Adapting typing for national laboratory-based surveillance of methicillin-resistant

A. Vainio (1) , S. Koskela (2) , A. Virolainen (1) , J. Vuopio (1) , S. Salmenlinna (1)

1 Department of Infectious Disease Surveillance and Control
2 Division of Clinical Microbiology, HUSLAB

Laboratory-based surveillance of methicillin-resistant (MRSA) monitors the baseline occurrence of different genotypes and identifies strains and transmission chains responsible for outbreaks. The consequences of substituting pulsed-field gel electrophoresis (PFGE) with typing as a first-line typing method were analyzed by typing 589 strains isolated between 1997 and 2006, with a focus on both short- and long-term correspondence between the PFGE and typing results. The study, covering these ten years, included all Finnish MRSA blood isolates and representatives of the two most prevalent MRSA strains (PFGE types FIN-4 and FIN-16) in Finland. In addition, all sporadic isolates from 2006 were included. typing was more expensive but approximately four times faster to perform than PFGE. Nearly 90% of FIN-4 and FIN-16 isolates showed consistent types, t172 and t067, respectively. typing predicted the PFGE result of the blood isolates by a Wallace coefficient of 0.9009, recognized internationally successful strains (t041, t067) to be common also in Finland, and identified a separate cluster of isolates, also related in time and place among the FIN-4 strains. Additional typing by another method was needed to provide adequate discrimination or to characterize isolates with a newly recognized type in Finland.

Mots clés: Life Sciences

A. Vainio, S. Koskela, A. Virolainen, J. Vuopio, S. Salmenlinna. Adapting typing for national laboratory-based surveillance of methicillin-resistant. European Journal of Clinical Microbiology and Infectious Diseases, 2011, pp.789-797. ⟨10.1007/s10096-011-1158-5⟩. ⟨hal-00663400⟩