Flashcards in Lecture 9 Deck (62):
Pathogens that produce disease both inside and outside the GIT
E.coli and Salmonella
Pathogens that cause disease only inside GIT
Shigella,Vibrio, Campyobacter, H pylori
Pathogens present in GIT but cause disease only outside
Kebsiella group, Pseudomonas, Bacteroids
G- rods belong to what family?
enterobacteriacea- primarily in colon of humans and animals as normal flora
Do gram - rods rely on oxygen?
all are facultative anaerobes except pseudomonas which is an obligate aerobe
What do Gram - rods have on their cell wall?
What does E.coli cause?
Urinary trac infections, travelers diarrhea and neonatal sepsis
Where is E.coli normal flora found?
in colon and feces
How do Gram - move?
move with single flagellum and plenty of pili
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
What is the most frequent nasocomial infection?
UTI- due to indwelling catheters
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
Symptoms of bladder infections
frequent urination along with feeling of need to urinate, nocturne, pain in pubic area, hematuria
Symptoms of Urethritis
discomfort, irritation or pain at urethral meatus or burning sensation on urination, pyuria, pyrexia, cloudy and foul urine
Symptoms of kidney infection
symptoms from urethritis as well as emesis, back/side pain, abdominal pain, high spiking fever, night sweats and fatigue
What E.coli looks like on a lab diagnosis when serious infection
pink colony- ferments lactose
urine examination shows pus cells
What is travelers diarrhea due to?
drinking water that has been contaminated by sewage
What is neonatal sepsis due to?
presence of E.coli in vagina of pregnant women
Treatment for GIT infection
no treatment, self-limiting, supplemental fluid may be necessary
Treatment for UTI infection
Oral trimethoprim and sulphamethoxazole/cephalosprin and amino glycoside
presence of what organism in drinking water is indicative of sewage contamination?
What can be done to remove coliform organisms from water?
chlorination of water
gram - rod that causes typhoid fever
Salmonella-- only through ingestion
How does salmonella move?
has a ton of flagellum
S.Typhi and S.Paratyphi are fever producing
non typhoidal species
diarrhea producing- Salm. Typhi murium is most common cause of diarrhea in US
Mode of transmission of salmonella
ingestion of food and water contaminated with human or animal waste
Is there an animal source of transmission for S. Typhi?
No- only human
So typhoid fever is mainly due to...?
water contamination with fecal materials- not animal source
Symptoms of typhoid fever
severe fever for 3 to 4 weeks, constipation, leukopenia, delirium, tender abdomen, enlarged spleen, rose spots
Complications of typhoid fever
intestinal hemorrhage/perforation, gall bladder infection can result in chronic carrier state- bacteria passed in feces for long time
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
Treatment for enterocolitis
fluids, electrolytes replacement- no antibiotics
Treatment for typhoid
ceftrioxone, cipro, ampicillin
What is sometimes advised to abolish chronic carrier state of salmonella?
Prevention of salmonella
Public health measures- proper disposal of sewage, chlorination of water, dean hands of those handling food
Is there a vaccine for salmonella?
yes but not 100% efficacy
What does Shigella cause?
causes bacillary dysentery- entercolitis
Can shigella move?
Non-motile: no flagellum --- highly virulent!
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
Where does shigella cause inflammation?
exclusively in the GIT- ulcerations- do not penetrate gut wall or enter blood stream
Clinical manifestations of shigella
fever, abdominal cramps, tenesmus (sensation of needing to pass bowels) resolves in 2-3 days (no antibodies or vaccines)
Treatment for shigella
fluids and electrolytes in mild cases
in sever cases, cipro and bactrim
Prevention of Shigella
proper disposal of night soils, chlorination, personal hygiene
What does vibrio cholera cause?
Transmission of Vibrio Cholera
transmitted by fecal contamination of water and food, primarily human source
What does Vibrio Cholera secrete?
enterotoxin which causes massive watery diarrhea without inflammation
Clinical symptoms of Vibrio Cholera
large watery diarrhea, no cramps, no fever, no inflammation of gut
What does Vibrio Cholera lead to?
rapid dehydration an electrolyte imbalance-- may cause hypovolemic shock, cardiac and renal failure
Is the mortality rate high for untreated Vibrio Cholera?
Treatment for Vibrio Cholera
fluid and electrolyte replacement, tetracycline
Prevention for Vibrio Cholera
public health measures and vaccination
What does H. pylori cause?
gastritis and peptic ulcer
natural habitat of H. pylori
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
Symptoms of H.pylori infection
recurrent pain in upper abdomen, bleeding in intestinal tract( no bacteremia or dissemination)
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)
Treatment for H. pylori
amoxicillin, metronidazole, pepto-bismol
What does campylobacter jejuni cause?
enterocolitis in children
What is the transmission of campylobacter jejune?
fecal-oral transmission from domestic animals (cattle, dogs, chicken)- puppies are the most common source in US
Symptoms of campylobacter jejuni
watery, foul smelling diarrhea, blood in stools, fever, abdominal cramps