Livestock-MRSA in Danish Pig Farms

Abstract

This study looks at factors contributing to LA-MRSA prevalence in Danish pig farms. LA-MRSA is a pathogenic bacteria that are resistant to methicillin (penicillin) and tetracycline antibiotics found in livestock such as pigs, poultry and cattle. By using logistic regression analysis, this study investigates which factors that might have increased the likelihood of having a positive LA-MRSA result in 2010-2011 (n=176 farms). The model consisted of both spatial and in-herd parameters including: average nearest distance to other farms, pig movement, use of antibiotics and zinc oxide, herd size and production systems. These were set against results from the first Danish cross sectional screening of LA-MRSA in pig herds, during 2010-2011. The results from the logistic regression only showed a modest connection between pig movement (the number of different farms sending pigs to a particular holding) while the other parameters were insignificant and did not indicate increased likelihood.

Popular Abstract

Antibiotic resistance has been described as one of the most staggering public health crisis. Industrial farming has been linked to the emergence of resistant bacteria – especially in counties with a large scale pig production. This study looks into what factors that contributed to resistant bacteria in Danish pig farms.
Livestock-associated Methicillin-resistant Staphylococcus Aureus (LA-MRSA) is a bacteria that causes skin infections in animals and humans. If the bacterium is transmitted to people or animals with reduced immune systems, it can lead to severe and even deadly infections. During the last decade, LA-MRSA has become a major concern worldwide. Pigs are the primary hosts and a particular type of LA-MRSA (CC398) is most predominant in countries with a large-scale pig production.
Denmark is the largest pig producer in the EU per capita and has experienced a dramatic increase in LA-MRSA. The first major Danish screening in 2010-11, found LA-MRSA in 16% of all pig herds. In the most recent screening of 2016, 88% were LA-MRSA positive. Even though most farms are infected at this stage, it is important to trace the onset to prevent similar outcomes in other countries.
What might behind early LA-MRSA onset?
This study tries to find out what made certain farms more vulnerable to LA-MRSA, already back in 2010-11. By comparing the use of antibiotic and zinc oxide, the size and type of farms, distance to other farms and how often pigs were moved - this study tries to figure out what might be behind an early positive result. The statistical method logistic regression was used to see which one of these factors that made it more likely to have a positive LA-MRSA result.
What the study showed
The outcome from the analysis showed rather weak results. Surprisingly enough, none of the previously established factors such as use of antibiotics or type of farm (organic – conventional) contributed to a positive result. The only variable that pointed towards a slight increase in likelihood, was how many senders of pigs a tested farms had. This link has been confirmed in other studies and could be an interesting factor to study in relation to the onset and spread in other pig producing countries.

• author: Tykesson Klubien, Mona
• supervisor: Ali Mansourian
• organization: Dept of Physical Geography and Ecosystem Science
• course: GISM01 20212
• year: 2021
• type: H2 - Master's Degree (Two Years)
• subject: Earth and Environmental Sciences
• keywords: GIS, epidemiology, MRSA, Denmark, pig production, logistic regression
• publication/series: Master Thesis in Geographical Information Science
• report number: 135
• language: English
• id: 9067683
• date added to LUP: 2021-11-09 09:18:53
• date last changed: 2021-11-09 09:18:53