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1.
Microb Pathog ; 196: 106993, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-39374884

RESUMEN

Otitis externa is an inflammatory disease of the external ear canal of complex and multifactorial etiology associated with recurrent bacterial infection. This study aimed to assess the antimicrobial and antibiofilm activity of promethazine against bacterial isolates from dogs with otitis externa, as well as the effect of this compound on the dynamics of biofilm formation over 120 h. Planktonic bacterial susceptibility to promethazine was evaluated to determine the minimum inhibitory concentrations (MIC). The minimum biofilm eradication concentration (MBEC) was also determined by broth microdilution. To evaluate the effect on biofilm growth, promethazine was tested at three concentrations MIC, MIC/2 and MIC/8, with daily readings at 48, 72, 96 and 120 h. The MICs of promethazine ranged from 48.83 to 781.25 µg mL-1. Promethazine significantly (P < 0.05) reduced mature biofilm biomass, with MBECs ranging from 48.8 to 6250 µg mL-1 and reduced (P < 0.01) biofilm formation for up to the 120-h, at concentrations corresponding to the MIC obtained against each isolate. Promethazine was effective against microorganisms associated with canine otitis externa. The data suggest that promethazine presents antimicrobial and antibiofilm activity and is a potential alternative to treat and prevent recurrent bacterial otitis in dogs. These results emphasize the importance of drug repurposing in veterinary otology as an alternative to reduce antimicrobial resistance.


Asunto(s)
Antibacterianos , Biopelículas , Enfermedades de los Perros , Pruebas de Sensibilidad Microbiana , Otitis Externa , Prometazina , Animales , Perros , Biopelículas/efectos de los fármacos , Prometazina/farmacología , Enfermedades de los Perros/microbiología , Enfermedades de los Perros/tratamiento farmacológico , Antibacterianos/farmacología , Otitis Externa/microbiología , Otitis Externa/veterinaria , Otitis Externa/tratamiento farmacológico , Bacterias/efectos de los fármacos , Bacterias/clasificación , Bacterias/aislamiento & purificación
2.
Biofouling ; 39(2): 135-144, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-37013808

RESUMEN

This study evaluated the effect of the iron chelator deferiprone (DFP) on antimicrobial susceptibility and biofilm formation and maintenance by Burkholderia pseudomallei. Planktonic susceptibility to DFP alone and in combination with antibiotics was evaluated by broth microdilution and biofilm metabolic activity was determined with resazurin. DFP minimum inhibitory concentration (MIC) range was 4-64 µg/mL and in combination reduced the MIC for amoxicillin/clavulanate and meropenem. DFP reduced the biomass of biofilms by 21 and 12% at MIC and MIC/2, respectively. As for mature biofilms, DFP reduced the biomass by 47%, 59%, 52% and 30% at 512, 256, 128 and 64 µg/mL, respectively, but did not affect B. pseudomallei biofilm viability nor increased biofilm susceptibility to amoxicillin/clavulanate, meropenem and doxycycline. DFP inhibits planktonic growth and potentiates the effect of ß-lactams against B. pseudomallei in the planktonic state and reduces biofilm formation and the biomass of B. pseudomallei biofilms.


Asunto(s)
Burkholderia pseudomallei , Meropenem/farmacología , Deferiprona/farmacología , Hierro/farmacología , Hierro/metabolismo , Biopelículas , Antibacterianos/farmacología , Combinación Amoxicilina-Clavulanato de Potasio/farmacología , Pruebas de Sensibilidad Microbiana , Quelantes del Hierro/farmacología
3.
Biofouling ; 39(2): 189-203, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-37144566

RESUMEN

This study evaluated the antimicrobial activity of promethazine against Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus mutans and its effect on the antimicrobial susceptibility of biofilms grown in vitro and ex vivo on porcine heart valves. Promethazine was evaluated alone and in combination with vancomycin and oxacillin against Staphylococcus spp. and vancomycin and ceftriaxone against S. mutans in planktonic form and biofilms grown in vitro and ex vivo. Promethazine minimum inhibitory concentration range was 24.4-95.31 µg/mL and minimum biofilm eradication concentration range was 781.25-3.125 µg/mL. Promethazine interacted synergistically with vancomycin, oxacillin and ceftriaxone against biofilms in vitro. Promethazine alone reduced (p < 0.05) the CFU-counts of biofilms grown on heart valves for Staphylococcus spp., but not for S. mutans, and increased (p < 0.05) the activity of vancomycin, oxacillin and ceftriaxone against biofilms of Gram-positive cocci grown ex vivo. These findings bring perspectives for repurposing promethazine as adjuvant in the treatment of infective endocarditis.


Asunto(s)
Endocarditis , Cocos Grampositivos , Humanos , Vancomicina/farmacología , Antibacterianos/farmacología , Prometazina/farmacología , Ceftriaxona/farmacología , Biopelículas , Oxacilina/farmacología , Staphylococcus , Pruebas de Sensibilidad Microbiana
4.
Lett Appl Microbiol ; 76(3)2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-36841231

RESUMEN

This study aimed to standardize the use of an ex vivo wound model for the evaluation of compounds with antibiofilm activity. The in vitro susceptibility of Staphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa ATCC 27853 to ciprofloxacin and polyhexamethylene biguanide (PHMB) was evaluated in planktonic and biofilm growth. The effects of ciprofloxacin and PHMB on biofilms grown on porcine skin explants were evaluated by colony-forming unit (CFU) counting and confocal microscopy. Minimum inhibitory concentrations (MICs) against S. aureus and P. aeruginosa were, respectively, 0.5 and 0.25 µg mL-1 for ciprofloxacin, and 0.78 and 6.25 µg mL-1 for PHMB. Minimum biofilm eradication concentrations (MBECs) against S. aureus and P. aeruginosa were, respectively, 2 and 8 µg mL-1 for ciprofloxacin, and 12.5 and >25 µg mL-1 for PHMB. Ciprofloxacin reduced (P < 0.05) log CFU counts of the biofilms grown ex vivo by 3 and 0.96 for S. aureus and P. aeruginosa, respectively, at MBEC, and by 0.58 and 8.12 against S. aureus and P. aeruginosa, respectively, at 2xMBEC. PHMB (100 µg/mL) reduced (P < 0.05) log CFU counts by 0.52 for S. aureus and 0.68 log for P. aeruginosa, leading to an overall decrease (P < 0.05) in biofilm biomass. The proposed methodology to evaluate the susceptibility of biofilms grown ex vivo led to reproducible and reliable results.


Asunto(s)
Ciprofloxacina , Staphylococcus aureus , Animales , Porcinos , Ciprofloxacina/farmacología , Biguanidas/farmacología , Biopelículas , Pseudomonas aeruginosa , Antibacterianos/farmacología , Pruebas de Sensibilidad Microbiana
5.
Lett Appl Microbiol ; 76(10)2023 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-37791895

RESUMEN

This study evaluated the antibiofilm activity of promethazine, deferiprone, and Manuka honey against Staphylococcus aureus and Pseudomonas aeruginosa in vitro and ex vivo in a wound model on porcine skin. The minimum inhibitory concentrations (MICs) and the effects of the compounds on biofilms were evaluated. Then, counting colony-forming units (CFUs) and confocal microscopy were performed on biofilms cultivated on porcine skin for evaluation of the compounds. For promethazine, MICs ranging from 97.66 to 781.25 µg/ml and minimum biofilm eradication concentration (MBEC) values ranging from 195.31 to 1562.5 µg/ml were found. In addition to reducing the biomass of both species' biofilms. As for deferiprone, the MICs were 512 and >1024 µg/ml, the MBECs were ≥1024 µg/ml, and it reduced the biomass of biofilms. Manuka honey had MICs of 10%-40%, MBECs of 20 to >40% and reduced the biomass of S. aureus biofilms only. Concerning the analyses in the ex vivo model, the compounds reduced (P < .05) CFU counts for both bacterial species, altering the biofilm architecture. The action of the compounds on biofilms in in vitro and ex vivo tests raises the possibility of using them against biofilm-associated wounds. However, further studies are needed to characterize the mechanisms of action and their effectiveness on biofilms in vivo.


Asunto(s)
Miel , Staphylococcus aureus , Animales , Porcinos , Prometazina/farmacología , Deferiprona/farmacología , Biopelículas , Pseudomonas aeruginosa , Antibacterianos/farmacología , Pruebas de Sensibilidad Microbiana
6.
Can J Microbiol ; 68(7): 493-499, 2022 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-35303412

RESUMEN

Paraquat (1,10-dimethyl-4,4-bipyridinium dichloride; PQ) is a free-radical producing herbicide that affects cell membranes and can upset the environmental balance of microorganisms present in soil, such as Cryptococcus spp. This study aimed to evaluate the in vitro activity of PQ against Cryptococcus spp. in planktonic and biofilm forms, as well as the protective effect of antioxidant agents against the antifungal effect of PQ and the kinetics of melanin production in response to PQ. Susceptibility to PQ was evaluated by microdilution. Cryptococcus sp. strains exposed to PQ were grown in media with ascorbic acid (AA) and glutathione (GSH). Melanin production was assessed in the presence of l-3,4-dihydroxyphenylalanine (l-DOPA) + PQ. The minimum inhibitory concentration of PQ against Cryptococcus spp. ranged from 8 to 256 µg/mL. Furthermore, PQ reduced biofilm formation. AA and GSH restored the fungal growth of Cryptococcus spp. exposed to PQ. In addition, l-DOPA + PQ delayed melanin production by 24 and 48 h for C. deuterogattii and C. neoformans sensu lato, respectively, suggesting that PQ induces a fitness trade-off in melanin production. Taken together, our data suggest that the antifungal effect of PQ against Cryptococcus spp. possibly exerts selective pressures interfering with biofilm formation and melanin production by these yeasts.


Asunto(s)
Cryptococcus gattii , Cryptococcus neoformans , Herbicidas , Antifúngicos/metabolismo , Antifúngicos/farmacología , Cryptococcus gattii/metabolismo , Cryptococcus neoformans/metabolismo , Herbicidas/metabolismo , Herbicidas/farmacología , Levodopa/metabolismo , Levodopa/farmacología , Melaninas/metabolismo , Melaninas/farmacología , Pruebas de Sensibilidad Microbiana , Paraquat/metabolismo , Paraquat/farmacología
7.
Biofouling ; 38(8): 778-785, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-36210505

RESUMEN

Trichosporon asahii and T. inkin are emergent agents of deep-seated and disseminated infections in immunocompromised patients. The present study aimed to investigate the role of extracellular DNA (eDNA) and the enzyme deoxyribonuclease (DNase) on the structure of T. asahii and T. inkin biofilms, as well as to examine their effect on the susceptibility to antifungals. Biofilms reached maturity at 48 h; eDNA concentration in the supernatant increased over time (6 < 24 h < 48h). Exogenous eDNA increased biomass of Trichosporon biofilms at all stages of development, enhanced their tolerance to antifungals and improved their structural complexity. DNase reduced biomass, biovolume and thickness of Trichosporon biofilms, thereby rendering them more susceptibility to voriconazole. The results suggest the relevance of eDNA in the structure and antifungal susceptibility of Trichosporon biofilms and highlight the potential of DNase as adjuvant in biofilm control.


Asunto(s)
Antifúngicos , Trichosporon , Humanos , Antifúngicos/farmacología , Biopelículas , Pruebas de Sensibilidad Microbiana , Trichosporon/genética , ADN , Desoxirribonucleasas
8.
Microbiology (Reading) ; 167(2)2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33427606

RESUMEN

Chlamydoconidium-producing Trichophyton tonsurans strains isolated in Northeastern Brazil have morphological features different from the classic description of this dermatophyte species. This study investigated the phylogenetic relationship of chlamydoconidium-producing T. tonsurans strains isolated in Northeastern Brazil. Also, the effect of terbinafine and farnesol on mature biofilms of T. tonsurans strains was evaluated. The mass spectra of T. tonsurans strains were investigated by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The ITS and LSU loci regions of rDNA and the partial ß-tubulin gene were sequenced and the phylogenetic tree was analysed. The effects of terbinafine and farnesol on mature T. tonsurans biofilms were evaluated through the analysis of metabolic activity, quantification of biomass and observation by scanning electron microscopy. MALDI-TOF MS spectra of the chlamydoconidium-producing T. tonsurans strains differed from the spectrum of the control strain (ATCC 28942), presenting an intense ion peak at m/z 4155 Da. Phylogenetic tree analysis showed that the chlamydoconidium-producing strains isolated in Northeastern Brazil are allocated to a single cluster, differing from strains isolated from other countries. As for mature T. tonsurans biofilms, farnesol reduced biomass and metabolic activity by 64.4 and 65.9 %, respectively, while terbinafine reduced the biomass by 66.5 % and the metabolic activity by 69 %. Atypical morphological characteristics presented by chlamydoconidium-producing T. tonsurans strains result from phenotypic plasticity, possibly for adaptation to environmental stressors. Also, farnesol had inhibitory activity against T. tonsurans biofilms, demonstrating this substance can be explored for development of promising anti-biofilm drugs against dermatophytes.


Asunto(s)
Antifúngicos/farmacología , Arthrodermataceae/clasificación , Biopelículas/efectos de los fármacos , Filogenia , Arthrodermataceae/citología , Arthrodermataceae/efectos de los fármacos , Arthrodermataceae/fisiología , Biopelículas/crecimiento & desarrollo , Brasil , ADN de Hongos/genética , ADN Ribosómico/genética , Farnesol/farmacología , Proteínas Fúngicas/genética , Humanos , Pruebas de Sensibilidad Microbiana , Análisis de Secuencia de ADN , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Esporas Fúngicas/clasificación , Esporas Fúngicas/citología , Terbinafina/farmacología , Tubulina (Proteína)/genética
9.
Med Mycol ; 59(8): 793-801, 2021 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-33550417

RESUMEN

Invasive fungal infections (IFIs) are important worldwide health problem, affecting the growing population of immunocompromised patients. Although the majority of IFIs are caused by Candida spp., other fungal species have been increasingly recognized as relevant opportunistic pathogens. Trichosporon spp. are members of skin and gut human microbiota. Since 1980's, invasive trichosporonosis has been considered a significant cause of fungemia in patients with hematological malignancies. As prolonged antibiotic therapy is an important risk factor for IFIs, the present study investigated if vancomycin enhances growth and virulence of Trichosporon. Vancomycin was tested against T. inkin (n = 6) and T. asahii (n = 6) clinical strains. Planktonic cells were evaluated for their metabolic activity and virulence against Caenorhabditis elegans. Biofilms were evaluated for metabolic activity, biomass production, amphotericin B tolerance, induction of persister cells, and ultrastructure. Vancomycin stimulated planktonic growth of Trichosporon spp., increased tolerance to AMB, and potentiates virulence against C. elegans. Vancomycin stimulated growth (metabolic activity and biomass) of Trichosporon spp. biofilms during all stages of development. The antibiotic increased the number of persister cells inside Trichosporon biofilms. These cells showed higher tolerance to AMB than persister cells from VAN-free biofilms. Microscopic analysis showed that VAN increased production of extracellular matrix and cells in T. inkin and T. asahii biofilms. These results suggest that antibiotic exposure may have a direct impact on the pathophysiology of opportunistic trichosporonosis in patients at risk. LAY ABSTRACT: This study showed that the vancomycin stimulated Trichosporon growth, induced morphological and physiological changes on their biofilms, and also enhanced their in vivo virulence. Although speculative, the stimulatory effect of vancomycin on fungal cells should be considered in a clinical scenario.


Asunto(s)
Antibacterianos/farmacología , Trichosporon/efectos de los fármacos , Vancomicina/farmacología , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Microscopía Electrónica de Rastreo , Plancton/efectos de los fármacos , Plancton/crecimiento & desarrollo , Plancton/patogenicidad , Trichosporon/crecimiento & desarrollo , Trichosporon/patogenicidad , Trichosporon/fisiología , Virulencia/efectos de los fármacos
10.
Microb Ecol ; 82(4): 1080-1083, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33723620

RESUMEN

This study aimed to identify Candida spp. from agricultural soils cultivated with azole fungicides and investigate their susceptibility to clinical (fluconazole, itraconazole, voriconazole, and amphotericin B) and agricultural (tetraconazole and tebuconazole) antifungals in planktonic form. Additionally, Candida biofilm-forming ability and biofilm susceptibility to agricultural antifungals and voriconazole were analyzed. Species identification was performed by phenotypic and molecular assays. The susceptibility of planktonic cells was evaluated by the broth microdilution method. The biofilm metabolic activity was evaluated by the XTT reduction assay. The recovered Candida spp. were identified as C. parapsilosis sensu stricto (n = 14), C. albicans (n = 5), C. tropicalis (n = 2), C. fermentati (n = 1), and C. metapsilosis (n = 2). Minimum inhibitory concentration ranges for clinical and agricultural antifungals were ≤ 0.03-4 µg/mL and 1-128 µg/mL, respectively. Two and one C. albicans strains were considered non-wild type for voriconazole and fluconazole, respectively. All strains were biofilm producers. The minimum biofilm inhibitory concentration ranges for tetraconazole and tebuconazole were 128-> 1024 µg/mL, while for voriconazole was 512-> 1024 µg/mL. In summary, this study shows that non-wild type and azole-resilient biofilm-producing Candida species colonize agricultural soils cultivated with azole fungicides.


Asunto(s)
Candida , Fungicidas Industriales , Antifúngicos/farmacología , Azoles/farmacología , Biopelículas , Candida/genética , Candida albicans , Fungicidas Industriales/farmacología , Pruebas de Sensibilidad Microbiana , Suelo
11.
Anaerobe ; 69: 102322, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33515722

RESUMEN

Clostridioides difficile is a Gram-positive, spore-forming, anaerobic bacillus which is the leading cause of health-care-associated infective diarrhea. The rising incidence of antibiotic resistance in pathogens such as C. difficile makes researches on alternative antibacterial products very important, especially those exploring natural products like propolis. Brazilian Red Propolis, found in the Northeast region of Brazil, is composed by products from regional plants that have the antimicrobial properties. This study aimed to evaluate the in vitro activity of Brazilian Red Propolis (BRP) against C. difficile strains in planktonic and biofilm forms. The susceptibility of four strains of C. difficile to BRP was analyzed by broth microdilution method and vancomycin was included as control drug. BRP-exposed C. difficile cells were evaluated by scanning electron microscopy (SEM). Then, the effects of BRP on growing and mature C. difficile biofilms were also evaluated. BRP minimum inhibitory concentration was 625 µg/mL against all tested strains, while vancomycin MIC range was 0.5-2 µg/mL. SEM showed the loss of homogeneity in bacterial cell wall and cell fragmentation, after BRP-exposure. BRP, at MIC, reduced (P < 0.05) the biomass, matrix proteins and matrix carbohydrates of growing biofilms, and, at 8xMIC, reduced (P < 0.05) the biomass and matrix proteins of mature biofilms. The present study demonstrated that BRP inhibits planktonic growth, damages cell wall, decreases biofilm growth and harms mature biofilms of C. difficile.


Asunto(s)
Antibacterianos/farmacocinética , Biopelículas/efectos de los fármacos , Clostridioides difficile/efectos de los fármacos , Plancton/efectos de los fármacos , Própolis/química , Própolis/farmacocinética , Vancomicina/farmacocinética , Brasil , Pruebas de Sensibilidad Microbiana
12.
Microb Pathog ; 143: 104123, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32169493

RESUMEN

Cryptococcus neoformans/Cryptococcus gattii complex species are etiological agents of cryptococcosis, a systemic mycosis that cause respiratory infection and meningoencephalitis. To establish the infection, these yeasts produce virulence factors, such as melanin, which contribute to pathogenicity and antifungal tolerance. The aim of this study was to investigate melanin production by the C. neoformans/C. gattii complex in the presence of different precursors of melanogenesis and evaluate the effect of melanization on the antifungal susceptibility of these species to fluconazole, flucytosine and amphotericin B. Epinephrine, norepinephrine, dopamine and caffeic acid were used as substrates for melanin production, and l-dopa was used as positive control. The susceptibility of melanized strains (n = 6), after exposure to epinephrine or l-dopa, was evaluated by broth microdilution assay, and non-melanized strains were used as control. The antifungal activity of amphotericin B against melanized strains was also investigated by time kill assay. All Cryptococcus spp. strains produced melanin after exposure to the tested substrates. After exposure to epinephrine, minimum inhibitory concentration (MIC) ranges were 1-8 µg/mL for fluconazole, 2-8 µg/mL for flucytosine and 0.125-1 µg/mL for amphotericin B, while, after exposure to l-dopa, MIC ranges were 2-8 µg/mL for fluconazole, 4-8 µg/mL for flucytosine, and 0.125-0.5 µg/mL for amphotericin B. Similar results were observed for non-melanized strains. The production of melanin after exposure to epinephrine was higher than that induced by l-dopa. Melanized cells of both species were more tolerant to amphotericin B than the non-melanized control, emphasizing the importance of melanin production for fungal virulence.


Asunto(s)
Anfotericina B/farmacología , Antifúngicos/farmacología , Cryptococcus gattii/metabolismo , Cryptococcus neoformans/metabolismo , Epinefrina/farmacología , Melaninas/metabolismo , Animales , Antibacterianos , Ácidos Cafeicos/metabolismo , Ácidos Cafeicos/farmacología , Cryptococcus gattii/efectos de los fármacos , Cryptococcus neoformans/efectos de los fármacos , Dopamina/metabolismo , Dopamina/farmacología , Epinefrina/metabolismo , Humanos , Pruebas de Sensibilidad Microbiana , Norepinefrina/metabolismo , Norepinefrina/farmacología
13.
Med Mycol ; 58(7): 896-905, 2020 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-31950176

RESUMEN

This study initially aimed at investigating the occurrence of azole resistance among Candida spp. from animals and analyzing the involvement of efflux pumps in the resistance phenomenon. Then, the dynamics of antifungal resistance was assessed, by comparing the antifungal epidemiological cutoff values (ECVs) against C. albicans and C. tropicalis from humans and animals. Fifty azole-resistant isolates (24 C. albicans, 24 C. tropicalis; 2 C. parapsilosis sensu lato) were submitted to the efflux pump inhibition assay with promethazine and significant MIC reductions were observed for fluconazole (2 to 250-fold) and itraconazole (16 to 4000-fold). Then, the antifungal ECVs against C. albicans and C. tropicalis from human and animal isolates were compared. Fluconazole, itraconazole and voriconazole ECVs against human isolates were lower than those against animal isolates. Based on the antifungal ECVs against human isolates, only 33.73%, 50.39% and 63.53% of C. albicans and 52.23%, 61.85% and 55.17% of C. tropicalis from animals were classified as wild-type for fluconazole, itraconazole and voriconazole, respectively. Therefore, efflux-mediated mechanisms are involved in azole resistance among Candida spp. from animals and this phenomenon seems to emerge in animal-associated niches, pointing to the existence of environmental drivers of resistance and highlighting the importance of the One Health approach to control it.


Asunto(s)
Candida albicans/efectos de los fármacos , Candida parapsilosis/efectos de los fármacos , Candida tropicalis/efectos de los fármacos , Candidiasis/tratamiento farmacológico , Farmacorresistencia Fúngica/efectos de los fármacos , Fluconazol/uso terapéutico , Itraconazol/uso terapéutico , Voriconazol/uso terapéutico , Animales , Antifúngicos/uso terapéutico , Candidiasis/veterinaria , Femenino , Humanos , Masculino
14.
Med Mycol ; 58(7): 906-912, 2020 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-32016364

RESUMEN

Cryptococcus neoformans/Cryptococcus gattii are fungal pathogens that affect the central nervous system, mainly in immunocompromised individuals. Due to the limited pharmacological arsenal available for the treatment of cryptococcosis associated with cases of antifungal resistance of Cryptococcus spp. reported in some studies, the search for new compounds with antifungal potential becomes relevant. Thus, the objective of this study was to evaluate the inhibitory effect of phenothiazines (promethazine and chlorpromazine) on C. neoformans/C. gattii planktonic cells and biofilms. In vitro planktonic susceptibility testing was performed using the broth microdilution assay. The effect of phenothiazines was evaluated against biofilm formation and mature Cryptococcus biofilms. Biofilm morphology and ultrastructure were also evaluated by scanning electron microscopy. Promethazine and chlorpromazine showed antifungal activity against planktonic cells, with minimum inhibitory concentrations of 8-32 µg/ml and 4-16 µg/ml, respectively. As for biofilm formation, phenothiazines reduced biomass by 60% and metabolic activity by 90% at 64 µg/ml; while in mature biofilms, reductions of 85% and 90% in biomass and metabolic activity, respectively, were observed at 1024 µg/ml. Promethazine and chlorpromazine were also able to disrupt and fragment biofilms. In conclusion, promethazine and chlorpromazine have antifungal activity against planktonic cells and biofilms of Cryptococcus spp. These data show the potential of promethazine and chlorpromazine as antibiofilm drugs.


Asunto(s)
Biopelículas/efectos de los fármacos , Clorpromazina/uso terapéutico , Criptococosis/tratamiento farmacológico , Cryptococcus gattii/efectos de los fármacos , Cryptococcus neoformans/efectos de los fármacos , Farmacorresistencia Fúngica/efectos de los fármacos , Plancton/efectos de los fármacos , Prometazina/uso terapéutico , Antifúngicos/uso terapéutico , Humanos , Pruebas de Sensibilidad Microbiana
15.
Med Mycol ; 2020 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-32926150

RESUMEN

The emergence of tolerant Cryptococcus neoformans strains to antifungals has been described. It has directed researchers to screen for new antimicrobial compounds. In this context, several plant-derived compounds, such as anthraquinones (aloe emodin, barbaloin, and chrysophanol), have been investigated for their antimicrobial properties. This study aimed to evaluate the in vitro effect of aloe emodin, barbaloin and chrysophanol on C. neoformans in vitro growth. In addition, the interaction between these anthraquinones and amphotericin B and itraconazole was evaluated. Initially, the minimum inhibitory concentrations (MIC) of these compounds were determined against 17 strains of C. neoformans by the broth microdilution method and then pharmacological interaction assays were performed with 15 strains by the checkerboard method. Aloe emodin, barbaloin, and chrysophanol showed minimum inhibitory concentrations of 236.82-473.65 µM (64-128 µg/mL), 153-306 µM (64-128 µg/ml) and ≥1007 µM (≥256 µg/ml), respectively. Furthermore, aloe emodin (11/15), barbaloin (13/15), and chrysophanol (12/15) showed pharmacological synergism (FICI < 0.5) with amphotericin B at subinhibitory concentrations (MIC/4). The itraconazole-aloe emodin interaction was additive (1/15) (0.5 < FICI < 1.0). The itraconazole-barbaloin interaction were synergistic (2/15) and additive (5/15); whereas itraconazole-chrysophanol interactions were additive (2/15). Anthraquinones, especially aloe emodin and barbaloin, present in vitro antifungal activity against C. neoformans and potentiate the antifungal activity of amphotericin B.

16.
Can J Microbiol ; 66(6): 377-388, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32319304

RESUMEN

Candida tropicalis is a prominent non-Candida albicans Candida species involved in cases of candidemia, mainly causing infections in patients in intensive care units and (or) those presenting neutropenia. In recent years, several studies have reported an increase in the recovery rates of azole-resistant C. tropicalis isolates. Understanding C. tropicalis resistance is of great importance, since resistant strains are implicated in persistent or recurrent and breakthrough infections. In this review, we address the main mechanisms underlying C. tropicalis resistance to the major antifungal classes used to treat candidiasis. The main genetic basis involved in C. tropicalis antifungal resistance is discussed. A better understanding of the epidemiology of resistant strains and the mechanisms involved in C. tropicalis resistance can help improve diagnosis and assessment of the antifungal susceptibility of this Candida species to improve clinical management.


Asunto(s)
Antifúngicos/farmacología , Azoles/farmacología , Candida tropicalis/genética , Candidiasis/microbiología , Farmacorresistencia Fúngica/genética , Candida tropicalis/efectos de los fármacos , Candidiasis/diagnóstico , Candidiasis/tratamiento farmacológico , Humanos
17.
Biofouling ; 36(7): 783-791, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32842796

RESUMEN

This study describes an ex vivo model that creates an environment for dermatophyte biofilm growth, with features that resemble those of in vivo conditions, designing a new panorama for the study of antifungal susceptibility. Regarding planktonic susceptibility, MIC ranges were 0.125-1 µg ml-1 for griseofulvin and 0.000097-0.25 µg ml-1 for itraconazole and terbinafine. sMIC50 ranges were 2->512 µg ml-1 for griseofulvin and 0.25->64 µg ml-1 for itraconazole and terbinafine. CLSM images demonstrated a reduction in the amount of cells within the biofilm, but hyphae and conidia were still observed and biofilm biomass was maintained. SEM analysis demonstrated a retraction in the biofilm matrix, but fungal structures and water channels were preserved. These results show that ex vivo biofilms are more tolerant to antifungal drugs than in vitro biofilms, suggesting that environmental and nutritional conditions created by this ex vivo model favor biofilm growth and robustness, and hence drug tolerance.


Asunto(s)
Arthrodermataceae , Biopelículas , Preparaciones Farmacéuticas , Antifúngicos/farmacología , Pruebas de Sensibilidad Microbiana
18.
Biofouling ; 36(9): 1129-1148, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-33349038

RESUMEN

Microbial biofilms are a natural adaptation of microorganisms, typically composed of multiple microbial species, exhibiting complex community organization and cooperation. Biofilm dynamics and their complex architecture are challenging for basic analyses, including the number of viable cells, biomass accumulation, biofilm morphology, among others. The methods used to study biofilms range from in vitro techniques to complex in vivo models. However, animal welfare has become a major concern, not only in society, but also in the academic and scientific field. Thus, the pursuit for alternatives to in vivo biofilm analyses presenting characteristics that mimic in vivo conditions has become essential. In this context, the present review proposes to provide an overview of strategies to study biofilms of medical interest, with emphasis on alternatives that approximate experimental conditions to host-associated environments, such as the use of medical devices as substrata for biofilm formation, microcosm and ex vivo models.


Asunto(s)
Biopelículas , Animales , Biomasa
19.
Microb Pathog ; 130: 219-225, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-30878621

RESUMEN

Trichosporon spp. have been increasingly recognized as an important pathogen of invasive and disseminated infections in immunocompromised patients. These species are prone to form biofilms in medical devices such as catheters and prosthesis, which are associated with antifungal resistance and therapeutic failure. Therefore, new antifungals with a broader anti-biofilm activity need to be discovered. In the present study we evaluate the inhibitory potential of sodium butyrate (NaBut) - a histone deacetylase inhibitor that can alter chromatin conformation - against planktonic and sessile cells of T. asahii and T. inkin. Minimum inhibitory concentration (MIC) of NaBut against planktonic cells was evaluated by microdilution and morphological changes were analyzed by optical microscopy on malt agar supplemented with NaBut. Biofilms were evaluated during adhesion, development and after maturation for metabolic activity and biomass, as well as regarding ultrastructure by scanning electron microscopy and confocal laser scanning microscopy. NaBut inhibited the growth of planktonic cells by 50% at 60 mM or 120 mM (p < 0.05) and also reduced filamentation of Trichosporon spp. NaBut reduced adhesion of Trichosporon cells by 45% (10xMIC) on average (p < 0.05). During biofilm development, NatBut (10xMIC) reduced metabolic activity and biomass up to 63% and 81%, respectively (p < 0.05). Mature biofilms were affected by NaBut (10xMIC), showing reduction of metabolic activity and biomass of approximately 48% and 77%, respectively (p < 0.05). Ultrastructure analysis showed that NaBut (MIC and 10xMIC) was able to disassemble mature biofilms. The present study describes the antifungal and anti-biofilm potential of NaBut against these opportunist emerging fungi.


Asunto(s)
Antifúngicos/farmacología , Biopelículas/efectos de los fármacos , Ácido Butírico/farmacología , Trichosporon/efectos de los fármacos , Adhesión Celular/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Microscopía , Microscopía Confocal , Microscopía Electrónica de Rastreo , Trichosporon/citología , Trichosporon/crecimiento & desarrollo
20.
Med Mycol ; 57(8): 1038-1045, 2019 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-30649480

RESUMEN

Trichosporon species have been considered important agents of opportunistic systemic infections, mainly among immunocompromised patients. Infections by Trichosporon spp. are generally associated with biofilm formation in invasive medical devices. These communities are resistant to therapeutic antifungals, and therefore the search for anti-biofilm molecules is necessary. This study evaluated the inhibitory effect of farnesol against planktonic and sessile cells of clinical Trichosporon asahii (n = 3) andTrichosporon inkin (n = 7) strains. Biofilms were evaluated during adhesion, development stages and after maturation for metabolic activity, biomass and protease activity, as well as regarding morphology and ultrastructure by optical microscopy, confocal laser scanning microscopy, and scanning electron microscopy. Farnesol inhibited Trichosporon planktonic growth by 80% at concentrations ranging from 600 to 1200 µM for T. asahii and from 75 to 600 µM for T. inkin. Farnesol was able to reduce cell adhesion by 80% at 300 µM for T. asahii and T. inkin at 600 µM, while biofilm development of both species was inhibited by 80% at concentration of 150 µM, altering their structure. After biofilm maturation, farnesol decreased T. asahii biofilm formation by 50% at 600 µM concentration and T. inkin formation at 300 µM. Farnesol inhibited gradual filamentation in a concentration range between 600 and 1200 µM. Farnesol caused reduction of filament structures of Trichosporon spp. at every stage of biofilm development analyzed. These data show the potential of farnesol as an anti-biofilm molecule.


Asunto(s)
Antifúngicos/farmacología , Biopelículas/efectos de los fármacos , Farnesol/farmacología , Trichosporon/efectos de los fármacos , Trichosporon/crecimiento & desarrollo , Adhesión Celular/efectos de los fármacos , Humanos , Metabolismo/efectos de los fármacos , Péptido Hidrolasas/análisis , Trichosporon/aislamiento & purificación , Trichosporon/metabolismo , Tricosporonosis/microbiología
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