Extracellular Enzymes and Mycotoxins as Virulence Factors in Fusarium and Aspergillus Keratitis

2014 ◽  
Vol 11 (2) ◽  
pp. 479-490 ◽  
Author(s):  
K.P. Selvam
Keyword(s):  
Virulence Factors ◽  
Extracellular Enzymes

Virulence determinants and production of extracellular enzymes in Enterococcus spp. from surface water sources

2016 ◽  
Vol 73 (8) ◽  
pp. 1817-1824 ◽  
Author(s):  
Lesego Gertrude Molale ◽  
Cornelius Carlos Bezuidenhout
Keyword(s):  
Surface Water ◽  
Virulence Factors ◽  
Virulence Genes ◽  
Extracellular Enzymes ◽  
Virulence Gene ◽  
Water Sources ◽  
Virulence Determinants ◽  
North West ◽  
Enterococcus Spp

Virulence factors in Enterococcus may be indicative of potential pathogenicity. The aim of this study was to determine the relationship between the presence of clinically relevant virulence genes, in Enterococcus spp. from environmental water, and their in vitro expression. One hundred and twenty-four Enterococcus isolates (seven species), from five surface water systems in the North West Province, South Africa, were screened for the presence of asa1, cylA, esp, gelE and hyl using polymerase chain reaction. The expression of cylA, hyl and gelE was determined by phenotypic assessments. Sixty-five percent of the isolates were positive for one virulence gene and 13% for two or more. Most frequently detected genes were gelE (32%) and cylA (28%). Enterococcal surface protein was absent in all isolates screened. The presence of virulence genes was correlated with their extracellular enzyme production. The results show that a large percentage of these environmental Enterococcus spp. possess virulence factors that could be expressed in vitro. This is a cause for concern and could have implications for individuals using this water for recreational and cultural purposes. Further investigation is required into the sources of these potential pathogenic Enterococcus isolates and measures to minimize their presence in water sources.

scholarly journals Predominance of Cryptococcus neoformans Var. grubii in Ahvaz, Molecular Identification and Evaluation of Virulence Factors

2021 ◽  
Vol 13 (11) ◽  
Author(s):  
Maryam Moslem ◽  
Mahnaz Fatahinia ◽  
Neda Kiasat ◽  
Ali Zarei Mahmoudabadi
Keyword(s):  
Cryptococcus Neoformans ◽  
Virulence Factors ◽  
Extracellular Enzymes ◽  
Co2 Concentration ◽  
Melanin Production ◽  
Worldwide Distribution ◽  
Molecular Microbiology ◽  
Pathogenic Factors ◽  
Pigeon Droppings ◽  
Cryptococcus Species

Background: Cryptococcus neoformans is an encapsulated yeast pathogen with worldwide distribution, and the highest incidence of cryptococcosis was attributed to C. neoformans (var. grubii. The pathogenicity of Cryptococcus species is associated with several factors, including capsule and melanin production, growth at 37 ºC, and secretion of extracellular enzymes. Objectives: The present study aimed to isolate and identify Cryptococcus species from pigeon guano in Ahvaz, Iran and investigate important virulence factors in the isolates. Methods: Seventy-three isolates of C. neoformans var. grubii were identified based on classical and molecular microbiology methods. Capsule size was measured by the grow yeasts in the presence of 5% CO2. Specific media demonstrated the activity of extracellular enzymes (phospholipase, hemolysin, proteinase, esterase, urease, catalase, and gelatinase). Besides, melanin production was evaluated by the niger seed agar medium. Results: Two hundred and seventeen samples were examined for the presence of Cryptococcus over 165 days in Ahvaz. All tested isolates were contained capsules with variable sizes under 5% CO2 concentration. Moreover, 100% of isolates were produced extracellular enzymes (urease, hemolysin, and catalase), whereas no proteinase and gelatinase activities were observed among isolates. Furthermore, most isolates had phospholipase (93.1%) and esterase activities (86.3%). Also, melanin was produced by all of the isolates. Conclusions: Although two methods were used for recovery of Cryptococcus, only Cryptococcus was isolated from pigeon guano, and swabs from the cage walls were negative. Cryptococcus neoformans var. grubii was the only species from pigeon droppings from Ahvaz with more pathogenic factors. Owing to the high pathogenicity of the isolates, the frequency of the disease is expected to be higher.

scholarly journals Molecular insights intoVibrio cholerae’s intra-amoebal host-pathogen interactions

2017 ◽  
Author(s):  
Charles Van der Henst ◽  
Stéphanie Clerc ◽  
Sandrine Stutzmann ◽  
Candice Stoudmann ◽  
Tiziana Scrignari ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Virulence Factors ◽  
Molecular Mechanisms ◽  
Extracellular Enzymes ◽  
Diarrheal Disease ◽  
Acanthamoeba Castellanii ◽  
Aqueous Environment ◽  
Aquatic Habitats ◽  
Fitness Advantage ◽  
Primary Habitat

Vibrio cholerae, which causes the diarrheal disease cholera, is a species of bacteria commonly found in aquatic habitats. Within such environments, the bacterium must defend itself against predatory protozoan grazers. Amoebae are prominent grazers, withAcanthamoeba castellaniibeing one of the best-studied aquatic amoebae. We previously showed thatV. choleraeresists digestion byA. castellaniiand establishes a replication niche within the host’s osmoregulatory organelle. In this study, we deciphered the molecular mechanisms involved in the maintenance ofV. cholerae’s intra-amoebal replication niche and its ultimate escape from the succumbed host. We demonstrated that minor virulence features important for disease in mammals, such as extracellular enzymes and flagellum-based motility, play a key role role in the replication and transmission ofV. choleraein its aqueous environment. This work, therefore, describes new mechanisms that provide the pathogen with a fitness advantage in its primary habitat, which may have contributed to the emergence of these minor virulence factors in the speciesV. cholerae.

Enterococcal Virulence Determinants In Urinary Tract Infection Patients

2012 ◽  
Vol 6 (1) ◽  
pp. 14-17
Author(s):  
Jabin Akhter ◽  
Shaheda Anwar ◽  
Sharmeen Ahmed
Keyword(s):  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Virulence Factors ◽  
Virulence Determinants ◽  
Microtitre Plate ◽  
Microbiological Method ◽  
Enterococcal Infection ◽  
Microtitre Plate Assay ◽  
Positive Frequency

Urinary tract infection caused by Enterococci has become frequent occurrences in health care settings. Currently they emerged with increasing resistance to multiple antibiotics.  Haemolysin, gelatinase and biofilm production are some markers that have been proposed as possible Enterococcal virulence factors. In view of the increasing importance of Enterococcal infection, the present study was designed to isolate and identify the Enterococci to the species level from urine of urinary tract infection patients and to investigate their possible virulence factors. Biofilm was detected on polystyrene microtitre plate to see the adherence of microorganism. Haemolysin production and gelatin hydrolysis detected by standard microbiological method. Fifty nine enterococcal isolates were speciated by conventional microbiological method and examined for their ability to form biofilm by microtitre plate assay. In this study, biofilm formations by Enterococci were found in 83.33% isolates from catheterized and 56.09% from non-catheterized patients. Aong them, E.faecalis & 50% E.faecium produced biofilm. About 43.63% E.faecalis & 10% E.faecium produced haemolysin and only one isolate were found to be gelatinase positive. Frequency of virulence factors (VFs) in combination was observed in this study. Two VFs (haemolysin and biofilm) were observed in 27.11% in combination and 3 VFs ( haemolysinm biofilm and gelatinase) were present in 1.69% isolates. These results suggest that although there may not be an absolute role for individual virulence determinants in infectivity, combinations of factors may play a role in allowing a biofilm infection to be more resistant to therapy.DOI: http://dx.doi.org/10.3329/bjmm.v6i1.19361 Bangladesh J Med Microbiol 2012; 06(01): 14-17

Microbiological characteristic bacteria of the genus Legionella: classification, morphology and physiology, virulence factors – part I

2014 ◽  
Vol 5 (1) ◽  
pp. 17-25
Author(s):  
Agnieszka Sikora ◽  
Małgorzata Wójtowicz-Bobin ◽  
Anna Sikora ◽  
Maria Kozioł-Montewka ◽  
Dagmara Strzelec - Nowak
Keyword(s):  
Virulence Factors

Aspergillus sydowii Strain SCAU066 and Aspergillus versicolor Isolate BAB-6580: Potential Source of Xylanolytic, Cellulolytic and Amylolytic Enzymes

2020 ◽  
Vol 14 (2) ◽  
pp. 15
Author(s):  
Zaidah Zainal ariffin
Keyword(s):  
Extracellular Enzymes ◽  
Biologically Active ◽  
Aspergillus Versicolor ◽  
Aspergillus Sydowii ◽  
Aspergillus Tamarii ◽  
Alternative Source ◽  
Amylolytic Enzymes ◽  
Potato Dextrose Broth ◽  
Wide Range ◽  
Pharmaceutical Industries

Fungi is known to produce a wide range of biologically active metabolites and enzymes. Enzymes produced by fungi are utilized in food and pharmaceutical industries because of their rich enzymatic profile. Filamentous fungi are particularly interesting due to their high production of extracellular enzymes which has a large industrial potential. The aim of this study is to isolate potential soil fungi species that are able to produce functional enzymes for industries. Five Aspergillus species were successfully isolated from antibiotic overexposed soil (GPS coordinate of N3.093219 E101.40269) by standard microbiological method. The isolated fungi were identified via morphological observations and molecular tools; polymerase chain reactions, ITS 1 (5’- TCC GTA GGT GAA CCT GCG G3’) forward primer and ITS 4 (5’-TCC TCC GCT TAT TGA TAT GC-3’) reverse primer. The isolated fungi were identified as Aspergillus sydowii strain SCAU066, Aspergillus tamarii isolate TN-7, Aspergillus candidus strain KUFA 0062, Aspergillus versicolor isolate BAB-6580, and Aspergillus protuberus strain KAS 6024. Supernatant obtained via submerged fermentation of the isolated fungi in potato dextrose broth (PDB) and extracted via centrifugation was loaded onto specific media to screen for the production of xylanolytic, cellulolytic and amylolytic enzymes. The present findings indicate that Aspergillus sydowii strain SCAU066 and Aspergillus versicolor isolate BAB-6580 have great potential as an alternative source of xylanolytic, cellulolytic and amylolytic enzymes.

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