Tissue bioengineering development is a global concern and different materials are studied and created to be safe, effective and with low cost. Nile Tilapia skin had shown its biological potential as covers for the burn wound. This study evaluates the tilapia skin histological, collagen properties and tensiometric resistance, after treatment by different sterilization methods. Tilapia skin samples were submitted to two sterilization processes: (1) chemical, which consisted in two 2% chlorhexidin baths, followed by sequential baths in increasing glycerol concentrations; and (2) radiation, when glycerolized skin samples were submitted to gamma radiation at 25, 30 and 50 kGy. Microscopic analyzes were performed through Haematoxylin-eosin and Picrosirius Red under polarized light. For tensiometric analysis, traction tests were performed. Glycerol treated skin presented a discrete collagen fibers disorganization within the deep dermis, while irradiated skin did not show any additional change. Throughout the steps of chemical sterilization, there was a higher proportion of collagen with red/yellow birefringence (type I) in the skin samples up to the first bath in chlorhexidin, when compared to samples after the first two glycerol baths (P < 0.005). However, there was no difference in relation to total collagen between groups. In irradiated skin, there was a larger total collagen preservation when using until 30 kGy (P < 0.005). Tensiometric evaluation did not show significant differences in relation to maximum load in the groups studied. We concluded that chemical and radiation (25 and 30 kGy) are efficient methods to sterilize Nile Tilapia skin without altering its microscopic or tensiometric characteristics.

Tyrosol is a quorum-sensing molecule of Candida albicans able to induce hyphal development in the early and intermediate stages of biofilm growth. In the present study, we evaluated the effect of high concentrations of exogenous tyrosol on planktonic cells and biofilms of C. albicans (n = 10) and C. tropicalis (n = 10), and investigated whether tyrosol could be synergic to antifungals that target cellular ergosterol. Antifungal susceptibility and drug interaction against planktonic cells were investigated by the broth microdilution method. Tyrosol was able to inhibit planktonic cells, with MIC values ranging from 2.5 to 5.0 mM for both species. Synergism was observed between tyrosol/amphotericin B (11/20 strains), tyrosol/itraconazole (18/20 strains) and tyrosol/fluconazole (18/20 strains). Exogenous tyrosol alone or combined with antifungals at both 10 × MIC and 50 × MIC were able to reduce biofilm of both Candida species. Mature biofilms were susceptible to tyrosol alone at 50 × MIC or combined with amphotericin at both 10 × MIC and 50 × MIC. On the other hand, tyrosol plus azoles at both 10 × MIC and 50 × MIC enhanced biofilm growth.

During recent years, comparative genomic analysis has allowed the identification of Mycobacterium leprae-specific genes with potential application for the diagnosis of leprosy. In a previous study, 58 synthetic peptides derived from these sequences were tested for their ability to induce production of IFN-γ in PBMC from endemic controls (EC) with unknown exposure to M. leprae, household contacts of leprosy patients and patients, indicating the potential of these synthetic peptides for the diagnosis of sub- or preclinical forms of leprosy. In the present study, the patterns of IFN-γ release of the individuals exposed or non-exposed to M. leprae were compared using an Artificial Neural Network algorithm, and the most promising M. leprae peptides for the identification of exposed people were selected. This subset of M. leprae-specific peptides allowed the differentiation of groups of individuals from sites hyperendemic for leprosy versus those from areas with lower level detection rates. A progressive reduction in the IFN-γ levels in response to the peptides was seen when contacts of multibacillary (MB) patients were compared to other less exposed groups, suggesting a down modulation of IFN-γ production with an increase in bacillary load or exposure to M. leprae. The data generated indicate that an IFN-γ assay based on these peptides applied individually or as a pool can be used as a new tool for predicting the magnitude of M. leprae transmission in a given population.

cThis study aimed to evaluate the in vitro combination of farnesol and ␤-lactams against Burkholderia pseudomallei. A total of 12 ␤-lactamase-positive strains were tested according to CLSI standards. All strains were inhibited by farnesol, with MICs ranging from 75 to 150 M. The combination of this compound with ␤-lactams resulted in statistically significant ␤-lactam MIC reduction (P < 0.05). This study provides new perspectives for the use of farnesol combined with ␤-lactam antibiotics against strains of B. pseudomallei. Burkholderia pseudomallei is a Gram-negative bacillus that causes melioidosis, a severe and potentially fatal disease endemic to Southeast Asia and hyperendemic to Northern Australia (2, 17).Some antibiotics currently recommended for the treatment of melioidosis are ceftazidime, imipenem, meropenem, amoxicillinclavulanate, cefoperazone-sulbactam, trimethoprim-sulfamethoxazole, doxycycline, and chloramphenicol (17). However, B. pseudomallei has developed resistance to these drugs (14,15,17,18); hence, it is necessary to search for new agents that are effective against this microorganism.The sesquiterpene alcohol farnesol is present in many essential oils of plants, such as Pluchea dioscoridis and Pittosporum undulatum, possibly to protect against attack by predators (5, 12). Farnesol has also been detected in the supernatant of Candida albicans broth cultures, as it is a quorum-sensing molecule of this fungal species (11).Moreover, farnesol is able to inhibit some microorganisms, such as Staphylococcus aureus, Streptococcus mutans, and Paracoccidioides brasiliensis, indicating its potential antimicrobial activity (4, 6-9), which has also been demonstrated against bacterial biofilms (16). Some studies have shown the ability of farnesol to increase the susceptibility of microorganisms to antimicrobials, indicating a possible applicability as an adjuvant drug (7). Brehm-Stecher et al. (1) reported increased susceptibility of S. aureus to ciprofloxacin, clindamycin, erythromycin, gentamicin, tetracycline, and vancomycin, as well as of Escherichia coli to polymyxin B, when these drugs were combined with farnesol. Thus, the objective of this study was to evaluate the in vitro activity of farnesol, alone and in combination with ␤-lactams, against strains of B. pseudomallei.We used 12 strains of ␤-lactamase-producing B. pseudomallei, stored in the Laboratory of Emerging and Reemerging Pathogens (LAPERE) of the Federal University of Ceará. Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, methicillinresistant Staphylococcus aureus (MRSA), and ␤-lactamase-negative S. aureus were used as experimental controls. Susceptibility testing was performed by the broth dilution method, as standardized by CLSI, described in document M07-A8 (3). The medium used was Mueller-Hinton broth (Difco, USA), and the concentration ranges were from 0.25 to 128 mg/ml for amoxicillin (Roche, Brazil), from 0.25/0.125 to 128/64 mg/ml for amoxicillin-clavulanate (Roche, Brazil), from 0.0312 to 16 mg/ml for imipenem (Ro...

This study aimed to investigate the influence of tetraconazole and malathion, both used in agricultural activities, on resistance to fluconazole, itraconazole and voriconazole in Candida parapsilosis ATCC 22019. The susceptibility to tetraconazole, malathion, fluconazole, itraconazole and voriconazole, through broth microdilution. Then, 12 independent replicates, were separated and exposed to four treatment groups, each one containing three replicates: G1: tetraconazole; G2: malathion; G3: fluconazole (positive control); G4: negative control. Replicates from G1, G2 and G3, were exposed to weekly increasing concentrations of tetraconazole, malathion and fluconazole, respectively, ranging from MIC/2 to 32 × MIC, throughout 7 weeks. The exposure to tetraconazole, but not malathion, decreased susceptibility to clinical azoles, especially fluconazole. The tetraconazole-induced fluconazole resistance is partially mediated by the increased activity of ATP-dependent efflux pumps, considering the increase in antifungal susceptibility after the addition of the efflux pump inhibitor, promethazine, and the increase in rhodamine 6G efflux and CDR gene expression in the G1 replicates. Moreover, MDR expression was only detected in G1 and G3 replicates, suggesting that MDR pumps are also involved in tetraconazole-induced fluconazole resistance. It is noteworthy that tetraconazole and fluconazole-treated replicates behaved similarly, therefore, resistance to azoles of clinical use may be a consequence of using azoles in farming activities.