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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