Methicillin-resistant Staphylococcus aureus ST398 in humans and animals, Central Europe.(RESEARCH)(Clinical report)

Methicillin-resistant Staphylococcus aureus of clonal lineage ST398 that exhibits related spa types and contains SCCmec elements of types IVa or V has been isolated from colonized and infected humans and companion animals (e.g., dog, pig, horse) in Germany and Austria. Of particular concern is the association of these cases with cases of nosocomial ventilator-associated pneumonia.

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Methicillin-resistant Staphylococcus aureus (MRSA) has become an infection control problem in hospitals worldwide, mainly associated with intrahospital and interhospital dissemination of particular epidemic clonal lineages of the S. aureus population (hMRSA; [1]). MRSA primarily associated with healthcare facilities may also be disseminated to the community through colonized medical staff or discharged patients. The emergence and spread of MRSA in the community during the past 5 years, independent of the healthcare setting and in the absence of typical risk factors for nosocomial MRSA infections, are matters of further concern. These community-acquired MRSA infections are less broadly resistant to antimicrobial agents than are healthcare-associated MRSA and often contain the determinants lukS-lukF, which code for Panton-Valentine leukocidin (2).

Even though MRSA has been known as a nosocomial pathogen for >30 years, its development in companion animals and livestock has been rare (3). Recent reports, however, have documented MRSA infections in animals such as horses from Canada (4) and Europe (3) and pets (5,6). Of particular interest is whether MRSA may be transmitted between animals and humans. MRSA of clonal lineage sequence type (ST) 22 is widely disseminated in human hospitals in the United Kingdom and Central Europe. The demonstration of this lineage among MRSA isolates from staff and from pets in a small animal referral hospital in United Kingdom suggests transmission between humans and animals (5). Nasal colonization of veterinary staff with MRSA (ST8) from infections in horses in a veterinary hospital was frequently observed in Canada (4), and it was also recorded in an Austrian university veterinary hospital where horses were affected by MRSA of clonal lineage ST254 (3).

We report on molecular characterization of MRSA, from sporadic infections in humans and in various animal species, that belong to clonal lineage ST398 according to multilocus sequence typing (MLST). These isolates were further characterized by spa-sequence typing (repeat polymorphism of the X-region of the spa gene) and by PCR for grouping of staphylococcal cassette chromosome mec (SCCmec) elements, which contain the mecA gene and of which at least 5 basic types have been described.

Methods

MRSA isolates from infections in humans and in animals were sent to the National Reference Center for Staphylococci at the Robert Koch Institute, Wernigerode Branch, in Germany, for typing by means of SmaI-macrorestriction pattern as well as spa typing. Selected isolates also underwent MLST. Four …