BacT/Alert: an automated colorimetric microbial detection system.

BacT/Alert (Organon Teknika Corp., Durham, N.C.) is an automated microbial detection system based on the colorimetric detection of CO2 produced by growing microorganisms. Results of an evaluation of the media, sensor, detection system, and detection algorithm indicate that the system reliably grows and detects a wide variety of bacteria and fungi. Results of a limited pilot clinical trial with a prototype research instrument indicate that the system is comparable to the radiometric BACTEC 460 system in its ability to grow and detect microorganisms in blood. On the basis of these initial findings, large-scale clinical trials comparing BacT/Alert with other commercial microbial detection systems appear warranted.

Extracellular enzymes of Legionella pneumophila.

All strains of Legionella pneumophila tested produced detectable levels of extracellular protease, phosphatase, lipase, deoxyribonuclease, ribonuclease, and beta-lactamase activity. Weak starch hydrolysis was also demonstrated for all strains. Elastase, collagenase, phospholipase C, hyaluronidase, chondroitinase, neuraminidase, or coagulase were not detected in any of these laboratory-maintained strains.

Negative enrichment procedure for isolation of Legionella pneumophila from seeded cooling tower water.

A negative enrichment procedure was developed which was capable of isolating Legionella pneumophila directly from seeded air-conditioning cooling tower water onto laboratory media. This procedure was based on an 8-h incubation under conditions that were bactericidal to the indigenous water microflora but merely bacteriostatic to L. pneumophila.