Pseudomonas et apparentés

Gram-negative nonfermenting rods have been for most of them initially accomodated in the genus Pseudomonas. Their taxonomic position has considerably changed as a result of successive genomic studies. They are now reclassified in new families and separate genera on the basis of phenotypic (growth parameters) and genotypic characteristics (% G+C content, DNA-DNA hybridization, 16S rRNA gene sequence analysis).For identification in clinical laboratories, the following genera, Pseudomonas, Burkholderia, Pandoraea, Ralstonia, Stenotrophomonas, Massilia, Alcaligenes, Achromobacter, Ochrobactrum, Comamonas, Acidovorax, Psychrobacter, Brevundimonas, Agrobacterium, Sphingomonas, Shewanella, Methylobacterium, Roseomonas, Chryseobacterium, Empedobacter, Myroides, Bergeyella, Weeksella, Sphingobacterium and Oligella, are classified according to a simplified approach (oxidase reaction, motility, indole production) and are described in tables giving phenotypic characteristics and growth parameters.Commercial and automatic systems are available for identification of Gram-negative nonfermenting rods, but suppose the determination of basic characters to avoid false identification.