Optimization of a Staphylococcus aureus adhesion assay for equine corneocytes.
Abstract: Meticillin-resistant Staphylococcus aureus (MRSA) causes serious skin and soft-tissue infections of humans and animals. Multiple strains of MRSA have been characterized, and one in particular, designated as strain USA 500, causes infections predominantly of horses and the people who work with them. The purpose of this study was to optimize an assay which could subsequently be used to compare the relative avidity of different S. aureus strains for equine corneocytes. Corneocytes were collected from the perineal skin of 10 healthy horses onto adhesive discs. The discs were then incubated at 37°C with an S. aureus field strain at each of three concentrations [10(7), 10(8) and 10(9) colony forming units (CFU)/mL] and for each of three incubation periods (45, 90 and 180 min). After standardized rinsing and staining procedures, discs were examined at ×1,000 magnification and areas containing confluent corneocytes photographed. The percentage of surface area occupied by adherent bacteria was analysed using image processing and analysis software. Significant colour space image processing was required to distinguish bacteria from the ubiquitous melanin granules present within equine corneocytes. Objective and subjective methods were used to determine optimal conditions for specific adherence without introducing confounding factors. A bacterial concentration of 10(8) CFU/mL incubated with corneocytes for 45 min produced maximal bacterial adhesion with the least amount of interbacterial clumping. Future studies should utilize these conditions for optimal assay performance.
© 2011 The Authors. Veterinary Dermatology © 2011 ESVD and ACVD, Veterinary Dermatology.
Publication Date: 2011-10-13 PubMed ID: 21992593PubMed Central: PMC3253182DOI: 10.1111/j.1365-3164.2011.01012.xGoogle Scholar: Lookup
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- Journal Article
- Research Support
- N.I.H.
- Extramural
Summary
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This study focuses on optimizing an assay that could be used in examining the relative avidity (attraction) of different strains of Staphylococcus aureus bacteria towards equine corneocytes (cells on the surface layer of the skin). The main strain under study is dubbed USA 500, known to cause infections in horses and their handlers.
Methodology
- The researchers collected corneocytes from the perineal skin of 10 healthy horses using adhesive discs.
- These discs were incubated at 37°C with a field strain of S. aureus at three different concentrations [10(7), 10(8), and 10(9) CFU/mL] and for three different incubation periods (45, 90, and 180 min).
- After certain rinsing and staining procedures, discs were examined under magnification and areas that had corneocytes clumped together were photographed.
- The percentage of surface area occupied by adherent bacteria was then analyzed using image processing and analysis software with significant color space image processing needed to discriminate bacteria from the regularly present melanin granules in equine corneocytes.
Findings
- Through objective and subjective methods, the researchers identified optimal conditions for specific bacterial adhesion without introducing confounding factors.
- The results suggested that a bacterial concentration of 10(8) CFU/mL incubated with corneocytes for 45 minutes produced maximum bacterial adhesion with minimal interbacterial clumping.
Implication of the Study
- The findings will be instrumental in fine-tuning the assay performance for future research work. Researchers could employ these conditions to effectively study the propensity of various S. aureus strains in adhering to equine corneocytes, which could help inform better treatment strategies for infections caused by this bacteria, particularly in horses and their handlers.
Cite This Article
APA
Griffeth GC, Callori N, Rankin SC, Boston RC, Morris DO.
(2011).
Optimization of a Staphylococcus aureus adhesion assay for equine corneocytes.
Vet Dermatol, 23(1), 57-e13.
https://doi.org/10.1111/j.1365-3164.2011.01012.x Publication
Researcher Affiliations
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, 3900 Delancey Street, Philadelphia, PA 19104, USA.
MeSH Terms
- Animals
- Bacterial Adhesion
- Biological Assay / veterinary
- Female
- Horses / microbiology
- Male
- Skin / cytology
- Staphylococcus aureus / physiology
Grant Funding
- R21 AI073328 / NIAID NIH HHS
- T35 OD010919 / NIH HHS
Conflict of Interest Statement
Conflict of interest: No conflicts of interest have been declared
References
This article includes 10 references
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Citations
This article has been cited 2 times.- Roy P, Horswill AR, Fey PD. Glycan-Dependent Corneocyte Adherence of Staphylococcus epidermidis Mediated by the Lectin Subdomain of Aap. mBio 2021 Aug 31;12(4):e0290820.
- Butler TE, Lee AJ, Yang Y, Newton MD, Kargupta R, Puttaswamy S, Sengupta S. Direct-from-sputum rapid phenotypic drug susceptibility test for mycobacteria. PLoS One 2020;15(8):e0238298.
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