Collagen-binding MSCRAMM Acm (Acm)

Enterococcus faecium Acm adhesin (Acm) is a cell wall-anchored protein belonging to the Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMM) family [1, 14]. It is primarily expressed by clinical isolates of E. faecium, particularly those associated with the high-risk hospital-adapted clonal complex 17 (CC17), and is often absent or non-functional in commensal strains [2, 4]. Acm functions as a collagen-binding adhesin, specifically targeting collagen types I and IV, which are abundant in host tissues such as heart valves [3, 10]. This binding is a critical virulence factor in the development of infective endocarditis, as it facilitates the initial attachment and subsequent formation of bacterial vegetations [1, 23]. Because of its central role in pathogenesis and its prevalence in multidrug-resistant strains, Acm is considered a promising therapeutic target [7, 16]. Experimental studies have demonstrated that antibodies directed against the Acm A-domain can effectively block bacterial adherence to collagen, suggesting potential for the development of passive immunotherapies or vaccines to prevent or treat enterococcal infections [4, 17].

Other names

Adhesin of collagen from Enterococcus faecium [1]Fms8 [14]Collagen-binding protein Acm [13]Acm adhesin [1]

Inhibition of bacterial adherence to host collagen [4, 23]