Serotype-independent inhibition of S. pneumoniae by SMiTE, a commensal-derived bacteriocin.

SMiTE, a bacteriocin from commensal streptococci, reduces pneumococcal loads by 65-fold in mice and inhibits multiple serotypes, including vaccine-resistant serotype 3.

• Why it matters: Current pneumococcal vaccines do not protect against all strains, especially serotype 3, highlighting the need for serotype-independent control strategies that spare beneficial microbiota.
• What they did: Researchers screened 58 bacteriocins using cell-free protein synthesis, identified SMiTE as the most potent, and demonstrated its ability to disrupt pneumococcal membranes, induce stress responses, and reduce bacterial colonization in a mouse model.
• The result: SMiTE effectively inhibits a broad range of pneumococcal serotypes, including serotype 3, without promoting resistance or harming most commensal bacteria, supporting its potential as a microbiota-sparing decolonization agent.