The Genus Klebsiella: An Ever-Expanding Panorama of Infections, Disease-Associated Syndromes, and Problems for Clinical Microbiologists

The molecular revolution in clinical and diagnostic microbiology has been fueled by such innovative technologies as polymerase chain reaction (PCR), matrix-assisted laser desorption ionization-time of flight mass spectroscopy (MALDI-TOF) and 16S rRNA and full genome sequencing [1,2]. This revolution has spurred numerous advancements in the field of microbiology in the area of rapid diagnostics, description of new and novel pathogenic microbes and the phylogenetic characterization of pathogenic genera and species. This last category has led to the discovery of hypervirulent clones such as Clostridium difficle NAP1/O27 [3] and the subspecies characterizations of taxa into distinct pathotypes of clinical and medical importance. The best characterized of these species that has been subdivided into phenotypically and genotypically distinct pathotypes is the preeminent pathogen of the family Enterobacteriaceae, Escherichia coli [4]. In its most simple form E. coli has been divided into two major groups composed of Intestinal Pathogenic E. coli or IPEC and Extraintestinal Pathogenic E. coli or ExPEC [4]. The former group consists of such pathotypes as Shiga Toxin-producing E. coli (STEC), enteropathogenic E. coli (EPEC), and enteroadherent E. coli (EAEC) while the latter group is comprised of uropathogenic E. coli (UPEC) and bloodstream/meningesassociated E. coli (MNEC, BMEC). Novel groups continue to be added to each category, in particular IPEC.