Shim J K, Johnson S, Samore M H, Bliss D Z, Gerding D N
Department of Medicine, Veterans Affairs Chicago Healthcare System, Northwestern University Medical School, Chicago, Illinois 60611, USA.
Lancet. 1998 Feb 28;351(9103):633-6. doi: 10.1016/S0140-6736(97)08062-8.
Little is known about whether patients who develop Clostridium-difficile-associated diarrhoea (CDAD) are culture-positive or culture-negative before illness. The most important risk factor is antibiotic exposure. We aimed to find out whether patients identified as primary symptom-free C difficile carriers are at higher risk of developing CDAD than patients who are culture-negative.
We reviewed four longitudinal studies in which 810 patients admitted to hospital were followed up by prospective rectal-swab culture. At least two consecutive weekly cultures were obtained. We calculated the difference in risk of CDAD between colonised and non-colonised patients in each study and combined the results of the four studies in a random-effects model.
Of 618 non-colonised patients (mean follow-up 1.7 weeks [SD 1.3]), 22 (3.6%) developed CDAD, whereas only two (1.0%) of 192 primary symptom-free carriers (1.5 [1.5]) developed CDAD (pooled risk difference -2.3% [95% CI 0.3-4.3], p=0.021). Of patients who received antibiotics, the risk difference was increased: 22 (4.5%) of 491 non-colonised patients compared with two (1.1%) of 176 colonised patients developed CDAD (-3.2% [0.4-6.0], p=0.024). Of the primary symptom-free C difficile carriers, 95 were colonised with toxigenic strains, 76 with non-toxigenic strains, 12 with both toxigenic and non-toxigenic strains (non-concurrently), and nine with strains of undetermined toxigenicity. Nine of the 12 toxogenic strains of C difficile isolates that cause CDAD were also recovered from stools of symptom-free patients.
Primary symptomless C difficile colonisation is associated with a decreased risk of CDAD. Although the mechanism is unknown, risk reduction is found in colonisation with non-toxigenic and toxigenic strains.
对于艰难梭菌相关性腹泻（CDAD）患者在患病前培养结果为阳性还是阴性知之甚少。最重要的风险因素是抗生素暴露。我们旨在查明被确定为无症状的艰难梭菌携带者的患者发生CDAD的风险是否高于培养结果为阴性的患者。
我们回顾了四项纵向研究，其中对810名住院患者进行前瞻性直肠拭子培养随访。至少连续每周进行两次培养。我们计算了每项研究中定植患者和未定植患者发生CDAD的风险差异，并将四项研究的结果合并到一个随机效应模型中。
在618名未定植患者（平均随访1.7周[标准差1.3]）中，22名（3.6%）发生了CDAD，而在192名无症状携带者（1.5[1.5]）中只有2名（1.0%）发生了CDAD（合并风险差异-2.3%[95%置信区间0.3 - 4.3]，p = 0.021）。在接受抗生素治疗的患者中，风险差异增加：491名未定植患者中有22名（4.5%）发生了CDAD，而176名定植患者中有2名（1.1%）发生了CDAD（-3.2%[0.4 - 6.0]，p = 0.024）。在无症状的艰难梭菌携带者中，95名被产毒菌株定植；76名被非产毒菌株定植；12名同时被产毒和非产毒菌株定植（不同时）；9名被毒力未确定的菌株定植。导致CDAD的12株艰难梭菌产毒菌株中有9株也从无症状患者的粪便中分离出来。
无症状的艰难梭菌定植与CDAD风险降低有关。尽管机制尚不清楚，但在被非产毒和产毒菌株定植时均发现风险降低
