GI Tract Diseases

gut-associated lymphoid tissues (GALT)

collection of multifollicular structures, including the tonsils, Peyer’s patches, appendix, colonic and cecal patches

Enterobacteriaceae

large family of small, non-spore-forming gram-negative rods

many inhabit soil, water, decaying matter, and the large intestines of animals (including humans)

account for almost 50% of hospital infections

all ferment glucose, are oxidase negative, and catalase positive

divided into coliforms (lactose fermenters) and non-coliforms (non-lactose fermenters)

E. coli

microbe associated with 70% of travel-associated diarrhea

red/pink

colorless

on MacConkey agar, E. coli will generate ____ colonies whereas Salmonella will be _______

endotoxins

membrane compounds of gram-negative bacteria that gives an inflammatory response in the host

ex. LPS

exotoxins

secreted proteins which act locally and at distance of the bacterial colonization site

in gram-negative bacteria, these include botulinum toxin produced by Clostridium botulinum, toxin of E. coli O157:H7

pathogen-associated molecular patterns (PAMPs)

molecules on microbes like bacteria and viruses hat are essential for their survival and are recognized by the innate immune system as foreign

pattern recognition receptor (PRR)

host immune proteins that detect and bind to molecules on pathogens

ex. LPS binds TLR4 (which is one of these)

major pathogenic strains of E. coli

EPEC (enteropathogenic E. coli)

EHEC (enterohemorrhagic E. coli)

EIEC (enteroinvasive E. coli)

ETEC (enterotoxogenic E. coli)

hemolytic uremic syndrome (HUS)

E. coli O157:H7

causes hemorrhagic syndrome and kidney damage

Salmonella typhi

causing agent of typhoid fever

Salmonella enterica serovar typhimurium

strain of Salmonella that’s responsible for food borne illness

Salmonella enteritidis

causing agent of animal salmonelloses

carriers of Salmonella enteritidis

cattle, poultry, rodents, reptiles, animal and dairy products

type 3 secretion system

yersinia, salmonella, and shigella species use the needle to provide the bacterial protein to the host

S. dysenteriae

S. sonnei

S. flexneri

S. boydii

species that cause Shigellosis or shigella dysentery

Campylobacter

causes 1.5 million illnesses each year in the US

major pathogen: Campylobacter jejuni —> causes diarrhea —> most common causes of GBS or Guillain-Barre Syndrome and its lead to paralysis

Camylobacter jejuni infection

causes diarrhea and is one of the most common causes of GBS or Gullain-BArre Syndrome and it leads to paralysis

Clostridium difficile

acute diarrhea that’s the most concern to the CDC due to its antibiotic resistance characteristics

responsible for antibiotic-associated colitis as well

cholera

caused by vibrio cholerae

rare in the US and other industrialized nations

Vibrio cholerae O1 and O139 strains with cholera toxin cause this

diarrhea is with rice water stool

vibrio cholerae

bacteria that causes cholera

vibrio cholerae O1 and O139

cholera toxins

cryptosporidiosis

microscopic parasite that causes the diarrheal disease with same name

viral diarrhea

rotavirus

norovirus

rotavirus

commonly causes severe, watery diarrhea and vomiting in infants and young children

C. perfringens

causing agent of botulism

C. perfringens

releases toxin botulin which is carried to neuromuscular junctions and blocks the release of acetylcholine, necessary for muscle contractions

involved in botulism

dental carries

most common noncommunicable disease worldwide

alpha hemolytic Streptococcus mutans = main cause

presence of polymicrobial consortium of bacteria and dietary carbohydrates are responsible

Streptococcus mutans

causing agent of dental carries

mumps

contagious disease caused by a virus mumps or paramyxovirus

typically starts with a few days of fever, headache, muscle aches, tiredness, and loss of appetite

most people will have swelling that ultimately causes the puffy cheeks and a tender, swollen jaw

mumps virus or paramyxovirus

causing agent of mumps

hepatitis

inflammation of the liver

often caused by a virus

common types: A, B, and C

heavy alcohol use, toxins, some medications, and certain medical conditions can cause this

B and C can cause liver cancer

symptoms of acute form can include fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, dark urine, light-colored stools, joint pain, and jaundice

hepatitis A

food-borne illness and can be spread through contaminated water and unwashed food

hepatitis B

can be transmitted through exposure to contaminated blood, needles, syringes or bodily fluids from mother to baby

chronic disorder and in some cases may lead to long-term liver damage, or liver cancer

hepatitis C

only transmitted through infected uropathogenic E. coli (UPEC) enters the urinary tract and travels to the bladder to cause cystitis

if left untreated, can ascend further into the kidneys to cause pyelonephritis

giardia and Entamoeba histolytica

parasites that cause chronic diarrhea

Entamoeba histolytica

parasite that causes chronic diarrhea

occurs via ingestion of mature cysts from fecally contaminated food, water, or hands