tailieunhanh - Chapter 123. Clostridium difficile–Associated Disease, Including Pseudomembranous Colitis (Part 1)

Chapter 123. Clostridium difficile–Associated Disease, Including Pseudomembranous Colitis (Part 1) Harrison's Internal Medicine Chapter 123. Clostridium difficile– Associated Disease, Including Pseudomembranous Colitis Etiology and Epidemiology 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. CDAD occurs most frequently in hospitals and nursing homes where the level of antimicrobial use is high and the environment is contaminated by C. difficile spores. Clindamycin, ampicillin, and cephalosporins were the first antibiotics associated with CDAD. The second- and third-generation cephalosporins, particularly cefotaxime, ceftriaxone, cefuroxime, and ceftazidime, are agents frequently responsible. | Chapter 123. Clostridium difficile-Associated Disease Including Pseudomembranous Colitis Part 1 Harrison s Internal Medicine Chapter 123. Clostridium difficile-Associated Disease Including Pseudomembranous Colitis Etiology and Epidemiology 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. CDAD occurs most frequently in hospitals and nursing homes where the level of antimicrobial use is high and the environment is contaminated by C. difficile spores. Clindamycin ampicillin and cephalosporins were the first antibiotics associated with CDAD. The second- and third-generation cephalosporins particularly cefotaxime ceftriaxone cefuroxime and ceftazidime are agents frequently responsible for this condition and the fluoroquinolones ciprofloxacin levofloxacin gatifloxacin and moxifloxacin are the most recent drug class to be implicated in hospital outbreaks. Penicillin p-lactamase-inhibitor combinations such as ticarcillin clavulanate and piperacillin tazobactam pose significantly less risk. However all antibiotics including vancomycin and metronidazole the agents most commonly used to treat CDAD have been found to carry a risk of subsequent CDAD. Rare cases are reported in patients without prior antibiotic exposure. C. difficile is acquired exogenously most frequently in the hospital and is carried in the stool of symptomatic and asymptomatic patients. The rate of fecal colonization is often 20 among adult patients hospitalized for 1 week in contrast the rate is 1-3 among community residents. The risk of C. difficile acquisition increases in proportion to length of hospital stay. Asymptomatic fecal carriage of C. difficile in healthy neonates is very common with rates often exceeding 50 during the first 6 months of life but associated disease in this population is rare. Spores of C. difficile are found on environmental surfaces where