Disclosed is the use of an effective amount of a composition comprising an isolated polypeptide having at least 80% sequence similarity to the amino acid sequence of truncated SYN1 (SEQ ID NO: 408 disclosed within the specification) for the manufacture of a medicament for the treatment of an infection in a subject having or at risk of having an infection caused by a Staphylococcus spp. Also disclosed is a composition comprising: an isolated polypeptide having at least 98% sequence similarity to the amino acid sequence of truncated SYN1 (SEQ ID NO: 408), with the proviso that if the isolated polypeptide includes one or more additional amino acids at the amino terminal, the one or more additional amino acids include at least one amino acid deletion or at least one amino acid substitution compared to amino acids 1-5 of full-length SYN1 (SEQ ID NO:415 disclosed within the specification).