Transcript Blue Lines and Gradients

Microbiology

Gastrointestinal diseases

Salmonella
Denisa Moorehouse
Please turn off your cell phones and enjoy the Show!
Salmonella
Salmonella (S.) is the genus name for a large number
(over 2,500) of types of bacteria.
Salmonella
Rod-shaped bacteria
Flagellated
Gram negative
Each type is distinctly
identifiable by its specific
protein coating (serovars)
Species Question
Various species of the
genus Salmonella ???
(f.e.:S. typhi, S. typhimurium,
S. enteritidis, S. cholerasuis,
S. saintpaul,...)
OR
Serovars of only two species:
S. enterica and S. bongori ???
History
Bacteria were first isolated:
1)
In 1885
2)
From pigs
3)
By Theobald Smith
Named after D.E. Salmon – Smith's director
How Can We Get It?
Is a food-borne illness; can't smell or taste in the food or its
presence can't be seen
Salmonellosis (infection) spreads by ingestion of Salmonella
bacteria
Can contaminate almost any food type; water
Outbreaks: raw eggs, raw meat (ground beef and other poorly
cooked meats), egg products, fresh vegetables, cereal,
pistachio nuts, and contaminated water
Contamination can come from animal or human feces during
the processing or harvesting
Potential direct sources of Salmonella are pets such as turtles,
dogs, cats, most farm animals, and humans that are infected or
are carriers of the organisms
Who Can Get It?
Known to cause disease in humans, animals, and birds
(especially poultry)
Worldwide
Approx. 40,000 cases/year in US get reported
CDC estimate 1.4 mil/year
Approx. 400 die each year
from acute salmonellosis
Children <1, old people,
people that take anti-acid,
people w/weakened immune
system
Diseases In Humans
1) Salmonellosis
2) Bacteremia – (presence of live bacteria in the bloodstream)
bacteremic illnesses:
a)
Typhoid fever
b)
Paratyphoid fever also called Enteric fever
Disease - Salmonellosis

Infection - 1 million–1 billion bacteria, but some can be
infected with fewer vacteria

Gastroenteritis characterized by nausea, vomiting & diarrhea

Reduced or eliminated by stomach acid

Symptoms develop 8-72 hours after infection

If bacteria gets into intestine:
– attaches and penetrates the cells
– toxins produced by bacteria can damage and kill the cells
that line the intestine
Disease - Bacteremia

Some Salmonella can survive in cells of the immune system

Can reach bloodstream & cause blood infection–bacteremia

Bacteria can spread from the intestine into the intestinal lymph
nodes, liver, spleen and other organs via the blood where they
multiply
Disease – Typhoid fever





Most commonly caused by the bacteria Salmonella typhi
Salmonella can be shed from the liver to the gallbladder,
leaving the affected patient a chronic carrier of the
organisms
Salmonella can then be shed with the bile from the
gallbladder into the feces and then may infect other people
High fevers over 104, sweating, inflammation of the stomach
& intestine, diarrhea, approx 50% develop slow heart beat &
30% slightly raised red or rose-colored spots
Common in developing countries (<400 US)
Disease-Paratyphoid fever

Also called Enteric fever

Resembles Typhoid fever

More abrupt onset, milder symptoms and a shorter course
Symptoms
I woke up in the middle of the night feeling headachy and I put it
down to sinus. The next day I felt bloated all day and when I
finished work I was exhausted my muscles and everything were
aching and I had a bloated feeling still in my belly. For the next
day I had really bad stomach cramps and felt very bloated
however I just put it down to stress. The next morning I had to
work at 7am and I felt very sick, but was determined to go to
work, so when done with my shower I started to dry off and
then I fainted. After that the diarrhea started which went on
with very bad stomach pains for about 3 days with fevers and
chills. I would wake up about 5 times a night with very bad
stomach pans only to be relived when I went to the bathroom. I
pretty much had no energy and my body was exhausted. I went
to see the doctor who took a stool sample and sent it away.
Symptoms

Nausea

Vomiting

Chills

Headache

Fever

Delirium

Pins & needles in legs



Rare cases – pains in the joints, irritation of the eyes & painful
urination – Reiter's syndrome that can cause chronic arthritis in
the feet & ankles
Can cause dehydration & even a death
Rash called "rose spots” only of typhoid fever (1/4 inch red spots
that appear most often on the abdomen and chest)
Diagnosis





The culture of the feces is tested for Salmonella
Occasionally, Salmonella can be cultured from blood samples
(An elevated white blood cell count in blood)
An ELISA test on urine may show Vi antigen specific for the
bacteria
Serovars are identified by serotyping (detecting bacterial
proteins by using specific immunological tests)
Often is diagnosed because of the outbreak – it is difficult to
determin the outbreak because of many possible toxins out
there that cause food poisoning.
Treatment






Antibiotics such as aciprofloxacin for 10-14 days
Some doctors recommend no antibiotics because disease can selflimit itself; some investigators believe antibiotics prolong the
carrier state
Cancer, AIDS and other immunosuppressed patients should
receive antibiotics
Typhoid or enteric fevers needs to be treated with antibiotics,
often given intravenously.
For Salmonella infections - antibiotics: fluoroquinolones and thirdgeneration cephalosporins (children)
Carriers can infect other people and need to be cured of the carrier
state. About 85% of carriers can be cured by a combination of
surgery to remove their gallbladder and antibiotic treatments.
Prognosis
4-7 days symptoms usually disappear. The illness usually resolves in 2
to 4 weeks with treatment. The outcome is likely to be good with early
treatment, but becomes poor if complications develop. Cases in
children are milder, and are more debilitating in the elderly.
Prevention


Cleanliness
Hand washing with soap and hot water - after handling eggs,
poultry, and raw meat

Antibacterial soaps

Chlorine-treated drinking water - washed produce

Not eating undercooked foods such as eggs, meat or other foods


Avoiding direct contact with animal carriers of Salmonella (turtles,
snakes, pigs,...)
Vaccines are available only for typhoid fever. The CDC does not
recommend that everyone get vaccinated for typhoid fever, only
those who travel into developing countries
Sources
Davis, Charles. “Salmonella.” 17 Nov. 2009.
<http://www.medicinenet.com/salmonella/article.htm>
CDC. “Salmonella Questions and Answers. ” 17. Nov. 2009.
<http://www.fsis.usda.gov/factsheets/salmonella_questions_&_answers/index.asp>