Methicillin‐Resistant Staphylococcus aureus (MRSA) in Three Dairy Herds in Southwest Germany

Abstract

The objective of this study was to analyse the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) in three dairy herds in the southwest of Germany that had experienced individual cases of clinical and subclinical mastitis associated with MRSA. The herds were identified by the detection of MRSA during routine resistance testing of mastitis pathogens. All quarters of all cows in the herds that were positive on California Mastitis Test were sampled for bacteriological analysis on two occasions. Bulk tank milk samples were also tested. Furthermore, nasal swabs were collected from people working on the farms and from cattle. Environmental samples were collected from associated pig holdings. Isolates were characterized using spa-typing and testing for antimicrobial resistance. Our results revealed a substantial spread of MRSA in the three dairy herds. In the first of the two investigations carried out on all cows in the three herds, milk samples of 5.1-16.7% of dairy cows were found positive for MRSA. The respective proportions in the second herd level investigation were 1.4-10.0%. Quarters harbouring MRSA had higher somatic cell counts than quarters that were negative on culture. Methicillin-resistant Staphylococcus aureus were also detected in nasal swabs of staff (7/9), cows (7/15) and calves (4/7), bulk tank milk samples (3/3) and environmental samples from pig premises (4/5) on the farm. Herds B and C had no contact to herd A. However, in all three herds MRSA of spa-type t011 were detected in milk samples. Results show that MRSA of spa-type t011 is a problem in dairy farms that needs urgent attention.

Outbreak of Staphylococcal Food Poisoning Due to SEA-ProducingStaphylococcus aureus

“…FT-IR allowed for rapid species identification of S. aureus isolates (Spohr et al, 2011). For this purpose, bacterial isolates were cultivated on sheep blood agar plates (Oxoid) at 37°C for 24 h. Sample preparation, FT-IR spectroscopy (using IFS 28/B spectrometer, BrukerOptics, Ettlingen, Germany) and data acquisition were performed as described previously (Kuhm et al, 2009).…”

“…4.2, BrukerOptics) and an artificial neural network built by the NeuroDeveloper software (Synthon, Heidelberg, Germany). The differentiation of S. aureus was performed with a method described previously (Spohr et al, 2011).…”

Methicillin-Resistant Staphylococcus Aureus (MRSA) in Cattle: Epidemiology and Zoonotic Implications

“…Spohr et al (2011) found MRSA in 5 out of 7 cows and in 4 out of 7 calves from nasal swabs in Germany. Huber et al (2010) reported 3 MRSA isolates from nasal swabs of 300 calves.…”

“…S. aureus inoculum is prepared by diluting 0.5 McFarland equivalent suspension of a strain with sterile normal saline to the concentration of 104 CFU/ml. The plates are spot inoculated and incubated at 35 °C for 24 h. An oxacillin MIC of less than or equal to 2 μg/ml is indicative of susceptible and that of > 2 μg/ml resistant (CLSI, 2007 (Spohr et al, 2011) and0.4% in Hungary (Juhasz-Kaszanyitzky, 2007). In a recent study by Paterson et al (2012) (Makovec and Ruegg, 2003) and 4% in Minnesota (Haran et al, 2012) has been reported.…”

Methicillin-Resistant Staphylococcus aureus (MRSA) in Food- Producing and Companion Animals and Food Products

“…Recently, another group of LA-MRSA strains (CC130, CC425, and CC1943) that were initially thought to be bovine-speciic lineages emerged in humans [101]. A number of multidrugresistant MRSA were isolated from bovine mastitis in Germany [97,102], the majority of which were MRSA ST398 related to animal strains, but an isolate of the clonal complex group CC8 was identiied as a human epidemic MRSA strain Irish-01 [103]. In 2010, Hata et al irst discovered MRSA in cow's milk in Japan and the genotypes (ST5-SCCmec II) were the same as or similar to human strains [104].…”