Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 334
Filtrar
Mais filtros

Tipo de documento
Intervalo de ano de publicação
1.
Med Oral Patol Oral Cir Bucal ; 26(6): e786-e794, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34023840

RESUMO

BACKGROUND: There is a debate as to whether some types of oral leucoplakias (OL) are caused by Candida species, and whether they contribute to the malignant transformation, associated with a minority of such lesions. As no detailed population analysis of yeast isolates from OL is available, we evaluated the virulence attributes, and genotypes of 35 C. albicans from OL, and compared their genotypes with 18 oral isolates from healthy individuals. MATERIAL AND METHODS: The virulence traits evaluated were esterase, phospholipase, proteinase, haemolysin and coagulase production, and phenotypic switching activity, and yeast adherence and biofilm formation. DNA from OL and control yeasts were evaluated for A, B or C genotype status. RESULTS: Phospholipase, proteinase, and coagulase activity and biofilm formation was observed in 80%, 66%, 97 % and 77 % of the isolates, respectively. Phenotypic switching was detected in 8.6%, while heamolytic, and esterase activity and adherence were noted in all isolates. CONCLUSIONS: The genotype A was predominant amongst both the OL and control groups. Due to the small sample size of our study a larger investigation to define the role of candidal virulent attributes in the pathogenicity of OL is warranted, and the current data should serve as a basis until then.


Assuntos
Candida albicans , Candida , Candida albicans/genética , Genótipo , Humanos , Leucoplasia Oral , Virulência/genética
2.
Oral Dis ; 24(4): 518-526, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-28513096

RESUMO

Pathobiology of dental caries is complex. Data from recent molecular microbiologic studies have further redefined the role of the oral microbiome in the etiology of dental caries. This new information challenges the conventional view on the hegemony of classic cariogenic prokaryotes such as Streptococcus mutans in caries etiology, and raises the intriguing possibility of the participation of the eukaryotic oral fungal pathogen Candida in the caries process. The virulence attributes of Candida species such as their acidogenicity and aciduric nature, the ability to develop profuse biofilms, ferment and assimilate dietary sugars, and produce collagenolytic proteinases are all indicative of their latent cariogenic potential. Based on the above, oral candidal counts have been used by some as a caries risk indicator. On the contrary, other studies suggest that Candida is merely a passenger extant in an acidic cariogenic milieu, and not a true pathogen. In this review, we critically examine the varying roles of Candida, and traditionally accepted cariogens such as the mutans group of streptococci in the pathobiology of dental caries. The weight of available data tends to imply that Candida may play a pivotal role as a secondary agent perpetuating the carious process, especially in dentinal caries.


Assuntos
Biofilmes , Candida albicans/metabolismo , Metabolismo dos Carboidratos , Cárie Dentária/microbiologia , Streptococcus mutans/metabolismo , Ácidos/metabolismo , Candida albicans/enzimologia , Humanos
3.
J Periodontal Res ; 52(3): 408-418, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27495271

RESUMO

BACKGROUND AND OBJECTIVE: Chronic periodontitis causes damage to tooth-supporting tissues, resulting in tooth loss in adults. Recently, cell-sheet-based approaches have been studied to overcome the limitations of conventional cytotherapeutic procedures for periodontal regeneration. The purpose of the present study was to investigate the regenerative potential of periodontal ligament stem cells (PDLSCs) and human umbilical vein endothelial cells (HUVECs) in three-dimensional (3D) cell sheet constructs for periodontal regeneration in vivo. MATERIAL AND METHODS: PDLSCs, HUVECs or co-cultures of both cells were seeded onto temperature-responsive culture dishes, and intact cell sheets were fabricated. Cell sheets were wrapped around the prepared human roots in three different combinations and implanted subcutaneously into immunodeficient mice. RESULTS: Histological evaluation revealed that after 2, 4 and 8 wk of implantation, periodontal ligament-like tissue arrangements were observed around the implanted roots in experimental groups compared with controls. Vascular lumens were also observed in periodontal compartments of HUVEC-containing groups. Periodontal ligament regeneration, cementogenesis and osteogenesis were evident in the experimental groups at both weeks 4 and 8, as shown by immunostaining for periostin and bone sialoprotein. Human cells in the transplanted cell sheets were stained by immunohistochemistry for the presence of human mitochondria. CONCLUSIONS: The 3D cell sheet-based approach may be potentially beneficial and is thus encouraged for future regenerative periodontal therapy.


Assuntos
Regeneração Tecidual Guiada Periodontal/métodos , Células Endoteliais da Veia Umbilical Humana/citologia , Ligamento Periodontal/citologia , Animais , Técnicas de Cocultura/métodos , Feminino , Células Endoteliais da Veia Umbilical Humana/fisiologia , Células Endoteliais da Veia Umbilical Humana/transplante , Humanos , Camundongos , Camundongos SCID , Ligamento Periodontal/fisiologia , Ligamento Periodontal/transplante , Alicerces Teciduais
4.
Oral Dis ; 22(3): 171-9, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26179810

RESUMO

Most viral infections encountered in resource-rich countries are relatively trivial and transient with perhaps fever, malaise, myalgia, rash (exanthema) and sometimes mucosal manifestations (enanthema), including oral in some. However, the apparent benignity may be illusory as some viral infections have unexpected consequences - such as the oncogenicity of some herpesviruses and human papillomaviruses. Infections are transmitted from various human or animal vectors, especially by close proximity, and the increasing movements of peoples across the globe, mean that infections hitherto confined largely to the tropics now appear worldwide. Global warming also increases the range of movement of vectors such as mosquitoes. Thus recent decades have seen a most dramatic change with the emergence globally also of new viral infections - notably human immunodeficiency viruses (HIV) - and the appearance of some other dangerous and sometimes lethal infections formerly seen mainly in, and reported from, resource-poor areas especially in parts of Asia, Latin America and Africa. This study offers a brief update of the most salient new aspects of the important viral infections, especially those with known orofacial manifestations or other implications for oral health care.


Assuntos
Doenças Transmissíveis Emergentes/complicações , Doenças Transmissíveis Emergentes/virologia , Infecções por Vírus de DNA/complicações , Dermatoses Faciais/virologia , Doenças da Boca/virologia , Infecções por Vírus de RNA/complicações , Febre de Chikungunya/complicações , Infecções por Coronavirus/complicações , Infecções por Vírus de DNA/prevenção & controle , Infecções por Vírus de DNA/transmissão , Dengue/complicações , Infecções por HIV/complicações , Doença de Mão, Pé e Boca/complicações , Doença pelo Vírus Ebola/complicações , Herpes Simples/complicações , Humanos , Caxumba/complicações , Infecções por Papillomavirus/complicações , Infecções por Parvoviridae/complicações , Infecções por Vírus de RNA/prevenção & controle , Infecções por Vírus de RNA/transmissão
5.
Mycopathologia ; 179(3-4): 195-204, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25515243

RESUMO

Candida albicans is a major agent of fungaemias and frequently causes systemic disease through seeded, blood stream dissemination. These infections, particularly common in hospitalized patients with central venous catheters (CVCs), appear to persevere due to biofilm reservoirs of the yeast that tend to develop on the device. Although it is known that candidal biofilms are intrinsically resistant to antifungals compared with their planktonic counterparts, there is a paucity of data on the expression of antifungal drug resistance genes (DRGs) in candidal biofilms in CVC reservoirs. Furthermore, notwithstanding the fact that CVCs are constantly bathed in human serum, there are no studies on the effect of the latter on the DRG expression in candidal biofilms. Hence, we developed in vitro biofilms of three different C. albicans strains on silicone CVC discs immersed in human serum and evaluated the temporal expression of nine antifungal DRGs. In an attempt to evaluate the effect of hyphal elements on DRG expression, we incorporated a hyphal mutant (HM) and its wild-type (WT) counterpart, as well as a fresh clinical isolate in the studies. Human serum significantly up-regulated DRG transcripts in Candida biofilms on CVCs, at different stages of biofilm growth, while the WT strain over-expressed more DRGs than the HM strain. Here, we report, for the first time, that both human serum and the hyphal elements of the yeast have a profound modulatory effect on DRG expression in C. albicans biofilms on CVCs.


Assuntos
Biofilmes/efeitos dos fármacos , Candida albicans/genética , Cateteres Venosos Centrais/microbiologia , Farmacorresistência Fúngica , Soro/química , Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Cateteres Venosos Centrais/efeitos adversos , Contaminação de Equipamentos , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Humanos , Hifas/efeitos dos fármacos , Hifas/genética , Hifas/crescimento & desenvolvimento , Masculino , Regulação para Cima
6.
J Periodontal Res ; 49(3): 299-306, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23738684

RESUMO

BACKGROUND AND OBJECTIVE: To investigate the expression of osteo/odontogenic differentiation markers and vascular network formation in a 3D cell sheet with varying cell ratios of periodontal ligament stem cells (PDLSCs) and human umbilical vein endothelial cells (HUVECs). MATERIAL AND METHODS: Human PDLSCs were isolated and characterized by flow cytometry, and co-cultured with HUVECs for the construction of cell sheets. Both types of cells were seeded on temperature-responsive culture dishes with PDLSCs alone, HUVECs alone and various ratios of the latter cells (1 : 1, 2 : 1, 5 : 1 and 1 : 5) to obtain confluent cell sheets. The expressions of osteo/odontogenic pathway markers, including alkaline phosphatase (ALP), bone sialoprotein (BSP) and runt-related transcription factor 2 (RUNX2), were analyzed at 3 and 7 d using RT-PCR. Further ALP protein quantification was performed at 7 and 14 d using ALP assay. The calcium nodule formation was assessed qualitatively and quantitatively by alizarin red assay. Histological evaluations of three cell sheet constructs treated with different combinations (PDLSC-PDLSC-PDLSC/PDLSC-HUVEC-PDLSC/co-culture-co-culture-co-culture) were performed with hematoxylin and eosin and immunofluorescence staining. Statistical analysis was performed using t-test (p < 0.05). RESULTS: Significantly higher ALP gene expression was observed at 3 d in 1 : 1 (PDLSC-HUVEC) (2.52 ± 0.67) and 5 : 1 (4.05 ± 1.07) co-culture groups compared with other groups (p < 0.05); this was consistent with ALP protein quantification. However, the expression of BSP and RUNX2 genes was higher at 7 d compared to 3 d. Significant calcium mineralization was detected as quantified by alizarin red assay at 14 d in 1 : 1 (1323.55 ± 6.54 µm) and 5 : 1 (994.67 ± 4.15 µm) co-cultures as compared with monoculture cell sheets (p < 0.05). Hematoxylin and eosin and CD31 immunostaining clearly exemplified the development of a layered cell sheet structure with endothelial cell islands within the constructed PDLSC-HUVEC-PDLSC and co-culture groups. Furthermore, HUVECs invaded the layered cell sheet, suggestive of rudimentary vascular network initiation. CONCLUSION: This study suggests that the PDLSC-HUVEC co-culture, cell sheet, model exhibits significantly high levels of osteo/odontogenic markers with signs of initial vascular formation. This novel 3D cell sheet-based approach may be potentially beneficial for periodontal regenerative therapy.


Assuntos
Células Endoteliais da Veia Umbilical Humana/fisiologia , Odontogênese/fisiologia , Osteogênese/fisiologia , Ligamento Periodontal/citologia , Células-Tronco/fisiologia , Fosfatase Alcalina/análise , Antraquinonas , Biomarcadores/análise , Calcificação Fisiológica/fisiologia , Técnicas de Cultura de Células , Diferenciação Celular/fisiologia , Sobrevivência Celular/fisiologia , Células Cultivadas , Técnicas de Cocultura , Corantes , Subunidade alfa 1 de Fator de Ligação ao Core/análise , Humanos , Sialoproteína de Ligação à Integrina/análise , Reação em Cadeia da Polimerase em Tempo Real/métodos , Fatores de Tempo , Engenharia Tecidual/instrumentação
7.
Mycopathologia ; 178(3-4): 207-15, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25142726

RESUMO

Secretion of hydrolytic enzymes such as hemolysin is considered an important virulence attribute of the opportunistic pathogenic fungus Candida. It is known that Candida spp. isolated from HIV-infected patients produce copious hemolysins. As common antifungal agents may perturb the production of extracellular enzymes, we evaluated the effect of three antifungals nystatin, amphotericin B and fluconazole on the hemolytic activity of Candida albicans and Candida tropicalis isolates from HIV-infected individuals. The impact of antimycotics on hemolytic activity was assessed by a previously described in vitro plate assay, after exposing ten isolates each of C. albicans and C. tropicalis recovered from HIV-infected individuals to sub-minimum inhibitory concentrations (sub-MIC) of nystatin, amphotericin B and fluconazole. All Candida isolates showed a significant reduction in hemolytic activity. The reduction was highest for amphotericin B-exposed C. albicans and C. tropicalis followed by nystatin and fluconazole. The effect of antimycotics was more pronounced on the hemolytic activity of C. tropicalis compared to that of C. albicans. Commonly used antifungal agents significantly suppress hemolysin activity of Candida species. This implies that the antifungals, in addition to their lethality, may modulate key virulence attributes of the yeast. The clinical relevance of this phenomenon in HIV disease and other similar pathologies remains to be determined.


Assuntos
Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/isolamento & purificação , Candida tropicalis/efeitos dos fármacos , Candida tropicalis/isolamento & purificação , Proteínas Hemolisinas/metabolismo , Anfotericina B/farmacologia , Candida albicans/metabolismo , Candida tropicalis/metabolismo , Candidíase Bucal/microbiologia , Fluconazol/farmacologia , Infecções por HIV/complicações , Proteínas Hemolisinas/antagonistas & inibidores , Humanos , Técnicas Microbiológicas , Nistatina/farmacologia , Fatores de Virulência/antagonistas & inibidores , Fatores de Virulência/metabolismo
8.
Oral Dis ; 18(3): 244-54, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22126675

RESUMO

The oral cavity serves as a reservoir of Staphylococcus aureus for infection of the lower respiratory tract and cross-infection to other patients. This systematic review was designed to examine the effectiveness of oral health promotion interventions on this pathogen. The PubMed, ISI Web of Science, and Cochrane Library databases were searched for clinical trials assessing the effect of oral health promotion interventions on oral and oropharyngeal carriage of S. aureus. Oral health promotion interventions on oral reservoirs of S. aureus in both systemically healthy and medically compromised groups consisted of oral hygiene interventions only. There was a lack of evidence pertaining to the effectiveness of mechanical oral hygiene interventions against this pathogen. Chlorhexidine delivered in oral hygiene products such as mouthrinses, gels, and sprays appeared to have some utility against S. aureus, although some studies found equivocal effects. There was a dearth of studies investigating the efficacy of other chemical agents. Although many chemical agents contained in oral hygiene products have proven in vitro activity against S. aureus, their clinical effectiveness and potential role as adjuncts or alternative therapies to conventional treatment remain to be confirmed by further high-quality randomized controlled trials.


Assuntos
Promoção da Saúde , Boca/microbiologia , Saúde Bucal , Staphylococcus aureus/isolamento & purificação , Anti-Infecciosos Locais/uso terapêutico , Humanos , Higiene Bucal/métodos , Orofaringe/microbiologia , Infecções Estafilocócicas/prevenção & controle
9.
J Med Microbiol ; 71(6)2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35687657

RESUMO

Candida auris is a recently emerged multidrug-resistant fungal pathogen that causes life-threatening infections to the human population worldwide. Recent rampant outbreaks of C. auris in coronavirus disease 2019 (COVID-19) patients, together with outbreaks in over 45 countries, highlight its threat to patients and healthcare economies. Unlike other pathogenic Candida species, C. auris is capable of surviving in abiotic surfaces of healthcare facilities for prolonged periods, leading to increased risk of transmission within nosocomial settings. C. auris is resistant to multiple classes of antifungal agents, forms dry biofilms and transmits independently to regional epicentres, making its eradication from nosocomial environment arduous. The lack of strategies for environmental decontamination of C. auris from nosocomial settings is evident from the generic guidance and recommendations provided by leading global healthcare bodies. Therefore, this minireview discusses the current guidelines for environmental decontamination of C. auris and compounds and strategies currently under investigation for potential future use. While established guidelines recommend the use of products mainly consisting of sodium hypochlorite and hydrogen peroxide, initial works have been reported on the promising anti-C. auris properties of various other compounds and some biocompatible alternatives. Further validation of these approaches, coupled up with environmentally friendly decontamination protocols, are warranted to achieve superior elimination of C. auris from healthcare settings.


Assuntos
COVID-19 , Infecção Hospitalar , Antifúngicos/farmacologia , COVID-19/prevenção & controle , Candida , Candida auris , Infecção Hospitalar/prevenção & controle , Descontaminação , Humanos
10.
Mycopathologia ; 172(5): 389-95, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21744043

RESUMO

Candida bloodstream infection has dramatically increased in the last decade due to the growing number of immunocompromised populations worldwide. In this study, we evaluated the antifungal susceptibility profiles and virulence attributes of Candida bloodstream isolates (CBIs) derived from Hong Kong and Finland, information which are vital for devising empirical clinical strategies. Susceptibility testing of a wide range of antifungals including fluconazole, itraconazole, voriconazole, ketoconazole, 5-fluorocytosine, amphotericin B and caspofungin was performed. Haemolytic activity and secretion of proteinase of CBIs were also examined. All CBIs derived from Hong Kong were susceptible to all the antifungals tested whilst some CBIs from Finland were resistant to azoles and caspofungin. C. albicans, C. glabrata and C. tropicalis showed higher haemolytic activity whereas C. parapsilosis and C. guilliermondii were non-haemolytic in general. Proteinase activity of the Finland C. albicans isolates was significantly higher than the Hong Kong isolates. Our data provide a glimpse of the possible evolutionary changes in pathogenic potential of Candida that may be occurring in different regions of the world. Therefore, continuous surveillance and availability of local data should be taken into consideration when treating candidemia patients.


Assuntos
Antifúngicos/farmacologia , Candida/efeitos dos fármacos , Candida/patogenicidade , Candidemia/microbiologia , Fatores de Virulência/metabolismo , Anfotericina B/farmacologia , Candida/isolamento & purificação , Caspofungina , Farmacorresistência Fúngica , Equinocandinas/farmacologia , Finlândia , Fluconazol/farmacologia , Flucitosina/farmacologia , Proteínas Hemolisinas/metabolismo , Hong Kong , Humanos , Itraconazol/farmacologia , Cetoconazol/farmacologia , Lipopeptídeos , Testes de Sensibilidade Microbiana , Peptídeo Hidrolases/metabolismo , Pirimidinas/farmacologia , Triazóis/farmacologia , Voriconazol
12.
Clin Microbiol Rev ; 22(1): 46-64, Table of Contents, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19136433

RESUMO

SUMMARY: The human gingival niche is a unique microbial habitat. In this habitat, biofilm organisms exist in harmony, attached to either enamel or cemental surfaces of the tooth as well as to the crevicular epithelium, subjacent to a rich vascular plexus underneath. Due to this extraordinary anatomical juxtaposition, plaque biofilm bacteria have a ready portal of ingress into the systemic circulation in both health and disease. Yet the frequency, magnitude, and etiology of bacteremias due to oral origin and the consequent end organ infections are not clear and have not recently been evaluated. In this comprehensive review, we address the available literature on triggering events, incidence, and diversity of odontogenic bacteremias. The nature of the infective agents and end organ infections (other than endocarditis) is also described, with an emphasis on the challenge of establishing the link between odontogenic infections and related systemic, focal infections.


Assuntos
Bacteriemia/epidemiologia , Bacteriemia/microbiologia , Bactérias/classificação , Endocardite/epidemiologia , Endocardite/microbiologia , Gengiva/microbiologia , Dente/microbiologia , Bactérias/isolamento & purificação , Humanos , Incidência
13.
BMC Microbiol ; 10: 125, 2010 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-20416106

RESUMO

BACKGROUND: Elucidation of the communal behavior of microbes in mixed species biofilms may have a major impact on understanding infectious diseases and for the therapeutics. Although, the structure and the properties of monospecies biofilms and their role in disease have been extensively studied during the last decade, the interactions within mixed biofilms consisting of bacteria and fungi such as Candida spp. have not been illustrated in depth. Hence, the aim of this study was to evaluate the interspecies interactions of Pseudomonas aeruginosa and six different species of Candida comprising C. albicans, C. glabrata, C. krusei, C. tropicalis, C. parapsilosis, and C. dubliniensis in dual species biofilm development. RESULTS: A significant reduction in colony forming units (CFU) of C. parapsilosis (90 min), C. albicans and C. tropicalis (90 min, 24 h and 48 h), C. dubliniensis and C. glabrata, (24 h and 48 h) was noted when co-cultured with P. aeruginosa in comparison to their monospecies counterparts (P < 0.05). A simultaneous significant reduction in P. aeruginosa numbers grown with C. albicans (90 min and 48 h), C. krusei (90 min, 24 h and 48 h),C. glabrata, (24 h and 48 h), and an elevation of P. aeruginosa numbers co-cultured with C. tropicalis (48 h) was noted (P < 0.05). When data from all Candida spp. and P. aeruginosa were pooled, highly significant mutual inhibition of biofilm formation was noted (Candida P < 0.001, P. aeruginosa P < 0.01). Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM) analyses confirmed scanty architecture in dual species biofilm in spite of dense colonization in monospecies counterparts. CONCLUSIONS: P. aeruginosa and Candida in a dual species environment mutually suppress biofilm development, both quantitatively and qualitatively. These findings provide a foundation to clarify the molecular basis of bacterial-fungal interactions, and to understand the pathobiology of mixed bacterial-fungal infections.


Assuntos
Antibiose , Biofilmes/crescimento & desenvolvimento , Candida/fisiologia , Pseudomonas aeruginosa/fisiologia , Candida/crescimento & desenvolvimento , Técnicas de Cocultura , Contagem de Colônia Microbiana , Viabilidade Microbiana , Microscopia Confocal , Microscopia Eletrônica de Varredura , Pseudomonas aeruginosa/crescimento & desenvolvimento
14.
Med Mycol ; 48(5): 725-34, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20092419

RESUMO

The post-antifungal effect (PAFE) has been shown to affect Candida pathogenicity, but there is little information on either PAFE or its association with the colonization traits of Candida glabrata. The objective of this study was to determine, in vitro, the PAFE on 14 C. glabrata isolates following exposure to amphotericin B (AMB), nystatin (NYS), ketoconazole (KETO) and 5-fluorocytosine (5FC). In addition, we evaluated the impact of PAFE on yeast adherence to buccal epithelial cells (BEC), cell-surface-hydrophobicity (CSH) and biofilm growth (BG) on denture acrylic surfaces. PAFE was induced following a 1-h exposure of yeasts to (x1-x4MIC) of AMB, NYS, KETO and 5FC in RPMI medium and, measured using automated turbidometry. The BEC adhesion, CSH and BG assays were performed by the methods of Kimura & Pearsall, Sweet et al., and Jin et al., respectively. Significant differences in PAFE (P < 0.001) were observed after exposure to AMB and NYS, but not KETO and 5FC. Following exposure to AMB, NYS, KETO and 5FC, significant inter-strain differences (P < 0.001) were observed in percentage terms in adhesion (39.0%, 43.48%, 38.28%, 35.07%) and biofilm growth (42.86%, 39.86%, 42.81%, 36.38%), respectively. Short exposure of C. glabrata to sub-cidal concentrations of antifungals modulates yeast growth and also affects some of their colonization traits.


Assuntos
Antifúngicos/farmacologia , Candida glabrata/efeitos dos fármacos , Candida glabrata/patogenicidade , Anfotericina B/farmacologia , Biofilmes/efeitos dos fármacos , Biomassa , Candida glabrata/crescimento & desenvolvimento , Candida glabrata/isolamento & purificação , Candidíase/microbiologia , Adesão Celular/efeitos dos fármacos , Parede Celular/química , Parede Celular/efeitos dos fármacos , Células Epiteliais/microbiologia , Flucitosina/farmacologia , Humanos , Interações Hidrofóbicas e Hidrofílicas , Cetoconazol/farmacologia , Nefelometria e Turbidimetria , Nistatina/farmacologia
15.
Oral Dis ; 16(3): 248-56, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19758406

RESUMO

The use of highly active antiretroviral therapy (HAART) in the management of human immunodeficiency virus (HIV) restores immune responses against pathogens and has greatly decreased mortality. However, in about 25% to 35% of patients receiving HAART, the reconstituted immune system leads to a pathological inflammatory response, commonly known as immune reconstitution inflammatory syndrome (IRIS), which causes substantial short-term morbidity or even mortality. Although we have gleaned some knowledge on IRIS in the past few years, a number of unanswered questions remain. In this review, we discuss the definition, diagnostic criteria, pathogenesis, risk factors, clinical spectrum including oral manifestations, and management of IRIS.


Assuntos
Infecções Oportunistas Relacionadas com a AIDS/complicações , Síndrome Inflamatória da Reconstituição Imune , Doenças da Boca/complicações , Terapia Antirretroviral de Alta Atividade/efeitos adversos , Candidíase Bucal/complicações , Herpes Zoster/complicações , Humanos , Síndrome Inflamatória da Reconstituição Imune/complicações , Síndrome Inflamatória da Reconstituição Imune/diagnóstico , Síndrome Inflamatória da Reconstituição Imune/etiologia , Síndrome Inflamatória da Reconstituição Imune/terapia , Neoplasias Bucais/complicações , Fatores de Risco , Sarcoma de Kaposi/complicações
16.
Oral Dis ; 16(2): 136-45, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19627515

RESUMO

OBJECTIVE: The oral cavity forms an indispensable part of the human microbiome, for its unique and diverse microflora distributed within various niches. While majority of these organisms exhibit commensalism, shifts in bacterial community dynamics cause pathological changes within oral cavity and distant sites. The aim of this review was to appraise the current and emerging methods of detecting bacteria of the oral cavity paying particular attention to the cultivation independent methods. DESIGN: Literature pertaining to cultivation based and cultivation independent methods of oral bacterial identification was reviewed. METHODS: The specific advantages and disadvantages of cultivation based, microscopic, immunological and metagenomic identification methods were appraised. RESULTS: Because of their fastidious and exacting growth requirements, cultivation based studies grossly underestimate the extent of bacterial diversity in these polymicrobial infections. Culture independent methods deemed more sensitive in identifying difficult to culture and novel bacterial species. CONCLUSION: Apart from characterizing potentially novel bacterial species, the nucleic acid sequence data analyzed using various bioinformatics protocols have revealed that there are in excess of 700 bacterial species inhabiting the mouth. Moreover, the latest pyrosequencing based methods have further broadened the extent of bacterial diversity in oral niches.


Assuntos
Bactérias/classificação , Boca/microbiologia , Bactérias/crescimento & desenvolvimento , Técnicas Bacteriológicas , Biodiversidade , Humanos , Metagenoma , Metagenômica , Doenças da Boca/microbiologia , Doenças Dentárias/microbiologia
17.
Mycoses ; 53(4): 285-95, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20406388

RESUMO

Candida species are common pathogens causing superficial mycoses primarily affecting the mucosa and the skin in humans. Crucial steps during pathogenesis of superficial candidiasis comprise fungal adhesion, colonisation and subsequent penetration of the respective tissues. Exploring these pathological events and perhaps fungal and tissue responses towards drug treatment is imperative in the management of this infection. Unfortunately, pathological biopsies of superficial candidiasis do not exhibit the early changes in the host-pathogen interaction as the tissues are already invaded by the fungi. In vivo experimental assessments of pathological processes of superficial candidiasis are also limited because of the difficulties in providing reproducible and comparable conditions in the host environment. Conversely, in vitro models have helped studying fungal-host interactions under more defined and controlled conditions. Some common in vitro models used to simulate superficial candidiasis are chick chorioallantoic membrane, mucosal explants and single layer or multiple layer cell cultures. Interestingly, these experimental approaches share advantages as well as disadvantages when compared with in vivo conditions. Hence, this review intends to discuss about the experimental superficial candidiasis produced in various tissue models and their advantages as well as disadvantages with a particular reference to further improvement of validity and reliability of such experiments.


Assuntos
Candida/patogenicidade , Candidíase/microbiologia , Interações Hospedeiro-Patógeno , Animais , Humanos , Técnicas de Cultura de Órgãos
18.
Mycoses ; 53(6): 495-9, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19538518

RESUMO

Metergoline, a serotonin receptor antagonist, was evaluated for its antifungal activity against the opportunistic human fungal pathogen Candida krusei by a broth microdilution assay. The minimal inhibitory concentration and minimal fungicidal concentration of metergoline against C. krusei were 4 and 8 µg ml(-1) respectively. Significant synergism was found in combination of metergoline with amphotericin B (fractional inhibitory concentration index: 0.375-0.5) by a chequerboard assay. Metergoline also inhibited extracellular phospholipase secretion in a dose-dependent manner, which may be a possible action mechanism of metergoline on C. krusei.


Assuntos
Antifúngicos/farmacologia , Candida/efeitos dos fármacos , Metergolina/farmacologia , Anfotericina B/farmacologia , Sinergismo Farmacológico , Proteínas Fúngicas/antagonistas & inibidores , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Fosfolipases/antagonistas & inibidores
19.
Sci Rep ; 10(1): 7769, 2020 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-32385378

RESUMO

Microorganisms employ quorum sensing (QS) mechanisms to communicate with each other within microbial ecosystems. Emerging evidence suggests that intraspecies and interspecies QS plays an important role in antimicrobial resistance in microbial communities. However, the relationship between interkingdom QS and antimicrobial resistance is largely unknown. Here, we demonstrate that interkingdom QS interactions between a bacterium, Pseudomonas aeruginosa and a yeast, Candida albicans, induce the resistance of the latter to a widely used antifungal fluconazole. Phenotypic, transcriptomic, and proteomic analyses reveal that P. aeruginosa's main QS molecule, N-(3-Oxododecanoyl)-L-homoserine lactone, induces candidal resistance to fluconazole by reversing the antifungal's effect on the ergosterol biosynthesis pathway. Accessory resistance mechanisms including upregulation of C. albicans drug-efflux, regulation of oxidative stress response, and maintenance of cell membrane integrity, further confirm this phenomenon. These findings demonstrate that P. aeruginosa QS molecules may confer protection to neighboring yeasts against azoles, in turn strengthening their co-existence in hostile polymicrobial infection sites.


Assuntos
Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/fisiologia , Farmacorresistência Fúngica , Fluconazol/farmacologia , Pseudomonas aeruginosa/fisiologia , Percepção de Quorum , Vias Biossintéticas , Ergosterol/biossíntese , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Interações Microbianas
20.
Int J Pharm ; 578: 119096, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-32006626

RESUMO

In contrast to the plethora of antibacterial agents, only a handful of antifungals are currently available to treat Candida albicans biofilm-associated infections. Additional novel antibiofilm strategies to eliminate C. albicans biofilm infections are needed. This study aims to improve the efficacy of a widely used azole, fluconazole by co-delivering it with a Pseudomonas aeruginosa quorum sensing molecule (QSM), N-3-oxo-dodecanoyl-L-homoserine lactone (C12AHL) in a liposomal formulation. C12AHL is known to inhibit C. albicans' morphological transition and biofilm formation. Four different formulations of liposomes with fluconazole (L-F), with C12AHL (L-H), with fluconazole and C12AHL (L-HF), and a drug-free control (L-C) were prepared using a thin-film hydration followed by extrusion method, and characterised. The effect of liposomes on colonising (90 min-24 h) and preformed (24 h) C. albicans biofilms were assessed using a standard biofilm assay. Biofilm viability (XTT reduction assay), biomass (Safranin-O staining) and architecture (confocal laser scanning microscopy, CLSM) were determined. Similar efficiencies of fluconazole entrapment were noticed in L-HF and L-F (11.74% vs 10.2%), however, L-HF released greater quantities of fluconazole compared to L-F during 24 h (4.27% vs 0.97%, P < 0.05). The entrapment and release of C12AHL was similar for L-H and L-HF liposomes (33.3% vs 33% and 88.9% vs 92.3% respectively). L-HF treated colonising, and preformed biofilms exhibited >80%, and 60% reduction in their respective viabilities at a fluconazole concentration as low as 5.5 µg/mL compared to 12% and 36%, respective reductions observed in L-F treated biofilms (P < 0.05). CLSM confirmed biofilm disruption, lack of hyphae, and reduction in biomass when treated with L-HF compared to other liposomal preparations. Liposomal co-delivery of C12AHL and fluconazole appears to suppress C. albicans biofilms through efficacious disruption of the biofilm, killing of constituent yeasts, and diminishing their virulence at a significantly lower antifungal dose. Therefore, liposomal co-formulation of C12AHL and fluconazole appears to be a promising approach to improve the efficacy of this common triazole against biofilm-mediated candidal infections.


Assuntos
4-Butirolactona/análogos & derivados , Antifúngicos/administração & dosagem , Candida albicans/efeitos dos fármacos , Sistemas de Liberação de Medicamentos , Fluconazol/administração & dosagem , Homosserina/análogos & derivados , Pseudomonas aeruginosa/fisiologia , Percepção de Quorum , 4-Butirolactona/administração & dosagem , 4-Butirolactona/química , Antifúngicos/química , Biofilmes/efeitos dos fármacos , Candida albicans/fisiologia , Liberação Controlada de Fármacos , Fluconazol/química , Homosserina/administração & dosagem , Homosserina/química , Lipossomos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA