Dial Sandra, Kezouh Abbas, Dascal Andre, Barkun Alan, Suissa Samy
Department of Medicine, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montréal, Que.
CMAJ. 2008 Oct 7;179(8):767-72. doi: 10.1503/cmaj.071812.
Previous observations have indicated that infection with Clostridium difficile occurs almost exclusively after exposure to antibiotics, but more recent observations have suggested that prior antibiotic exposure may be less frequent among cases of community-acquired disease.
We used 2 linked health databases to perform a matched, nested case-control study of elderly patients admitted to hospital with community-acquired C. difficile infection. For each of 836 cases among people 65 years of age or older, we selected 10 controls. We determined the proportion of cases that occurred without prior antibiotic exposure and estimated the risk related to exposure to different antibiotics and the duration of increased risk.
Of the 836 cases, 442 (52.9%) had no exposure to antibiotics in the 45-day period before the index date, and 382 (45.7%) had no exposure in the 90-day period before the index date. Antibiotic exposure was associated with a rate ratio (RR) of 10.6 (95% confidence interval [CI] 8.9-12.8). Clindamycin (RR 31.8, 95% CI 17.6-57.6), cephalosporins (RR 14.9, 95% CI 10.9-20.3) and gatifloxacin (RR 16.7, 95% CI 8.3-33.6) were associated with the highest risk. The RR for C. difficile infection associated with antibiotic exposure declined from 15.4 (95% CI 12.2-19.3) by about 20 days after exposure to 3.2 (95% CI 2.0-5.0) after 45 days. Use of a proton pump inhibitor was associated with increased risk (RR 1.6, 95% CI 1.3-2.0), as were concurrent diagnoses of inflammatory bowel disease (RR 4.1, 95% CI 2.6-6.6), irritable bowel syndrome (RR 3.4, 95% CI 2.3-5.0) and renal failure (RR 1.7, 95% CI 1.2-2.2).
Community-acquired C. difficile infection occurred in a substantial proportion of individuals with no recent exposure to antibiotics. Among patients who had been exposed to antibiotics, the risk declined markedly by 45 days after discontinuation of use.
既往观察表明，艰难梭菌感染几乎仅在接触抗生素后发生，但最近的观察提示，社区获得性疾病病例中既往抗生素接触可能不那么常见。
我们使用两个相关的健康数据库，对因社区获得性艰难梭菌感染入院的老年患者进行匹配的巢式病例对照研究。对于65岁及以上人群中的836例病例，我们各选取10名对照。我们确定了无既往抗生素接触而发生的病例比例，并估计了与接触不同抗生素相关的风险以及风险增加的持续时间。
在836例病例中，442例（52.9%）在索引日期前45天内未接触抗生素，382例（45.7%）在索引日期前90天内未接触抗生素。抗生素接触与率比（RR）为10.6（95%置信区间[CI]8.9 - 12.8）相关。克林霉素（RR 31.8，95% CI 17.6 - 57.6）、头孢菌素（RR 14.9，95% CI 10.9 - 20.3）和加替沙星（RR 16.7，95% CI 8.3 - 33.6）与最高风险相关。与抗生素接触相关的艰难梭菌感染RR在接触后约20天从15.4（95% CI 12.2 - 19.3）降至45天后的3.2（95% CI 2.0 - 5.0）。使用质子泵抑制剂与风险增加相关（RR 1.6，95% CI 1.3 - 2.0），同时诊断为炎症性肠病（RR 4.1，95% CI 2.6 - 6.6）、肠易激综合征（RR 3.4，95% CI 2.3 - 5.0）和肾衰竭（RR 1.7，95% CI 1.2 - 2.2）时也是如此。
相当一部分近期未接触抗生素的个体发生了社区获得性艰难梭菌感染。在接触过抗生素的患者中，停药后45天时风险显著下降。
