(Gram negative rods enteric tract) Enterobacteriaceae I (Gram negative rods enteric tract) Lecture 34 Faculty: Dr. Alvin Fox

Key Words Opportunistic diseases Shigella Diarrhea - Bacillary dysentery Dysentery - Shiga toxin Urinary tract infections Salmonella enteritidis Pili Salmonellosis Lactose positive/negative Salmonella cholerae-suis Enterohemorrhagic E. coli Salmonella typhi - Vero toxin (Shiga-like) - Typhoid - Hemolysin - Vi Enterotoxigenic E. coli Yersinia entercolitica - Heat stable toxin Vibrio cholerae - Heat labile toxin Choleragen (cholera toxin) Enteropathogenic E. coli Campylobacter jejuni Enteroaggregative E. coli Helicobacter pylori Enteroinvasive E. coli

Opportunistic diseases -Enterobacteriaceae septicemia, pneumonia, meningitis urinary tract infections Citrobacter Enterobacter Escherichia Hafnia Morganella Providencia Serratia

Enterobacteriaceae gastrointestinal diseases Escherichia coli Salmonella Shigella Yersinia entercolitica

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

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

E. coli fimbriae Type 1 mannose P galactose glycolipids glycoproteins

Enterobacteriaceae gram negative facultative anaerobic rods – oxidase negative (no cytochrome oxidase)

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

Enterobacteriaceae other sites identified biochemically

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

Diarrhea (watery feces) and Dysentery (blood in stools)

Caption: E. coli Escherichia coli

Escherichia coli E. coli and Shigella genetically very similar separated for historical reasons overlap in pathogenesis

Enterohemorrhagic E. coli Usually O157:H7 Transmission electron micrograph Flagella

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

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

Enterotoxigenic E. coli diarrhea like cholera milder travellers diarrhea

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

Enteropathogenic E. coli destruction of surface microvilli fever diarrhea vomiting nausea non-bloody stools (not generally seen as dysentery) Gut lumen

Enteroaggregative Mucus biofilm inhibits fluid absorption Diarrhea Brick-like bacterial aggregates - cell surfaces Mucus biofilm inhibits fluid absorption Diarrhea

Enteroinvasive E. coli (EIEC ) Dysentery - resembles shigellosis Gut lumen

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

Shigella Modified from Fig, Dennis Kunkel

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

Shigellosis within 2-3 days epithelial cell damage Gut lumen

Shiga toxin enterotoxic cytotoxic inhibits protein synthesis lysing 28S rRNA

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

Treating shigellosis manage dehydration patients respond to antibiotics disease duration diminished

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 |

Salmonella 2000 antigenic "types” genetically single species S. enterica disease category S. enteritidis many serotypes S. cholerae-suis S. typhi

Salmonellosis S. enteritidis the common salmonella infection poultry, eggs no human reservoir Gastroenteritis nausea vomiting non-bloody stool self-limiting (2 - 5 days)

Control of salmonellosis Monitoring of food in the US is limited microbiology is difficult Regulation is not optimal Chickens are not vaccinated in US UK, salmonellosis largely erradicated

Salmonellosis uncomplicated cases (the vast majority) Gut lumen uncomplicated cases (the vast majority) antibiotic therapy not useful

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