Download Enteric pathogen bacteria

Enteric pathogen bacteria
• Enterobacteriaceae
• Gram negative
• Exotoxin  enterotoxin
• Endotoxin in cell walls(LPS)
Antigens
3 major groups of antigens:
1. Somatic O Lipopolysacharides
2. Capsular K antigens / Vi antigen
3. Flagellar H proteins
Virulence Factors
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Enterotoxin
Capsule
Antigenic phase variation
Exotoxin production
Adhesion factors
Intracellular survival and multiplication 
protecting from antibiotic&immune reaction
• Antimicrobial resistance  exposure to
antibiotic
• Resistance to serum killing  capsule
Endotoxin.
- Lipid A component of LPS
- Release upon cell death & lysis
Endotoxin Mediated Toxicity:
- Fever
- Leukopenia
- Activation of complement
- Thrombocytopenia
- Disseminated Intravascular coagulation
- Decreased peripheral circulation
- Shock
- Death
Exotoxin production
- Enterotoxin
- Shiga&shiga like toxin cytotoxic,enterotoxic
- Hemolysins
Desease due to Enterobacteriaceae
1. 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: pus&bloody in the stoolmucosal
ulceration.
Pathogenesis
1. Bacteremia- Septicemia
Ingestion of bacteriasmall intestine
mesenteric lymph node  bacteremia
RES system(multiplication)septicemia and
BileGall bladder:. Cholecystitis
. Carriage stage
 Inflamation&ulceration of Peyer’s patches
2. Infection is limited to the mucosa and sub
mucosa of the intestine
Clinically Significant Nonfermentative
Gram Negative Bacilli
• Pseudomonas
• Acinetobacter
Virulence Factors Assosiated with Pseudomonas:
. Pili
. Exotoxin
. Capsule
. Enzymes
. Endotoxin
Infections
Opportunistic pathogen
1. Bacteremia
2. Endocarditis
3. Pulmonary Infections
4. Ear Infection
5. Burn wound Infection
6. UTI
7. Eye Infections ,ect