CLOSTRIDIUM
Morphology
• Gram positive bacilli
• Spore forming
• Ubiquitous
• Spores are wider than the body giving spindle shape
• The name derived from word Kolster(Greek) meaning spindle
• First described in 1880 by Prazmowski
• 0.6 μm across by 3 to 7 μm long
• Occur singly or in chains
• Highly pleomorphic, straight or slightly curved rods
• Rods are common – Rarely spherical or irregular shape
• Ends may vary from rounded to pointed ends
• Motile - peritrichous flagella
• Non capsulated – Except Cl.perfringens and Cl.butyricum
• There are 200+ species of Clostridium – near about 30 are associated with
human diseases
• Clostridium difficile
• Clostridium perfringens (also called Clostridium welchii)
• Clostridium botulinum
• Clostridium Sporogenes
• Clostridium leptum
Cultural Characteristics
• Obligate Anaerobe/ Microaerophilic
• Oxygen tolerance varies among the species
• Optimum temp: 37°C
• pH: 7-7.4
• On blood agar → β-hemolytic colonies
, Media
• Robertson’s cooked meat broth - blackening of meat with the production of H2S
and NH3
• Most species produce gas in this medium
• Saccharolytic species turn the meat pink
• Proteolytic species turn the meat black with foul smell
• Thiglycollate broth-Sodium thioglycolate in the medium consumes oxygen and
permits the growth of obligate anaerobes
BIOCHEMICAL REACTIONS
• Glucose, Lactose, Maltose-Fermented with acid and gas production
• Indole: -ve
• MR: +ve
• VP: -ve
• H2S production and Nitrate reduction test: +ve
RESISTANCE
• Spores of Cl.botulinum survive boiling at 105°C after 3-4 hrs - not killed
completely
• Spores of Cl.perfringens are destroyed by boiling for 5 minutes
• Cl.tetani spores persist for years in dry soil, and resist boiling for 15-90 min
• All species are killed by autoclaving at 121°C for 20 minutes
• Halogens are effective;1% Iodine soln. kills spores within 3 hrs
• 2% glutaraldehyde kills spores
Clostridium
• Few Clostridium spp are pathogenic causing human and animal disease (C.
botulinum, C. difficile, and C. tetani)
• Some species are non-pathogenic and some have beneficial industrial
applications
• Majority are saprophytes -breakdown various organic matters and contributes
to humus
• Produce variety of toxins which are fatal
Who are at risk?
• Children under 5
• Older adults
• People with weak immune systems
Morphology
• Gram positive bacilli
• Spore forming
• Ubiquitous
• Spores are wider than the body giving spindle shape
• The name derived from word Kolster(Greek) meaning spindle
• First described in 1880 by Prazmowski
• 0.6 μm across by 3 to 7 μm long
• Occur singly or in chains
• Highly pleomorphic, straight or slightly curved rods
• Rods are common – Rarely spherical or irregular shape
• Ends may vary from rounded to pointed ends
• Motile - peritrichous flagella
• Non capsulated – Except Cl.perfringens and Cl.butyricum
• There are 200+ species of Clostridium – near about 30 are associated with
human diseases
• Clostridium difficile
• Clostridium perfringens (also called Clostridium welchii)
• Clostridium botulinum
• Clostridium Sporogenes
• Clostridium leptum
Cultural Characteristics
• Obligate Anaerobe/ Microaerophilic
• Oxygen tolerance varies among the species
• Optimum temp: 37°C
• pH: 7-7.4
• On blood agar → β-hemolytic colonies
, Media
• Robertson’s cooked meat broth - blackening of meat with the production of H2S
and NH3
• Most species produce gas in this medium
• Saccharolytic species turn the meat pink
• Proteolytic species turn the meat black with foul smell
• Thiglycollate broth-Sodium thioglycolate in the medium consumes oxygen and
permits the growth of obligate anaerobes
BIOCHEMICAL REACTIONS
• Glucose, Lactose, Maltose-Fermented with acid and gas production
• Indole: -ve
• MR: +ve
• VP: -ve
• H2S production and Nitrate reduction test: +ve
RESISTANCE
• Spores of Cl.botulinum survive boiling at 105°C after 3-4 hrs - not killed
completely
• Spores of Cl.perfringens are destroyed by boiling for 5 minutes
• Cl.tetani spores persist for years in dry soil, and resist boiling for 15-90 min
• All species are killed by autoclaving at 121°C for 20 minutes
• Halogens are effective;1% Iodine soln. kills spores within 3 hrs
• 2% glutaraldehyde kills spores
Clostridium
• Few Clostridium spp are pathogenic causing human and animal disease (C.
botulinum, C. difficile, and C. tetani)
• Some species are non-pathogenic and some have beneficial industrial
applications
• Majority are saprophytes -breakdown various organic matters and contributes
to humus
• Produce variety of toxins which are fatal
Who are at risk?
• Children under 5
• Older adults
• People with weak immune systems
