scholarly journals Yeast microbiota of free-ranging amphibians and reptiles from Caatinga biome in Ceará State, Northeast Brazil: High pathogenic potential of Candida famata

2021 ◽  
Vol 51 (7) ◽  
Author(s):  
Débora de Souza Collares Maia Castelo-Branco ◽  
Renan Vasconcelos da Graça-Filho ◽  
Jonathas Sales de Oliveira ◽  
Maria Gleiciane da Rocha ◽  
Géssica dos Santos Araújo ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Virulence Factors ◽  
Antifungal Susceptibility ◽  
Hydrolytic Enzymes ◽  
Protease Production ◽  
Pathogenic Potential ◽  
Candida Famata ◽  
Caatinga Biome ◽  
Fungal Microbiota ◽  
Free Ranging

ABSTRACT: Studies on the fungal microbiota of reptiles and amphibians are necessary to better understand of host-microbe interactions and the establishment of fungal disease in these animals. However, these studies are limited. The present researchidentified yeasts from free-ranging reptiles and amphibians from the Caatinga biome andevaluated the virulence factors production, the antifungal susceptibility in planktonic and biofilm growth and the pathogenicity of Candida famata isolates. Twenty-nine isolates of the genera Candida, Cryptococcus and Rhodotorula were identified by phenotypic and/or molecular methods and production of hydrolytic enzymes in vitro by these genera of fungi was evaluated. In addition, susceptibility of planktonic cells and biofilms to azoles and amphotericin B was evaluated. The pathogenicity of C. famata, the most prevalent yeast species isolated, was evaluated using Caenorhabditis elegans model. C. famata was the most prevalent yeast in amphibian and reptilian microbiota. Phospholipase and protease production was observed in 18/29 and 11/29 of the yeast isolates, respectively, while 100% formed biofilms. Itraconazole presented high minimal inhibitory concentrations against C. famata and C. tropicalis. Amphotericin B reduced the biomass and metabolic activity of biofilms. C. famata induced the mortality of C. elegans. In conclusion, reptiles and amphibians are colonized by yeasts capable of producing important virulence factors, especially by Candida spp. that present low susceptibility to azoles which may result from imbalances in ecosystem. Finally, C. famata isolated from these animals presented high pathogenicity, showing the importance of the study of reptile and amphibians fungal microbiota.

scholarly journals Relationship between the Antifungal Susceptibility Profile and the Production of Virulence-Related Hydrolytic Enzymes in Brazilian Clinical Strains ofCandida glabrata

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Maria Helena Galdino Figueiredo-Carvalho ◽  
Lívia de Souza Ramos ◽  
Leonardo Silva Barbedo ◽  
Jean Carlos Almeida de Oliveira ◽  
André Luis Souza dos Santos ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Antifungal Susceptibility ◽  
Hydrolytic Enzymes ◽  
Antifungal Drug ◽  
Clinical Strains ◽  
Antifungal Drug Resistance ◽  
Opportunistic Fungal Pathogen ◽  
Esterase Production ◽  
In Vitro Antifungal Susceptibility

Candida glabratais a facultative intracellular opportunistic fungal pathogen in human infections. Several virulence-associated attributes are involved in its pathogenesis, host-pathogen interactions, modulation of host immune defenses, and regulation of antifungal drug resistance. This study evaluated the in vitro antifungal susceptibility profile to five antifungal agents, the production of seven hydrolytic enzymes related to virulence, and the relationship between these phenotypes in 91 clinical strains ofC. glabrata. AllC. glabratastrains were susceptible to flucytosine. However, some of these strains showed resistance to amphotericin B (9.9%), fluconazole (15.4%), itraconazole (5.5%), or micafungin (15.4%). Overall,C. glabratastrains were good producers of catalase, aspartic protease, esterase, phytase, and hemolysin. However, caseinase and phospholipase in vitro activities were not detected. Statistically significant correlations were identified between micafungin minimum inhibitory concentration (MIC) and esterase production, between fluconazole and micafungin MIC and hemolytic activity, and between amphotericin B MIC and phytase production. These results contribute to clarify some of theC. glabratamechanisms of pathogenicity. Moreover, the association between some virulence attributes and the regulation of antifungal resistance encourage the development of new therapeutic strategies involving virulence mechanisms as potential targets for effective antifungal drug development for the treatment ofC. glabratainfections.

scholarly journals Mapping the Global Network of Extracellular Protease Regulation in Staphylococcus aureus

2019 ◽  
Author(s):  
Brittney D. Gimza ◽  
Maria I. Larias ◽  
Bridget G. Budny ◽  
Lindsey N. Shaw
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factors ◽  
Global Network ◽  
Protease Production ◽  
Secondary Circuit ◽  
Pathogenic Potential ◽  
Regulatory Circuit ◽  
Primary Network ◽  
The Impact ◽  
Protease Expression

AbstractA primary function of the extracellular proteases of Staphylococcus aureus is to control the progression of infection by selectively modulating the stability of virulence factors. Consequently, a regulatory network exists to titrate protease abundance/activity, to influence accumulation, or lack thereof, of individual virulence factors. Herein, we comprehensively map this system, exploring regulation of the four protease loci by known and novel factors. In so doing, we determine that seven major elements (SarS, SarR, Rot, MgrA, CodY, SaeR, and SarA) form the primary network of control, with the latter three being the most powerful. We note that expression of aureolysin is largely repressed by these factors, whilst the spl operon is subject to the strongest upregulation of any protease loci, particularly by SarR and SaeR. Furthermore, when exploring scpA expression, we find it to be profoundly influenced in opposing fashions by SarA (repressor) and SarR (activator). We also present the screening of >100 regulator mutants of S. aureus, identifying 7 additional factors (ArgR2, AtlR, MntR, Rex, XdrA, Rbf, and SarU) that form a secondary circuit of protease control. Primarily these elements serve as activators, although we reveal XdrA as a new repressor of protease expression. With the exception or ArgR2, each of the new effectors appear to work through the primary network of regulation to influence protease production. Collectively, we present a comprehensive regulatory circuit that emphasizes the complexity of protease regulation and suggest that its existence speaks to the importance of these enzymes to S. aureus physiology and pathogenic potential.ImportanceThe complex regulatory role of the proteases necessitates very tight coordination and control of their expression. Whilst this process has been well studied, a major oversight has been the consideration of proteases as a single entity, rather than 10 enzymes produced from four different promoters. As such, in this study we comprehensively characterized the regulation of each protease promoter, discovering vast differences in the way each protease operon is controlled. Additionally, we broaden the picture of protease regulation using a global screen to identify novel loci controlling protease activity, uncovering a cadre of new effectors of protease expression. The impact of these elements on the activity of proteases and known regulators was characterized producing a comprehensive regulatory circuit that emphasizes the complexity of protease regulation in Staphylococcus aureus.

scholarly journals Yeasts from the oral cavity of children with AIDS: exoenzyme production and antifungal resistance

2003 ◽  
Vol 17 (3) ◽  
pp. 217-222 ◽  
Author(s):  
Vera Lúcia Bosco ◽  
Esther Goldenberg Birman ◽  
Arlete Emily Cury ◽  
Claudete Rodrigues Paula
Keyword(s):  
Oral Cavity ◽  
Amphotericin B ◽  
Virulence Factors ◽  
Outpatient Treatment ◽  
Healthy Subjects ◽  
Antifungal Agents ◽  
Clinical Manifestations ◽  
Control Group ◽  
Test Kit ◽  
Fungal Microbiota

The oral fungal microbiota of 30 children with AIDS, of both genders, aged from two to six years, receiving outpatient treatment, was evaluated and compared with that of a control group composed of 30 healthy subjects with matching ages and genders. Virulence factors, such as exoenzyme production, and susceptibility to five antifungal agents using an E-Test kit were evaluated. C. albicans predominated over other species in the AIDS group, showing a higher production of proteinase and phospholipase when compared with that observed in the control group. In this study few clinical manifestations of and low selectivity for C. albicans (23.3%) were observed in the AIDS group. The enzymatic studies showed that 53.8% of the AIDS strains were strongly positive whereas only 33.3% of the non-AIDS strains were positive. Amphotericin B was the most effective drug among the antifungal agents tested against C. albicans. The frequency, selectivity and level of exoenzyme production by C. albicans suggest a higher pathogenicity in the AIDS children than in the control children.

scholarly journals Mapping the Global Network of Extracellular Protease Regulation in Staphylococcus aureus

mSphere ◽  
2019 ◽  
Vol 4 (5) ◽  
Author(s):  
Brittney D. Gimza ◽  
Maria I. Larias ◽  
Bridget G. Budny ◽  
Lindsey N. Shaw
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factors ◽  
Global Network ◽  
Protease Production ◽  
Pathogenic Potential ◽  
Content Type ◽  
Regulatory Circuit ◽  
Primary Network ◽  
The Impact ◽  
Protease Expression

ABSTRACT A primary function of the extracellular proteases of Staphylococcus aureus is to control the progression of infection by selectively modulating the stability of virulence factors. Consequently, a regulatory network exists to titrate protease abundance/activity to influence the accumulation, or lack thereof, of individual virulence factors. Herein, we comprehensively map this system, exploring the regulation of the four protease loci by known and novel factors. In so doing, we determined that seven major elements (SarS, SarR, Rot, MgrA, CodY, SaeR, and SarA) form the primary network of control, with the latter three being the most powerful. We note that expression of aureolysin is largely repressed by these factors, while the spl operon is subject to the strongest upregulation of any protease loci, particularly by SarR and SaeR. Furthermore, when exploring scpA expression, we find it to be profoundly influenced in opposing fashions by SarA (repressor) and SarR (activator). We also present the screening of >100 regulator mutants of S. aureus, identifying 7 additional factors (ArgR2, AtlR, MntR, Rex, XdrA, Rbf, and SarU) that form a secondary circuit of protease control. Primarily, these elements serve as activators, although we reveal XdrA as a new repressor of protease expression. With the exception or ArgR2, each of the new effectors appears to work through the primary network of regulation to influence protease production. Collectively, we present a comprehensive regulatory circuit that emphasizes the complexity of protease regulation and suggest that its existence speaks to the importance of these enzymes to S. aureus physiology and pathogenic potential. IMPORTANCE The complex regulatory role of the proteases necessitates very tight coordination and control of their expression. While this process has been well studied, a major oversight has been the consideration of proteases as a single entity rather than as 10 enzymes produced from four different promoters. As such, in this study, we comprehensively characterized the regulation of each protease promoter, discovering vast differences in the way each protease operon is controlled. Additionally, we broaden the picture of protease regulation using a global screen to identify novel loci controlling protease activity, uncovering a cadre of new effectors of protease expression. The impact of these elements on the activity of proteases and known regulators was characterized by producing a comprehensive regulatory circuit that emphasizes the complexity of protease regulation in Staphylococcus aureus.

scholarly journals Candiduria—Study of Virulence Factors and Its Antifungal Susceptibility Pattern in Tertiary Care Hospital

2021 ◽  
Author(s):  
Subramanian Pramodhini ◽  
Sreenivasan Srirangaraj ◽  
Joshy Maducolil Easow
Keyword(s):  
Amphotericin B ◽  
Virulence Factors ◽  
Candida Species ◽  
Antifungal Susceptibility ◽  
Test Method ◽  
Care Hospital ◽  
Susceptibility Pattern ◽  
Significant Difference ◽  
Tract Infections ◽  
Urinary Isolates

Abstract Background The increased incidence of candiduria in hospitalized patients is due to the use of indwelling devices, long-term antibiotics, parenteral nutrition, and immunocompromised status of the patient. In this study, an attempt was made to speciate, characterize, and determine the antifungal susceptibility pattern of Candida isolated from urinary tract infections (UTIs). Materials and Methods A total of 70 Candida isolates were obtained from urine samples. The isolated Candida species were studied for the production of virulence factors like phospholipase, protease activities, hemolysin, and biofilm production. Antifungal susceptibility testing of the isolated yeasts was done using Mueller-Hinton agar supplemented with 0.5 mg/mL methylene blue by E-test method for amphotericin B, fluconazole, caspofungin, and voriconazole. Results Out of 70 isolates, Candida tropicalis was the most frequently isolated species (65.7%), followed by Candida albicans (14.3%), Candida glabrata (7.1%), Candida krusei (5.7%), Candida parapsilosis (4.3%), and Candida dubliniensis (2.9%). A total of 37.1% were biofilm producers, 62.9% showed proteinase activity, 38.6% were phospholipase positive, and 58.6% isolates showed hemolytic activity. Antifungal susceptibility profile of Candida species showed 38.6, 25.7, 15.7, and 12.9% resistance to amphotericin B, fluconazole, caspofungin, and voriconazole, respectively. Conclusion A rising trend in isolation of non-albicans Candida from urinary isolates was noticed, which was statistically significant when comparing catheterized and noncatheterized urinary isolates from our study. However, there was no statistically significant difference when different virulence factor expressions were compared among Candida spp. isolated from catheterized and noncatheterized urinary samples. Due to this rise in non-albicans Candida species causing UTI that are intrinsically resistant to certain antifungal agents like azoles and increasing incidence of antifungal resistance, it is essential to monitor the antifungal susceptibility profile of Candida species causing candiduria.

Novel Sulfones with Antifungal Properties: Antifungal Activities and Interactions with Candida spp. Virulence Factors

2018 ◽  
Vol 19 (1) ◽  
pp. 12-21 ◽  
Author(s):  
Małgorzata Gizińska ◽  
Monika Staniszewska ◽  
Zbigniew Ochal
Keyword(s):  
Antifungal Activity ◽  
Virulence Factors ◽  
Hydrolytic Enzymes ◽  
Candida Spp ◽  
Pathogenic Potential ◽  
Robust Response ◽  
New Strategies ◽  
Sulfone Derivatives

Since candidiasis is so difficult to eradicate with an antifungal treatment and the existing antimycotics display many limitations, hopefully new sulfone derivatives may overcome these deficiencies. It is pertinent to study new strategies such as sulfone derivatives targeting the virulence attributes of C. albicans that differentiate them from the host. During infections, the pathogenic potential of C. albicans relies on the virulence factors as follows: hydrolytic enzymes, transcriptional factors, adhesion, and development of biofilms. In the article we explored how the above-presented C. albicans fitness and virulence attributes provided a robust response to the environmental stress exerted by sulfones upon C. albicans; C. albicans fitness and virulence attributes are fungal properties whose inactivation attenuates virulence. Our understanding of how these mechanisms and factors are inhibited by sulfones has increased over the last years. As lack of toxicity is a prerequisite for medical approaches, sulfones (non-toxic as assessed in vitro and in vivo) may prove to be useful for reducing C. albicans pathogenesis in humans. The antifungal activity of sulfones dealing with these multiple virulence factors and fitness attributes is discussed.

scholarly journals Uncommon Non-Candida Yeasts in Healthy Turkeys—Antimicrobial Susceptibility and Biochemical Characteristic of Trichosporon Isolates

Pathogens ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 538
Author(s):  
Kamila Bobrek ◽  
Ireneusz Sokół ◽  
Andrzej Gaweł
Keyword(s):  
Gastrointestinal Tract ◽  
Amphotericin B ◽  
Antimicrobial Susceptibility ◽  
Antifungal Susceptibility ◽  
Range Limit ◽  
Biochemical Tests ◽  
Lower Range ◽  
Normal Microflora ◽  
Severe Infections ◽  
Diverse Community

The microbiota of the gastrointestinal tract of humans and animals is inhabited by a diverse community of bacteria, fungi, protozoa, and viruses. In cases where there is an imbalance in the normal microflora or an immunosuppression on the part of the host, these opportunistic microorganisms can cause severe infections. The study presented here evaluates the biochemical and antifungal susceptibility features of Trichosporon spp., uncommon non-Candida strains isolated from the gastrointestinal tract of healthy turkeys. The Trichosporon coremiiforme and Trichosporon (Apiotrichum) montevideense accounted for 7.7% of all fungi isolates. The biochemical tests showed that Trichosporon coremiiforme had active esterase (C4), esterase-lipase (C8) valine arylamidase, naphthol-AS-BI phosphohydrolase, α-galactosidase, and β-glucosidase. Likewise, Trichosporon montevideense demonstrated esterase-lipase (C8), lipase (C14), valine arylamidase, naphthol-AS-BI phosphohydrolase, α-galactosidase, and β-glucosidase activity. T.coremiiforme and T. monteviidense isolated from turkeys were itraconazole resistant and amphotericin B, fluconazole, and voriconazole susceptible. Compared with human isolates, the MIC range and MIC values of turkey isolates to itraconazole were in a higher range limit in both species, while MIC values to amphotericin B, fluconazole, and voriconazole were in a lower range limit. Furthermore, the obtained ITS1—5.8rRNA—ITS2 fragment sequences were identical with T. coremiiforme and T. montevideense sequences isolated from humans indicating that these isolates are shared pathogens.

Use of spectrophotometric reading for in vitro antifungal susceptibility testing ofAspergillusspp.

1999 ◽  
Vol 45 (10) ◽  
pp. 871-874 ◽  
Author(s):  
Eric Dannaoui ◽  
Florence Persat ◽  
Marie-France Monier ◽  
Elisabeth Borel ◽  
Marie-Antoinette Piens ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Antifungal Susceptibility Testing ◽  
Aspergillus Species ◽  
National Committee ◽  
Broth Microdilution Method

A comparative study of visual and spectrophotometric MIC endpoint determinations for antifungal susceptibility testing of Aspergillus species was performed. A broth microdilution method adapted from the National Committee for Clinical Laboratory Standards (NCCLS) was used for susceptibility testing of 180 clinical isolates of Aspergillus species against amphotericin B and itraconazole. MICs were determined visually and spectrophotometrically at 490 nm after 24, 48, and 72h of incubation, and MIC pairs were compared. The agreement between the two methods was 99% for amphotericin B and ranged from 95 to 98% for itraconazole. It is concluded that spectrophotometric MIC endpoint determination is a valuable alternative to the visual reference method for susceptibility testing of Aspergillus species.Key words: antifungal, susceptibility testing, Aspergillus, spectrophotometric reading.

scholarly journals Trends in Antifungal Drug Susceptibility of Cryptococcus neoformans Isolates Obtained through Population-Based Surveillance in South Africa in 2002-2003 and 2007-2008

2011 ◽  
Vol 55 (6) ◽  
pp. 2606-2611 ◽  
Author(s):  
Nelesh P. Govender ◽  
Jaymati Patel ◽  
Marelize van Wyk ◽  
Tom M. Chiller ◽  
Shawn R. Lockhart ◽  
...  
Keyword(s):  
South Africa ◽  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Fungal Infections ◽  
Antifungal Susceptibility ◽  
Drug Susceptibility ◽  
Population Based ◽  
Content Type ◽  
Microdilution Method ◽  
Broth Microdilution Method

ABSTRACTCryptococcus neoformansis the most common cause of meningitis among adult South Africans with HIV infection/AIDS. Widespread use of fluconazole for treatment of cryptococcal meningitis and other HIV-associated opportunistic fungal infections in South Africa may lead to the emergence of isolates with reduced fluconazole susceptibility. MIC testing using a reference broth microdilution method was used to determine if isolates with reduced susceptibility to fluconazole or amphotericin B had emerged among cases of incident disease. Incident isolates were tested from two surveillance periods (2002-2003 and 2007-2008) when population-based surveillance was conducted in Gauteng Province, South Africa. These isolates were also tested for susceptibility to flucytosine, itraconazole, voriconazole, and posaconazole. Serially collected isolate pairs from cases at several large South African hospitals were also tested for susceptibility to fluconazole. Of the 487 incident isolates tested, only 3 (0.6%) demonstrated a fluconazole MIC of ≥16 μg/ml; all of these isolates were from 2002-2003. All incident isolates were inhibited by very low concentrations of amphotericin B and exhibited very low MICs to voriconazole and posaconazole. Of 67 cases with serially collected isolate pairs, only 1 case was detected where the isolate collected more than 30 days later had a fluconazole MIC value significantly higher than the MIC of the corresponding incident isolate. Although routine antifungal susceptibility testing of incident isolates is not currently recommended in clinical settings, it is still clearly important for public health to periodically monitor for the emergence of resistance.

scholarly journals Virulence of Clinical Candida Isolates

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 466
Author(s):  
Martyna Mroczyńska ◽  
Anna Brillowska-Dąbrowska
Keyword(s):  
Virulence Factors ◽  
Biofilm Formation ◽  
Galleria Mellonella ◽  
Hydrolytic Enzymes ◽  
Morphological Transition ◽  
Candida Spp

The factors enabling Candida spp. infections are secretion of hydrolytic enzymes, adherence to surfaces, biofilm formation or morphological transition, and fitness attributes. The aim of this study was to investigate the correlation between known extracellular virulence factors and survival of Galleria mellonella larvae infected with clinical Candida. The 25 isolates were tested and the activity of proteinases among 24/24, phospholipases among 7/22, esterases among 14/23, hemolysins among 18/24, and biofilm formation ability among 18/25 isolates was confirmed. Pathogenicity investigation using G. mellonella larvae as host model demonstrated that C. albicans isolates and C. glabrata isolate were the most virulent and C. krusei isolates were avirulent. C. parapsilosis virulence was identified as varied, C. inconspicua were moderately virulent, and one C. palmioleophila isolate was of low virulence and the remaining isolates of this species were moderately virulent. According to our study, virulence of Candida isolates is related to the expression of proteases, hemolysins, and esterases.

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