Qualitative analysis of preputial and vaginal bacterial microbiota in owl monkeys (Aotus azarai infulatus) raised in captivity

Background: The aim of this study was to identify the aerobic bacteria of the preputial and vaginal microbiota in owl monkeys that have been raised in captivity and to evaluate the antimicrobial susceptibility of these bacteria by gender and social organization. Methods: Thirty clinically healthy Aotus azarai infulatus were used. A total of 134 samples were collected, 60 from the preputial mucosa and 74 from the vaginal mucosa. An automated system of bacterial identification was used. Results and Conclusions: Staphylococcus intermedius and Proteus mirabilis were the microorganisms that were most frequently identified according to gender and social organization. The antimicrobial susceptibility of the isolated gram-positive bacteria was similar in both sexes. However, the gram-negative strains had some differences. The aerobic bacterial population of the vaginal and preputial microbiota is similar in owl monkeys, and there are no differences in the number and bacterial species according to sex and social organization. © 2012 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

Microplate alamarblue assay for paracoccidioides susceptibility testing

CLSI method M27-A3 is not available for use with dimorphic fungi, such as those of the Paracoccidioides genus. In this study, we developed a microdilution method and added the alamarBlue reagent to test the responses of Paracoccidioides brasiliensis and Paracoccidioides lutzii against amphotericin B and itraconazole antifungals. The test proved to be sensitive, practical, and inexpensive and can be used to monitor the activity of low-growth microorganisms and their response to various drugs. © 2013, American Society for Microbiology.

Hydrophobic effect of amphiphilic derivatives of chitosan on the antifungal activity against aspergillus flavus and aspergillus parasiticus

Low molecular weight amphiphilic derivatives of chitosan were synthesized, characterized and their antifungal activities against Aspergillus flavus and Aspergillus parasiticus were tested. The derivatives were synthesized using as starting material a deacetylated chitosan sample in a two step process: the reaction with propyltrimethylammonium bromide (Pr), followed by reductive amination with dodecyl aldehyde. Aiming to evaluate the effect of the hydrophobic modification of the derivatives on the antifungal activity against the pathogens, the degree of substitution (DS1) by Pr groups was kept constant and the proportion of dodecyl (Dod) groups was varied from 7 to 29% (DS2). The derivatives were characterized by 1H-NMR and FTIR and their antifungal activities against the pathogens were tested by the radial growth of the colony and minimum inhibitory concentration (MIC) methods. The derivatives substituted with only Pr groups exhibited modest inhibition against A. flavus and A. parasiticus, like that obtained with deacetylated chitosan. Results revealed that the amphiphilic derivatives grafted with Dod groups exhibited increasing inhibition indexes, depending on polymer concentration and hydrophobic content. At 0.6 g/L, all amphiphilic derivatives having from 7.0 to 29% of Dod groups completely inhibited fungal growth and the MIC values were found to decrease from 4.0 g/L for deacetylated chitosan to 0.25-0.50 g/L for the derivatives. These new derivatives open up the possibility of new applications and avenues to develop effective biofungicides based on chitosan. © 2013 by the authors.

Anti-Candida properties of urauchimycins from actinobacteria associated with Trachymyrmex ants

After decades of intensive searching for antimicrobial compounds derived from actinobacteria, the frequency of isolation of new molecules has decreased. To cope with this concern, studies have focused on the exploitation of actinobacteria from unexplored environments and actinobacteria symbionts of plants and animals. In this study, twenty-four actinobacteria strains isolated from workers of Trachymyrmex ants were evaluated for antifungal activity towards a variety of Candida species. Results revealed that seven strains inhibited the tested Candida species. Streptomyces sp. TD025 presented potent and broad spectrum of inhibition of Candida and was selected for the isolation of bioactive molecules. From liquid shake culture of this bacterium, we isolated the rare antimycin urauchimycins A and B. For the first time, these molecules were evaluated for antifungal activity against medically important Candida species. Both antimycins showed antifungal activity, especially urauchimycin B. This compound inhibited the growth of all Candida species tested, with minimum inhibitory concentration values equivalent to the antifungal nystatin. Our results concur with the predictions that the attine ant-microbe symbiosis may be a source of bioactive metabolites for biotechnology and medical applications. © 2013 Thais D. Mendes et al.

Orbifloxacin: A Review of Properties, Its Antibacterial Activities, Pharmacokinetic/Pharmacodynamic Characteristics, Therapeutic Use, and Analytical Methods

Orbifloxacin is a third generation of fluoroquinolone that exhibits increased antibacterial activity against the Enterobacteriaceae, gram-negative and gram-positive bacteria, anaerobes, and mycobacteria. This drug was synthesized in 1987 and developed as a veterinary chemotherapeutic to use for livestock and domestic pets. Orbifloxacin is labeled for the treatment of skin, soft tissue, and urinary tract infections in dogs, and skin and soft tissue infections in cats, but in some countries, orbifloxacin has been given for the treatment of gastrointestinal and respiratory infections in cattle and swine and other animals. The in vitro activity and clinical efficacy of orbifloxacin against naturally occurring bacterial infections of the skin, ear, soft tissue, udder, and gastrointestinal and respiratory systems in different animals have been evaluated and good responses have been found. The minimum inhibitory concentration of orbifloxacin has been determined in various different pathogens and the results found in the literature are shown in this work. The pharmacokinetics of orbifloxacin has been evaluated by different routes of administration in goats, horses, pigs, rabbits, dogs, cats, camels, cattle, sheep, and fish. Orbifloxacin exhibits excellent pharmacokinetic parameters that suggest that this drug may have good clinical effects on various bacterial infections in these species. All methods described in the scientific literature for determination of orbifloxacin in different matrices were collected and discussed. © 2013 Copyright Taylor and Francis Group, LLC.

Synthesis, cytotoxicity, antibacterial and antileishmanial activities of imidazolidine and hexahydropyrimidine derivatives

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

In Vitro and In Vivo Activities of Ruthenium(II) Phosphine/Diimine/Picolinate Complexes (SCAR) against Mycobacterium tuberculosis

Rifampicin, discovered more than 50 years ago, represents the last novel class of antibiotics introduced for the first-line treatment of tuberculosis. Drugs in this class form part of a 6-month regimen that is ineffective against MDR and XDR TB, and incompatible with many antiretroviral drugs. Investments in R&D strategies have increased substantially in the last decades. However, the number of new drugs approved by drug regulatory agencies worldwide does not increase correspondingly. Ruthenium complexes (SCAR) have been tested in our laboratory and showed promising activity against Mycobacterium tuberculosis. These complexes showed up to 150 times higher activity against MTB than its organic molecule without the metal (free ligand), with low cytotoxicity and high selectivity. In this study, promising results inspired us to seek a better understanding of the biological activity of these complexes. The in vitro biological results obtained with the SCAR compounds were extremely promising, comparable to or better than those for first-line drugs and drugs in development. Moreover, SCAR 1 and 4, which presented low acute toxicity, were assessed by Ames test, and results demonstrated absence of mutagenicity. © 2013 Pavan et al.

Dimerization of aurein 1.2: Effects in structure, antimicrobial activity and aggregation of Cândida albicans cells

Antimicrobial peptides (AMPs) are a promising solution to face the antibiotic-resistant problem because they display little or no resistance effects. Dimeric analogues of select AMPs have shown pharmacotechnical advantages, making these molecules promising candidates for the development of novel antibiotic agents. Here, we evaluate the effects of dimerization on the structure and biological activity of the AMP aurein 1.2 (AU). AU and the C- and N-terminal dimers, (AU)2K and E(AU)2, respectively, were synthesized by solid-phase peptide synthesis. Circular dichroism spectra indicated that E(AU)2 has a coiled coil structure in water while (AU)2K has an α-helix structure. In contrast, AU displayed typical spectra for disordered structures. In LPC micelles, all peptides acquired a high amount of α-helix structure. Hemolytic and vesicle permeabilization assays showed that AU has a concentration dependence activity, while this effect was less pronounced for dimeric versions, suggesting that dimerization may change the mechanism of action of AU. Notably, the antimicrobial activity against bacteria and yeast decreased with dimerization. However, dimeric peptides promoted the aggregation of C. albicans. The ability to aggregate yeast cells makes dimeric versions of AU attractive candidates to inhibit the adhesion of C. albicans to biological targets and medical devices, preventing disease caused by this fungus. © 2013 Springer-Verlag Wien.

In Vitro Susceptibility of Environmental Isolates of Exophiala dermatitidis to Five Antifungal Drugs

Several dematiaceous fungi frequently isolated from nature are involved in cases of superficial lesions to lethal cerebral infections. Antifungal susceptibility data on environmental and clinical isolates are still sparse despite the advances in testing methods. The objective of this study was to examine the activities of 5-flucytosine, amphotericin B, itraconazole, voriconazole and terbinafine against environmental isolates of Exophiala strains by minimum inhibition concentration (MIC) determination. The strains were obtained from hydrocarbon-contaminated soil, ant cuticle and fungal pellets from the infrabuccal pocket of attine gynes. Broth microdilution assay using M38-A2 reference methodology for the five antifungal drugs and DNA sequencing for fungal identification were applied. Terbinafine was the most active drug against the tested strains. It was observed that amphotericin B was less effective, notably against Exophiala spinifera, also studied. High MICs of 5-flucytosine against Exophiala dermatitidis occurred. This finding highlights the relevance of studies on the antifungal resistance of these potential opportunistic species. Our results also contribute to a future improvement of the standard methods to access the drug efficacy currently applied to black fungi. © 2012 Springer Science+Business Media Dordrecht.

Systemic CA-MRSA infection following trauma during soccer match in inner Brazil: Clinical and molecular characterization

Even though community-acquired methicillin resistant Staphylococcus aureus (CA-MRSA) was described a decade ago, reports from Brazil are scarce and cases occurred in large urban centers. We report MRSA sepsis in a 16-year-old male from a small town and who had no history of exposure to healthcare or recent travel. After trauma during a soccer match, he presented swelling in the right thigh, which evolved in a month to cellulitis complicated by local abscess, orchitis and pneumonia. The patient presented severe sepsis, with fever and respiratory failure. Laboratory findings included blood leukocyte counts above 40,000/mm3 and thrombocytopenia. He was submitted to mechanical ventilation and therapy with vancomycin and imipenem. He had a slow but favorable response to therapy and was discharged after six weeks of hospitalization. MRSA grew from blood cultures and respiratory aspirates obtained before antimicrobial therapy. The isolate belonged to sequence type 5, spa type t311, harbored SCCmec type IV and genes for Panton-Valentine leukocidin and Enterotoxin A. The pulsed-field gel electrophoresis pattern was distinct from North American classic CA-MRSA clones. However, the sequence type and the spa type revealed that the clone belong to the same clonal complex isolated in Argentina. This is the first CA-MRSA infection reported in that region, with significant epidemiologic and clinical implications. © 2013 Elsevier Inc.

Staphylococcus epidermidis biofilms control by N-acetylcysteine and rifampicin

Medical device-associated infections caused by Staphylococcus epidermidis usually involve biofilm formation and its eradication is particularly challenging. Although rifampicin has been proving to be one of the most effective antibiotics against S. epidermidis biofilms, its use as a single agent can lead to the acquisition of resistance. Therefore, we assessed the combined effect of rifampicin with N-acetylcysteine (NAC) known by its mucolytic effect, in the control of S. epidermidis biofilms. Biofilms of 2 S. epidermidis strains (9142 and 1457) were treated with 1× minimum inhibitory concentration (4 mg/mL) and 10× minimum inhibitory concentration (40 mg/mL) of NAC and 10 mg/L (peak serum) of rifampicin alone and in combination. NAC at 40 mg/L alone or in combination with rifampicin (10 mg/L) significantly reduced (4 log 10) the number of biofilm cells. Considering their different modes of action, the association of NAC with rifampicin constitutes a promising therapeutic strategy in the treatment of infections associated to S. epidermidis biofilms. © 2013 Lippincott Williams & Wilkins.

Atividade antimicrobiana in vitro de extrato de Punica granatum L. sobre staphylococcus aureus isolado em leite bovino

Bovine mastitis is considered important disease causing major economic losses in dairy herds. Antimicrobial drug can promote resistance, chemical residues in food and environmental contamination. The purpose of this study was to evaluate the antibacterial activity in vitro of pomegranate extract on Staphylococcus aureus isolated from bovine milk, evaluate its antioxidant activity, and quantify levels of total phenols and fravonoides of the different extracts used. Aqueous extracts were used in nature and dry, from the peel of the fruit (EAC) and leaves (EAF). Additionally, it was evaluated the antioxidant activity (AA%), total phenols and flavonoids. Milk samples were inoculated, incubated, and the colonies were characterized as Staphylococcus aureus were adjusted to 1.0x106 UFC/mL in the 6 standard of the MacFarland scale. The sensitivity of the microbial isolates were determined in quintuplicate, in disk diffusion test. The minimum inhibitory concentration was determined by visible inhibition zone greater than 15mm. The results were evaluated by ANOVA, Tukey 5%, using the program SISVAR 5.3 - DEX/UFLA. Results implied that the aqueous extract from the bark of dried fruit was capable of inhibiting bacterial growth at concentrations of 3%. The other treatments only showed this activity, from the concentrations of 15%, 20% and 30% for dry EAF, in nature EAC and in nature EAF, respectively. Regarding the action antioxidant of dry EAC, was not correlated with total phenols and flavonoids. Probably other alkaloids substances present in the extract studied, may have been responsible for this activity. It is concluded that extracts of Punica granatum L., especially those obtained by the shell of the fruit, showed inhibitory activity against S. aureus, indicating your use potential for the control of bovine mastitis.

N-acetylcysteine and vancomycin alone and in combination against staphylococci biofilm

Introduction: The ability of staphylococci to produce biofilm is an important virulence mechanism that allows bacteria both to adhere and to live on artificial surfaces and to resist to the host immune factors and antibiotics. Staphylococcal infections have become increasingly difficult to treat due their antibiotic resistance. Therefore, there is a continuous need for new and effective treatment alternatives against staphylococcal infections. The main goal of this study was to test N-acetylcysteine (NAC) and vancomycin alone and in combination against S. epidermidis and S. aureus biofilms. Methods: Biofilms were treated with NAC at minimum inhibitory concentration (MIC) and 10 × MIC concentrations and vancomycin at MIC and peak serum concentrations. Results: The use of NAC 10 × MIC alone showed a significant antibactericidal effect, promoting a 4-5 log10 CFU/ mL reduction in biofilm cells. The combination of NAC 10 × MIC with vancomycin (independently of the concentration used) reduced significantly the number of biofilm cells for all strains evaluated (5-6 log10). Conclusion: N-acetylcysteine associated to vancomycin can be a potential therapeutic strategy in the treatment of infections associated to biofilms of S. epidermidis or S. aureus.

Cytotoxicity of Brazilian plant extracts against oral microorganisms of interest to dentistry

Background: With the emergence of strains resistant to conventional antibiotics, it is important to carry studies using alternative methods to control these microorganisms causing important infections, such as the use of products of plant origin that has demonstrated effective antimicrobial activity besides biocompatibility. Therefore, this study aimed to evaluate the antimicrobial activity of plant extracts of Equisetum arvense L., Glycyrrhiza glabra L., Punica granatum L. and Stryphnodendron barbatimam Mart. against Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans, Candida albicans, Candida tropicalis, and Candida glabrata, and to analyze the cytotoxicity of these extracts in cultured murine macrophages (RAW 264.7).Methods: Antimicrobial activity of plant extracts was evaluated by microdilution method based on Clinical and Laboratory Standards Institute (CLSI), M7-A6 and M27-A2 standards. The cytotoxicity of concentrations that eliminated the microorganisms was evaluated by MTT colorimetric method and by quantification of proinflammatory cytokines (IL-1β and TNF-α) using ELISA.Results: In determining the minimum microbicidal concentration, E. arvense L., P. granatum L., and S. barbatimam Mart. extracts at a concentration of 50 mg/mL and G. glabra L. extract at a concentration of 100 mg/mL, were effective against all microorganisms tested. Regarding cell viability, values were 48% for E. arvense L., 76% for P. granatum L, 86% for S. barbatimam Mart. and 79% for G. glabra L. at the same concentrations. About cytokine production after stimulation with the most effective concentrations of the extracts, there was a significant increase of IL-1β in macrophage cultures treated with S. barbatimam Mart. (3.98 pg/mL) and P. granatum L. (7.72 pg/mL) compared to control (2.20 pg/mL) and a significant decrease of TNF-α was observed in cultures treated with G. glabra L. (4.92 pg/mL), S. barbatimam Mart. (0.85 pg/mL), E. arvense L. (0.83 pg/mL), and P. granatum L. (0.00 pg/mL) when compared to control (41.96 pg/mL).Conclusions: All plant extracts were effective against the microorganisms tested. The G. glabra L. extract exhibited least cytotoxicity and the E. arvense L. extract was the most cytotoxic. © 2013 de Oliveira et al.; licensee BioMed Central Ltd.

Evaluation of Syngonanthus nitens (Bong.) Ruhl. extract as antifungal and in treatment of vulvovaginal candidiasis

The purpose of this study was to evaluate the in vitro anticandidal activity of a methanolic extract of Syngonanthus nitens scapes against different Candida species and clinical isolates from patients with vulvovaginal candidiasis (VVC), and its effect in vivo in the treatment of vaginal infection. Chemical characterization of the extract was performed by HPLC-UV analyses and showed the presence of flavones derivatives. The extract was effective against several Candida strains from our collection and species recovered from VVC patients, and was able to inhibit the yeast-hyphal transition. No cytotoxic activity against human female reproductive tract epithelial cells and no hemolytic activity against human red blood cells were observed. In the in vivo model of VVC, we evaluated the efficacy of the intravaginal treatment with a cream containing the extract at doses of 0.5, 1.0 and 2.0%. The treatment eradicated the vaginal fungal burden in infected rats after 8 days of treatment. S. nitens extract could be considered as an effective and non-toxic natural antifungal agent in the treatment of vulvovaginal candidiasis. © 2013 ISHAM.