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

Abstract

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 pneumophilia. Fifteen of these contained antimicrobial agents. Five antibiotic-containing media which performed best in growing the stock strain were then tested for their ability to grow L. pneumophilia from clinical respiratory tract specimens. One of the media, BMPAα, which contained cefamandole, polymyxin B, anisomycin, an organic buffer, and α-ketoglutarate, performed better than the others. This medium greatly enhanced recovery of L. pneumophilia from contaminated clinical specimens and, in conjunction with an acid wash treatment, facilitated recovery of the bacterium from potable water.