Virulence Factors in Sporothrix schenckii, One of the Causative Agents of Sporotrichosis

2020 ◽  
Vol 21 (3) ◽  
pp. 295-312 ◽  
Author(s):  
Alma K. Tamez-Castrellón ◽  
Orazio Romeo ◽  
Laura C. García-Carnero ◽  
Nancy E. Lozoya-Pérez ◽  
Héctor M. Mora-Montes
Keyword(s):  
Virulence Factors ◽  
Sporothrix Schenckii ◽  
Toxin Production ◽  
Extracellular Vesicle ◽  
Medical Mycology ◽  
Limited Attention ◽  
Causative Organism ◽  
Causative Agents ◽  
Response To Stress ◽  
Etiological Agents

: Sporothrix schenckii is one of the etiological agents of sporotrichosis, a fungal infection distributed worldwide. Both, the causative organism and the disease have currently received limited attention by the medical mycology community, most likely because of the low mortality rates associated with it. Nonetheless, morbidity is high in endemic regions and the versatility of S. schenckii to cause zoonosis and sapronosis has attracted attention. Thus far, virulence factors associated with this organism are poorly described. Here, comparing the S. schenckii genome sequence with other medically relevant fungi, genes involved in morphological change, cell wall synthesis, immune evasion, thermotolerance, adhesion, biofilm formation, melanin production, nutrient uptake, response to stress, extracellular vesicle formation, and toxin production are predicted and discussed as putative virulence factors in S. schenckii.

Isolation and Identification of Fungal Isolates caused Otomycosis from some Hospitals and Clinics in Mosul with Determination of Their Virulence Factors

2021 ◽  
Vol 26 (4) ◽  
Author(s):  
Nabeel Al-Sharrad ◽  
Muhammad A. Al-Kataan ◽  
Maha A. Al-Rejaboo
Keyword(s):  
Fungal Infection ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Fungal Pathogens ◽  
Candida Parapsilosis ◽  
Isolation And Identification ◽  
Fungal Isolates ◽  
Biofilm Production ◽  
Etiological Agents

Otomycosis is a fungal infection that frequently involves the external auditory canal. In this study, we aimed to isolation and identification the fungal isolates as etiological agents of otomycosis from some hospitals and clinics in Mosul with determination of their virulence factors of fungal etiological agents. Positive fungal infection was found in (43) samples (71.6%). The most common fungal pathogens were Candida and Aspergillus species, with Candida parapsilosis being the predominant isolates in (11) samples (16.6%). Otomycosis was more common in Female in (26) samples (43.3%).Otomycosis was the highest prevalence aged group 15-40 years (19) samples (31.3%). The present study of virulence factors revealed that the highest biofilm formation isolates were C. parapsilosis is (10) isolates which were distributed between (2) strong and (8) weak biofilm formation.Where C.trpicales, was recorded as least isolates for biofilm production.

scholarly journals Toxin production by Campylobacter spp.

1997 ◽  
Vol 10 (3) ◽  
pp. 466-476 ◽  
Author(s):  
T M Wassenaar
Keyword(s):  
Animal Model ◽  
Campylobacter Jejuni ◽  
Virulence Factors ◽  
Clinical Data ◽  
Related Species ◽  
Toxin Production ◽  
Biochemical Properties ◽  
Future Directions ◽  
Model Studies ◽  
Campylobacter Spp

Of all the virulence factors that were proposed for Campylobacter jejuni and related species to cause disease in humans, the discovery of toxin production was the most promising but led to a rather confusing and even disappointing stream of data. The discussion of whether proteinaceous exotoxins are relevant in disease remains open. One important reason for this lack of consensus is the anecdotal nature of the literature reports. To provide a basis for an unbiased opinion, this review compiles all described exotoxins, compares their reported properties, and provides a summary of animal model studies and clinical data. The toxins are divided into enterotoxins and cytotoxins and are sorted according to their biochemical properties. Since many Campylobacter toxins have been compared with toxins of other species, some key examples of the latter are also discussed. Future directions of toxin research that appear promising are defined.

Pathogenic Fungi Isolated from Desiccated Mushrooms, Seaweed, Anchovies and Rice Sticks Imported from the Orient1

1987 ◽  
Vol 50 (11) ◽  
pp. 933-939 ◽  
Author(s):  
NURIA KAZANAS
Keyword(s):  
Intraperitoneal Injection ◽  
Fungal Pathogens ◽  
Sporothrix Schenckii ◽  
Pathogenic Fungi ◽  
Opportunistic Fungi ◽  
Toxigenic Fungi ◽  
Yeast Fungi ◽  
Commercial Sources ◽  
Etiological Agents ◽  
The U.S

Desiccated mushrooms, seaweed, rice sticks and anchovies imported from the Orient were obtained from commercial sources or from products detained by the U.S. Food and Drug Administration and examined for pathogenic fungi. The etiological agents isolated were mycelial and yeast fungi known to produce deep sporotrichosis, phaeohyphomycosis, mycetoma, chromoblastomycosis, candidosis and cryptococcosis. Other fungi isolated were opportunistic fungi and/or producers of mycotoxins. Total mold counts in the foods examined varied from 2 × 102 to 5 × 106. The predominant pathogens in the mushrooms were Sporothrix schenckii and Wangiella dermatitidis, and counts in the mushrooms imported from Thailand and Taiwan were as high as 1 × 106; however, these pathogens were not isolated from rice sticks, seaweed or anchovies. All presumed pathogenic strains were pathogenic for mice by intraperitoneal injection of 1 × 106 to 107 conidia in saline suspension. It was concluded that food can harbor “virulent” fungal pathogens and potentially opportunistic invaders as well as potentially toxigenic fungi.

scholarly journals Agrobacterium tumefaciens-Mediated Transformation of Fonsecaea monophora and Fonsecaea erecta for Host-Environment Interaction Studies

2020 ◽  
Vol 6 (4) ◽  
pp. 325
Author(s):  
Cristina Isabel Ferrer Villena ◽  
Renata Rodrigues Gomes ◽  
Larissa Fernandes ◽  
Camille Silva Florencio ◽  
Amanda Bombassaro ◽  
...  
Keyword(s):  
Environment Interaction ◽  
Bactris Gasipaes ◽  
Invasive Potential ◽  
Brain Infection ◽  
Fonsecaea Monophora ◽  
Confocal Fluorescence ◽  
Causative Agents ◽  
Potential Link ◽  
Foreign Dna ◽  
Etiological Agents

The fungal genus Fonsecaea contains etiological agents of human chromoblastomycosis, a (sub)tropical, (sub)cutaneous implantation disease caused by plant contact. The invasive potential differs significantly between species. Infections by Fonsecaea monophora are believed to originate from the environment and the species has been reported as one of the main causative agents of the disease, but also of cases of primary brain infection. The epidemiology of the disease has not been fully elucidated and questions related to its infection route and virulence are still to be clarified. The environmental species Fonsecaea erecta was isolated from organic material and living plants in endemic areas for chromoblastomycosis in Brazil. The present paper describes Agrobacteriumtumefaciens-mediated transformation (AMT) of the environmental species F. erecta and the pathogenic species F. monophora. We propose the use of Agrobacterium transformation for future gene function studies related to Fonsecaea virulence and pathogenicity. We evaluated the co-cultivation ratios 1:1, 10:1 and 100:1 (Agrobacterium:conidia) at 28 °C during 72 h. pAD1625 and pCAMDsRed plasmids were inserted into both species. Confirmation of transformation was realized by hph gene amplification and Southern blot determined the amount of foreign DNA integrated into the genome. In order to evaluate a potential link between environmental and clinical strains, we obtained red fluorescent transformants after pCAMDsRed insertion. We observed by confocal fluorescence microscopy that both F. monophora and F. erecta were able to colonize the palm Bactris gasipaes, penetrating the epidermis. These results contribute to understanding the ability of Fonsecaea species to adapt to different environmental and host conditions.

scholarly journals A series of enterococcal brain abscesses

2015 ◽  
Vol 6 (03) ◽  
pp. 434-437 ◽  
Author(s):  
Tanmoy K. Maiti ◽  
S. Nagarathna ◽  
H. B. Veena Kumari ◽  
Dhaval P. Shukla
Keyword(s):  
Developing Countries ◽  
Brain Abscess ◽  
Clinical Profile ◽  
Clinical Feature ◽  
Causative Organism ◽  
Brain Abscesses ◽  
Etiological Agents

ABSTRACT Background: Neurosurgeons in developing countries come across brain abscess frequently, but Enterococcus as a cause of abscess is rare. Aims: To describe clinical profile and treatment of a series of patients with enterococcal brain abscess. Materials and Methods: We retrospectively reviewed microbiological records of patients with brain abscess to identify Enterococcus as a causative organism. Results: 12 patients (nine males) were diagnosed to have enterococcal brain abscess. All were due to E. species. All were due to E. species. Conclusions: The clinical feature and management are not different from other etiological agents. The prognosis of enterococcal brain abscess is more favourable than bacteremia.

scholarly journals Genotypic and phenotypic diversity of Staphylococcus aureus from cystic fibrosis lung infections and their interactions with Pseudomonas aeruginosa

2019 ◽  
Author(s):  
Eryn E. Bernardy ◽  
Robert A. Petit ◽  
Vishnu Raghuram ◽  
Ashley M. Alexander ◽  
Timothy D. Read ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Phenotypic Diversity ◽  
Laboratory Strain ◽  
Toxin Production ◽  
Reference Isolate ◽  
Patient Health ◽  
Lung Infections

AbstractPseudomonas aeruginosa and Staphylococcus aureus are the most common bacteria that infect the respiratory tract of individuals with the genetic disease cystic fibrosis (CF); in fact, S. aureus has recently overtaken P. aeruginosa to become the most common. Substantial research has been performed on the epidemiology of S. aureus in CF; however, there appears to be a gap in knowledge in regard to the pathogenesis of S. aureus in the context of CF lung infections. Most studies have focused on a few S. aureus isolates, often exclusively laboratory adapted strains, and how they are killed by P. aeruginosa. Because of this, little is known about the diversity of S. aureus CF lung isolates in both virulence and interaction with P. aeruginosa. To begin to address this gap in knowledge, we recently sequenced 65 clinical S. aureus isolates from the Emory CF Biospecimen Registry and Boston Children’s Hospital, including the reference isolate JE2, a USA300 strain. Here, we analyzed antibiotic resistance genotypes, sequence type, clonal complex, spa type, and agr type of these isolates. We hypothesized that major virulence phenotypes of S. aureus that may be associated with CF lung infections, namely toxin production and mucoid phenotype, would be retained in these isolates. To test our hypothesis, we plated on specific agars and found that most isolates can hemolyze both rabbit and sheep blood (67.7%) and produce polysaccharide (69.2%), consistent with virulence retention in CF lung isolates. We also identified three distinct phenotypic groups of S. aureus based on their survival in the presence of nonmucoid P. aeruginosa laboratory strain PAO1 and its mucoid derivative. Altogether, our work provides greater insight into the diversity of S. aureus CF isolates, specifically the distribution of important virulence factors and their interaction with P. aeruginosa, all of which have implications in patient health.Author SummaryStaphylococcus aureus is now the most frequently detected pathogen in the lungs of individuals who have cystic fibrosis (CF), followed closely by Pseudomonas aeruginosa. When these two pathogens are found to coinfect the CF lung, patients have a significantly worse prognosis. While P. aeruginosa has been rigorously studied in the context of bacterial pathogenesis in CF, less is known about S. aureus. Here we present an in-depth study of 64 S. aureus CF clinical isolates where we investigated genetic diversity utilizing whole genome sequencing, virulence phenotypes, and interactions with P. aeruginosa. We have found that S. aureus isolated from the CF lung are phylogenetically diverse, most retain known virulence factors, and they vary in interactions with P. aeruginosa from highly sensitive to completely tolerant. Deepening our understanding of how S. aureus responds to its environment and other microbes in the CF lung will enable future development of effective treatments and preventative measures against these formidable infections.

scholarly journals Comparison of Cell Wall Polysaccharide Composition and Structure Between Strains of Sporothrix schenckii and Sporothrix brasiliensis

2021 ◽  
Vol 12 ◽  
Author(s):  
Héctor L. Villalobos-Duno ◽  
Laura A. Barreto ◽  
Álvaro Alvarez-Aular ◽  
Héctor M. Mora-Montes ◽  
Nancy E. Lozoya-Pérez ◽  
...  
Keyword(s):  
Cell Wall ◽  
Sporothrix Schenckii ◽  
Cell Wall Composition ◽  
Cell Wall Polysaccharide ◽  
Sporothrix Brasiliensis ◽  
Composition And Structure ◽  
Causative Agents ◽  
Polysaccharide Composition ◽  
Pathogenic Process

Sporothrix schenckii, Sporothrix brasiliensis, and Sporothrix globosa are the main causative agents of sporotrichosis, a human subcutaneous mycosis. Differences in virulence patterns are associated with each species but remain largely uncharacterized. The S. schenckii and S. brasiliensis cell wall composition and virulence are influenced by the culturing media, with little or no influence on S. globosa. By keeping constant the culturing media, we compared the cell wall composition of three S. schenckii and two S. brasiliensis strains, previously described as presenting different virulence levels on a murine model of infection. The cell wall composition of the five Sporothrix spp. strains correlated with the biochemical composition of the cell wall previously reported for the species. However, the rhamnose-to-β-glucan ratio exhibits differences among strains, with an increase in cell wall rhamnose-to-β-glucan ratio as their virulence increased. This relationship can be expressed mathematically, which could be an important tool for the determination of virulence in Sporothrix spp. Also, structural differences in rhamnomannan were found, with longer side chains present in strains with lower virulence reported for both species here studied, adding insight to the importance of this polysaccharide in the pathogenic process of these fungi.

scholarly journals A Perspective Study on the Etiology of Diarrhea in Children Less than 12 Years of age attending Kanti Children’s Hospital

1970 ◽  
Vol 29 (1) ◽  
pp. 10-16 ◽  
Author(s):  
M Pokharel ◽  
JB Sherchand ◽  
HC Upreti ◽  
A Katuwal ◽  
P Gauchan
Keyword(s):  
Bacterial Isolate ◽  
University Teaching ◽  
Age Group ◽  
Mortality And Morbidity ◽  
Children's Hospital ◽  
Microbiological Methods ◽  
Children’S Hospital ◽  
Causative Agents ◽  
Key Words Bacteria ◽  
Etiological Agents

Introduction: Diarrhea is the most common illness among children causing highest number of mortality and morbidity in the developing countries. Objective: This study was conducted to determine the etiological agents of diarrhea in children less than 12 years of age. Methods: The study was carried out in Tribhuvan University Teaching Hospital, Health Research Laboratory and stool specimen were collected from Kanti Children's Hospital between February 2007 and August 2007. The specimens were processed by standard microbiological methods, serological diagnosis for the complete identification of bacterial isolate and use of Rotaclone for diagnosis for Rotavirus. Results: A total 500 specimen were processed and 312 (62.4%) cases were identified with enteropathogens. Out of 500, 165 (33%) showed significant bacterial growth, 110 (22%) single or multiple parasitic infestation, and 167 (21.4%) Rotavirus. Among the bacterial isolate, Escherichia. coli (20.2%) were highest in number, Entamoeba. histolytica (10%), among the protozoa and Ascaris lumbricoide (1.4%) among the helminth. Age group 0-2 years showed most number of cases. The prevalence of Rotavirus infection was more in Inpatient (65.4%) than Outpatient (34.6%) (P>0.05). Ethnicgroup wise distribution showed that Gurung/Magar/ Rai/Tamang were highly infected (34.6%) (P>0.05). Conclusion: The results showed that bacteria were the major etiological agents of diarrhea in children than parasites and Rotavirus. E. coli among the bacteria, E. histolytica among the parasite and Rotavirus constituted the major causative agents identified. The age group 0-2years was the most vulnerable group where most of the enteropathogens were detected. Key words: Bacteria, Children Diarrhea, Parasites, Rotavirus doi:10.3126/jnps.v29i1.1594 J. Nepal Paediatr. Soc. Vol.29(1) p.10-16

scholarly journals Deciphering the Dynamics of Signaling Cascades and Virulence Factors of B. cinerea during Tomato Cell Wall Degradation

2021 ◽  
Vol 9 (9) ◽  
pp. 1837
Author(s):  
Almudena Escobar-Niño ◽  
Inés M. Morano Bermejo ◽  
Rafael Carrasco Reinado ◽  
Francisco Javier Fernandez-Acero
Keyword(s):  
Signal Transduction ◽  
Virulence Factors ◽  
Plant Defenses ◽  
Therapeutic Targets ◽  
Pathogenic Fungi ◽  
Toxin Production ◽  
Infection Process ◽  
Membrane Receptors ◽  
Phenotypic Characterization ◽  
Go Annotation

The ascomycete Botrytis cinerea is one of the most relevant plant pathogenic fungi, affecting fruits, flowers, and greenhouse-grown crops. The infection strategy used by the fungus comprises a magnificent set of tools to penetrate and overcome plant defenses. In this context, the plant-pathogen communication through membrane receptors and signal transduction cascades is essential to trigger specific routes and the final success of the infection. In previous reports, proteomics approaches to B. cinerea signal transduction cascades changes in response to different carbon source and plant-based elicitors have been performed. Analyzing the secretome, membranome, phosphoproteome, and the phosphomembranome. Moreover, phenotypic changes in fungal biology was analyzed, specifically toxin production. To obtain the whole picture of the process and reveal the network from a system biology approach, this proteomic information has been merged with the phenotypic characterization, to be analyzed using several bioinformatics algorithms (GO, STRING, MCODE) in order to unravel key points in the signal transduction regulation crucial to overcome plant defenses, as well as new virulence/pathogenicity factors that could be used as therapeutic targets in the control of the gray mold rot disease. A total of 1721 and 663 exclusive or overexpressed proteins were identified under glucose (GLU) and deproteinized tomato cell walls (TCW), summarizing all of the protein identifications under phenotypic characterized stages. Under GO analysis, there are more biological process and molecular functions described in GLU, highlighting the increase in signaling related categories. These results agree with the high number of total identified proteins in GLU, probably indicating a more varied and active metabolism of the fungus. When analyzing only GO annotations related with signal transduction, it was revealed that there were proteins related to TOR signaling, the phosphorelay signal transduction system, and inositol lipid-mediated signaling, only under GLU conditions. On the contrary, calcium-mediated signaling GO annotation is only present between the proteins identified under TCW conditions. To establish a potential relationship between expressed proteins, cluster analyses showed 41 and 14 clusters under GLU and TCW conditions, confirming an increase in biological activity in GLU, where we identified a larger number of clusters related to transcription, translation, and cell division, between others. From these analyses, clusters related to signal transduction and clusters related to mycotoxin production were found, which correlated with the phenotypic characterization. The identification of the proteins encompassed in each condition and signal transduction cascade would provide the research community with new information about the B. cinerea infection process and potential candidates of pathogenicity/virulence factors, overcoming plant defenses, and new therapeutic targets.

scholarly journals Virulence Factors of Clostridioides (Clostridium) difficile Linked to Recurrent Infections

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Laura Tijerina-Rodríguez ◽  
Licet Villarreal-Treviño ◽  
Rayo Morfín-Otero ◽  
Adrián Camacho-Ortíz ◽  
E. Garza-González
Keyword(s):  
Virulence Factors ◽  
Toxin Production ◽  
Negative Regulator ◽  
Binary Toxin ◽  
Recurrent Infections ◽  
Accessory Gene ◽  
Accessory Gene Regulator ◽  
Cell Internalization ◽  
Adhesion Efficiency ◽  
First Recurrence

From 20 to 30% of Clostridioides (Clostridium) difficile infection (CDI), patients might develop recurrence of the infection (RCDI) and, after the first recurrence, the risk of further episodes increases up to 60%. Several bacterial virulence factors have been associated with RCDI, including the elevated production of toxins A and B, the presence of a binary toxin CDT, and mutations in the negative regulator of toxin expression, tcdC. Additional factors have shown to regulate toxin production and virulence in C. difficile in RCDI, including the accessory-gene regulator agr, which acts as a positive switch for toxin transcription. Furthermore, adhesion and motility-associated factors, such as Cwp84, SlpA, and flagella, have shown to increase the adhesion efficiency to host epithelia, cell internalization, and the formation of biofilm. Finally, biofilm confers to C. difficile protection from antibiotics and acts as a reservoir for spores that allow the persistence of the infection in the host. In this review, we describe the key virulence factors of C. difficile that have been associated with recurrent infections.

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