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An ex vivo porcine nasal mucosa explants model to study MRSA colonization
Pawel Tulinski1, Ad C Fluit, Jos P M van Putten
1Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
Abstract:
Staphylococcus aureus is an opportunistic pathogen able to colonize the upper respiratory tract and skin surfaces in mammals. Methicillin-resistant S. aureus ST398 is prevalent in pigs in Europe and North America. However, the mechanism of successful pig colonization by MRSA ST398 is poorly understood. To study MRSA colonization in pigs, an ex vivo model consisting of porcine nasal mucosa explants cultured at an air-liquid interface was evaluated. In cultured mucosa explants from the surfaces of the ventral turbinates and septum of the pig nose no changes in cell morphology and viability were observed up to 72 h. MRSA colonization on the explants was evaluated followed for three MRSA ST398 isolates for 180 minutes. The explants were incubated with 3×10(8) CFU/ml in PBS for 2 h to allow bacteria to adhere to the explants surface. Next the explants were washed and in the first 30 minutes post adhering time, a decline in the number of CFU was observed for all MRSA. Subsequently, the isolates showed either: bacterial growth, no growth, or a further reduction in bacterial numbers. The MRSA were either localized as clusters between the cilia or as single bacteria on the cilia surface. No morphological changes in the epithelium layer were observed during the incubation with MRSA. We conclude that porcine nasal mucosa explants are a valuable ex vivo model to unravel the interaction of MRSA with nasal tissue.
Insights
This study introduces a new ex vivo model using pig nasal tissue to investigate how Methicillin-resistant Staphylococcus aureus ST398 colonizes pigs. The model effectively shows MRSA interactions with nasal surfaces without damaging tissue.
Area of Science:
- Veterinary Microbiology
- Pathogen Colonization Studies
- Mammalian Host-Pathogen Interactions
Background:
- Staphylococcus aureus, particularly Methicillin-resistant S. aureus (MRSA) ST398, is a significant pathogen in livestock.
- MRSA ST398 is widespread in pigs, but the mechanisms of its colonization in this host are not well understood.
- Understanding pig colonization is crucial for controlling MRSA transmission and public health.
Purpose of the Study:
- To evaluate an ex vivo model of porcine nasal mucosa for studying MRSA ST398 colonization.
- To characterize the interaction between MRSA ST398 and the porcine nasal epithelium.
- To provide a suitable model for investigating MRSA colonization mechanisms in pigs.
Main Methods:
- Utilized porcine nasal mucosa explants cultured at an air-liquid interface.
- Exposed explants to MRSA ST398 isolates (3×10^8 CFU/ml) for adherence and colonization assessment.
- Monitored bacterial viability (CFU counts) and localization on explants over time (up to 180 minutes).
- Assessed tissue morphology and cell viability using microscopy.
Main Results:
- Porcine nasal mucosa explants maintained structural integrity and cell viability for up to 72 hours.
- MRSA ST398 exhibited varied growth dynamics (growth, no growth, decline) post-adherence.
- Bacteria localized as clusters or single cells on cilia; no epithelial damage was observed.
- Initial bacterial numbers decreased within 30 minutes post-adherence.
Conclusions:
- Porcine nasal mucosa explants provide a stable and relevant ex vivo model for MRSA colonization studies.
- The model facilitates detailed investigation of MRSA interactions with the porcine nasal environment.
- This approach is valuable for unraveling the mechanisms of MRSA ST398 colonization in pigs.
