(A) Amplification of the entire spa locus. By use of primers flanking the entire spa locus, spa could be amplified in five of eight non-spa-typeable strains: NT935, NT937, NT938, NT939, and NT941. (B) Results of sequencing of the spa locus for five non-spa-typeable S. aureus strains: NT935, NT937, NT938, NT939, and NT941. The deletions are indicated by gray rectangles. Strain NT935 revealed a deletion from the middle part of IgG-binding domain C up to the beginning of the repeat region XR, resulting in a frameshift mutation, presumably leading to a premature stop codon. In strain NT937, a deletion of the three IgG-binding domains A, B, and C occurred; in strains NT938 and NT939, a deletion of IgG-binding domain C was observed; and in strain NT941, a deletion of the four IgG-binding domains D, A, B, and C was demonstrated.