Improved semiselective medium for isolation of Legionella pneumophila from contaminated clinical and environmental specimens.

Eighteen types of media, all of which used charcoal yeast extract medium as a base, were tested for their ability to support the growth of a stock strain of Legionella pneumophila. Fifteen of these contained antimicrobial agents. Five antibiotic-containing media which performed best in growing the stock strain were then tested for the ability to grow L. pneumophila from clinical respiratory tract specimens. One of the media, BMPA alpha, which contained cefamandole, polymyxin B, anisomycin, an organic buffer, and alpha-ketoglutarate, performed from contaminated clinical specimens and, in conjunction with an acid wash treatment, facilitated recovery of the bacterium from potable water.