_______________________________________________________________ Healthcare-Associated Infections
hospitals, and 5% to 7% among elderly patients in long-term care facilities [35]. In contrast, the prevalence of C. difficile in the stool of asymptomatic adults without recent healthcare facility exposure is <2% [35]. Although colonization with C. difficile is relatively common among patients in healthcare facilities, clinical illness emerges only when there is produc- tion of toxins (A and B) that cause inflammation, secretion of mucous and fluid, and damage to the mucosa, resulting in diarrhea or colitis [270]. Disease can further progress to toxic megacolon, sepsis with or without intestinal perforation, and death [271; 272]. The incidence of C. difficile -associated diarrhea has increased dramatically in recent decades. The incidence more than tripled between the 1990s and 2005 (from 30 to 40 cases per 100,000 individuals to 131 per 100,000), and in 2011, the inci- dence was reported to be 147.2 cases per 100,000 [273; 274]. During this same time, some bacterial strains have become more virulent and perhaps more resistant [275]. As with other HAIs, C. difficile infection in the healthcare setting has been associated with increased length of stays, increased mortality, and higher costs [136; 276; 277; 278; 279]. Beginning in 2009, the CDC has conducted ongoing surveil- lance of C. difficile infection in the community and healthcare environment through the Emerging Infections Program, a sentinel network of 10 reporting sites in 35 counties of 10 states. Data from 2021 showed a total of 13,348 C. difficile infections reported within this population group of 12,109,721 persons, for a total annual rate of 110.2 incident infections per 100,000 population [280]. The rate of C. difficile HAI was 54.3 cases per 100,000, compared with the community-based incidence of 55.9 per 100,000. The incidence rate of CDI increased with age and was higher in women than in men and higher in White persons than in persons of other races. [280]. Serial surveys show that C. difficile accounts for 15% of all HAIs, and the incidence has remained stable during the period 2011 to 2015. When extrapolated to the nation at large, CDC data analysis shows that C. difficile causes more than 430,000 incident infections in the United States each year and is associated with approximately 20,500 deaths [281]. The 2023 HAI progress report showed a more positive trend, with about an 13% decrease in C. difficile infections reported from acute care hospitals between 2022 and 2023 [85]. Risk Factors The primary risk factors for infection with C. difficile are antibiotic use, older age, and hospitalization [35]. Exposure to antibiotic agents is the most modifiable risk factor, an associa- tion reported in more than 96% of hospitalized patients in one study [282]. Antibiotics increase the risk by suppressing or alter- ing normal bowel microflora, thereby facilitating overgrowth of relatively dormant C. difficile organisms. Many antibiotics
have been implicated, but fluoroquinolones, cephalosporins, carbapenems, and clindamycin have been found to confer high risk [35]. The likelihood of infection increases with longer hos- pitalizations, with a 15% to 45% risk of colonization among patients hospitalized for one to three weeks [282]. Transmission C. difficile is an exogenous infection that is transmitted person- to-person through the fecal-oral route and possibly via contact with contaminated environmental surfaces (e.g., bedding, commodes, bath tubs). Prevention and Control Guidelines developed by SHEA/IDSA in 2010, and updated in 2017 and 2021, offer recommendations for prevention, diagnosis, and management of C. difficile [35; 274]. (The scope of the 2021 focused update is restricted to adults and includes new data for fidaxomicin and for bezlotoxumab, a monoclonal antibody targeting toxin B produced by C. difficile [274].) Control measures include restriction of antibiotic use; isola- tion precautions for healthcare workers, patients, and visitors; and environmental cleaning and disinfection ( Table 16 ) [35]. The guidelines note that the use of antibiotics should be mini- mized and that an antibiotic stewardship program should be developed and implemented by all hospitals [35]. Appropriate hand hygiene is essential, and soap and water should be used rather than alcohol-based handrubs, as alcohol is not effective at killing C. difficile spores [35]. Gowns, gloves, and contact pre- cautions for the duration of diarrhea are also recommended. The guidelines suggest that removing environmental sources of C. difficile , such as replacing rectal thermometers with disposable ones, can help reduce the incidence of C. difficile infection. The guidelines also note that the following are not recommended: routine environmental screening for C. difficile (level III, C); routine identification of asymptomatic carriers for infection control purposes (level III, A); and use of probiotics to prevent infection (level I, B) [35]. Diagnosis Infection with C. difficile is diagnosed on the basis of clinical findings and the results of laboratory testing [35]. C. difficile infection is defined as (1) the presence of diarrhea (passage of three or more unformed stools in up to 24 consecutive hours) and (2) positive results on stool testing for the presence of toxigenic C. difficile or its toxins or findings of pseudomem- branous colitis on colonoscopy or histopathologic evaluation [35]. Diarrhea may be absent in up to 20% of patients with fulminant colitis or postoperative ileus [282]. Other symptoms include fever, nausea, vomiting, abdominal pain or tenderness, and loss of appetite, but these symptoms are found in about half of patients with the infection [35; 270].
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