Week 3 - C.Diff Case Study Flashcards
Hfow many americans die each year from c.diff infections?
500,000
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
nosocomial
Disease that originates in the hospital..
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
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
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
Why do C. Diff infections frequently reoccur?
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
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
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
C. Diff Diagnosis
Positive stool test for toxin
Increased WBC > 15,000 cells/mm3
Direct visualization by sigmoidoscopy of pseudomembranous colitis
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
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.
What is pseudomembranous colitis composed of?
Neutrophils, dead epithelial cells, and inflammatory debris
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*
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
Intracolonic vancomycin
Intravenous Immunoglobulin against C. diff antitoxin
