Chapter 52 : Algorithms for Identification of Curved and Spiral-Shaped Gram-Negative Rods

Abstract:

This chapter mainly focuses on algorithms used for identification of curved and spiral-Shaped Gram-negative rods. Curved and spiral-shaped bacteria have a common microscopic morphology but represent diverse bacterial pathogens. Helicobacter cinaedi and Helicobacter fennelliae are two important Helicobacter species isolated from fecal specimens. Helicobacter pylori is the most common curved gram-negative rod isolated from gastric tissue, but other Helicobacter species have also been reported in this site. Other less commonly isolated curved gram-negative rods include the anaerobes Desulfovibrio spp., Sutterella wadswortkensis, Wolinella succinogenes, and Anaerobiospirillum succiniciproducens, which may be isolated from blood, abscess material, or other clinical samples. The spirochetes Borrelia spp. and Leptospira spp. cause systemic infections and are infrequently isolated in clinical laboratories, usually only with specialized media. Treponema spp. of clinical importance are diagnosed based on clinical and epidemiologic findings, as well as microscopic, serologic, and molecular test procedures. Various details about curved gram-negative bacilli that may be encountered in clinical specimens are described in the chapter.