Question | Answer |
Gram + bacillus, SPORE FORMING, strict anaerobe
produces seven different strains of exotoxin depending on strain of bacteria | Clostridium botulinum |
how many different types of toxin are produced by each strain of Clostridium botulinum | one toxin per strain
Toxins are A,B, C1, D, E, F and G |
What are the possible sources of infection with Clostridium botulinum | ingesting contaminated foods w either bacteria or simply ingesting toxins produced by the bacteria |
What is the progression of infection if you just eat toxins of Clostridium botulinum | Toxin Resists destruction in stomach
is absorbed by intestines into bloodstream
toxin affects motor neurons inducing paralysis and death |
What is the progression of infection if you eat auctual bacteria Clostridium botulinum | Bacteria grow in intestines
produce exotoxins
bacteria eventually get cleared by normal flora of intestines and immune system |
what are the s/sx of ingestion of toxins (botulism poisoning) | Progressive paralysis leading to death |
What aret hte s/sx of intestinal botulism (ingestion of bac) | variable degrees of paralysis from lethargy to respiratory failure
-most often in immunocompromised adults and infants
-may also infect dirty wounds |
What are exotoxins compoused of | A and B subunits
B subunit- Bind receptors at nerve terminals
A subunit- blocks neurotransmitter release |
What can be given after botulism infection/poisoning that will stop progression of s/sx | anti-toxin can be given but must be delivered rapidly |
What will clear Clostridium botulinum bacteria from intestines | immune system will eventually clear bacteria |
What is the tx for intestinal botulism | Anti toxin
suppoortive tx until bacteria is cleared
-feeding tube
-respirator
-etc depending on level of paralysis from exotoxin produced |
What is the tx for botulsim poisoning (ingestion of just the toxin) | give anti-toxin |
-Gram positive bacillus
-Spore forming, anaerobe
-Produces a double zone of hemolysis on blood agar | Clostridium perfringens |
What are the sources of infection w/ Clostridium perfringens | food poisoning- one of the most common causes of food poisoning |
What is the progression of infection w/ Clostridium perfringens | ingestion of spores or bacteria
growth in intestines and production of toxins
symptoms appear
bacteria are cleared |
what are the s/sx of food poisoning w/ Clostridium perfringens | water diarrhea with abdominal cramps occuring 7-15 hours after eating
-less frequently associated w/ nausea, vomiting, fever |
If you get a severe infection w/ Clostridium perfringens what will the s/sx change from the typically water diarrhea | acute onset of severe abdominal pain and diarrhea usually blood between 5-6 hours after ingestion, often accompanied by vomiting |
Do you need a vaccination for food poisoning | no it is self-limiting and usually clears within 48 hrs |
What is the tx for food poisoning | symptomatic tx and hydration as needed |
Gram positive bacillus
Spore forming, facultative anaerobe
b-hemolytic | Bacillus cereus |
What is the emetic syndrome of Bacillus cereus infections | ingest toxin that resist digestion
sympotms start |
What is the progression of infection of diarrheal syndrome of Bacillus cereus | Ingest bacteria or spores
bacteria grows in intestines and produces exotoxins
symptoms begin
then bacteria is cleared |
What are the s/sx of emetic syndrome of Bacillus cereus | nausea, vomiting within 1-6 hours of eating, one third present w/ diarrhea
-caused by eating preformed toxins |
What are the s/sx of diarrheal syndrome of Bacillus cereus | abdominal cramps and diarrhea 8-16 hours after eating
caused by production of toxins after bacterial growth |
is there a vaccine available for Bacillus cereus | no, most cases are self limiting and short duration |
What is the tx for Bacillus cereus | symptomatic only |
Gram positive cocci
Coagulase positive (important diagnostic)
b-hemolytic | Staphylococcus aureus |
What are the sources of infection of food poisoning from Staphylococcus aureus | Ingesting preformed toxins
S. Aureues can cause many other types of diseases apart from food poisoning |
what is the progression of infection of food poisoning from Staphylococcus aureus | 1 ingest enterotoxins
2 entertoxins casue
-super antigen like effect (polycolonal stimulation of t cells to secrete cytokines
-stimule upper GI neurons to induce vomiting reflex
3 symptoms rearely last more than 24 hours |
what are the s/sx of food poisoning from Staphylococcus aureus | abrupt onset of nausea, vomiting, and abdominal cramps
-infrequently associated with diarrhea |
is there a vaccine for staph aureues | no, infection is self-limiting and short duration |
what is the tx for food poisoning from Staphylococcus aureus | symptomatic tx
is the 2nd or 3rd leading cause of food poisoning |
Gram negative bacillus
Facultative anaerobe
Most produce H2S, and do NOT ferment lactose
Genetically diverse species
(many serotypes and adaptations | Salmonella |
what are the main sources of infection w/ salmonella | ingesting infected foods that were improperly maintained
- mostly POULTRY, milk, EGGS, and egg products |
what is the progression of infection from Salmonella | 1- ingest cont food
2- bacteria pass through intestinal mucous and epithelium to LAMINA PROPRIA
3- induce inflammatory response and symptoms begin
4- clearance of bacteria |
What are the s/sx of salmonellosis | -abdominal cramps, fever, chills, vomiting, and diarrhea
-symptoms start 1-2 days after meal and last 3-4 days |
What complication can arise from salmonellosis mostly in elderly, immune compromised and neonates | Bacteria in invasive and can cause bacteremia |
What type of immune response do you get to Salmonella | Both cellular and humoral immune responses to infection |
what is the tx for salmonella | hydration
antibiotic only for prophylaxis from bacteremia in at risk groups |
What GI infections have short incubation time of 1-6 hours because they have preformed toxins | S. Aureus
C. Botulinum (Botulism poisoning)
B. Cereus (Emetic Syndrome) |
What GI infections have long incubation time to GI symptoms 8-16 hours because bacterial growth precedes toxin release | -C. Perfringens
B. Cereus (diarrheal syndrome)
E. Coli
V. Cholera
C. Botulinum (intestinal botulism) |
Giardia lamblia (intestinalis)
Cryptosporidium (parvum)
Cyclospora cayetanensis
Entamoeba histolytica | Protozoan Pathogens |
What is the common diagnostic method for Protozoan Pathogens | microscopy of fecal samples looking for cysts |
Flagellated protozoan
Trophozoite carries two (2) nuclei
Cyst is after fission and has 4 nuclei | Giardia lamblia (intestinalis) |
what is the source of infection w/ Giardia lamblia (intestinalis) | drinking contaminated water
fecal to oral route (daycare centers)
less common
eating contaminated foods |
What is the progression of infection w/ Giardia lamblia (intestinalis) | ingest cytst
excyzoites release
differentiates into trophozoites
that being to replicate by binary fission |
How many cysts are needed to initiate infection of Giardia lamblia (intestinalis) | as few as 10-100 cysts |
How common is giardiasis | one of the most common parasitic diseases world-wide |
what are the s/sx of giardiasis | asymptomatic to severe diarrhea
malabsorption and weight loss |
How can giardiasis be prevented | boiling or filtering water |
what is the tx for giardiasis | quanicrine or metronidazole |
Sporozoan
Have alternative asexual and sexual life cycles depending on environment
Like most sporozoans it is an obligate intracellular parasite | Cryptosporidium (parvum) |
What is the most common source of infection w/ Cryptosporidium (parvum) | drinking contaminated water
also eating contaminated food |
what are the s/sx of Cryptosporidium (parvum) | fever
loss of appetite
nausea
vomiting
headache |
How long do s/sx of Cryptosporidium (parvum) generally last | 10-14 days cyst can be shed for 2 weeks after symptoms clear |
What groups are most likely to be infected by Cryptosporidium (parvum) | young children
immune compromised |
What is the tx for Cryptosporidium (parvum) | no effective tx just prevention |
how can you detect Cryptosporidium (parvum) | modified acid=fast stain with concentration method allows bright red ooctyes to be detected |
Sporozoan
Have alternative asexual and sexual life cycles depending on environment
Excreted oocysts are non-infectious and must mature in the environment
Therefore person-to-person spread is NOT possible | Cyclospora cayetanensis |
what is the source of infection of Cyclospora cayetanensis | eating contaminated foods |
what are the s/sx of cyclosporiasis | Fatigue
loss of apetite
myalgias
vomiting
water diarrhea
flatus
weight loss |
typicall how long do s/sx of cyclosporiasis last | s/sx last 1-2 weeks but my occur as cyclical relapsing up to 7 weeks later |
Are exreted oocytes infectious | no they are immature and non-infectious |
what is the tx for Cyclospora cayetanensis | trimethoprim-sulfameithoxazole
prevenition is key sanitation in food and water |
how can you dx Cyclospora cayetanensis | shows fluorescence under UV light |
Ameoba
Still has trophozoite and cyst stages/forms
Feed on bacteria and tissue cells
Including erythrocytes
Two species | Entamoeba histolytica
E. histolytica – More pathogenic
E. dispar – Will not secrete toxins or spread outside the GI tract |
what is the progression of infection with Entamoeba histolytica | 1- ingest cyst from contaminated food or water
2- excysting in intestine to become trophozite
3- encysts
4- can leave intestine and get to liver and for hepatic abscesses |
what are the s/sx of intestinal disease of Entamoeba histolytica | can by asymptomatic
abdominal pain ( can be severe)
frequent bowel movements, tenesmus
Can develop Amebic Dysentary:
-bloody bowel movements up to 20/day |
What can develop if Entamoeba histolytica has extraintestinal sites of invasion | you can get amoebic liver abscess
or abscess in brain, lung, GI tract |
What are the s/sx of amoebic liver abscess from extraintestinal invasion of Entamoeba histolytica | fever
RUQ pain w/ tender hepatomegaly
LFTS are normal
Jaundice is unusual
abscess will be visualized in CT/MRI upper right lobe is common site |
What is the tx for intestinal infection of Entamoeba histolytica | diloxanide furoate |
What is the tx of extraintestinal infection w/ Entamoeba histolytica | metronidazole and tinidazole |
What sets protozoan infections arpart from the other GI infections | typically protozoan infection last longer than bacterial infections |