Preventing transmission of MRSA from livestock to humans through competitive exclusion
Pig farms act as reservoir of Livestock-Associated Methicillin-resistant Staphylococcus aureus (LA-MRSA). Through occupational exposure to farm dust and contact with pigs, farm workers are at risk for acquiring LA-MRSA. Although health care institutions can cope with the current situation, it is a burden for patients, health care staff, and finances. In addition, the recent observed adaptation of LA-MRSA originating from pigs to humans in Denmark further highlights the need to reduce LA-MRSA colonization in pigs and subsequent transmission to humans. In a pilot study of the nasal microbiome we observed that piglets become LA-MRSA positive after a few days of birth. The presence of several other bacterial species, including coagulase-negative staphylococci was negatively associated with the presence of LA-MRSA. More evidence is needed regarding which bacterial species and/or strains compete with LAMRSA. The project aims to establish the effect of colonization resistance (bacterial competition) on the transmission of LA-MRSA from pigs to humans by i) identifying bacterial species that compete with LA-MRSA (S. aureus in general) in a systematic way using state of the art bioinformatics and metagenomics methods at strain level, ii) studying the efficacy of applying a nasal microflora for piglets which will be produced under GMP conditions by the industrial partner in the project and tested under field conditions at conventional farms, and iii) to estimate the risk reduction as a result from limiting MRSA transmission to humans by reducing shedding and consequently a more limited environmental contamination. Communication with farmers, veterinarians, public health workers and other stakeholders, with the help of our supporting organizations, will prepare the stakeholders for the outcome of the project, bringing it close to immediate use in practice. ExcludeMRSA will deliver a reduction of MRSA colonization or will lead to complete prevention of MRSA colonization by precolonization of piglets with microflora. The efficacy will be assessed in two countries by using proven environmental risk models for human exposure and evaluating changes in the exposure risk association. Because of the earlier performed successful pilot studies, the experience of the partners and the inclusion of an industrial partner experienced in production of live strains, this project is feasible in three years’ time.
- Jaap Wagenaar, Utrecht University, Netherlands (Coordinator)
- Marcus Claesson, University College Cork, Ireland (Partner)
- Peadar Lawlor, Teagasc Environmental Research Centre, Ireland (Partner)
- Dick Heederik, University Medical Centre Utrecht, Netherlands (Partner)
- Christian Elend, EW Nutrition GmbH, Germany (Partner)
Pig farms act as reservoir of Livestock-Associated Methicillin-resistant Staphylococcus aureus (LA-MRSA). Through occupational exposure, farm workers are at risk for acquiring LA-MRSA. In countries with low-prevalent health care associated MRSA and community acquired MRSA, LA-MRSA adds considerably to the MRSA-burden for patients, health care staff, and finances. The recent observed adaptation of LA-MRSA to humans in Denmark highlights the need to reduce LA-MRSA colonization in pigs. The project aims to establish the effect of colonization resistance on the transmission of LA-MRSA from pigs to humans by i) identifying bacterial species that compete with LA-MRSA, ii) studying the efficacy of applying a nasal microflora for piglets, and iii) to estimate the risk reduction for MRSA transmission to humans due to a reduced shedding and environmental contamination. Currently, we analyzed our pilot study data in which the nasal microbiome of piglets was followed over a period of 42 days. We detected in total 15 bacterial species negatively correlated with Staphylococcus aureus and/or MRSA colonization. Because samples were not collected for culturing in the pilot, it functions primarily as a method to determine which timepoint is optimal to find competing bacteria. We completed the sampling phase of the full study and these samples are being analyzed. The strains will be isolated from samples of the investigated piglets. We will produce a nasal microflora carrying a mix of competing micro-organisms that will either prevent or strongly reduce colonization of MRSA in piglets. Finally we will use this microflora in a farm setting, the level of colonization of MRSA will be tracked in treated and untreated animals to assess the reduction in spread.
- Irish Veterinary Journal, 2021. Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) prevalence in humans in close contact with animals and measures to reduce on-farm colonisation
- mSystems, 2021. Differential Analysis of Longitudinal Methicillin-Resistant Staphylococcus aureus Colonization in Relation to Microbial Shifts in the Nasal Microbiome of Neonatal Piglets