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Updated: Jul 29, 2026
Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria
Published on: May 8, 2013
Findings and measures to eradicate methicillin resistant Staphylococcus aureus clonal complex 7 spa-type t091 in two
O M Karlsen1, K D Sandbu2, C A Grøntvedt3
1Nortura, Pb 360, Økern, 0513, Oslo, Norway. odd.magne.karlsen@nortura.no.
Background:
The Norwegian LA-MRSA surveillance and control strategy in pig farms has been largely successful in preventing the establishment of MRSA in the pig population by identifying positive pig herds and eradicating MRSA from these. It can, however, be challenging to determine whether a particular type of MRSA is livestock-associated, particularly in cases where there is little evidence available to aid in classification.
Case Presentation:
In two Norwegian pig farms linked by trade of live pigs, MRSA CC7 t091 was found in samples from pigs and their environment. Longitudinal sampling, with a time interval of 25 days, in one farm demonstrated an increase in samples positive for MRSA CC7 t091, supporting a classification of the finding as livestock associated. Measures to eradicate MRSA from both farms were imposed by the National Food Safety Authority. Different measures of MRSA sanitation were applied in the two farms, and MRSA was successfully eradicated from both farms.
Conclusions:
A high-cost, labor intensive and a lower-cost, less labor intensive MRSA eradication protocol, both including total depopulation and repopulation were successful in eradicating MRSA CC7 t091 from two case farms.
Insights
Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) was eradicated from two pig farms using depopulation and repopulation strategies. Both high- and low-cost protocols successfully eliminated MRSA CC7 t091.
Area of Science:
- Veterinary Microbiology
- Public Health
- Epidemiology
Background:
- The Norwegian strategy for controlling livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) in pigs has been effective.
- Classifying MRSA strains as livestock-associated can be challenging without sufficient evidence.
Purpose of the Study:
- To investigate the eradication of a specific MRSA strain (CC7 t091) identified in two linked Norwegian pig farms.
- To evaluate the effectiveness of different eradication protocols for LA-MRSA in swine.
Main Methods:
- MRSA CC7 t091 was detected in pigs and environmental samples from two interconnected farms.
- Longitudinal sampling confirmed an increase in MRSA presence, supporting a livestock-associated classification.
- The National Food Safety Authority mandated MRSA eradication, employing distinct sanitation measures on each farm.
Main Results:
- MRSA CC7 t091 was successfully eradicated from both pig farms.
- Two distinct eradication protocols, one high-cost/labor-intensive and one lower-cost/less labor-intensive, were both effective.
- Both protocols involved total depopulation and repopulation of the farms.
Conclusions:
- Total depopulation and repopulation are effective strategies for eradicating LA-MRSA from pig farms.
- Both intensive and less intensive eradication protocols achieved successful MRSA elimination.
- The study demonstrates successful control of MRSA CC7 t091 in a challenging epidemiological scenario.
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