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Flashcards in Lecture 9 Deck (62):
1

Pathogens that produce disease both inside and outside the GIT

E.coli and Salmonella

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Pathogens that cause disease only inside GIT

Shigella,Vibrio, Campyobacter, H pylori

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Pathogens present in GIT but cause disease only outside

Kebsiella group, Pseudomonas, Bacteroids

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G- rods belong to what family?

enterobacteriacea- primarily in colon of humans and animals as normal flora

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Do gram - rods rely on oxygen?

all are facultative anaerobes except pseudomonas which is an obligate aerobe

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What do Gram - rods have on their cell wall?

Endotoxin

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What does E.coli cause?

Urinary trac infections, travelers diarrhea and neonatal sepsis

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Where is E.coli normal flora found?

in colon and feces

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How do Gram - move?

move with single flagellum and plenty of pili

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Pathogenicity of E.coli

adheres to mucous membranes of jejunum and ilium by pili causes intestinal, systemic and urinary infections- some strains cause watery diarrhea and some cause bloody diarrhea

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What is the most frequent nasocomial infection?

UTI- due to indwelling catheters

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What other type of infection can E.coli cause from UTI?

infection of bladder known as cystitis- pyelonephritis can occur if infection goes further up

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Symptoms of bladder infections

frequent urination along with feeling of need to urinate, nocturne, pain in pubic area, hematuria

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Symptoms of Urethritis

discomfort, irritation or pain at urethral meatus or burning sensation on urination, pyuria, pyrexia, cloudy and foul urine

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Symptoms of kidney infection

symptoms from urethritis as well as emesis, back/side pain, abdominal pain, high spiking fever, night sweats and fatigue

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What E.coli looks like on a lab diagnosis when serious infection

pink colony- ferments lactose
urine examination shows pus cells

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What is travelers diarrhea due to?

drinking water that has been contaminated by sewage

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What is neonatal sepsis due to?

presence of E.coli in vagina of pregnant women

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Treatment for GIT infection

no treatment, self-limiting, supplemental fluid may be necessary

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Treatment for UTI infection

Oral trimethoprim and sulphamethoxazole/cephalosprin and amino glycoside

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presence of what organism in drinking water is indicative of sewage contamination?

coliform organism

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What can be done to remove coliform organisms from water?

chlorination of water

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gram - rod that causes typhoid fever

Salmonella-- only through ingestion

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How does salmonella move?

has a ton of flagellum

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typhoidal species

S.Typhi and S.Paratyphi are fever producing

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non typhoidal species

diarrhea producing- Salm. Typhi murium is most common cause of diarrhea in US

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Mode of transmission of salmonella

ingestion of food and water contaminated with human or animal waste

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Is there an animal source of transmission for S. Typhi?

No- only human

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So typhoid fever is mainly due to...?

water contamination with fecal materials- not animal source

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Symptoms of typhoid fever

severe fever for 3 to 4 weeks, constipation, leukopenia, delirium, tender abdomen, enlarged spleen, rose spots

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Complications of typhoid fever

intestinal hemorrhage/perforation, gall bladder infection can result in chronic carrier state- bacteria passed in feces for long time

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How do you diagnose salmonella in the lab?

organism isolated from stool sample in enterocolitis
+ blood cultures in typhoid- color less colonies on plate- non lactose fermenter

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Treatment for enterocolitis

fluids, electrolytes replacement- no antibiotics

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Treatment for typhoid

ceftrioxone, cipro, ampicillin

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What is sometimes advised to abolish chronic carrier state of salmonella?

Cholecystectomy

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Prevention of salmonella

Public health measures- proper disposal of sewage, chlorination of water, dean hands of those handling food

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Is there a vaccine for salmonella?

yes but not 100% efficacy

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What does Shigella cause?

causes bacillary dysentery- entercolitis

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Can shigella move?

Non-motile: no flagellum --- highly virulent!

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Path of infection from shigella

transmission by fecal-oral route by finger, flies, food, feces-- no animal reservoir (only humans), water outbreaks, disease exclusively GIT invades mucosa of ilium and colon

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Where does shigella cause inflammation?

exclusively in the GIT- ulcerations- do not penetrate gut wall or enter blood stream

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Clinical manifestations of shigella

fever, abdominal cramps, tenesmus (sensation of needing to pass bowels) resolves in 2-3 days (no antibodies or vaccines)

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Treatment for shigella

fluids and electrolytes in mild cases
in sever cases, cipro and bactrim
NO VACCINATION

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Prevention of Shigella

proper disposal of night soils, chlorination, personal hygiene

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What does vibrio cholera cause?

epidemic diarrhea

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Transmission of Vibrio Cholera

transmitted by fecal contamination of water and food, primarily human source

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What does Vibrio Cholera secrete?

enterotoxin which causes massive watery diarrhea without inflammation

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Clinical symptoms of Vibrio Cholera

large watery diarrhea, no cramps, no fever, no inflammation of gut

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What does Vibrio Cholera lead to?

rapid dehydration an electrolyte imbalance-- may cause hypovolemic shock, cardiac and renal failure

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Is the mortality rate high for untreated Vibrio Cholera?

YES- 40%

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Treatment for Vibrio Cholera

fluid and electrolyte replacement, tetracycline

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Prevention for Vibrio Cholera

public health measures and vaccination

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What does H. pylori cause?

gastritis and peptic ulcer

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natural habitat of H. pylori

stomach

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What does H.pylori produce?

an enzyme urease which causes large amounts of ammonia which neutralizes acidity and helps organismal growth and damage of mucosa

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Symptoms of H.pylori infection

recurrent pain in upper abdomen, bleeding in intestinal tract( no bacteremia or dissemination)

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Lab diagnosis of H. pylori

biopsy of gastric muscoa, urease breath test (radio labeled urea is ingested- if present ammonia will be radioactive and radioactive CO2 will be detected)

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Treatment for H. pylori

amoxicillin, metronidazole, pepto-bismol

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What does campylobacter jejuni cause?

enterocolitis in children

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What is the transmission of campylobacter jejune?

fecal-oral transmission from domestic animals (cattle, dogs, chicken)- puppies are the most common source in US

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Symptoms of campylobacter jejuni

watery, foul smelling diarrhea, blood in stools, fever, abdominal cramps

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Medicine for treatment of campylobacter jejnui

erythromycin, cipro, aminogycosides