class 15 Corynebacterium.pdf

GENUS CORYNEBACTERIUM Dr. Bincy Joseph Assistant Professor PGIVER, Jaipur  CLASSIFICATION  Kingdom Bacteria  Phylum Actinobacteria  Order Actinomycetales  Family Corynebacteriaceae  Genus Corynebacterium  Species Coryneba...

GENUS CORYNEBACTERIUM Dr. Bincy Joseph Assistant Professor PGIVER, Jaipur  CLASSIFICATION  Kingdom Bacteria  Phylum Actinobacteria  Order Actinomycetales  Family Corynebacteriaceae  Genus Corynebacterium  Species Corynebacterium bovis HISTORY  Genus Corynebacterium was originally created by Lehmann and Neumann (1896)  Corynebacterium diphtheriae (Klebs–Loffler bacillus) It was discovered in 1884 by German bacteriologists Edwin Klebs and Friedrich Loffler  Various selective media were formulated for C. diphtheriae, by the following scientist ◦ Frobisher, 1937 - Cystine-tellurite blood agar ◦ Hoyle, 1941 - Hoyle’s lysed blood tellurite agar ◦ Tinsdale, 1947 - Tinsdale agar  INTRODUCTION  Gram positive  Coccobacilli with some metachromatin granules  Pleomorphic irregularly stained  Stained tissue smears reveal groups of cells in parallel (Palisades) or cells at sharp angles to each other “V” or “Y” configurations (Chinese letter or Cuneiform arrangement). HABITAT AND ECOLOGY  Soil born and often found in manure.  Survive as commensals on normal mucous membrane and skin of cattle and other domestic animals.  Chronic cases and adult animals are the common carriers.  Most species of Corynebacterium are opportunistic pathogens.  Present in the intestines of horses and persist for long periods in the manure and litter of stables.  As commensals, they can be found on the skin or on mucous membranes of animals MORPHOLOGY  Gram-positive slender rod with a tendancy to clubbing at one or both ends  Non-sporing, Non-motile, Non-capsulated , Non-acid fast.  Palisades or Chinese letter or Cuneiform arrangement  Small, pleomorphic (club-shaped), Gram-positive rods  Cell size is 2 to 6 µm long and 0.5 to 1 µm in diameter.  Modified ZN staining positive  Straight to slightly curved, often with tapered ends  Coryne bacterial cell walls contain thin spots which leads to some Gram variability and "ballooning" that produces a "club-shaped" cell.  Lipid-rich cell wall contains meso-diaminopimelic acid, arabino-galactan polymers, and short-chain mycolic acids GRANULES  High energy phosphate granules – polymetaphosphate.  Strongly Gram positive than the rest of the bacterial cell.  Stained with Loeffler’s methylene blue, the granules take up a reddish purple color and hence they are called metachromatic granules.  They are called as volutin or Babes Ernst Granules. GRANULES  They are often situated at the poles of the bacilli and are called polar bodies.  Special stains, such as Albert’s, Neisser’s and Ponder’s have been devised for demonstrating the granules clearly. CULTURAL CHARACTERISTICS  Growth on enriched media (Fastidious) scanty- a gray pin point to small colonies.  Enrichment with blood, serum or egg is necessary for good growth.  Optimum temperature for growth is 37ºC  Optimum pH is 7.2.  Aerobe and facultative anaerobe.  Some of them are beta hemolytic while renale groups are non-haemolytic  Diptheroids are readily destroyed by heat, 600C for one hour.  They are highly susceptible to disinfectants.  It is more resistant to the action of light, desiccation and freezing.  Corynebacterium equi is resistant to 2.5% oxalic acid for one hour.  Corynebacterium bovis is a lipophilic bacterium which produces small, white, dry, non-haemolytic colonies in the well of plates inoculated with a bovine milk sample.  Corynebacteriurn kutscheri produces whitish colonies. Occasional isolates are haemolytic.  Corynebacteriurn pseudotuberculosis has small, whitish colonies surrounded by a narrow zone of complete haemolysis, which may not be evident for up to 72 hours. After several days, the colonies become dry, crumbly and cream-coloured  Members of the C. renale group produce small non- haemolytic colonies after incubation for 24 hours. Pigment production after incubation for 48 hours is one of the differentiating features of the three species in the group Enhancement of haemolysis test  The haemolysis produced by C. pseudotuberculosis is enhanced when the organisms are inoculated across a streak of Rhodococcus equi BIOCHEMICAL PROPERTIES  Catalase-positive  Oxidase negative  Except Corynebacterium bovis others are urease positive.  Renale group is very strong urease positive (less than one hour).  All diptheroids ferments sugar except Rhodococcus equi.  Corynebacterium bovis and Corynebacterium renale ferments both glucose and maltose.  Two biotypes of Corynebacterium ovis are recognized.  Ovine/Caprine strains lack nitrate-reducing capacity, while the equine/bovine strains usually reduce nitrate. CORYNEBACTERIUM OF VETERINARY IMPORTANCE  Corynebacterium pseudotuberculosis (Corynebacterium ovis or Preisz Nocard Bacillus)  Corynebacteriurn kutscheri  Corynebacterium renale  Corynebacterium cystitidis  Corynebacterium pilosum  Corynebacterium bovis  Arcanobacterium pyogenes (C. Pyogenes)  Rhodococcus equi (Corynebacterium equi) IMPORTANT ANIMAL DISEASES IMPORTANT ANIMAL DISEASES  Bovine pyelonephritis, ureteritis and cystitis is caused by C. renale group, previously designated as type I, II, and III. They have been (C. renale Group) classified into three species on the basis of their distinct pili and biochemical properties. 1. C. renale Mostly affects cows and causes chronic cystitis, pyelonephritis (Important). 2. C. pilosum