Methicillin-resistant Staphylococcus aureus (MRSA): not detected from chickens, but present on retai
Methicillin-resistant Staphylococcus aureus, called MRSA, is an important health issue, which can cause a variety of conditions ranging from superficial skin infection to very severe infections impairing different organs. These bacteria are resistant to all antibiotics in the beta-lactam family, posing an additional challenge for the treatment of infected people and animals.
Globally, public and animal health experts study these MRSAs in both humans and animals in order to characterize and compare them. Furthermore, these experts assess the risk of colonization of those bacteria in different animal species and follow their antibiotic resistance profiles and find out if the situation is improving or worsening.
Humans usually get infected through contamination in their community or through a stay in health services. Much more rarely, contamination is associated with animals through direct contact or following the handling of meat. In Germany and Canada, pig farmers have been shown to carry porcine MRSA in their respiratory tract without being sick. The presence of MRSA in pigs is recognized worldwide.
Several studies show that in farm animals, MRSA is believed to originate from human contamination, and that these bacteria have then genetically adapted to their new animal host. In order to estimate the health risk posed by poultry industry, an interuniversity team from CRIPA wanted to estimate the prevalence of MRSA in chicken farms in Quebec. In 2014, samples from 200 broilers from 38 farms were taken over a 9-month period. In addition, 309 samples of poultry meat from food businesses in Montérégie were collected over a period of 6 months in 2013. No chicken was detected carrying the MRSA bacteria. On the other hand, 4 samples of chicken meat were contaminated by two different types of MRSA, one of animal origin in three food retailers and one of human origin in another shop, suggesting contamination during slaughter or meat processing. The prevalence of MRSA in chicken meat in Quebec has been estimated at 1.3%, similar to the prevalence in several European countries and the USA.
Following guidance of Professors Marie Archambault, expert in antimicrobial resistance, and François Malouin, expert in genetics of MRSA, the team checked if the genetic profile of MRSA is consistent with their ability to resist various antibiotics, and to form biofilms. Biofilms are populations of bacteria that multiply in a protective gel. These biofilms can, among other things, adhere to the surface of equipment used in the food industry, and constitute an asset for the persistence of the bacteria. Yet, the 2 types of MRSAs isolated from poultry meat are capable of forming biofilms. Efforts must therefore continue to limit the risk of contamination of meat in the food industry.
Source: PLoS ONE. 2020; 15(1):e0227183. Prevalence and characteristics of Livestock-Associated Methicillin-Resistant Staphylococcus aureus (LA-MRSA) isolated from chicken meat in the province of Quebec, Canada. Bernier-Lachance J, Arsenault J, Usongo V, Parent É, Labrie J, Jacques M, Malouin F, Archambault M. doi: 10.1371/journal.pone.0227183. eCollection 2020.
