<p>GI Pathogens</p><p>Mechanisms: </p><p>1) Toxin production invitro/in vivo</p><p>2) Adhesive/aggregative- occupy microvilli</p><p>3) Invasive- inflammation</p><p>Transmission: 7 Fs: feces, food, fluids, fingers, fomites, fornication, flies; depends on # CFUs required to cause disease</p><p>Defenses: </p><p>1) Stomach- low pH</p><p>2) Small Intestine: large volume; proteases, bile, IgA</p><p>3) Large Intestine: large # flora produces inhibitory substances and occupies adhesive sites</p><p>Bug General characteristics Epidemiology Transmission Virulence Factors Treatment V. Chorlea - net loss of water - Gulf coast/ Africa - Human pathogen Cholera toxin: encoded Abs can shorten Dehyration: rice water - Warm months - Consumption of phage duration of toxin stool contaminated - Bind to cells secretion and - Not invasive water/food - ADP-ribosylating enzyme decrease spread - Acid Sensitive - No person to person (↑ cAMP) - halophilic, can grow in transmision -turns off Na absorption Support with IV absence - increase Cl secretion fluids - caused by serotype O1/O139</p><p>V. para-hemolyticus - requires salt - Gastroenteritis year - consumption of See V. Chorlea round improperly cooked - Septicemia and wound seafood or raw infections in warm months oysters V. Vulnificus - severe wound infections - Eating raw oysters See V. Chorlea and sepsis (sepsis) - Protein capsule protects - Esp. affects ICH: cirrhosis, against phagocytosis and renal fail complement Entero-bacteriaceae Gram negative rods E. coli Motile Lactose fermenter Commensals, or acquired virulence ETEC Weanling diarrhea (ST) - exposure can induce - High infectious dose - Labile toxin similar to Antibiotics decrease Traveler’s diarrhea mucosal immunity (IgA) - Contaminated cholera toxin; activates duration/severity of - Watery diarrhea - asymptomatic carrier food/water (no adenylate cyclase ↑ cAMP diarrhea states person to person) - Stable toxin: ↑ cGMP, - Incubation: 14-50 stimulates CL secretion, Prevent: bismuth hrs inhibits NaCl abs. subsalicylate 4x/day EPEC Infant diarrhea, no - Oral/fecal, hands, Diagnosis: WBC; sometimes foods, tabletops phenotypic culture vomiting - Reservoir: HeLa cells; genotype - Effacing microvilli and asymptomatic kids/ PCR attaching cell adults membrane leads to Rehydrate and Abs activation of signal transduction - Mortality 25-50% EHEC - O157:H7 assoc w/ - age extremes, esp kids - Reservoir: animals - attach Gb3R to renal Diagnosis: culture HUS, causes bloody <10 yrs - contaminated beef, epithelium and damages stool on SMAC, diarrhea (4-10 days), lamb, pultry, apple glomeruli detect non 0157:H7 also fever, cramps (1st) jice, salami, by PCR or DNA - Hus: hemolytic mayonnaise, radish probes anemia, oliguric RF, sprouts thrombocytopenia - Person to person too Do not give - Hemorrhage and - Low infectious dose antimotility drugs or edema of transverse AB (makes it worse) and ascending colon “thumbprinting” Shigella - invasive enteric - s. dysenteriae: developing - human only - invades intestinal Fecal sample: pathogen contries (most severe, only - low infectious dose epithelium (inflammatory leukocyte + -watery diarrhea to 1 w/ shiga toxin) - direct contact, sex, leukocytes in LP) Diagnose w/ DNA Dysentery- freq stools of - s. sonnei: most common food and water - Release inflamm mediators probe/PCR small vol, w/ pus and US, mildest results in blood in lumen blood - s. flexneri/ boydii - Invade colonic mucosa, Treat: Abs reduce - nonmotile, lactose The rest have cytotoxins multiply intracellular and duration of illness nonfermenting - 70% of kids <15 spread from cell to cell, and period of Endemic in homosexual leads to focal mucosal ulcers infectivity, AB males and inflammation resistance is Epidemics in DCC, jails - Shiga toxin inactivates 60S common ribosomal subunit stops protein synthesis Salmonella typhi - Typhoid fever - Host-human - invades across mucosa and - Isolate org from - High daily fevers 4-8 - Person to person hids in mononuclear cells in blood, stool, or (S. typhimurium is most weeks - Low ID, more lymph nodes urine common in US) - invased gallbladder common in PPI and - Multiples and causes (carrier), kidney, and antacid use bacteremia that spreads to - Amp, cefriaxone, reinvasion of gut liver and spleen bactrim mucosa (causes - Multiplys in macrophages inflammation and can in liver and spleen (not killed For carriers use lead to diarrhea) intracellularly) amp+ probenecid or - doesn’t adhere to - Increases then released Bactrim x6 wks endothelium and causes continuous - Motile, lactose bactermia w/ high fevers nonfermenter Salmonella choleraesuis - focal infection: - conditions impairing - Host: pigs - Multiplies in LP - nonlactose vascular endothelium phagocytosis are - more common in - induce fluid secretion by ↑ fermenter and endocarditis or vascular susceptible to bacteremia PPI and antacid use cAMP and prostaglandins biochem properities infections (HbSS, AIDS, leukemia) - get from food, - Enters BS (rapid kill by - Treat ICH and - Diarrhea water, zoonosis phagocytes) bacteremia w/ AB - adheres well (turtles and chickens) Salmonella enteritides - Osteomyelitis (in HbSS) See above - Host: humans/ See above - no AB, due to ↑ and diarrhea animals (2000+) shedding duration - adheres well can cause - more common in I.E., intravascular PPI and antacid use infections - get from food, water, zoonosis Yersinia enterocolitica - Plasmids w/ virulence genes - Resist phagocytosis Yersinia pseudo- - Diarrhea, fever, ab - common in Scandinavian - Zoonotic infections - Plasmids w/ virulence Treat w/ Cipro, 3rd tuberculosis pain for 2 wks and Europe in contaminated genes gen cephalopsporin, - Chronic disease can foods like milk, meat, - Resist phagocytosis bactrim develop water (Belgian - can grow at 4C - Affects mainly terminal chocolates) ileum, if mesenteric - Blood transfusion lymph nodes involved - Incub: 1-10 days (can mimic appendicitis) - nonmotile, lactose nonfermenter</p><p>H. pylori - spiral, gram neg rod w/ - highest colonization due - human primary - Urease + (neutralizes Diagnose: IgM, IgG, corkscrew motility to poor sanitation source stomach acid) IgA antibody ELISA - Gastritis, peptic ulcers, - colonization in US ↑ w/ - fecal-oral trans - pass through gastric - Titer no correlate gastric carcinoma, MALT age (protects against mucosa cause epithelial w/ severe associated lymphoma esophageal reflux) damage - warthin-starry - Stimulates inflame silver stain response (ulcers) - Biopsy specimen: urease+ - urease breath test</p><p>Treat: PPI+ tetra+ metronidazole+ bismuth or amox, clarithro</p>