Evaluation of the Biolog automated microbial identification system

Abstract

Biolog's identification system was used to identify 39 American Type Culture Collection reference taxa and 45 gram-negative isolates from water samples. Of the reference strains, 98% were identified to genus level and 76% to species level within 4 to 24 h. Identification of some authentic strains of Enterobacter, Klebsiella, and Serratia was unreliable. A total of 93% of the water isolates were identified. Although rapid automated identification systems for identifying bacteria from clinical specimens exist, few systems that can identify environmental isolates quickly and reliably are available (3, 4, 8, 27). Traditional biochemical tests and commercial test kits used to identify nonenteric organisms are labor-intensive and slow (9, 10, 13, 14, 16, 19, 21-24, 26, 28, 29, 31). An automated ground-based system is needed for identifying archived environmental isolates obtained from the space shuttle and eventually from the U.S. space station Freedom (1, 20). Identification of isolates from the station's recycled water supply is of particular concern. Biolog Inc., (Hayward, Calif.) recently introduced an automated system designed to identify 434 species or groups of aerobic gram-negative bacteria within 4 to 24 h. Their data base includes environmental taxa that are not included in the data bases of other commercial systems (3, 4). Because the Biolog system has been available for a relatively short time, few published assessments of its accuracy and reliability are available (6, 18). To assess the system's potential to identify gramnegative aerobic rods, we tested 41 American Type Culture Collection (ATCC) organisms representing 39 taxa and 45 unknown isolates recovered from a prototype water-recycling system proposed for use on the U.S. space station Freedom. Biolog's identification system, consisting of a Microstation computer, turbidimeter (optical density at 590 nm), MicroLog software (MicroLog 2N, Release 2), microplate reader, and gram-negative microplates, was purchased from Biolog Inc. For comparative purposes, the Vitek system, turbidimeter, and gram-negative identification cards were purchased from Vitek Systems, Inc. (Hazelwood, Mo.). Petri plates (160-mm diameter) prepared with Trypticase soy agar, blood agar (Trypticase soy agar plus 5% sheep erythrocytes), plate count agar, or Emmon's Sabouraud dextrose agar were purchased from BBL Microbiology Systems (Cockeysville, Md.). Sterile saline (0.45 and 0.85%) was purchased from Baxter Healthcare Corp. (Deerfield, Ill.). Cards, microplates, and agar plates were stored at 4°C and then equilibrated at room temperature for 30 min (cards and microplates) or overnight (agar plates) before use.

Identification ofVibriospp. with a set of dichotomous keys

“…Moreover, it has been reported that the use of commercial biochemical kits for the identification of environmental isolates could require certain modifications to the manufacturer's protocols as most are typically intended for clinical use. Indeed, this situation has been widely reported for both API 20E (Kent 1982;Grisez et al 1991) and Biolog (Miller and Rhoden 1991;Klingler et al 1992). The addition of highly concentrated inocu- Thompson and Swings 2006) have proposed that the family Vibrionaceae be split into four new families, with the revised Vibrionaceae family comprising only the genus Vibrio.…”

Characterization of a free-living maize-rhizosphere population of Burkholderia cepacia: effect of seed treatment on disease suppression and growth promotion of maize

“…In order to characterize the metabolic and genetic pro¢les of the B. cepacia isolates and to obtain information on the relatedness between the rhizosphere isolates, Biolog and RAPD analyses were carried out. The Biolog analysis, a commercial system for identifying bacterial isolates by means of sole carbon source utilization [22,44], con¢rmed the ability of B. cepacia to multiply using a wide range of organic compounds and indicated that rhizosphere isolates di¡ered in some biochemical traits. The unrooted tree representing the phenotypic relatedness between the rhizosphere B. cepacia isolates, the type strain B. cepacia ATCC 25416 of clinical origin and B. cepacia LMG 11351 isolated from the maize rhizosphere, and the reference strains of closely related species belonging to the L-subclass of the proteobacteria revealed that all rhizosphere isolates were grouped together in a principal cluster, which included the reference strain B. cepacia LMG 11351, and were clearly distinct from the other reference strains examined (i.e.…”

“…In the present work, a B. cepacia population naturally occurring in the rhizosphere of maize and isolated at the elongation stage of plant growth was investigated in order to: (i) analyze the metabolic and genetic pro¢les of bacterial isolates using Biolog automated analysis [22] and the random ampli¢ed polymorphic DNA (RAPD) method [23]; (ii) investigate traits involved in biocontrol activity, such as the ability to inhibit the in vitro growth of several Fusarium spp. phytopathogens of maize, and to synthesize Fe(III) chelator(s); (iii) analyze the increased growth response of maize plants due to seed bacterization with B. cepacia strains, in soil arti¢cially infested with F. proliferatum ITEM-381 and F. moniliforme ITEM-504; (iv) evaluate the ability of isolated strains to promote maize growth.…”

Mobilization of a recombinant nonconjugative plasmid at the interface between wastewater and the marine coastal environment

“…Gram-negative strains were identified using GN microplates (BIOLOG, Hayward, California). The BIOLOG identification system has been evaluated [20]. GN microplate results were recorded after 24 h, or after 72 h if they were slow to develop.…”