Related Experiment Video
Updated: May 11, 2026
Microtiter Dish Biofilm Formation Assay
Published on: January 30, 2011
Characterization of the biofilm forming ability of Staphylococcus pseudintermedius from dogs
Ameet Singh1, Meagan Walker, Joyce Rousseau
1Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada. amsingh@uoguelph.ca
Background:
Staphylococcus pseudintermedius is an opportunistic pathogen of dogs and has emerged as a leading cause of skin, wound and surgical site infections worldwide. Methicillin resistance is common and clinical infections as a result of methicillin-resistant S. pseudintermedius (MRSP) pose a clinical challenge. In other staphylococci, biofilm formation has been shown to be a virulence factor for infection, however, it has received little attention in S. pseudintermedius. The objectives of this study were to evaluate the biofilm forming ability of clinical isolates of S. pseudintermedius obtained from dogs using phenotypic and genotypic techniques.
Results:
96% (136/140) of S. pseudintermedius isolates were classified as strong or moderate biofilm producers, with the majority of isolates being able to produce biofilm. There was no difference in biofilm formation between MRSP and MSSP (p=0.8), amongst isolates from clinical infections compared with isolates obtained from colonized dogs (p=0.08), and between isolates from sequence type (ST) 71 and ST 68 (P=0.09). icaA was detected in 77.9% (109/140) of isolates and icaD was detected in 75.7% (106/140) of isolates. Scanning electron microscopic evaluation of S. pseudintermedius biofilm production revealed aggregates of cocci and irregularly produced extracellular polymeric matrix.
Conclusion:
The majority of S. pseudintermedius isolates evaluated in this study were able to produce biofilm and this may be an important virulence factor in the rapid emergence of this bacterium in veterinary hospitals worldwide. Further study into the mechanisms of biofilm formation by S. pseudintermedius is warranted.
Insights
Most dog Staphylococcus pseudintermedius isolates form biofilms, a potential virulence factor contributing to infections. This study investigated biofilm production in clinical isolates using various methods.
Area of Science:
- Veterinary Microbiology
- Bacterial Pathogenesis
- Infectious Diseases
Background:
- Staphylococcus pseudintermedius is a common opportunistic pathogen in dogs, causing various infections.
- Methicillin-resistant S. pseudintermedius (MRSP) presents a significant clinical challenge.
- Biofilm formation, a known virulence factor in other staphylococci, has been understudied in S. pseudintermedius.
Purpose of the Study:
- To evaluate the biofilm-forming capacity of clinical S. pseudintermedius isolates from dogs.
- To utilize both phenotypic and genotypic methods to assess biofilm production.
Main Methods:
- Phenotypic assessment of biofilm production in 140 S. pseudintermedius isolates.
- Genotypic analysis for the presence of biofilm-associated genes (icaA, icaD).
- Scanning electron microscopy (SEM) for visualizing biofilm structure.
Main Results:
- 96% of isolates demonstrated strong or moderate biofilm production.
- No significant difference in biofilm formation was observed between MRSP and methicillin-susceptible S. pseudintermedius (MSSP).
- Genes icaA and icaD were detected in 77.9% and 75.7% of isolates, respectively; SEM revealed bacterial aggregates and extracellular matrix.
Conclusions:
- The majority of S. pseudintermedius isolates possess the ability to form biofilms.
- Biofilm production may be a crucial virulence factor in the increasing prevalence of S. pseudintermedius infections in veterinary settings.
- Further research into the mechanisms of S. pseudintermedius biofilm formation is recommended.
Related Concept Videos
01:25Clinical Significance of Antibiotic Resistance
01:29Biofilms