Distribution and frequencies of different spa-types of MRSA from Norway

  • Frode Gran, Department of Medical Microbiology, St. Olavs Hospital, Trondheim University Hospital, Norway, Norway
  • Petter Elstrøm, Norwegian Institute of Public Health, Norway
  • Lillian Marstein, Department of Medical Microbiology, St. Olavs Hospital, Trondheim University Hospital, Norway, Norway
  • Anne Kilnes, Department of Medical Microbiology, St. Olavs Hospital, Trondheim University Hospital, Norway, Norway
  • Janne Fossum, Department of Medical Microbiology, St. Olavs Hospital, Trondheim University Hospital, Norway, Norway
  • Trond Jacobsen, Department of Medical Microbiology, St. Olavs Hospital, Trondheim University Hospital, Norway, Norway

    • Objective: From 1970-1974, University Hospital in Trondheim had a larger nosocomial outbreak of MRSA (ST 239, SCCmec III). 144 patients from 8 different departments where infected. 48 patients died. This was the first outbreak seen in Norway. Despite early start of hygiene preventive measures, the outbreak lasted for approximate 5 years.1 Since then we have not seen any similar outbreaks in Norway. By 2007 Norway still have less than 1% MRSA and with the rest of the Nordic countries and Netherlands still belonging to the low-prevalent countries.2 This study describes the distribution and frequencies of the most common spa-types of MRSA in Norway in the period 2006-2008, single-patient isolates only.

    Method: Data on Methicillin Resistant Staphylococcus aureus submitted to the National Reference Laboratory in Trondheim, Norway and the Norwegian Institute of Public Health (NIPH) by 22 laboratories from January 2006 to April 2008 (n=958) were reviewed.

    Results: In the period 2006-2008 the national reference laboratory has performed 958 spa-typing3 analysis from different patients. We found 173 different spa-types where 10 of the most frequent spa-types accounted for 49,5 % of all the isolates. Single spa-types accounted for 9,3 % (89 isolates). Spa-types that occurred >5 times accounted for 22,3 % of the total (214 isolates) Of the 958 isolates submitted to the reference laboratory, we have clinical information on 874 isolates. 545 isolates caused infections (62,4 %). Among these we found 133 different spa-types. The five most frequent where t008 (12,1 %), t019 (11,7 %), t002 (10,6 %), t044 (9,0 %) and t437 (2,7 %).


    Spa-types
    Diagnosis Total number t008 t019 t002 t044 t437
    SST 396 57 60 45 42 12
    RTI 34 2 1 3 4 0
    SSI 37 0 1 4 1 0
    BJI 10 2 0 0 0 2
    UTI 24 2 0 2 0 0
    Septicemia 8 1 0 1 0 0
    Others 36 2 2 3 2 1
    Sum infections 545 66 64 58 49 15
    Carriers 329 12 10 38 11 2
    Total 874 78 74 96 60 17

    Table 1: Most frequent spa-types causing infection distributed on clinical diagnosis.

    Conclusions: In the period 2006-2008 we did not see any predominant spa-type. 214 different spa-types occurring >5 times accounted for 22,3 % of all the strains. This could indicate a large genetic diversity.

    References:
    1. Kvittingen J, Trymer A. Sykehusendemi med methicillinresistente stafylokokker. Tidsskr Nor Lægeforen 1977; 97: 813 - 6.
    2. http://www.rivm.nl/earss/
    3. http://www.ridom.de/