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Aim: This study evaluated the effect of the biosurfactant rhamnolipid on the antimicrobial susceptibility, biofilm growth dynamics and production of virulence factors by Burkholderia pseudomallei. Materials & methods: The effects of rhamnolipid on planktonic and biofilm growth and its interaction with antibacterial drugs were evaluated. Then, its effects on growing and mature biofilms and on protease and siderophore production were assessed. Results: Rhamnolipid did not inhibit B. pseudomallei growth, but significantly enhanced the activity of meropenem and amoxicillin-clavulanate against mature biofilms. Rhamnolipid significantly reduced the biomass of mature biofilms, significantly increased protease production by growing and mature biofilms and siderophore release by growing biofilms. Conclusion: Rhamnolipid enhances the antimicrobial activity against B. pseudomallei, assists biofilm disassembly and alters protease and siderophore production by bacterial biofilms.

Aim: This study investigated the effect of terpinen-4-ol against Sporothrix schenckii complex and its interactions with antifungals. Materials & methods: The antifungal activity of terpinen-4-ol was evaluated by broth microdilution. The potential effect on cellular ergosterol concentration was evaluated by spectrophotometry. The antibiofilm activity was evaluated by violet crystal staining and XTT reduction assay. The potential pharmacological interactions with antifungals were evaluated by the checkerboard assay. Results: terpinen-4-ol (T-OH) showed minimal inhibitory concentrations ranging from 4 to 32 mg/l decreasing cellular ergosterol content and presented a SMIC ranging from 64 to 1024 mg/l for Sporothrix spp. The combinations of T-OH with itraconazole or terbinafine were synergistic. Conclusion: T-OH has antifungal activity against Sporothrix spp. and acts synergistically with standard antifungals.

AIM This study aimed to assess an ex situ model of biofilm-associated wounds on porcine skin for the study of Staphylococcus aureus and Pseudomonas aeruginosa biofilms in a host-like environment, after 48 to 120 h of incubation. MATERIAL AND RESULTS Ex situ and in vitro biofilms were comparatively analysed. Overall, CFU-counts and matrix quantification yielded significantly (P

Aim: The purpose of this study was to evaluate the effects of the antileishmanials meglumine antimoniate and pentamidine against Sporothrix schenckii complex. Materials & methods: The antifungal activity of the two antileishmanials was assessed by broth microdilution. The interaction between the antileishmanials and antifungal drugs (amphotericin B, itraconazole and terbinafine) was evaluated by the checkerboard assay. The effect of prior exposure of Sporothrix spp. yeast cells to antileishmanials was evaluated by broth microdilution. Results: Only pentamidine showed antifungal activity against Sporothrix spp. Synergistic interactions were observed between pentamidine and the antifungals. Also, the pre-exposure to meglumine antimoniate reduced the susceptibility of Sardinella brasiliensis and S. schenckii sensu stricto to amphotericin B and itraconazole. Conclusion: Pentamidine showed antifungal activity against Sporothrix spp., indicating it is a possible therapeutic alternative for the treatment of sporotrichosis.

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.

This study evaluated the in vitro interaction between ciprofloxacin (CIP) and classical antifungals against Histoplasma capsulatum var. capsulatum in mycelial (n = 16) and yeast-like forms (n = 9) and Coccidioides posadasii in mycelial form (n = 16). This research was conducted through broth microdilution and macrodilution, according to Clinical Laboratory Standards Institute. Inocula were prepared to obtain from 0.5 × 10(3) to 2.5 × 10(4) cfu ml(-1) for H. capsulatum and from 10(3) to 5 × 10(3) cfu ml(-1) for C. posadasii. Initially, minimum inhibitory concentration (MIC) for each drug alone was determined. Then, these MICs were used as the highest concentration for each drug during combination assays. The procedures were performed in duplicate. For all combination assays, MICs were defined as the lowest concentration capable of inhibiting 80% of visible fungal growth, when compared to the drug-free control. Drug interaction was evaluated by paired sample t-Student test. The obtained data showed a significant MIC reduction for most tested combinations of CIP with antifungals, except for that of CIP and voriconazole against yeast-like H. capsulatum. This study brings potential alternatives for the treatment of histoplasmosis and coccidioidomycosis, raising the possibility of using CIP as an adjuvant antifungal therapy, providing perspectives to delineate in vivo studies.

Aims This study aimed to evaluate the in vitro activity of miltefosine and levamisole against strains of Coccidioides posadasii in the filamentous phase and strains of Histoplasma capsulatum in filamentous and yeast phases. Methods and Results Strains of C. posadasii in the filamentous phase (n = 22) and strains of H. capsulatum in filamentous (n = 40) and yeast phases (n = 13) were, respectively, submitted to broth macrodilution and broth microdilution methods, as described by the Clinical and Laboratory Standards Institute, to determine the minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) of miltefosine and levamisole. The effect of the drugs on cell membrane permeability under osmotic stress conditions and total ergosterol production were also assessed, along with quantification of extravasated molecules. The results show the inhibitory effect of levamisole and miltefosine against C. posadasii and H. capsulatum and the effect of these drugs on ergosterol synthesis and the permeability of the plasma membrane using subinhibitory concentrations against strains subjected to osmotic stress. Levamisole was also able to cause the release of nucleic acids. Conclusions Miltefosine and levamisole are capable of inhibiting the in vitro growth of C. posadasii and H. capsulatum, probably by altering the permeability of the cellular membrane. Significance and Impact of the Study This work presents alternatives for the treatment of histoplasmosis and coccidioidomycosis, raising the possibility of the use of miltefosine and levamisole as adjuvants in antifungal therapy, providing perspectives for the design of in vivo studies.

O objetivo do presente trabalho foi avaliar in vitro o padrão do biofilme formado sobre um selante resinoso (SR) e selante ionomérico quimicamente ativado (SI) incorporados com digluconato de clorexidina (DC) a 0,5% e sobre o esmalte dentário adjacente a esses materiais, através de microscopia confocal de varredura a laser (MCVL). Blocos de esmalte dentário bovino (8x8x4 mm) foram restaurados, de acordo com os grupos: SR (Bioseal®), SRDC (Bioseal® + 0,5% de DC), SI (Riva Protect ®) e SIDC (Riva Protect ® + 0,5% de DC). Para a indução de cárie em esmalte, utilizou-se um modelo microbiológico de formação de biofilme de S. mutans UA 159 durante cinco dias, sendo três blocos de cada grupo para cada triplicata experimental. Após 5 dias de incubação, o biofilme foi avaliado através de MCVL. Os parâmetros avaliados do biofilme foram biomassa total, espessura média, espessura média total, coeficiente de homogeneidade e relação superfície/volume para células vivas. Os dados foram analisados utilizando Teste t pareado, com nível de significância em 5% (SigmaStat 3.5). Quando comparado o biofilme formado sobre o esmalte dentário adjacente e sobre o selante, todos os parâmetros avaliados foram estatisticamente significantes para o grupo SR, no grupo SI nenhuma diferença foi observada, já para os grupos SRDC e SIDC somente a relação área/volume foi significante. Os selantes resinosos apresentaram um maior efeito antibiofilme, no entanto a incorporação de DC promoveu dispersão em selantes resinosos e ionoméricos.Palavras-chave: Biofilmes. Clorexidina. Selantes de Fóssulas e Fissuras.

This study aimed to evaluate the in vitro combination of farnesol and β-lactams against Burkholderia pseudomallei . A total of 12 β-lactamase-positive strains were tested according to CLSI standards. All strains were inhibited by farnesol, with MICs ranging from 75 to 150 μM. The combination of this compound with β-lactams resulted in statistically significant β-lactam MIC reduction ( P ≤ 0.05). This study provides new perspectives for the use of farnesol combined with β-lactam antibiotics against strains of B. pseudomallei .

Small ruminant production is a common agricultural activity worldwide. However, studies on the fungal microbiota of these animals are scarce. Therefore, this study aimed at isolating yeasts from goats and sheep and evaluating the antifungal susceptibility of the recovered Candida albicans. A total of 120 animals from farms in Ceara State, Brazil, were assessed in this study. The samples were collected from nasal, oral and rectal cavities with sterile swabs. Candida spp., Trichosporon spp. and Rhodotorula spp. were isolated from small ruminants. Resistance to three azole drugs was observed in C. albicans. In summary, Candida spp. were predominantly observed as part of the microbiota of the nasal, oral and rectal cavities of small ruminants, including azole-resistant strains of C. albicans.

This study evaluated the in vitro interaction between ciprofloxacin (CIP) and classical antifungals against Histoplasma capsulatum var. capsulatum in mycelial (n = 16) and yeast-like forms (n = 9) and Coccidioides posadasii in mycelial form (n = 16). This research was conducted through broth microdilution and macrodilution, according to Clinical Laboratory Standards Institute. Inocula were prepared to obtain from 0.5 × 10(3) to 2.5 × 10(4) cfu ml(-1) for H. capsulatum and from 10(3) to 5 × 10(3) cfu ml(-1) for C. posadasii. Initially, minimum inhibitory concentration (MIC) for each drug alone was determined. Then, these MICs were used as the highest concentration for each drug during combination assays. The procedures were performed in duplicate. For all combination assays, MICs were defined as the lowest concentration capable of inhibiting 80% of visible fungal growth, when compared to the drug-free control. Drug interaction was evaluated by paired sample t-Student test. The obtained data showed a significant MIC reduction for most tested combinations of CIP with antifungals, except for that of CIP and voriconazole against yeast-like H. capsulatum. This study brings potential alternatives for the treatment of histoplasmosis and coccidioidomycosis, raising the possibility of using CIP as an adjuvant antifungal therapy, providing perspectives to delineate in vivo studies.

Candida meningitis is a rare condition that occurs more frequently in premature infants, immunocompromised patients or patients after neurosurgery. We describe a case of a previously healthy 41-year-old man with Candida parapsilosis meningitis associated with oropharyngeal candidiasis as the first manifestation of AIDS.

Histoplasmosis is a systemic infection caused by the fungus Histoplasma capsulatum. Environmental sources of infection for humans and animals in certain regions and the prevalence of infection in animals are frequently unknown. Because of the clinical and epidemiological similarities between histoplasmosis and leishmaniasis in northeastern Brazil, we decided to investigate the serologic evidence of H. capsulatum in dogs, considering that these animals can act as sentinels for histoplasmosis. A total of 224 serum samples from dogs were tested for antibodies against H. capsulatum through immunodiffusion. A total of 128 (57.14%) samples were positive for leishmaniasis by indirect immunofluorescence assay and four (1.78%) samples were positive for antibodies against H. capsulatum. Immunological evidence of the co-existence of histoplasmosis and leishmaniasis in dogs living in urban areas was observed. Diagnosis and clinical management of these diseases in endemic areas should be improved by veterinarians.

Cryptococcosis is a fungal infection caused by yeasts of the genus Cryptococcus , with Cryptococcus neoformans and Cryptococcus gattii as the primary pathogenic species. This disease is a threat to immunocompromised patients, especially those who have AIDS. However, the disease has also been described in healthy individuals. The tests used to identify these microorganisms have limitations that make final diagnosis difficult. However, currently there are specific gene sequences that can be used to detect C. neoformans and C. gattii from clinical specimens and cultures. These sequences can be used for identification, typing, and the study of population genetics. Among the main identification techniques are hybridization, which was the pioneer in molecular identification and development of specific probes for pathogen detection; PCR and other PCR-based methods, particularly nested PCR and multiplex PCR; and sequencing of specific genomic regions that are amplified through PCR, which is especially useful for diagnosis of cryptococcosis caused by unconventional Cryptococcus sp. Concerning microorganism typing, the following techniques have shown the best ability to differentiate between fungal serotypes and molecular types: PCR fingerprinting, PCR–RFLP, AFLP, and MLST. Thus, the accumulation of data generated by molecular methods can have a positive impact on monitoring resistant strains and treating diseases.

Cockatiels are the world's second most popular psittacine pet bird, but no data characterizing their gastrointestinal microbiota have been found. Thus, the aim of this work was to characterize the yeast gastrointestinal microbiota of cockatiels and to evaluate the relevance of cockatiels as carriers of potentially pathogenic yeasts. A total of 60 cockatiels, from 15 different premises, were assessed. A thorough clinical examination was performed with each bird, and samples were collected from oral cavity, crop and cloaca. The stools were collected from cages where the birds were kept. The isolates were identified according to morphological and biochemical characteristics. Yeasts were isolated from at least one anatomical site of 65 % of the birds and 64.3 % of the stool samples. The oral cavity (53.3 %) and the crop (58.3 %) were the anatomical sites with the highest prevalence and the highest number of yeast isolates. Overall, 120 yeast isolates, belonging to 13 species, were obtained. The most frequently isolated species were Candida albicans, with 39 (32.5 %) isolates, followed by Candida tropicalis (20 %), Trichosporon asteroides (12.5 %), Candida famata (10 %) and others. Mixed yeast colonies were isolated from 23.3 % of the birds and C. albicans was seldom found in association with other species (P