GI- Upper Flashcards
What breaks down breast milk for digestion
Bifidobacterium
What is needed to digest formula
Lactobacilli
Normal flora of the mouth
Strtococcus Neisseria Actinomyces Veillonella Lactobacillus Yeast
What kind of bacteria is found in stomach
Sterile
Streptococcus
Staphylococcus
Lactobacillus
What predisposes you to H pylori
Gastritis
Peptic ulcers
Do you find bacteria in the small intestine
No
Bacteria in duodenum
Aerobic streptococci
Staphylococci
Lactobacilli
Yeast
What bacteria do you find at LI
Anaerobic
Which part of the Digestive system has the most amt of bacteria
LI 10^10-10^12
What is Allogenic
Factors outside the ecosystem affecting the microbrial composition of GI flora
Diet Age Georgraphic location Antibiotics Surgery
How does diet change flora of GI
Vegetarians have lower bacteroides, higher enterococci
How does antibiotics change flora of GI
Makes you susceptible to c. difficile
What is autogenic
Factors affecting GI from within the ecosystem
Environment
Activities of microorganisms
At risk groups of lower GI infections
CHildren <5
Elderly
Immunocompromised
Food hazards
Microbial contamination Naturally occurring toxicants Environment contaminants Nutritional problems Pesticides Food additives
What are the routinely screened bacteria from stool samples
Campylobacter
Salmonella
Shigella
STECs (if stool is bloody)
What is the highest contamination for GI infections
Norwalk virus
What is food poisoning
Toxin in food- short incubation period Toxemia C. Botulinum S. Aureus B. Cereus
What is food associated infections
Consumption of food containing organism
Longer incubation period since organisms need to colonize first
Enteritis
Inflammation of intestinal mucosa
Gastro enteritis
Inflammation of stomach and intestinal linings
Colitis
Inflammation of LI
Enterocolitis
Inflammation of small and large intestine
Dysentery
Inflammation of GI tract and blood and pus in faeces
Acute Diarrhea
Resolves in 2 weeks
Infectious agents
Chronic diarrhea
Persistent Lasts longer than 4 weeks Need to know what meds taken Possible syndrome Parasite
What is the cause of non inflammatory gastroenteritis
Food poisoning
What are the infectious causes of gastroenteritis
S. Aureus B. Cereus C. Botulinum Wild mushroom Ciguatera Scrombroid Shellfish
What are the sx of food borne infections
Non inflammatory diarrhea
Inflammatory diarrhea
What the the pathogens of inflammatory diarrhea
Shigella EIEC Salmonella Campylobactor V. Vulnificus V. Parahaemolyticus Yersinia STEC C. Difficile
What are the pathogens of non inflammatory diarrhea
ETEC EPEC V. Cholerae C. Perfringens B. Cereus Rotavirus Norovirus Adenovirus Astrovirus C.difficile
Which pathogen is not food borne
c difficile
General sx of toxemia
Rapid onset
No fever/faecal leukocytes
Affects CNS and sometimes CNS and Intestines
Characteristics of S. Aureus
Aerobic
Coagulase/catalase +
Heat stable enterotoxin production
Is S. aureus found naturally in humans
yes
What are the toxins released by s. aureus
Exotoxins (8)
A&D typically implicated
What are the sx from s. aureus
Neurological (Vomiting)
Enteric (Diarrhea)
Self limiting recovery 24-48 hours
Is adenylate cyclase stimulated by s. aureus
No
Foods at risk for s. aureus
Meat Bakery foods Dairy produce Fruit Veg Salad
What causes the spread of s. aureus
poor food handling
When is highest incidence of s aureus
summer
Winter holiday periods
S. aureus confirmation test
Coagulase test
Bacillus cereus characteristics
Gram + Rods Aerobic Spore former Emetic toxin and enterotoxin
How does bacillus cereus spread
Air
How does b. cereus look under blood agar
Wrinkly
Baby sx to botulism
constipation Lethargy Suck/gag reflex diminish Head control lost Infant becomes flaccid
Tx for botulism
Antitoxin hepatavalent
Baby- immune globulin
Mushroom toxin characteristics
Short acting- wild mushrooms
Long acting- uncultivated mushrooms (amantia toxin)
Mycotoxigenic fungi characteristics
Aflatoxin
Contamination of nuts
Causes: acute necrosis, cirrhosis, carcinoma of liver
Ciguatera poisoning characteristics
Caribbean tropical fish
Large predatory reef fish
Acute GI sx- Watery diarrhea
Neurological sx- paresthesia, temp reversal
Scromboid poisoning
Non allergic histamine
Tuna mahi mahi bluefin
metallic taste
Shell fish poisoning
Brevetoxin
Paralytic shellfish poisoning
Dinoflagellate algae
Saxitoxin
Muscular in coordination
What does ecoli activate via its toxins
Heat Labile (LT)- adenylate cyclase Heat stable (ST)- gunylate cyclase
Action of E coli toxin
B binding subunit adheres to GM1 receptor of epithillia cells. Allows for subunit A entrance. Entry of A activates G proteins of adenylate cyclase… hyper secretion of electrolytes and water
What is a way to contract c. perfringens
Not well cooked pig
Papua new guinea
WHat type of c perfringens is food borne
Type A
What is the toxin from c. perfringens called?
CPE
WHat are the parasitic causes of diarrhea
Cryptosporidium
Cyclospora
Entamoeba
Giardia
CHaracteristics of Rotavirus
11 segments
ds RNA
What are the important serotypes of rotavirus
G1-G4
Epidemiology of rotavirus
ages 4-5
Asia, africa, latin america
Developed countries- winter
Less developed countries- summer
What causes rotavirus
unsafe water
When are kids asymptomatic from rota virus
5 years and older
6months and younger
Pathogenesis of rotavirus
Fecal oral
Replication on epithelial cells of SMALL intestine
peaks in 8 days
Histopath of rotavirus
Shortening and blunting of villi
Clinical sx of rota
Sudden watery diarrhea
Complications from rota
Extreme dehydration (more severe than cholera)
Detection of rota
Latex agglutination
EIA
Sapovirus is mostly seen in this population (norovirus)
Elderly
in Winter
What is the main sx of sapovirus (norovirus)
vomiting
Transmission of noro virus
fecal oral
Spares large intestine (no faecal leukocytes)
How long does noro last
24-60 hours
Best way to detect noro in stool
RT-qPCR
Adenovirus characteristics
Icosahedral
ds DNA
40/41 serotype, Group F
Target of adenovirus in GI
Small intestine
Epi of adeno
Children less than 5
Diarrhea w/ w.o vomiting
Astrovirus characteristics
non enveloped
star shaped
Scotland
+ RNA
Hepatitis A transmission
Fecal oral
Non enveloped
ss + RNA
Hep E
Non enveloped
icoshedral
Endemic in India
Inflammation Diarhea overview
Food associated invasion of intestines
Sx- bloody diarrhea
Toxin: enterotoxin/ cytotoxin
Shigella groups
A-D
A is the most severe
What are the virulence factors for Shigella
Endotoxin (O toxin) Exotoxin: Neurotoxin causes coma meningismus NAD glycohydrolase (destroys NAD in cells- cell death)
Main sx of shigellosis sonnei
Watery diarrhea
Main sx of shigellosis flexneri
Stool mucus
Shigella pathogenesis
Invades distal ileum and colon through specialized epithelial cells (M cells) that overlie mucosal lymphoid follicles → escapes endocytic vesicle → replicates intracellularly, spreads cell-to-cell
Action of shiga toxin
cytotoxin- inhibit protein synthesis
Enterotoxin: produces diarrhea
Exotoxin: inhibit sugar aa absorption in SI
Neurotoxin effects
Epi shigella sonnei
Children <5
Epi shigella flexneri
Homosexuals
Transmission of shigella
Food
Fingers
Flies
Feces
Diagnosis of shigella
MacConkey agar
S-S agar
Stool is watery to bloody
General characteristics of shigella
Gram - No fermentation lactose No utilization of citric acid No H2S production No gas from glucose
Which shigella produces H2S
Shigella flexneri
Which is more infective shiga and enteroinvasive
Enteroinvasive Ecoli only 10 organisms needed for infection
Enteroinvasive E coli pathogenesis
Invasion in LI
Enters via endocytosis
Inhibits protein synthesis
Dead wbc, rbcs, mucosal cells in stool
3 types of clinical sx of salmonella
Gastroenteritis (s. typhimurium, s. enteritidis, s. newport)
Septicemia (s. cholerasuis)
Enteric Typhoid fever
Review chart in ipad for Salmonella (bookmarked)
Enteroinvasive vs septic vs typhoid
book mark
Where does Salmonella replicate
pyers patches
Where does salmonella infect
Columnar epithelial cells of the small intestine
What is most at risk for carrying enterocolitis
poultry
Highest incidence of salmonella
Serotype enteritidis
What besides food carries salmonella
reptiles
Enteric fever characteristics
Only found in travelers from asia mexico india
S. typhi
What is one weird fruit that carries salmonella typhi
Mamey fruit pulp
Diagnosis of salmonella
Macconkey agar
General characteristics of salmonella
Motile Gram - rod No fermentation lactose H2S production Gas from glucose serotype
Clinical diagnosis of salmonella
Hx of travel
Rose colored spots on abdomen
Examine blood for absece of eosinophils
Positive widal reaction
Characteristics of campylobacter
Gram - non sporing microaerophilic Does not ferment CH2O Catalase +
Epi of campylobacter compared to h pylori
Campylobacter- Spike in summer
H pylori same level each season
What is the #1 food borne disease
Campylobacter
Pathogenesis of campylobacter
Invasion
Toxin: Endo/entero (watery diarrhea)
Cytotoxin: Verotoxin similar to shiga
Clinical sx of campylobacter
sx after 3-5 days of ingestion
Profuse diarrhea sometimes Green
Fever
Prostration
Campylobacter lab
Culture: Spreading, grey color
Catalase/oxidase definitive diagnosis
Microscopy: gram- (presumptive diagnosis)
Characteristics of yersinia
Psychrotroph- facultative psychrophile
common in children < 7
What is the toxin released by yersinia
ST enterotoxin
Increases cGMP
How long does yersinia last
14-21 days
What is a complication related to yersinia
Reactive arthritis
Induced polyclonal T cell stimulation (toxin)
Lab diagnosis of yersinia
MacConkey look for pinpoints
Specialized media for yersinia
General characterisitc of non cholera vibrio
Not agglutinated
Halophilic organisms
Coastal waters
Vibrio parahaemolyticus
Eat raw seafood
look out for sushi
Watery diarrhea
Vibrio vulnificus
Diarrhea
INfection of cuts
Skin lesions
Diagnosis of non vibrios
Screen stool for oxidase
TCBS agar
Sucrose: differentiating agent
Sucrose - : v. parahaemolyticus, v. vulnificus
Pathogenesis of EAEC
- Initial adherence to intestinal mucosa (fimbriae)
- enhanced mucus production- biofilm
- cytotoxin production - damage to intestinal cells
Prognosis of EHEC
Life threatening
Haemorrhagic colitis
Uremic syndrome: renal failure
Toxin for EHEC
Phage encoded cytotoxin verotoxin
VT1: biochem structure similar to shiga toxin
VT2: B toxin bound to receptor allows for subunit A into cell. Activates 28 rna
Pathogenesis of EHEC
No invasion
Attaches via fimbrae
Diagnosis of e coli
Pink colonies on mac conkey agar Sortibol macconkey agar ETEC ELISA DNA probe
What are the antibiotics associated with C diff
ampicillin
Cephalosporins
clindamycin
Amoxicillin
Toxins in C diff
Toxin A: Enterotoxin
Toxin B: cytotoxin
Clinical sx of c diff
Varies
watery diarrhea
non bloody
hyposlcumineia, leukocytosis
Diagnosis of c diff
presence of pseudomembrane
Tx of c diff
Discontinue antibiotics
Tx w/ vancomycin, metronidazole
Gastric cancer w. H. Pylori seen with
Low acid production
Pan gastritis
Peptic ulcer w. h. pylori seen with
high acid production
antral predominant gastritis
What allows for h. pylori to survive at low pH
Urease
Virulence factor for H. pylori
cagPAI
VacA cytoxin
Non invasive tests for h pylori
Breath (rapid presumptive)
Serology (definitive)
Invasive tests for h pylori
Urease (rapid presumptive)
Culture (definitive)
Histo (definitive)
Tx for h pylori
Triple/quadruple therapy
Gastrointestinal abscess pathogenesis general
Reduced O2 tension/ oxidation reduction potential
Impaired blood supply
Provides anaerobic environment
Common cause of peritonitis
Primary: e coli, tb, n. gonorrhoeae, c. thrachomatis
secondary: Spillage of bacteria from GI into peritoneal cavity
Common cause of diverticulitis
bacteroides
Ecoli enterococci
Common cause of pancreatic absces
e coli Klebsiella Enterobacter enterococci streptococci
Diagnosis of abscess
location of pain
WBC count
imagining
Treatment of abscess
improve vascular perfusion
eliminate source of infection
Aspirate infected exudate
Treat complications
Anaerobes are resistant to what
penicillins
cephalosporins
Amino glycosides
Non toxic b. fargils promotes what
Mucosal health
Toxic b fragilis causes what
inflammatory diarrhea coloniziation
Toxins 1-3