Spa -typing

Epidemiological typing of Staphylococcus aureus using spa typing. Spa is the acronym for "Staphylococcus Protein A".

The study is performed by sequencing the spa gene (Staphylococcus aureus Protein A gene) of the staphylococcal strain under investigation. The typing is based on an assignment of the DNA sequence in the hypervariable X-region of the spa gene to a staphylococcal type. In the sequence, the sequence of these characteristic 22-25mers is determined and a numerical code is assigned to the sequence. By comparing the numerical code with the Ridom Spa-Server database (http://www.ridom.de/spaserver/) the spa type is determined.

Only pure cultures of the relevant pathogens can be used as test material. Mixed cultures can lead to unusable or falsified results. The average processing time is 5 - 10 working days.

The questions for spa gene typing are primarily of epidemiological nature, but also the tracing of transmission paths is at least partially possible. If different spa types are present, transmission between several examined patients can be excluded, whereas an identical spa type alone does not constitute proof of transmission but may indicate an outbreak.

1. Jokinen E et al (2018) Spa type distribution in MRSA and MSSA bacteremias and association of spa clonal complexes with the clinical characteristics of bacteremia. Eur J Clin Microbiol Infect Dis 37: 937-943.