Diagnostic, characterisation, epidemiology and zoonotic potential of methicillin-resistant staphylococci (MRSA, MRSP)

Investigation of coagulase-positive staphylococci of animal origin is an important task within our research group. Since the late 70's, nosocomial infections due to methicillin-resistant Staphylococcus aureus (MRSA) have been a major problem in the field of human medicine worldwide. In recent years, methicillin-resistant staphylococci (MRS) such as MRSA and Staphylococcus pseudintermedius (MRSP) have caused a rising awareness in veterinary medicine due to an increase of severe infections in different animal species. In addition, MRS seem to be major pathogens associated with spread of nosocomial infections in veterinary clinics worldwide. Therefore, applied clinical research of MRS infectious diseases is one of the main topics in the working group IME.

Among potential pathogenic bacteria, staphylococci are often more resistant against exsiccation or other uncomfortable environmental circumstances. These bacteria are able to adhere to multiple surfaces, including furniture, medical devices or simply hands. Insufficient hygiene management may allow the spread from contaminated hands or other sources to animal patients. Transferred to wounds or bloodstream, MRS are able to cause severe and life-threatening infections. Apart from resistance against all ß-lactams, MRS are frequently resistant towards several other antibiotic classes, which often results in a very limited panel of chemotherapeutic options for MRS-diseased animal patients.

In warm-blooded animals, staphylococci (including S. aureus and S. pseudintermedius) present a natural part of the microbiota in different hosts, colonizing the skin and mucosal surfaces. Among this bacterial flora, MRS such as MRSA or MRSP have been identified in several healthy individuals (man and animal). However, colonized human or animal carriers of MRS are a potential source of infection for other individuals, and the zoonotic character especially of MRSA should not be underestimated. Therefore, protection of animal owners, veterinary staff and family members is necessary in cases of MRS.

One of the main research areas of our working group IME is the epidemiology of MRS isolates of animal origin. Therefore, detailed molecular characterisation of clinical isolates is inevitable. A wide bundle of typing methods has been established in our institute, including pulsed-field gelelectrophoresis (PFGE), multilocus sequence typing (MLST), microarray hybridisation (MH), spa- and SCCmec typing.

The apparent extended host spectrum of certain MRSA genotypes (EHSG) is a further focus topic of our current research activities, including strains from human and various animal origins. Our work intends to raise the awareness of MRS in veterinary medicine and supports the development of hygienic recommendations to prevent nosocomial and/or zoonotic spread of MRSA in veterinary medicine.



Ruscher, C., Lübke-Becker, A., Semmler, T., Wleklinski, C.G., Paasch, A., Soba, A., Stamm, I., Kopp, P.,     Wieler, L.H., Walther, B., 2010, Widespread rapid emergence of a distinct methicillin- and multidrug-resistant Staphylococcus pseudintermedius (MRSP) genetic lineage in Europe. Vet. Microbiol. 144, 340-346.

Cuny, C., Friedrich, A., Kozytska, S., Layer, F., Nübel, U., Ohlsen, K., Strommenger, B., Walther, B., Wieler, L., Witte, W., 2010, Emergence of methicillin-resistant Staphylococcus aureus (MRSA) in different animal species. Int. J. Med. Microbiol. 300, 109-117.

Walther, B., Grobbel, M., 2009, Nosokomiale Infektionen in der Kleintierpraxis. Kleintierpraxis 54, 33-42.

Ruscher, C., Lübke-Becker, A., Wleklinski, C.G., Soba, A., Wieler, L.H., Walther, B., 2009, Prevalence of Methicillin-resistant Staphylococcus pseudintermedius isolated from clinical samples of companion animals and equidaes. Vet. Microbiol. 136, 197-201.

Walther, B., Lübke-Becker, A., Wieler, L.H., 2008a, Methicillin-resistente Staphylococcus aureus (MRSA): Die Renaissance der Wundinfektion. Leipziger Blaue Hefte (LBH) Proceedings 4. Leipziger Tierärztekongress.

Walther, B., Monecke, S., Ruscher, C., Friedrich, A.W., Ehricht, R., Slickers, P., Soba, A., Wleklinski, C.G., Wieler, L.H., Lübke-Becker, A., 2009a, Comparative molecular analysis substantiates a zoonotic potential of equine Methicillin- resistant Staphylococcus aureus (MRSA). J. Clin. Microbiol.47, 704-710.

Walther, B., Wieler, L.H., Friedrich, A.W., B., K., Brunnberg, L., Lübke-Becker, A., 2009b, Staphylococcus aureus and MRSA colonization rates among personnel and dogs in a small animal hospital: Effect on nosocomial infections. Berl. Münch. Tierarztl. Wochenschr. 122, 178–185.

Walther, B., Lübke-Becker, A., Wieler, L.H., 2008b, Wundinfektionen durch methicillinresistente Staphylococcus spp.(MRS) bei Kleintieren und Pferden: klin. Bedeutung, Therapie und Prophylaxe. Tierärztliche Praxis: Ausgabe K, Kleintiere, Heimtiere 36, 5-10.

Walther, B., Wieler, L.H., Friedrich, A.W., Hanssen, A.M., Kohn, B., Brunnberg, L., Lübke-Becker, A., 2008c, Methicillin-resistant Staphylococcus aureus (MRSA) isolated from small and exotic animals at a university hospital during routine microbiological examinations. Vet. Microbiol. 127, 171-178.

Walther, B., Wieler, L.H., Kohn, B., Brunnberg, L., Lübke-Becker, A., 2006, Occurence and clonal spread of Methicillin-resistant Staphylococcus aureus (MRSA) in a small animal hospital (articel in German). Berliner und Münchener Tierärztliche Wochenschrift (BMTW).

Friedrich, A.W., Friedrich, K.G., Walther, B., Lübke-Becker, A., Wieler, L.H., 2004, Methicillin resistent Staphylococcus aureus infections in a modern animal hospital - professional infection management (articel in German). Praktischer Tierarzt 85, 742-747.