DIAGNOSTIC BASTERIOLOGYPlesiomonas shigelloides an emerging pathogen with unusual propertiesStock, Ingo Author Information From the Institute of Medical Microbiology and Immunology, Pharmaceutical Microbiology, University of Bonn, Bonn, Germany Correspondence to I. Stock, Gleueler Str. 61, 50931 Köln, Germany. E-mail: [email protected] Reviews in Medical Microbiology: October 2004 - Volume 15 - Issue 4 - p 129-139 Buy Abstract Plesiomonas shigelloides is a Gram-negative, motile and oxidase-positive bacterium that is widely distributed in nature. It is also a significant pathogen causing mainly intestinal diseases in humans. Diarrhoea is the leading symptom of most of these infections and may occur as a watery, invasive and chronic form. Food- and water-borne outbreaks of intestinal infections due to Plesiomonas have been reported. P. shigelloides also causes a variety of extraintestinal infections with high mortality rates; sepsis and meningitis represent the most common extraintestinal forms of disease. In spite of its close phylogenetic relationship to other Enterobacteriaceae, P. shigelloides is biochemically distant from other species of this family. One biovar, but more than 100 serovars have been described. P. shigelloides is thermo-, alkali-, acido- and halotolerant and has been discussed as a ‘natural’ vaccine against shigellosis. In the laboratory, Plesiomonas appears inconspicuous on the surface of several agar plates, and some enteric media are known to inhibit its growth. Plesiomonas shows unusual antibiotic susceptibility patterns, its susceptibility to some agents is highly dependent on inoculum size. The formation of extensive cell filamentation at high bacterial densities in the presence of certain β-lactam antibiotics is distinctive. © 2004 Lippincott Williams & Wilkins, Inc.