration (MIC) and minimum microbicide concentration (MMC) of the extract were determined against the standard strains (ATCC) of Fusobacterium nucleatum, Parvimonas micra, Prevotella intermedia, Porphyromonas gingivalis and Porphyromonas endodontalis. BGP-AqExt was chemically characterized by high-performance liquid chromatography with diode-array detection (HPLC-DAD) analysis. Antibiofilm action was measured by MTT and crystal violet tests. The data were statistically analyzed by ANOVA and Tukey (5%) tests. The extract had antimicrobial action against all tested anaerobic bacteria, with an MIC value of 55 mg/mL for all bacteria, an MMC of 27.5 mg/mL for F. nucleatum and P. micra and 55 mg/mL for P. intermedia. Chemically, BGP-AqExt is composed of quercetin, gallic acid, caffeic and p-coumaric acid, drupani, kaempferol and Artepillin C. Significant reductions in biomass and metabolic action of biofilms were found after BGP-AqExt application. Therefore, BGP-AqExt has an antimicrobial and antibiofilm effect against dental anaerobic bacteria.

The biocompatibility and antifungal effect of Rosmarinus officinalis against Candida albicans in Galleria mellonella model.

This study was performed to evaluate the biocompatibility and antifungal effect of Rosmarinus officinalis against Candida albicans in Galleria mellonella model. Five different concentrations of R. officinalis glycolic extract (50; 25; 12.5 e 6.25 mg/mL) were used to evaluate its biocompatibility in G. mellonella model, in which the nystatin suspension (100; 50; 25; 12.5 e 6.25%) was used as a control group. The antifungal action of R. officinalis glycolic extract was evaluated on C. albicans for 72, 48 and 12 h at two different phases: (1) using the extract as therapeutic agent; and (2) using the extract as prophylactic agent. PBS was used as a negative control group. G. mellonella survival curves were plotted using the Kaplan-Meier method and statistical analysis was performed using the log-rank test (Mantel-Cox) and the significance level was set at (α ≤ 0.05). There was no significant difference among the groups in which all were biocompatible except of a significant death rate of 26.6% with nystatin 100%. In phase 1, it was found that after 7 days, there was no statistically significant difference among the prophylactic treatment groups. In phase 2, the groups of R. officinalis 6.25 mg/mL for 72 h and R. officinalis of 12.5 mg/mL for 24 h promoted the survival rate of the larvae in comparison with the control group with a significant difference (p = 0.017) and (p = 0.032) respectively. Therefore, R. officinalis extract is biocompatible in different concentrations and can be used as a prophylactic agent against fungal infection.

Punica granatum L. Extract Antibiofilm Action against Acinetobacter baumannii Carbapenem-Resistant and Biocompatibility over Human Keratinocytes / Ação Antibiofime de Extrato dePunica granatum L Contra Acinetobacter baumannii Resistente a Carbapnêmicos e Biocompatibilidade em Queratinócitos Humanos

Acinetobacter baumannii is a multi-drug resistant microorganism. The objective of this study was to evaluate the antimicrobial and antibiofilm action of the pomegranate natural extract against eight strains of multidrug resistant Acinetobacter baumanii and to assess the extract cytotoxicity in a culture of Human Keratinocytes (HaCat). Broth microdilution method was used to determine the minimum inhibitory and minimum microbicidal concentrations of the extracts. The extract antibiofilm action was analysed by the MTT colorimetric test. The cytotoxicity evaluation was performed by the MTT colorimetric test, which analysed the mitochondrial cellular action, after contact of the extract for 5 min. The results were statistically analysed by ANOVA and Tukey test with a significance level α≤ 0.05. Punica granatum L. (pomegranate) extract had antimicrobial action on all the 8 clinical strains of Acinetobacter baumannii evaluated. The extract showed a significant reduction in metabolic action in biofilm for all the strains, with results statistically different from growth control (p≤0.05%). P. granatum extract applied for 5 min on human keratinocytes (HaCat) promoted cell viability in all the tested concentrations. The pomegranate extract is effective in reducing the multidrug-resistant clinical strains of Acinetobacter baumanni and is biocompatible. (AU)

Acinetobacter baumannii é um microrganismo multirresistente. O objetivo deste estudo foi avaliar a ação antimicrobiana e antibiofilme do extrato natural de romã contra oito cepas de A. baumanii multirresistente e avaliar a citotoxicidade do extrato em uma cultura de queratinócitos humanos (HaCat). O método de microdiluição em caldo foi utilizado para determinar as concentrações inibitórias mínimas e microbicidas mínimas dos extratos. A ação antibiofilme do extrato foi analisada pelo teste colorimétrico MTT. A avaliação da citotoxicidade foi realizada pelo teste colorimétrico MTT, que analisou a ação celular mitocondrial, após contato do extrato por 5 min. Os resultados foram analisados ​​estatisticamente por ANOVA e teste de Tukey com nível de significância α≤ 0,05. O extrato de Punica granatum L. (romã) apresentou ação antimicrobiana em todas as 8 cepas clínicas avaliadas de A. baumannii. O extrato apresentou redução significativa na ação metabólica no biofilme para todas as linhagens, com resultados estatisticamente diferentes do controle de crescimento (p≤0,05%). O extrato de P. granatum aplicado por 5 min em queratinócitos humanos (HaCat) promoveu viabilidade celular em todas as concentrações testadas. O extrato de romã é eficaz na redução das cepas clínicas multirresistentes de Acinetobacter baumanni e é biocompatível. (AU)

In vitro synergistic effects of fluoxetine and paroxetine in combination with amphotericin B against Cryptococcus neoformans.

Cryptococcus neoformans is a yeast that mainly affects immunocompromised individuals and causes meningoencephalitis depending on the immune status of the host. The present study aimed to validate the efficacy of selective serotonin reuptake inhibitors, fluoxetine hydrochloride (FLH) and paroxetine hydrochloride (PAH), alone and in combination with amphotericin B (AmB) against C. neoformans. Susceptibility tests were conducted using the broth microdilution method and synergistic effects of combining FLH and PAH with AmB were analyzed using the checkerboard assay. Effects of minimum inhibitory concentration (MIC) and synergistic concentration were evaluated in biofilms by quantifying the biomass, measuring the viability by counting the colony-forming units (CFU/mL) and examining the size of the induced capsules. Cryptococcus neoformans was susceptible to FLH and PAH and the synergistic effect of FLH and PAH in combination with AmB reduced the MIC of AmB by up to 8-fold. The isolated substances and combination with AmB were able to reduce biofilm biomass and biofilm viability. In addition, FLH and PAH alone or in combination with AmB significantly decreased the size of the yeast capsules. Collectively, our results indicate the use of FLH and PAH as a promising prototype for the development of anti-cryptococcal drugs.

Efeito do cloridrato de verapamil, cloridrato de fluoxetina e paroxetina isolados e combinados com anfoteicina B contra Cryptococcus neoformans: estudo in vitro e in vivo / Effect of verapamil hydrochloride, fluoxetine hydrochloride and paroxetine alone and combined with amphotericin B against Cryptococcus neoformans: in vitro and in vivo study

Cryptococcus neoformans são leveduras que acometem principalmente indivíduos imunocomprometidos, podendo causar a meningoencefalite dependendo do estado imunológico do hospedeiro. Os tratamentos convencionais têm enfrentado grandes desafios. Dessa forma, o objetivo desse estudo foi avaliar os efeitos antifúngicos dos fármacos cloridrato de verapamil (CV), cloridrato de fluoxetina (CF) e cloridrato de paroxetina (CP) isolados e combinados com anfotericina B (AmB) contra C. neoformans. Foram determinados os valores de Concentração Inibitória Mínima (CIM) e Concentração Fungicida Mínima (CFM) de acordo com a técnica de microdiluição em caldo proposta pelo Comitê Europeu de Teste de Susceptibilidade Antimicrobiana (EUCAST). Posteriormente, foi avaliada a atividade sinérgica dos fármacos combinados com AmB (EUCAST). Os efeitos das CIMs e das concentrações sinérgicas selecionadas foram avaliados em biofilmes, quantificando a biomassa por cristal violeta e sua viabilidade por contagem de colônias (UFC/mL). Além disso, foram analisados os efeitos dos mesmos na cápsula induzida desta levedura. Os ensaios in vivo foram realizados em Galleria mellonella avaliando a toxicidade dos compostos e a eficácia por análise de curva de sobrevivência e também o efeito em concentração de hemócitos. Os fármacos CV, CF e CP apresentaram valores de CIM de 113, 9,6 e 41µg/mL, respectivamente, e quando combinados com AmB resultaram em vinte concentrações sinérgicas, e uma concentração de cada combinação foi eleita para os ensaios seguintes. CV reduziu a biomassa do biofilme em até 38%, já CF e CP reduziram a biomassa de 22-30% quando isolados, e as combinações reduziram até 35 % da biomassa. O CP diminuiu a viabilidade do biofilme em até 25 % e quando o CF e CP foram combinados com AmB a redução chegou a 11 %. Além disso, todos os fármacos isolados e combinados reduziram o tamanho da cápsula da levedura, de 48-72 %. Em G. mellonella os fármacos não apresentaram toxicidade, eficácia ou ação na concentração de hemócitos. Assim, os fármacos avaliados apresentaram potencial antifúngico frente C. neoformans em todos os ensaios in vitro, podendo ser considerados novas alternativas para o tratamento destes patógenos(AU)

Cryptococcus neoformans are yeasts that mainly affect immunocompromised individuals, and may cause meningoencephalitis depending on the immunological state of the host. Conventional treatments have faced major challenges. Verapamil hydrochloride (CV), fluoxetine hydrochloride (CF) and paroxetine hydrochloride (CP) were isolated and combined with amphotericin B (AmB) against C. neoformans. Minimum Inhibitory Concentration (MIC) and minimum Fungicidal Concentration (CFM) values were determined according to the broth microdilution technique proposed by the European Committee for Antimicrobial Susceptibility Testing (EUCAST). Subsequently, the synergistic activity of drugs combined with AmB (EUCAST) was evaluated. The effects of MICs and selected synergistic concentrations were evaluated in biofilms, quantifying the biomass by violet crystal and its viability by colony-forming unit analysis (CFU / mL). In addition, the effects of the same in the induced capsule of this yeast were evaluated. In vivo assays were performed in Galleria mellonella evaluating the toxicity of the compounds and the efficacy by analysis of survival curve and also the effect on hemocyte concentration. The CV, CF and CP drugs had MIC values of 113, 9.6 and 41 µg / mL, respectively, and when combined with AmB resulted in twenty synergistic concentrations, and a concentration of each combination was chosen for the following trials. CV reduced biofilm biomass to 38%, while CF and CP reduced biomass to 22-30% when isolated, and combinations reduced to 35% of biomass. CP decreased biofilm viability to 25% and when CF and CP were combined with AmB the reduction reached to 11%. In addition, all drugs isolated and combined reduced the size of the yeast capsule to 48-72%. In G. mellonella the drugs did not present toxicity, efficacy or action in the concentration of hemocytes. We suggest that the liposolubility of the compounds has been a limiting factor in vivo analyzes. Thus, the evaluated drugs presented antifungal potential against C. neoformans in all in vitro assays, and could be considered new alternatives for the treatment of these pathogens(AU)

Recent Advances in the Use of Galleria mellonella Model to Study Immune Responses against Human Pathogens.

The use of invertebrates for in vivo studies in microbiology is well established in the scientific community. Larvae of Galleria mellonella are a widely used model for studying pathogenesis, the efficacy of new antimicrobial compounds, and immune responses. The immune system of G. mellonella larvae is structurally and functionally similar to the innate immune response of mammals, which makes this model suitable for such studies. In this review, cellular responses (hemocytes activity: phagocytosis, nodulation, and encapsulation) and humoral responses (reactions or soluble molecules released in the hemolymph as antimicrobial peptides, melanization, clotting, free radical production, and primary immunization) are discussed, highlighting the use of G. mellonella as a model of immune response to different human pathogenic microorganisms.