Sabouraud Agar for Fungal Growth

Author(s):  
Janelle M. Hare
Keyword(s):  
Author(s):  
H.M. Mazzone ◽  
G. Wray ◽  
R. Zerillo

The fungal pathogen of the Dutch elm disease (DED), Ceratocystis ulmi (Buisman) C. Moreau, has eluded effective control since its introduction in the United States more than sixty years ago. Our studies on DED include establishing biological control agents against C. ulmi. In this report we describe the inhibitory action of the antibiotic polymyxin B on the causal agent of DED.In screening a number of antibiotics against C. ulmi, we observed that filter paper discs containing 300 units (U) of polymyxin B (Difco Laboratories) per disc, produced zones of inhibition to the fungus grown on potato dextrose agar or Sabouraud agar plates (100mm x 15mm), Fig. 1a. Total inhibition of fungal growth on a plate occurred when agar overlays containing fungus and antibiotic (polymyxin B sulfate, ICN Pharmaceuticals, Inc.) were poured on the underlying agar growth medium. The agar overlays consisted of the following: 4.5 ml of 0.7% agar, 0.5 ml of fungus (control plate); 4.0 ml of 0.7% agar, 0.5 ml of fungus, 0.5 ml of polymyxin B sulfate (77,700 U). Fig. 1, b and c, compares a control plate and polymyxin plate after seven days.


Author(s):  
Ankur Bhargava ◽  
Sonal Saigal

Background: Infection due to fungi have increased dramatically in recent years and are of prime importance because of the rising number of immunocompromised patients, such as cancer patients receiving chemotherapy, and human immunodeficiency virus infected patients. The aim of the analysis was to compare the candidal count at the time of insertion and after one month of wearing complete dentures.Methods: It was a quasi-experimental study which consisted of forty edentulous patients with no previous denture history. They obtained new complete dentures. Samples were taken using the oral rinse technique and cultured on sabouraud agar for fungal growth and cultured positive samples had undergone for germ tube test in serum media.Results: Candidal colonies were detected and counted as colony forming units at the time of insertion and after one month of wearing complete dentures. Change in candidal count was significantly higher after one month of wearing complete dentures (p=0.0001). Difference in candidal count was significantly higher in females than males.Conclusions: Candidal count was significant after wearing complete dentures and this should be considered as an important factor that can pre-dispose the patients to candida induced denture stomatitis.


2001 ◽  
Vol 53 (5) ◽  
pp. 568-573 ◽  
Author(s):  
G.C. Paixão ◽  
J.J.C. Sidrim ◽  
G.M.M. Campos ◽  
R.S.N. Brilhante ◽  
M.F.G. Rocha

The possible involvement of saprobe fungi in dermatomycoses, as well as the determination of the incidence of dermatophytes in dogs and cats were studied. During a period of one year, 74 dogs and 18 cats, with cutaneous lesions suggesting mycoses were included in this study. The mycological analyses were conducted by direct microscopy and by fungal culture on Sabouraud agar, chloramphenicol Sabouraud agar and mycosel agar. Of the 92 samples, 21 resulted in positive cultures for dermatophytes. Dermatophyte fungi pure cultures were obtained from 13 samples. A simultaneous growth of dermatophytes plus saprobe fungi was observed in 8 of the samples. Of the remaining 71 samples, no fungal growth was observed in 10 samples, and at minimum the growth of one saprobe fungi in 61. One, two and three genera of saprobe fungi were isolated in 29, 30 and 2 samples, respectively. Microsporum canis was isolated in 6 (28.6 %) and 10 samples (47.6 %) from cats and dogs, respectively, and Trichophyton mentagrophytes in 2 (9.5 %) and 3 samples (14.3 %) from cats and dogs, respectively. The following genera of saprobe fungi were also isolated: Alternaria sp (1.9%), Chaetomium sp (1.9%), Rhizopus sp (2.9%), Curvularia sp (3.9%), Candida sp (6.8%), Trichoderma sp (6.8%), Fusarium sp (7.8%), Cladosporium sp (8.7%), Penicillium sp (21.4%) and Aspergillus sp (37.9%).


2017 ◽  
Vol 45 (1) ◽  
pp. 7
Author(s):  
Cibele Floriano Fraga ◽  
Andréia Spanamberg ◽  
Laerte Ferreiro ◽  
Gisele Alabora da Silva ◽  
Natália Tomazi Francheschi ◽  
...  

Background: Dermatophytes are infectious agents responsible for dermatophytosis, an important worldwide zoonosis. Cats are considered potential hosts and reservoir of these fungi, especially Microsporum canis. The prevalence in cats without dermatopathies varies according to the region, climate and animal husbandry. The aim of this study was to estimate the frequency of dermatophytes in cats without clinical signs of dermatopathy in the Metropolitan Area of Florianópolis, situated in the coast of Southern Brazil.Materials, Methods & Results: A total of 198 samples were obtained from cats without dermatopathies domiciled in the metropolitan area of Florianópolis. The collections were made through vigorous hair brushing throughout the body of the animal, using a sterile toothbrush. Mycological culture was performed onto Sabouraud Agar Chloramphenicol-Cyclohexamide (SCC), and incubated at 25-27°C for 21-28 days. The diagnosis was based on the macro and micromorphological characteristics of the isolated dermatophyte. One hundred and ten samples (55.6%) were collected in veterinary clinics and 88 (44.4%) in multiple household cats (average 11). The frequency of dermatophytes corresponded to 3.0% (6/198). Only the genus Microsporum was observed with predominance of M. canis (66.7%), followed by M. gypseum (33.3%). Saprotrophic fungi were observed in 94.4% of the cultures and 5.6% of the samples did not occurred fungal growth. Most of the isolates were obtained from adult cats (66.7%), females (83.3%) and with long hair (5.4%) in comparison to short hair samples (2.1%). Thirty percent of the cats (59/198) had been tested for retroviruses, and, among them, 27.0% were positive (22% FeLV and 5% FIV). M. gypseum was isolated from one feline FeLV positive. Various saprotrophic species were isolated from multiple household cats.Discussion: Dermatophytosis is considered as the most common occupational zoonosis among veterinarians, and it is recognized as a biological risk associated to the direct contact with cats. There are reports of regional outbreaks in Brazil where the pets were indicated as sources of dermatophytes to humans in the domestic environment. The frequency of dermatophytes observed in this study (3.0%) was lower than shown in others papers. Microsporum canis is commonly isolated from cats in hot weather regions and crowded living facilities; once introduced in to the creation on a cattery it is difficult to be eliminated. There is evidence of a higher occurrence of M. canis in cats FIV positive than seronegative ones. Dermatophytes were isolated from cats in contact with other cats (5/165). However, multiple household cats had no positive cultures and this outcome can be associated to high contamination by saprotrophic fungi. For diagnosis of dermatophytosis, mycological culture is indicated as the most efficient and easy to perform method, but it is necessary to be aware of false negative results, since it can occur in situations of intense contamination. Thus, it is advisable to prophylactically perform a clinical examination as a routine and also laboratory analyses in each cat before introducing it to a new environment.


2020 ◽  
Vol 26 (1) ◽  
pp. 93-99
Author(s):  
Munekazu Kishimoto ◽  
Kazuo Nakamura ◽  
Takuto Tasaki ◽  
Kinya Matsumoto ◽  
Rina Nakano ◽  
...  

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 476e-476
Author(s):  
Craig S. Charron ◽  
Catherine O. Chardonnet ◽  
Carl E. Sams

The U.S. Clean Air Act bans the use of methyl bromide after 2001. Consequently, the development of alternative methods for control of soilborne pathogens is imperative. One alternative is to exploit the pesticidal properties of macerated tissues of Brassica spp. This study tested the potential of several Brassica spp. for control of fungal pathogens. Pythium ultimum Trow or Rhizoctonia solani Kühn plugs on potato-dextrose agar on petri dishes were sealed in 500-ml glass jars (at 22 °C) containing macerated leaves (10 g) from one of six Brassica spp. Radial growth was measured 24, 48, and 72 h after inoculation. Indian mustard (B. juncea) was the most suppressive, followed by `Florida Broadleaf' mustard (B. juncea). Volatile compounds in the jars were sampled with a solid-phase microextraction device (SPME) and identified by gas chromatography-mass spectrometry (GC-MS). Allyl isothiocyanate (AITC) comprised over 90% of the total volatiles measured from Indian mustard and `Florida Broadleaf' mustard. Isothiocyanates were detected in jars with all plants except broccoli. (Z)-3-hexenyl acetate was emitted by all plants and was the predominant volatile of `Premium Crop' broccoli (B. oleracea L. var. italica), `Michihili Jade Pagoda' Chinese cabbage (B. pekinensis), `Charmant' cabbage (B. oleracea L. var. capitata), and `Blue Scotch Curled' kale (B. oleracea L. var. viridis). To assess the influence of AITC on radial growth of P. ultimum and R. solani, AITC was added to jars to give headspace concentrations of 0.10, 0.20, and 0.30 mg·L–1 (mass of AITC per volume of headspace). Growth of both fungi was inhibited by 0.10 mg·L–1 AITC. 0.20 mg·L–1 AITC was fungicidal to P. ultimum although the highest AITC level tested (0.30 mg·L–1) did not terminate R. solani growth. These results indicate that residues from some Brassica spp. may be a viable part of a soilborne pest control strategy.


2004 ◽  
Vol 4 (4) ◽  
pp. 175-182 ◽  
Author(s):  
K. Rojek ◽  
F.A. Roddick ◽  
A. Parkinson

Phanerochaete chrysosporium was shown to rapidly decolorise a solution of natural organic matter (NOM). The effect of various parameters such as carbon and nitrogen content, pH, ionic strength, NOM concentration and addition of Mn2+ on the colour removal process was investigated. The rapid decolorisation was related to fungal growth and biosorption rather than biodegradation as neither carbon nor nitrogen limitation, nor Mn2+ addition, triggered the decolorisation process. Low pH (pH 3) and increased ionic strength (up to 50 g L‒1 added NaCl) led to greater specific removal (NOM/unit biomass), probably due to increased electrostatic bonding between the humic material and the biomass. Adsorption of NOM with viable and inactivated (autoclaved or by sodium azide) fungal pellets occurred within 24 hours and the colour removal depended on the viability, method of inactivation and pH. Colour removal by viable pellets was higher under the same conditions, and this, combined with desorption data, confirmed that fungal metabolic activity was important in the decolorisation process. Overall, removals of up to 40–50% NOM from solution were obtained. Of this, removal by adsorption was estimated as 60–70%, half of which was physicochemical, the other half metabolically-dependent biosorption and bioaccumulation. The remainder was considered to be removed by biodegradation, although some of this may be ascribed to bioaccumulation and metabolically-dependent biosorption.


Toxins ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 391
Author(s):  
Christopher Hernandez ◽  
Laura Cadenillas ◽  
Anwar El Maghubi ◽  
Isaura Caceres ◽  
Vanessa Durrieu ◽  
...  

Aflatoxin B1 (AFB1) is a potent carcinogenic mycotoxin that contaminates numerous crops pre- and post-harvest. To protect foods and feeds from such toxins without resorting to pesticides, the use of plant extracts has been increasingly studied. The most interesting candidate plants are those with strong antioxidative activity because oxidation reactions may interfere with AFB1 production. The present study investigates how an aqueous extract of Mimosa tenuiflora bark affects both the growth of Aspergillus flavus and AFB1 production. The results reveal a dose-dependent inhibition of toxin synthesis with no impact on fungal growth. AFB1 inhibition is related to a down-modulation of the cluster genes of the biosynthetic pathway and especially to the two internal regulators aflR and aflS. Its strong anti-oxidative activity also allows the aqueous extract to modulate the expression of genes involved in fungal oxidative-stress response, such as msnA, mtfA, atfA, or sod1. Finally, a bio-guided fractionation of the aqueous extract demonstrates that condensed tannins play a major role in the anti-aflatoxin activity of Mimosa tenuiflora bark.


Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Jing Wang ◽  
Chaoyun Xu ◽  
Qiming Sun ◽  
Jinrong Xu ◽  
Yunrong Chai ◽  
...  

Abstract Background Microbiome interactions are important determinants for ecosystem functioning, stability, and health. In previous studies, it was often observed that bacteria suppress potentially pathogenic fungal species that are part of the same plant microbiota; however, the underlying microbe-microbe interplay remains mostly elusive. Here, we explored antagonistic interactions of the fungus Fusarium graminearum and bacterium Streptomyces hygroscopicus at the molecular level. Both are ubiquitous members of the healthy wheat microbiota; under dysbiosis, the fungus causes devastating diseases. Results In co-cultures, we found that Streptomyces alters the fungal acetylome leading to substantial induction of fungal autophagy. The bacterium secrets rapamycin to inactivate the target of rapamycin (TOR), which subsequently promotes the degradation of the fungal histone acetyltransferase Gcn5 through the 26S proteasome. Gcn5 negatively regulates fungal autophagy by acetylating the autophagy-related protein Atg8 at the lysine site K13 and blocking cellular relocalization of Atg8. Thus, degradation of Gcn5 triggered by rapamycin was found to reduce Atg8 acetylation, resulting in autophagy induction in F. graminearum. Conclusions Autophagy homeostasis plays an essential role in fungal growth and competition, as well as for virulence. Our work reveals a novel post-translational regulation of autophagy initiated by a bacterial antibiotic. Rapamycin was shown to be a powerful modulator of bacteria–fungi interactions with potential importance in explaining microbial homeostasis in healthy plant microbiomes. The autophagic process provides novel possibilities and targets to biologically control pathogens.


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