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Clostridioides difficile infection (CDI) is a unique colonic disease that is acquired most commonly in association with antimicrobial use and the consequent disruption of the normal colonic microbiota. The most commonly diagnosed diarrheal illness acquired in the hospital, CDI results from the ingestion of spores of C. difficile that vegetate, multiply, and secrete toxins, causing diarrhea and, in the most severe cases, pseudomembranous colitis (PMC).
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ETIOLOGY AND EPIDEMIOLOGY
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C. difficile is an obligately anaerobic, gram-positive, spore-forming bacillus whose spores are found widely in nature, particularly in the environment of hospitals and chronic-care facilities. CDI occurs frequently in hospitals and nursing homes (or shortly after discharge from these facilities) where the level of antimicrobial use is high and the environment is contaminated by C. difficile spores.
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Clindamycin, ampicillin, and cephalosporins were the first antibiotics associated with CDI. The second- and third-generation cephalosporins, particularly cefotaxime, ceftriaxone, cefuroxime, and ceftazidime, are agents frequently responsible for this condition, and the fluoroquinolones (ciprofloxacin, levofloxacin, and moxifloxacin) are the most recent drug class to be implicated in hospital outbreaks. Penicillin/β-lactamase-inhibitor combinations such as ticarcillin/clavulanate and piperacillin/tazobactam pose significantly less risk. However, all antibiotics, including vancomycin (the agent most commonly used to treat CDI) and metronidazole, have been found to carry a risk of subsequent CDI. A minority of cases, especially in the community, are reported in patients without documentation of prior antibiotic exposure.
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C. difficile is acquired exogenously—most often in the hospital or nursing home, but also in the outpatient setting—and is carried in the stool of both symptomatic and asymptomatic patients. The rate of fecal colonization increases in proportion to length of hospital stay and is often ≥20% among adult patients hospitalized for >2 weeks; in contrast, the rate is 1–3% among community residents. CDI is the most common health care–associated infection in the United States, with an estimated 462,100 cases in 2017. Between 2011 and 2017, the total burden of CDI in the United States decreased by 24%, which was primarily due to decreases in health care–associated CDI. The estimated burden of community-associated CDI was unchanged.
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Asymptomatic fecal carriage of C. difficile in healthy neonates is very common, with repeated colonization by multiple strains in infants <1–2 years of age, but associated disease in these infants is extremely rare if it occurs at all. Spores of C. difficile are found on environmental surfaces (where the organism can persist for months) and on the hands of hospital personnel who fail to practice good hand hygiene. Hospital epidemics of CDI have been attributed to a single C. difficile strain and to multiple strains present simultaneously. Other identified risk factors for CDI include older age, greater severity of underlying illness, gastrointestinal surgery, use of electronic rectal thermometers, enteral tube feeding, and antacid treatment. Use of proton pump inhibitors may be a risk factor, but this ...