The use of spa and phage typing for characterization of a MRSA population in a Belgian hospital: comparison between 2002 and 2007.

UNLABELLED

TARGET OF THE STUDY: Strain typing of pathogens is essential to pinpoint the sources and routes of transmission and to forecast future trends. In a general hospital, we studied possible changes in the MRSA population.

PATIENTS AND METHODS

MRSA isolates received from a Belgian general hospital, during 2002 (n=150) and the second half of 2007 (n=105), were compared by phage and spa typing.

RESULTS

In 2002, [J]* phage types characterized 45% of the MRSA isolates, 13% belonged to the [O]* phage types, 12% to a local phage type 29/42E/54/D11* and 28% were not assigned to a defined group. Thirteen different spa types were found among the isolates: 39% belonged to t038, 27% to t121, 14% to t041, 5% to t740, and 4% to t002 and t024 each. Two spa types were found respectively in two and three isolates, five were unique. In 2007, 35% belonged to [J], 23% to [O] and 39% could not be put in a defined group. Eighteen different spa types were found: 30% belonged to t740, 29% to t121, 13% to t038 and 10% to t002. Three spa types were represented in two isolates, eleven were unique. The t041 spa type was specific for the 29/42E/54/D11* and the majority of the t121 isolates were related to [J]*.

CONCLUSION

[J]* remained the dominant phage types group but decreased whereas [O]*, the second phage types group, increased. As to the spa types, t740 became dominant while t121 remained second. Phage and spa typing point to some quantitative changes among the Belgian MRSA population.