LA-MRSA in cows

LA-MRSA is the acronym for "Livestock-associated MRSA ", where MRSA stands for methicillin-resistant Staphylococcus aureus, a species of MRSA that is associated with conventional animal fattening. This includes humans in close working contact with these animals (especially pigs, but also cattle for fattening and poultry for fattening) (Layer et al. 2012). In horse husbandry, for example, it is primarily CA-MRSA that appear to be a problem.

Ruminants: As early as the 1970s, MRSA was detected in a dairy cow with mastitis, the first case of MRSA in veterinary medicine in connection with farm animals (Devriese et al. 1972). Staphylococcal mastitis is one of the most important infectious diseases in cattle farming worldwide, the main pathogen being S. aureus. MRSA has been detected in ruminants throughout Europe in recent years. In Belgium, MRSA could be isolated in dairy herds in up to 15 % of the examined cattle, the isolates belonged to MLST 398. MRSA could also be detected in tank milk samples . In 118 S. aureus from tank milk samples, 11 (9.3%) MRSA could be isolated via detection of mecA and antibiotic testing (Vanderhaeghen et al. 2010). In the Asian region, however, a study as early as 2003 was able to isolate MRSA in 75% of their milking samples tested (Lee, 2003). The transmission of MRSA to humans working with the animals can also be demonstrated and supported with studies, for example, Hungarian investigations of MRSA positive cattle and a likewise positive farm employee, showed the same spa type t127 (associated with ST1) in all isolates. In the investigation of 17 cattle farms, MRSA ST 398 were isolated in both cattle and farm workers.

The MRSA belonged to the three spa types t011, t034 and t2576 and SCCmec IV and V (Fessler et al. 2010). Finally, high detection rates were also obtained in Holland in veal calves and the families of farmers belonging to the farms. Herd prevalence was 88% and 33% of farmers and 8% family members had MRSA genetically identical isolates (ST398, t011 and t034). However, adequate hygiene management was associated with lower prevalence and, in contrast, an increase in prevalence when animals were pretreated with antibiotics (Graveland et al. 2010). In relation to the risk of MRSA carriage in calves, attention is drawn to the link between antibiotic use and MRSA status. They had emphasized group treatments with antibiotics as one of the risk factors for MRSA carriage in a study of 102 farms in the Netherlands. However, it is not only herd employees or their families living on the farm who are at risk of being exposed to MRSA, but also visitors. By visiting a MRSA positive calf farm, the risk of acquiring MRSA as a temporary carrier exists (van Cleef et al. 2011). MRSA could not only be associated with cattle themselves. Also in Germany, a spread into the food chain seems to be possible. MRSA of the clonal complex CC398 were found, for example, in collected tank milk samples from German farms (Kreausukon et al. 2012).

1. Fessler A et al.(2010). Characterization of methicillin-resistant Staphylococcus aureus ST398 from cases of bovine mastitis. The Journal of antimicrobial chemotherapy 65, 619-625.
2. Ferreira JP et al.(2011) Transmission of methicillin-resistant Staphylococcus aureus between human and hamster. Journal of Clinical microbiology 49, 1679-1680.
3. Graveland H et al.(2010) Methicillin-resistant Staphylococcus aureus ST398 in veal calf farming: human MRSA carriage related with animal antimicrobial usage and farm hygiene. PloS one: 5 e10990.
4. Kreausukon K et al.(2012) Prevalence, antimicrobial resistance, and molecular characterization of methicillin-resistant Staphylococcus aureus from bulk tank milk of dairy herds. Journal of dairy science 95: 4382-4388.
5. Layer F et al.(2012) Current data and trends on methicillin-resistant Staphylococcus aureus (MRSA)]. Bundesgesundheitsblatt health research, health protection 55: 1377-1386.
6. Lee JH 2003. methicillin (oxacillin)-resistant Staphylococcus aureus strains isolated from major food animals and their potential transmission to humans. Applied and environmental microbiology 69, 6489-6494.
7. Loeffler A et al.(2010). Companion animals: a reservoir for methicillin-resistant Staphylococcus aureus in the community? Epidemiology and infection 138: 595-605.
8. Sunde M et al.(2011) Detection of methicillin-resistant Staphylococcus aureus sequence type 8 in pigs, production environment, and human beings. Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc 23: 348-350.
9. van Cleef BA et al.(2011) Persistence of livestock-associated methicillin-resistant Staphylococcus aureus in field workers after short-term occupational exposure to pigs and veal calves. Journal of clinical microbiology 49, 1030-1033.
10. Vanderhaeghen W et al (2010). Methicillin-resistant Staphylococcus aureus (MRSA) ST398 associated with clinical and subclinical mastitis in Belgian cows. Veterinary microbiology 144: 166-171.
11. Voss A et al .(2007). Emergence of methicillin-resistant Staphylococcus aureus of animal origin in humans. Emerging infectious diseases 13, 1834-1839.