BACTERICIDAL is a 12 letter word that starts with B.

1. Capable of killing bacteria.
2. Pertaining to the killing of bacteria. A term often used to describe the property of antibiotics. However, it is now known that the effectiveness of drug action depends on more than whether or not the antibiotic "kills" bacteria in experiments conducted on petri dishes. First the drug has to reach the tissue compartment where its action is needed, e.g. the mid-ear, in the case of otitis media. Second, the elimination of bacteria is also dependent on the availability of functioning white cells, and on other components of the immune system. Therefore many immunologically compromised patients do not do well against an infection despite the administration of potent antibiotics.