Comparison of four selective media for the isolation of Burkholderia mallei and Burkholderia pseudomallei.

Currently there are no commercially available selective media indicated for the isolation of Burkholderia mallei and Burkholderia pseudomallei. Ashdown's agar, a custom selective medium for isolation of B. pseudomallei, is well described in the literature but unavailable commercially. Three commercially available media, Burkholderia cepacia selective agar (BCSA), oxidative-fermentative-polymyxin B-bacitracin-lactose (OFPBL) agar, and Pseudomonas cepacia (PC) agar are recommended for isolation of B. cepacia from respiratory secretions of cystic fibrosis patients. We evaluated the sensitivity and selectivity of these four media using 20 B. mallei, 20 B. pseudomallei, 20 Burkholderia spp., and 15 diagnostically challenging organisms. Ashdown's agar was the most sensitive medium for the isolation of B. pseudomallei, but it was unable to support growth of B. mallei. Pseudomonas cepacia agar was highly sensitive and selective for both organisms. In non-endemic areas, we suggest the use of the commercially available PC agar for the isolation of B. mallei and B. pseudomallei.