Enteric pathogen bacteria

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Enteric pathogen bacteria

• Enterobacteriaceae
• Gram negative
• Exotoxin ? enterotoxin
• Endotoxin in cell walls(LPS)

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Antigens

• 3 major groups of antigens
• Somatic O Lipopolysacharides
• Capsular K antigens / Vi antigen
• Flagellar H proteins

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Virulence Factors

• Enterotoxin
• Capsule
• Antigenic phase variation
• Exotoxin production
• Adhesion factors
• Intracellular survival and multiplication ?
• protecting from antibioticimmune reaction

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• Antimicrobial resistance ? exposure to antibiotic
• Resistance to serum killing ? capsule

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• Endotoxin.
• Lipid A component of LPS
• Release upon cell death lysis
• Endotoxin Mediated Toxicity
• Fever
• Leukopenia
• Activation of complement
• Thrombocytopenia

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• - Disseminated Intravascular coagulation
• - Decreased peripheral circulation
• - Shock
• - Death
• Exotoxin production
• Enterotoxin
• Shigashiga like toxin? cytotoxic,enterotoxic
• Hemolysins

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Desease due to Enterobacteriaceae

• Intestinal Infections
• Pathogenic processes?invasive
• 2. Extra intestinal Infections
• Enteric commensals? opportunistic pathogens

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• Enteritis non bloody diarrhea
• Septicemia
• Enteric fever
• Asymptomatic carriage/chronic carriage
• Shigellosis pusbloody in the stool?mucosal
• ulceration.

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Pathogenesis

• Bacteremia- Septicemia
• Ingestion of bacteria?small intestine?
• mesenteric lymph node ? bacteremia?
• RES system(multiplication)?septicemia and
• Bile?Gall bladder. Cholecystitis
• . Carriage stage
• ? Inflamationulceration of Peyers patches

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• 2. Infection is limited to the mucosa and sub
  mucosa of the intestine

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Clinically Significant Nonfermentative Gram
Negative Bacilli

• Pseudomonas
• Acinetobacter
• Virulence Factors Assosiated with Pseudomonas
• . Pili . Exotoxin
• . Capsule . Enzymes
• . Endotoxin

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Infections

• Opportunistic pathogen
• Bacteremia
• Endocarditis
• Pulmonary Infections
• Ear Infection
• Burn wound Infection
• UTI
• Eye Infections ,ect