scholarly journals Diagnosis and therapeutic management of malasseziosis in dogs

2021 ◽  
Vol 52 (3) ◽  
Author(s):  
Ajithkumar S. ◽  
Ajithkumar S. ◽  
Ajithkumar S. ◽  
Ajithkumar S. ◽  
Ajithkumar S.
Keyword(s):  
Large Subunit ◽  
Opportunistic Pathogens ◽  
Malassezia Pachydermatis ◽  
Gram Staining ◽  
Pure Cultures ◽  
Oral Itraconazole ◽  
Total Dna ◽  
Malassezia Spp ◽  
Microscopic Morphology ◽  
Pcr Targeting

Malassezia spp. are commensals of the normal cutaneous microbiota of humans and animals. These yeasts may become opportunistic pathogens under certain conditions and cause dermatitis and otitis externa in dogs. Malassezia pachydermatis is the most common cause of malasseziosis in dogs. In this study skin and ear swabs from suspected cases were cultured on Modified Dixon’s Agar (MDA). The isolates obtained were initially characterized on the basis of colony characteristics, result of Gram staining and microscopic morphology. Total DNA was extracted from the pure cultures of the isolates and subjected to confirmation by polymerase chain reaction (PCR) targeting large subunit ribosomal RNA gene. Positive cases were treated with oral itraconazole at 5 mg/kg bodyweight, orally once daily for 28 days.

scholarly journals Fungi of the genus Malassezia as opportunists of humans and animals

2018 ◽  
Vol 72 ◽  
pp. 359-375 ◽  
Author(s):  
Urszula Czyżewska ◽  
Magdalena Siemieniuk ◽  
Marek Bartoszewicz ◽  
Adam Tylicki
Keyword(s):  
Extracellular Enzymes ◽  
Cell Structure ◽  
Seborrheic Dermatitis ◽  
Epidemiological Data ◽  
Protein Profiling ◽  
Specific Cell ◽  
Malassezia Pachydermatis ◽  
Malassezia Folliculitis ◽  
Malassezia Spp

Yeasts from the genus Malassezia are common commensals and pathogens found in humans and animals, and are responsible for tinea cases. Due to their specific cell structure, they may be resistant to environmental stresses and difficult to eliminate by the host’s immune system. In spite of several virulence factors, the pathogenicity of Malassezia spp. and their interactions with hosts still arouse great interest. Genomes of particular isolates, representing the majority of species from the Malassezia genus, have been sequenced in recent years. Moreover, reconstruction of the phylogeny, by the usage of ITS and IGS sequences, has been attempted as well. Biochemical analyzes led to a better understanding of those fungi’s ecology and virulence. Lipid and protein profiling, the assessment of phospholipases and extracellular enzymes activities, brought new insight into the genesis and courses of diverse illnesses, including pityriasis versicolor, seborrheic dermatitis, atopic dermatitis, Malassezia folliculitis, psoriasis and systemic fungemia. Special attention should be paid to Malassezia pachydermatis, which is a potential model of zoophilic species with an increasing frequency of tinea cases caused in humans. Furthermore, in vitro experiments suggest its possible drug resistance. The members of Malassezia genus are a serious medical and therapeutic challenge. Because of difficulties in the assessment of their virulence, high genetic and biochemical diversity and, finally, complicated evolutionary traits, they require further research. Genomic and proteomic analyses, supported with biochemical profiling and epidemiological data, will contribute to a better understanding of the biology of the yeasts, especially the issue of opportunism among fungi.

NoteIdentification of atypical strains ofMalasseziaspp. from cattle and dog

2002 ◽  
Vol 48 (8) ◽  
pp. 749-752 ◽  
Author(s):  
Eduardo Robson Duarte ◽  
Marc-André Lachance ◽  
Júnia Soares Hamdan
Keyword(s):  
Yeast Species ◽  
Large Subunit ◽  
External Ear ◽  
Cremophor El ◽  
Malassezia Pachydermatis ◽  
Physiological Characterization ◽  
Malassezia Species ◽  
Large Subunit Rrna ◽  
Rrna Sequences ◽  
Atypical Strains

Yeast species in the genus Malassezia are lipophilic with the exception of Malassezia pachydermatis. During a study of the occurrence of Malassezia species in the external ear of 964 cattle and 6 dogs in Minas Gerais, Brazil, six lipid-dependent isolates could not be identified to known species. Four isolates came from healthy cows, one from a cow with otitis, and one from a healthy dog. When tested with Tweens and Cremophor EL as single sources of lipids, the strains grew on all sources except Cremophor EL. None of the six strains hydrolyzed esculin, and all produced catalase. Pigment production from tryptophan was variable. Partial large subunit rRNA sequences were obtained for two isolates that remained viable in culture. The strain from the cow with otitis was identified as a lipid-dependent variant of M. pachydermatis, and the strain from the dog was an atypical variant of Malassezia furfur.Key words: atypical Malassezia strains, biochemical and physiological characterization, ribosomal DNA.

scholarly journals A College–High School Collaboration to Support Authentic Microbiology Research

2020 ◽  
Vol 82 (4) ◽  
pp. 201-208
Author(s):  
Joan Petersen ◽  
Patrick Chan
Keyword(s):  
High School ◽  
High School Students ◽  
School Teacher ◽  
High School Teacher ◽  
School Students ◽  
Gram Staining ◽  
Pure Cultures ◽  
Students Attitudes ◽  
Written Assignments ◽  
Microbiology Research

A partnership between a community college biology professor and a local high school teacher was established to engage high school students in authentic microbiology research. High school students isolated actinomycetes from soil samples and tested them for their ability to produce antimicrobial chemicals. They also designed and carried out their own experiments with these isolates. Laboratory reports, written assignments, and quizzes were used to assess the scientific learning of the subject covered by the research project. The students' attitudes about science and scientific research were assessed using a standardized survey and written reflection questions. In completing this project, the students applied their knowledge of the scientific method and experimental design to address authentic research questions. They also learned several hands-on laboratory skills, including serial dilution, aseptic technique, isolation of pure cultures, Gram staining, microscopy, and antimicrobial testing. Student feedback was overwhelmingly positive – many expressed an increased interest in pursuing a career in science, and most felt that the project helped them gain confidence in their ability to do science. This project illustrates the importance of establishing partnerships between secondary schools and academic institutions to successfully introduce research to younger students.

Loop-mediated isothermal amplification (LAMP) for detection of the red ring nematode, Bursaphelenchus cocophilus

Nematology ◽  
2017 ◽  
Vol 19 (5) ◽  
pp. 559-565 ◽  
Author(s):  
Tatsuya Ide ◽  
Natsumi Kanzaki ◽  
Pedro Pablo Parra Giraldo ◽  
Robin M. Giblin-Davis
Keyword(s):  
Large Subunit ◽  
Isothermal Amplification ◽  
Internal Transcribed Spacers ◽  
Simple Method ◽  
Loop Mediated Isothermal Amplification ◽  
Third Stage ◽  
Stage Juvenile ◽  
Total Dna ◽  
Primer Sets ◽  
Rna Genes

As a first step in developing a quick, accurate and simple method for the diagnosis of red ring disease, the loop-mediated isothermal amplification (LAMP)-based identification procedure was applied to the causative agent,Bursaphelenchuscocophilus. Two LAMP primer sets were designed using two loci of ribosomal RNA genes,i.e., D2-D3 expansion segments of the large subunit (D2-D3 LSU), and internal transcribed spacers (ITS). Within those two sets of primers, the D2-D3 LSU primer set successfully yielded amplicons fromB. cocophilusnematode lysate prepared from 3-year-old DESS-fixed specimens. The specificity of the primers was examined using 18 species of confamilial Aphelenchoididae nematodes and primer sensitivity was tested using a diluted series ofB. cocophiluslysate. The primer set did not amplify the DNA from other aphelenchoidids, and sensitivity was achieved by ‘1:100 diluted’B. cocophilusDNA (roughly 1/1500 of total DNA from a single third-stage juvenile).

Bacterial survival and biofilm formation on conventional and antibacterial toothbrushes

Biofilms ◽  
2004 ◽  
Vol 1 (2) ◽  
pp. 123-130 ◽  
Author(s):  
R. L. Sammons ◽  
D. Kaur ◽  
P. Neal
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Bacterial Survival ◽  
Opportunistic Pathogens ◽  
Mechanical Agitation ◽  
Gram Staining ◽  
Colony Forming Units ◽  
Significant Difference ◽  
Number Of Bacteria

The aim of this study was to investigate bacterial survival and biofilm formation on toothbrushes. Fifteen healthy volunteers each used a normal toothbrush and an antibacterial toothbrush of the same design for two separate 5 week periods. Bacteria were removed from the brush head by swabbing and mechanical agitation in 10ml of tryptone soya broth, cultured aerobically on selective and non-selective media, and classified by Gram staining, catalase and oxidase tests. Survival of Staphylococcus epidermidis and Pseudomonas aeruginosa was monitored in the laboratory on both types of brush over 8 days. Scanning electron microscopy was used to observe biofilm formation on antibacterial and conventional brushes used for various times. Numbers of bacteria isolated from conventional and antibacterial brushes from different individuals ranged from 8.3×103 to 4.7×106 and from 1×102 to 1.2×106 colony-forming units/ml, respectively. A larger number of bacteria were isolated from conventional brushes than from antibacterial brushes used by the same individuals but no statistically significant difference was demonstrated. No differences in the relative proportions of Gram-negative and Gram-positive rods or cocci were seen. Staphylococci, presumptive coliforms and pseudomonads were isolated from 48%, 28% and 16% of brushes, respectively. Pseudomonas aeruginosa was viable for at least 4 days on conventional, and 2–3 days on antibacterial, brushes, whilst S. epidermidis survived for 6–8 days on antibacterial and more than 8 days on conventional brushes. Biofilms formed on the heads and bristles of both conventional and antibacterial brushes. Extensive, mixed community biofilms developed after several months of use. We conclude that toothbrushes may be a reservoir of opportunistic pathogens including staphylococci and pseudomonad-like organisms and must be considered as a potential source of haematogenous infections and cross-infection.

scholarly journals Antifungal Susceptibility of Malassezia pachydermatis Isolates from Dogs

2019 ◽  
Vol 63 (2) ◽  
pp. 15-20
Author(s):  
Z. Sihelská ◽  
E. Čonková ◽  
P. Váczi ◽  
M. Harčárová
Keyword(s):  
Antifungal Agents ◽  
Antifungal Susceptibility ◽  
Diffusion Method ◽  
Opportunistic Pathogens ◽  
Ear Canal ◽  
Disk Diffusion Method ◽  
Malassezia Pachydermatis ◽  
Resistant Strains ◽  
Standard Disk

Abstract The genus Malassezia belongs to Basidiomycota and includes 16 species, from which M. pachydermatis is the most common in dogs. M. pachydermatis is a member of the normal mycobiota of the skin and mucosal sites of dogs. Under certain conditions, these yeasts can be opportunistic pathogens and involved skin and ear canal infections of these animals. Topical and oral antifungal agents are used for the therapy of Malassezia dermatitis and otitis. With the expanding use of antifungal agents, resistant strains of Malassezia are increasingly detected. In this study, the susceptibility of 40 M. pachydermatis isolates to fluconazole, itraconazole, ketoconazole, clotrimazole and nystatin were evaluated in vitro based on the modified standard disk diffusion method M44-2A.

scholarly journals Microbial Degradation of 2,4-Dichlorophenoxyacetic Acid on the Greenland Ice Sheet

2012 ◽  
Vol 78 (15) ◽  
pp. 5070-5076 ◽  
Author(s):  
Marek Stibal ◽  
Jacob Bælum ◽  
William E. Holben ◽  
Sebastian R. Sørensen ◽  
Anders Jensen ◽  
...  
Keyword(s):  
Microbial Community ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
Dichlorophenoxyacetic Acid ◽  
Total Dna ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Surface Ice ◽  
Pcr Targeting

ABSTRACTThe Greenland ice sheet (GrIS) receives organic carbon (OC) of anthropogenic origin, including pesticides, from the atmosphere and/or local sources, and the fate of these compounds in the ice is currently unknown. The ability of supraglacial heterotrophic microbes to mineralize different types of OC is likely a significant factor determining the fate of anthropogenic OC on the ice sheet. Here we determine the potential of the microbial community from the surface of the GrIS to mineralize the widely used herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). Surface ice cores were collected and incubated for up to 529 days in microcosms simulatingin situconditions. Mineralization of side chain- and ring-labeled [14C]2,4-D was measured in the samples, and quantitative PCR targeting thetfdAgenes in total DNA extracted from the ice after the experiment was performed. We show that the supraglacial microbial community on the GrIS contains microbes that are capable of degrading 2,4-D and that they are likely present in very low numbers. They can mineralize 2,4-D at a rate of up to 1 nmol per m2per day, equivalent to ∼26 ng C m−2day−1. Thus, the GrIS should not be considered a mere reservoir of all atmospheric contaminants, as it is likely that some deposited compounds will be removed from the system via biodegradation processes before their potential release due to the accelerated melting of the ice sheet.

scholarly journals Evaluation of a Novel Mitochondrial Pan-Mucorales Marker for the Detection, Identification, Quantification, and Growth Stage Determination of Mucormycetes

2019 ◽  
Vol 5 (4) ◽  
pp. 98 ◽  
Author(s):  
Rita Caramalho ◽  
Lisa Madl ◽  
Katharina Rosam ◽  
Günter Rambach ◽  
Cornelia Speth ◽  
...  
Keyword(s):  
Growth Stage ◽  
Limit Of Detection ◽  
Fungal Infections ◽  
Large Subunit ◽  
Mucor Circinelloides ◽  
Cross Reactivity ◽  
Clinical Samples ◽  
Species Complexes ◽  
Pure Cultures ◽  
Sensitivity Specificity

Mucormycosis infections are infrequent yet aggressive and serious fungal infections. Early diagnosis of mucormycosis and its discrimination from other fungal infections is required for targeted treatment and more favorable patient outcomes. The majority of the molecular assays use 18 S rDNA. In the current study, we aimed to explore the potential of the mitochondrial rnl (encoding for large-subunit-ribosomal-RNA) gene as a novel molecular marker suitable for research and diagnostics. Rnl was evaluated as a marker for: (1) the Mucorales family, (2) species identification (Rhizopus arrhizus, R. microsporus, Mucor circinelloides, and Lichtheimia species complexes), (3) growth stage, and (4) quantification. Sensitivity, specificity, discriminatory power, the limit of detection (LoD), and cross-reactivity were evaluated. Assays were tested using pure cultures, spiked clinical samples, murine organs, and human paraffin-embedded-tissue (FFPE) samples. Mitochondrial markers were found to be superior to nuclear markers for degraded samples. Rnl outperformed the UMD universal® (Molyzm) marker in FFPE (71.5% positive samples versus 50%). Spiked blood samples highlighted the potential of rnl as a pan-Mucorales screening test. Fungal burden was reproducibly quantified in murine organs using standard curves. Identification of pure cultures gave a perfect (100%) correlation with the detected internal transcribed spacer (ITS) sequence. In conclusion, mitochondrial genes, such as rnl, provide an alternative to the nuclear 18 S rDNA genes and deserve further evaluation.

scholarly journals Prevalence of Adhesion Genes fnbA & fnbB of Staphylococcus aureus Isolated from Dental Patients Attending Dentistry Department of Tehsil Headquarter Hospital Pasrur, Pakistan

2020 ◽  
Vol 1 (4) ◽  
Author(s):  
Muhammad Danish Mehmood ◽  
Huma Anwar Ul-Haq ◽  
Khushbu Farva ◽  
Zuhaib Farooq ◽  
Gul Muhammad Shaikh ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Specific Primers ◽  
Dental Patients ◽  
Gram Staining ◽  
Microbiological Methods ◽  
Highly Sensitive ◽  
Genes Encoding ◽  
Pure Cultures ◽  
Polymerase Chain ◽  
Adhesive Molecules

Introduction: The present study was intended to isolate, characterize and investigate the prevalence of virulence genes encoding fibronectin (fnbA and fnbB) adhesive molecules of S. aureus from dental patients attending outpatient department of THQ Hospital Pasur. Methodology: A total of 100 oral samples were collected from dental patients, pure cultures was segregated and identified through conventional microbiological methods to evaluate the prevalence of S. aureus. Isolates were further characterized by using specific primers for genotype fnbA and fnbB. Results: Results of the study declared that 68 samples were positive (68%) for staphylococcus aureus on the basis of growth on selective media and appearance of typical colonies supported by gram staining. These gram positive staphylococci were positive (86.7%) in coagulase and catalase testing. The results of polymerase chain reaction (PCR) revealed that 47 (69.1%) and 23 (33.8%) isolates showed amplification with type specific primer 23Sr RNA and NUC gene respectively. Furthermore, fnbA and fnbB type specific genes of S. aureus did not show any amplification in PCR reaction. Conclusion: Irrespectively the data in the present study showed the prevalence of S. aureus is significantly high in males and of age group of 20-40 years but no positive result was found for prevalence of fnbA and fnbB genes. All the S. aureus isolates were highly sensitive to vancomycin, linezolid and clindamycin.

scholarly journals Molecular Identification of GemellaSpecies from Three Patients with Endocarditis

1998 ◽  
Vol 36 (4) ◽  
pp. 866-871 ◽  
Author(s):  
Bernard La Scola ◽  
Didier Raoult
Keyword(s):  
Specific Problem ◽  
Rrna Gene ◽  
Gram Negative Bacteria ◽  
Opportunistic Pathogens ◽  
Gram Negative ◽  
Identification Schemes ◽  
Gram Positive Bacteria ◽  
Gram Staining ◽  
Testing Susceptibility ◽  
Severe Infections

Gemella morbillorum and Gemella haemolysansare opportunistic pathogens which cause endocarditis and other severe infections. We report on three patients with endocarditis, one with endocarditis caused by G. haemolysans and two with endocarditis caused by G. morbillorum. The paucity of reports concerning these bacteria is probably related to the difficulties associated with their identification. For example, one of the strains reported in this study was originally sent to our laboratory with a preliminary characterization as a short “gram-negative” coccobacillus, highlighting the specific problem associated with Gram staining of these bacteria. The usefulness of 16S rRNA gene amplification, partial sequencing, and comparison of the nucleotide sequence to those in databases when standard phenotypic identification schemes are not helpful is emphasized. We also suggest that the use of simple tests, such as testing susceptibility to vancomycin for gram-negative bacteria and colistin for gram-positive bacteria, could prevent misinterpretation of Gram staining in gram-variable bacteria such as Gemella spp.

Sign in / Sign up

Export Citation Format

Share Document