Volume 36 Number 4 | August 2022
Patient Safety Corner
Rose Hanna, DCLS, MS, MLS(ASCP)CM, Patient Safety Committee
In 2016, Clostridium difficile went through a genus name change based on genotypic and phylogenetic information to Clostridioides difficile.1 C. difficile is a spore-forming gram positive bacillus that is commonly found in water, soil, human and animal feces, and hospital surfaces. The spores can survive on surfaces for months to years, and they are resistant to environmental stresses, making them difficult to eradicate.2 The spores are transmitted through oral-fecal route, and once ingested, they can colonize the host in the vegetative state or produce toxins (toxins A and B) in the late growth stages. Altered gut microbiome due to an immunocompromised state or antibiotic use create favorable conditions for C. difficile infection, resulting in diarrhea.3,4
C. difficile is the leading cause of antibiotic-associated and hospital acquired diarrhea, and it has received a lot of attention due to the increased burden it has placed on our patients and healthcare system.5 There are half a million cases each year in the United States that contribute to an average additional cost of $42,316 per case and annual additional cost of $6.3 billion.6 C. difficile infection (CDI) presents with diarrhea as the initial symptom, which according to the Centers for Disease Control and Prevention (CDC) is defined as three or more loose stools within 24 hours. Other symptoms include fever, nausea, abdominal pain, and cramps, which may progress to complications including pseudomembranous colitis, toxic megacolon, or perforation of the colon that leads to sepsis and death.5 Therefore, differentiating colonization from infection depends on the absence/presence of diarrhea accompanied by the presence of a spore-shedding C. difficile organism or toxin gene; colonization exhibits no clinical symptoms. Colonization is more common in infants less than 12 months of age with a rate of 60-70 percent compared to 3 percent in healthy adults.7,8
“The clinical assessment and sample consistency criteria are essential in ensuring that our patients are accurately diagnosed and treated to avoid harm, reduce unnecessary healthcare costs, and prevent potential antibiotic resistant strains.”
The recommended antimicrobial agents for CDI are vancomycin, fidaxomicin, and metronidazole. Vancomycin was always assumed to be effective until resistant cases were reported.9 Based on the 2021 changes by the Infectious Disease Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA), fidaxomicin is recommended as the preferred standard course of treatment over vancomycin for initial and recurrent CDI.10 The concern with vancomycin-resistant C. difficile strains raises the question, “Is there an over-utilization of C. difficile testing leading to overdiagnoses and overtreatment?” Appropriate clinical assessment of patients presenting with diarrhea is the initial and essential approach to accurate C. difficile testing. Therefore, formed stool samples that are sent to the laboratory should be rejected to prevent testing colonized patients. The next approach is investigating laxative administration within 48 hours; testing patients who have diarrhea due to laxative use increases the chance of testing colonized patients which potentially leads to false positive test results and overtreatment.
The clinical assessment and sample consistency criteria are essential in ensuring that our patients are accurately diagnosed and treated to avoid harm, reduce unnecessary healthcare costs, and prevent potential antibiotic resistant strains. Education becomes beneficial by instructing nursing staff to evaluate the consistency of the stool sample at the time of collection, improving communication between the nursing staff and ordering provider if a formed stool is collected, and rejecting formed stool samples if submitted to the laboratory for C. difficile testing.
- Lawson PA, Citron DM, Tyrell KL, Finegold SM. Reclassification of Clostridium difficile as Clostridioides difficile (Hall and O’Toole 1935) Prevot 1938. Anaerobe. 2016; 40:95-99
- Kochan TJ, Foley MH, Shoshieve MS. Updates on Clostridium difficile Spore Germination. Journal of Bacteriology. 2018; 200:16
- Edwards AN, McBride SM. Isolating and Purifying Clostridium difficile Spores. Methods Mol Biol. 2016; 1476:117-128
- Schaffler H, Breitruck A. Clostridium difficile-From Colonization to Infection. Front Microbiology. 2018; 9:646
- Centers for Disease Control and Prevention (CDC). Clostridioides difficile (C. diff). CDC. 2018.
- Zhan S, Palazuelos-Munoz S, Balsells EM. Cost of Hospital Management of Clostridium difficile Infection in United States-a Meta-Analysis and Modelling Study. BMC Infect Dis. 2016; 16(1)
- Yorkgitis BK, Frain V. Clostridium difficile Infection. Clinician Reviews. 2011; 21(2)
- Crobach MJT, Vernon JJ. Clostridium difficile Colonization. Clinical Microbiology Reviews. 2018; 3(2): e000021-17
- Melville NA. C. difficile: New Vancomycin-Resistant StrainsRaise Concerns. Medscape. 2022
- Johnson S, Lavergne V, Skinner AM. Clinical Practice Guideline by Infectious Disease Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA): 2021 Focused Update Guidelines on Management of Clostridioides difficile Infection in Adults. Clinical Infectious Diseases. 2021; 73(5): e1029-44
Rose Hanna is a Scientist at CareDx in San Francisco.