Enterobacteriaceae, Vibrio, Campylobacter And Helicobacter (1) Faculty: Dr. Alvin Fox

ENTEROBACTERIACEAE, VIBRIO, CAMPYLOBACTER AND HELICOBACTER (1) Faculty: Dr. Alvin Fox

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Key Words Opportunistic diseases Diarrhea Dysentery Urinary tract infections Lactose positive/negative Enteropathogenic E. coli Enterotoxigenic E. coli Heat stable toxin Heat labile toxin Enteroinvasive E. coli Enterohemorrhagic E. coli Vero toxin (Shiga-like) Hemolysin pili

Shigella Bacillary dysentery Shiga toxin Salmonella enteritidis Salmonellosis Salmonella cholerae-suis Salmonella typhi Typhoid Vi Yersinia entercolitica Vibrio cholerae Choleragen (cholera toxin) Campylobacter jejuni Helicobacter pylori 2

Opportunistic diseases -Enterobacteriaceae – – – –

septicemia, pneumonia, meningitis urinary tract infections

Citrobacter Enterobacter Escherichia Hafnia Morganella Providencia Serratia

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Enterobacteriaceae • gastrointestinal diseases – Escherichia coli – Salmonella – Shigella – Yersinia entercolitica

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Reiter's syndrome • Histocompatibility antigen (HLA) B27 – Enterobacteriaceae *Salmonella *Shigella *Yersinia – Non-Enterobacteriaceae *Campylobacter *Chlamydia 5

Enterobacteriaceae • community acquired • otherwise healthy people – Klebsiella pneumoniae * respiratory diseases * prominent capsule –urinary tract infection –fecal contamination *E. coli *Proteus – urease (degrades urea) – alkaline urine

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Enterobacteriaceae

• gram negative facultative anaerobic rods – oxidase negative (not cytochrome oxidase)

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Feces • E. coli – lactose positive – not usually identified – lactose positive sp. common, healthy intestine • Shigella, Salmonella,Yersinia – lactose negative – identified 8

Enterobacteriaceae • other sites – identified biochemically

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Serotypes • reference laboratory – antigens • O (lipopolysaccharide) • H (flagellar) • K (capsular)

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Diarrhea and Dysentery

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Caption: E. coli

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Escherichia coli • E. coli and Shigella – genetically very similar – many similarities in diseases

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Enteropathogenic E. coli destruction of surface microvilli • fever • diarrhea • vomiting • nausea • non-bloody stools

Gut lumen

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Enterotoxigenic E. coli • diarrhea like cholera • milder • travellers diarrhea

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Enterotoxigenic E. coli • Heat labile toxin – like choleragen – Adenyl cyclase activated – cyclic AMP – secretion water/ions • Heat stable toxin – Guanylate cyclase activated – cyclic GMP – uptake water/ions 16

Enteroinvasive E. coli (EIEC ) • Dysentery - resembles shigellosis

Gut lumen 17

Enterohemorrhagic E. coli • Usually O157:H7 Flagella

Transmission electron micrograph

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Transmission – meat products or sewage-contaminated vegetables • Hemorrhagic – bloody, copious diarrhea – few leukocytes – afebrile • hemolytic-uremic syndrome – hemolytic anemia – thrombocytopenia (low platelets) – kidney failure

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Enterohemorrhagic E. coli • Vero toxin – “shiga-like” • Hemolysins

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Treatment -gastrointestinal disease • fluid replacement • antibiotics – not used usually unless systemic – e.g. hemolytic-uremia syndrome

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E. coli fimbriae Type 1 mannose

P

galactose – glycolipids – glycoproteins 22

Shigella

Modified from Fig, Dennis Kunkel

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Shigella • S. flexneri, S. boydii, S. sonnei, S. dysenteriae – bacillary dysentery – shigellosis • bloody feces • intestinal pain • pus 24

Shigellosis • within 2-3 days – epithelial cell damage

Gut lumen

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Shiga toxin • • •

enterotoxic cytotoxic inhibits protein synthesis – lysing 28S rRNA

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Shigellosis • man only "reservoir" • mostly young children – fecal to oral contact – children to adults • transmitted by adult food handlers – unwashed hands

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Treating shigellosis • manage dehydration • patients respond to antibiotics – disease duration diminished

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Salmonella [417]

Caption: Salmonella typhi - Gram-

negative, enteric, rod prokaryote (dividing); causes typhoid fever. Magnification*: x5,530 Type: SEM Keywords: 96430B.TIF bacilli bacillus bacteria bacterial pathogen bacterium division Gram-negative human disease infection prokaryote rod Salmonella typhi typhoid fever enteric bacterial pathogen intestinal tract infection SEM |

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Salmonella • 2000 antigenic "types” • genetically single species – S. enterica

• disease category – S. enteritidis

– many serotypes

– S. cholerae-suis – S. typhi

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Salmonellosis • S. enteritidis – the common salmonella infection – poultry, eggs – no human reservoir – Gastroenteritis • • • •

nausea vomiting non-bloody stool self-limiting (2 - 5 days)

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Salmonellosis

Gut lumen

uncomplicated cases (the vast majority) antibiotic therapy not useful

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S. cholerae-suis • much less common • septicemia • antibiotic therapy essential

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