Clostridium Perfringens

INTRODUCTION:
  • Anaerobic,Large gram-positive rods.
  • The spores are usually wider than the rods, and are located terminally or sub terminally.
  • Clostridium perfringens is considered as an ideal bac­teriological indicator as acceptability aspect of water
  • Most clostridia are motile by peritrichous flagella.
SPECIES:
  • C. perfringens: gas gangrene; food poisoning
  • C. tetani: tetanus
  • C. botulinum: botulism
  • C. difficile: pseudomembranous colitis
MORPHOLOGY:
  • Large Gram-positive bacilli with straight, parallel sides & slightly rounded ends.
  • Measure 4-6x1μm in size,occuring singly or in chains
  • Pleomorphic,capsulated & non-motile.
  • Spores are central or sub terminal. Spores are rarely seen in culture media or material from pathogenic lesions, a characteristic morphologic feature
CULTURAL CHARACTERISTICS
  • Robertson’s cooked meat broth is ideal; meat is turned pink but not digested with sour odor.
  • Stormy fermentation of lactose in litmus milk; the acid coagulates casein-acid clot.
  • On BAM: Target haemolysis
BIOCHEMICAL REACTIONS:
  • Glucose Indole -ve
  • Lactose Fermented with MR +ve
  • Maltose A & G production VP -ve
  • H2S prodn. test & Nitrate redn. test +ve
TOXINS:
  • 12 distinct types of Preformed enterotoxins elaborated:
  • α toxin-lethal,dermonecrotic & hemolytic( principle toxin) 
  • β,ε & ι toxins- lethal & necrotizing
  • γ & η toxins- minor lethal action
  • δ toxin-lethal & hemolytic for red cells
  • θ toxin-lethal & cytolytic
  • κ toxin- collagenase
  • λ toxin-proteinase & gelatinase
  • μ toxin- hyaluronidase & ν toxin-deoxyribonuclease
ENZYMES
  • Neuraminidase-destroys myxovirus receptors on red cells
  • Hemagglutinin-active against red cells of humans
  • Fibrinolysin
  • Hemolysin(shows double zone of hemolysis)
  • Lecithinase(produce opacity around colonies by spliting lecithin into phosphorylcholine and diacylglycerol that appear opalescence in serum or egg yolk media.)
  • Bursting factor- has specific action on muscle tissue & responsible for muscle lesions in gas gangrene.
  • Circulatory factor-causes an increase in adrenaline sensitivity of capillary bed ,also inhibits phagocytosis
PATHOGENICITY
  • Three Clinical conditions produced include;
  • Simple wound contamination: Slow wound healing & crepitations in wounds
  • Anaerobic or clostridial cellulitis:
  • Clostridiae invade fascial planes(fasciitis) with minimal toxin production but no invasion of muscle tissue.
  1. Lesions vary from limited ‘gas abscess’ to extensive involvement of limbs.
  2. Seropurulent discharges with offensive odor produced
  3. 3. Anaerobic myositis or myonecrosis or gas gangrene
  4. Most serious complication of clostridial invasion of healthy muscle tissue (rhabdomyolysis)
  5. Abundant formation of exotoxin & production of gas.
  6. GG is rarely infection of single clostridium; several species found in association with anaerobic streptococci & facultative anaerobes (E.coli,Stap,Proteus)
  7. Among pathogenic clostridiae,Cl.perfringens is most frequently encountered(60%) followed by Cl.Novyi & Cl.septicum(20-40%).
OTHER INFECTIONS:
  • Food poisoning: usually caused by Type A strains(produces heat resistance spores)
  • Gangrenous appendicitis: Cl.perfringens Type A & occasionally by Type D
  • Necrotizing enteritis: caused by Type C strains
  • Biliary tract infection: Rare but serious -EC & PCS
  • Gasterointestinal enteritis necroticans 
  • Endogenous gas gangrene of intra-abdominal origin
  • Brain abscess & meningitis: Rare
  • Panophthalmitis: Rare
  • Thoracic infections
  • Emphysematous cholecystitis
  • Urogenital infections(myoglbinuria)
LABORATORY DIAGNOSIS:
  • Specimen: Wound swabs,human faeces,necrosed tissue, muscle fragments, exudates from active parts etc.
  • Microscopy:Gram +ve, non-motile, capsulated bacilli.
  • Spores are rarely observed in Cl.perfringens
Culture:
  1. On RCM→ meat turned pink but not digested
  2. On blood agar → target hemolysis
Nagler’s Reaction
  1. Rapid detection of Cl.perfringens from clinical sample
  2. Done to detect the lecithinase activity of alpha toxin
  3. Characteristics opalescence is produced around colonies in +ve test due to breakdown of lipoprotein complex in the medium
Reverse CAMP Test:
  1. Used for differentiation of Cl.perfringens from other clostridium species.
  2. CAMP +ve Group B Streptococcus is streaked in SBA & Cl.perfringens is streaked perpendicular to it “arrowhead”(enhanced) hemolysis is seen between growth of Cl.perfringens & Group B streptococcus
Exam Question
  • Food poisoning causing strains of cl. perfringens produce heat resistant Spores
  • Cl. perfringens Show positive naegler reaction
  • Cl perfringens is the most common cause of gas gangrene
  • The principle toxin of C. perfringens is the alpha toxin
  • It is normally present in Wound swabs,human faeces,necrosed tissue, muscle fragments, exudates from active parts
  • Life-threatening intravascular hemolysis, due to a toxin with lecithinase activity, occurs with sepsis due to Clostridium perfringens
  • Bacteria most frequently cultured in the setting of emphysematous cholecystitis is clostridium perfringens
  • Opacity around colonies of clostridium perfringens is due to lecithinase
  • Gasterointestinal enteritis necroticans is caused by Clostridium perfringens
  • Preformed enterotoxins are formed by Clostridium perfringens
  • Rhabdomyolysis and Myoglobinuria may be seen in Clostridium perfringens infection
  • Clostridium perfringens is responsible for crepitations in wounds
  • Clostridium perfringens is considered as an ideal bac­teriological indicator as acceptability aspect of water
  • Subterminal spores are seen in Clostridium perfringens
  • Double zone of hemolysis is seen in Clostridium perfringens
  • Spores of clostridium perfringens are located Between middle and pole of cells
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