See this article: Bacteriocins: mechanism of membrane insertion and pore formation G N Moll, W N Konings & A J Driessen Antonie Van Leeuwenhoek 1999 76 (1-4) 185–198.

And attached file.

There is usually a specific interaction where the bacteriocin binds to a receptor on the bacterial cell. This is the step that generally confers specificity and is why most bacteriocins are not broad spectrum anti-microbials.

It is true that most kill by pore formation in the membrane, however there are a number of notable exceptions that kill by inhibiting protein synthesis, degrade DNA or RNA or other mechanisms. Pore formation or membrane disruption is the most common though.

Thank you sir.