Genomic analyses of pneumococci reveal a wide diversity of 
bacteriocins – including pneumocyclicin, a novel circular bacteriocin 

Bogaardt, van Tonder and Brueggemann analysed a collection of 336 pneumococcal genomes from as early as 1916 and found that one third of them possessed a cassette encoding a circular bacteriocin they've called pnemocyclicin.