Week 3 - C.Diff Case Study Flashcards by Thomas Krumme

Hfow many americans die each year from c.diff infections?

500,000

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How is c.diff transmitted?

C. diff- transmitted fecal-oral route and hospital workers and devices (fomite) may be intermediaries

Acquired through the ingestion of endospores

Increase in incidence and severity possibly due to the emergence of more virulent strains like B1/NAP1/027, which produce more toxin as well as binary toxin

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nosocomial

Disease that originates in the hospital..

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What are some risk factors for CDI?

Living with infants (84% are carriers)

Taking an antibiotic

Gastric acid suppression - proton pump inhibitors

Antineoplastic (anti cancer drug)

Hospitilization

Immunocomproamised or elderly individuals

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What does an antibiotic do that increases the risk for acquiring C.Diff?

Antibiotics diminish healthy bacteria allowing C. diff to multiply and begin producing toxins

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How do proton pump inhibitors increase risk for C.Diff?

Acidic environment is inhibited and therfore is less effective in killing foreign organisms when they enter the body

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Why do C. Diff infections frequently reoccur?

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What are symptoms of C. Diff infection?

Fever

Abdominal pain

Watery diarrhea (key symptom)

-3 or more loose stools for 1-2 days sans blood

Dehydration

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Pseudomembranous Colitis

Severe complications include perforation of colon, dehydration, death

Sepsis- inflammation leading to decrease in blood volume

Toxic megacolon becomes so
swollen that it creates pressure on lungs making breathing difficult

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DDx

Diarrhea can be side effect from many antibiotics

So first step to see if it is C.Diff is to STOP antibiotic

Watery diarrhea is often caused by viruses (rotavirus, Norovirus)

Bacteria (E. coli 157:H7, Vibrio cholerae, Campylobacter, Salmonella, Shigella, Yersinia, and Clostridium difficile)
Protozoan (Giardia, Cryptosporidium, and Cyclospora)

Most if these infections are self-limiting and not life-threatening, but knowing cause is critical for choosing the correct antimicrobial

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C. Diff Diagnosis

Positive stool test for toxin

Increased WBC > 15,000 cells/mm3

Direct visualization by sigmoidoscopy of pseudomembranous colitis

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What is ELISA?

Enzyme linked immunosorbent assay

It tests for toxin A and B, some strains are A-neg and B-pos

If target substance is present in immobilized sample then peroxidase enzyme
generates purple color or can use fluorescence to detect
Toxin only stable for 2hrs

Some pts will be false negative* so more tests may need to be done

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What test is recommended over ELISA?

GDH

C. Diff culture - problem is that pts may carry strain but aren’t having infection.. not used any more.

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What is pseudomembranous colitis composed of?

Neutrophils, dead epithelial cells, and inflammatory debris

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What is a general feature of the class of bacterial Clostridium?

They produce more toxins than any other bacteria genus

Not all of the toxins cause disease*

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What do clostridium endospores do outside of host?

What is basic outline of endosport to active bacteria?

Allows stability of the bacteria..

What is the pathology of C. Diff?

Healthy microbiome in gut suppresses C. Diff growth

When microbiome is killed (antibiotic) C. Diff can proliferate and the toxins are expressed

Both A and B exotoxins bind recepters to the host colon walls and are glucosylated by glucosyltransferases

Toxin A (enterotoxin) activates the inflammatory cascade and disrupts the intercellular tight junctions causing fluid secretion, mucosal injury, edema, and inflammation.

Toxin B (cytotoxin) disrupts the cytoskeleton, leading to mucosal injury and activation of the inflammatory cascade.
 Inflammation results in fever, watery diarrhea, increase in white blood cells

Draw out the infectoin of C. Diff in gut

How to prevent spread of C. Diff?

Some of the EPA approved hospital disinfectants do not kill C. diff spores even though they said they did on the labels
Alcohol-based disinfectants are not effective against spore forming bacteria.

What are 6 steps of prevention of C. Diff?

Decontamination

Sterilization

Disinfectant

Antiseptic

Sanitizer

Aseptic

Decontamination

occurs prior to sterilization doesn’t remove microbes but removes chemicals, radioactivity to make safe to handle

Sterilization

destroys all living organisms, viruses, and endospores so they are no longer able to reproduce

Disinfectant

reduce organisms to a low enough level that disease is unlikely; inanimate objects since often too toxic to use on human tissues

Antiseptic

microbicide safe to use on human tissue

Sanitizer

decrease number of microbes to a safe level but doesn’t eliminate

Aseptic

procedure performed under sterile conditions

What factors effecg sterilization?

Concentration of microbe or chemical Time over which the agent is applied Temperature (higher temp. takes less time) Type of organism Material bearing the microorganism (dirt) May affect normal flora -absent growth does not necessarily indicate sterility

Draw out the diffeent micro organisms in order form resistant to susceptible..

Methods of sterilization

A patient being treated with clindamycin for aspiration pneumonia develops diarrhea. The stool contains a toxin that kills cultured epithelial cells. Stool culture grows an anaerobic gram-positive rod. The same organism is cultured from the patients’ bed pan. Which method will sterilize the bed pan? A. Boiling 45 minutes B. Benzalkonium chloride C. Ethylalcohol 1 hr D. Saturated steam 121°C 15 min. E. Heating in an oven 150°C 30 min

A. Boiling 45 minutes (must boil for \>6hr) B. Benzalkonium chloride 1hr (dissociates cell membrane lipids) C. Ethylalcohol 1 hr (not effective) D. Saturated steam 121°C 15 min.(best answer) E. Heating in an oven 150°C 30 min. (must heat at 160°C/ 2h)

What are recommendations for hospital in preventing C. Diff infections..

Track and report Rapid identification and isolation: anyone admitted with diarrhea or antibiotic history is screened Controls on antibiotics- limit those antibiotic use and track what prescriptions were being used by patients who contract C. diff Strategies to minimize infections: wash hands and use gowns or gloves Put individual in private room or in with another C. diff positive patient Cleaning rooms with C. diff patients with dedicated or disposable toilet brush Interdisciplinary team at Jewish Hospital-Mercy health Cut rates 50% in 6 months. CampaignZERO

Treatment steps for metronidazole and vancomycin

What route would be ideal for a antibiotic in a pt with a C. Diff infection

Oral. The infection is in the guts. There for want to target it. Also would want to have a low absorption

Costs of antibiotics used for C. DIff

What are other things to remember with treating C. Diff?

Rehydration and stop offending antibiotics (20% of patients infection with resolve) Don’t use antidiarrheal meds since they may slow down removal of bacteria and toxins prolonging infection Don’t treat asymptomatic carriers If perforations, surgery to remove colon and use of colonoscopy bag Recurrence of symptoms is one of the challenges (5-47%) of cases (new antibiotic Fidaxomicin be better at preventing recurrence)

What is fecal microbiota therapy?

What other therapies have been tried?

Probiotics are inconsistent in preventing recurrence Lactobacillus, Streptococcus salivarius, Saccharomyces boutardii and may harbor resistance elements and risk of blood stream infection ## Footnote Intracolonic vancomycin Intravenous Immunoglobulin against C. diff antitoxin