Fernandez Canigia L, Nazar J, Arce M, Dadamio J, Smayevsky J, Bianchini H
Laboratorio de Bacteriología, CEMIC (Centro de Educación Médica e Investigaciones Clínicas Dr. N. Quirno), Billinghurst 2447, 1425 Buenos Aires, Argentina.
Rev Argent Microbiol. 2001 Apr-Jun;33(2):101-7.
Clostridium difficile has been recognized as the most important enteric pathogen of nosocomial antibiotic-associated diarrhea (CDAD) in adults from industrialized countries. The importance of C. difficile as a cause of diarrhea in ambulatory patients appears underestimated or under-recognized. Since the 1980's, outbreaks of CDAD have been increasingly reported, but there are few data available in Argentina. We developed a retrospective study to provide some information about CDAD in our country. From July 1998 to November 1999, a total of 245 fecal specimens from hospitalized and some ambulatory patients were tested in order to confirm the diagnosis of CDAD. C. difficile cytotoxin (toxin B) was identified by detecting its cytopathic effect on monolayers of McCoy culture cells. For culture and isolation of C. difficile, stool samples were prepared by ethanol shock prior to plating onto a selective medium which contained blood, cefoxitin and fructose. Of the 245 samples, 14 (5.8%) were identified as positive by the cell cytotoxicity assay. Using the criteria of isolation of cytotoxigenic C. difficile positivity increased to 6.5% (16 samples). Thirteen of the positive results were from hospitalized patients (81.3%) and 3 (18.7%) from outpatients. The mean age of inpatients was 72.9 years (ranging from 47 to 88). All patients had received 2 or more antimicrobial agents (most of them beta-lactams) 2 months before the appearance of diarrhea. There was one patient who had received only chemotherapy. The prevalence of CDAD in this study was less than in others previously reported. This difference may be due to the fact that not all general practitioners include testing for C. difficile when the patient with diarrhea had previously received antibiotics. More educational programs should be directed to all physicians, concerning the role of C. difficile as an important enteric pathogen in patients who have undergone treatment with antimicrobial or chemotherapeutic agents.
艰难梭菌已被公认为工业化国家成年人医院获得性抗生素相关性腹泻（CDAD）最重要的肠道病原体。艰难梭菌作为门诊患者腹泻病因的重要性似乎被低估或认识不足。自20世纪80年代以来，CDAD的暴发报告日益增多，但阿根廷的相关数据很少。我们开展了一项回顾性研究，以提供我国CDAD的一些信息。1998年7月至1999年11月，共检测了245份来自住院患者和部分门诊患者的粪便标本，以确诊CDAD。通过检测艰难梭菌细胞毒素（毒素B）对 McCoy 培养细胞单层的细胞病变效应来鉴定。为培养和分离艰难梭菌，粪便样本在接种到含有血液、头孢西丁和果糖的选择性培养基上之前，先进行乙醇休克处理。在245份样本中，14份（5.8%）通过细胞毒性试验鉴定为阳性。按照产细胞毒素艰难梭菌分离标准，阳性率增至6.5%（16份样本）。13份阳性结果来自住院患者（81.3%），3份（18.7%）来自门诊患者。住院患者的平均年龄为72.9岁（范围为47至88岁）。所有患者在出现腹泻前2个月都接受了2种或更多抗菌药物（大多数为β-内酰胺类）治疗。有1名患者仅接受了化疗。本研究中CDAD的患病率低于先前报道的其他研究。这种差异可能是由于并非所有全科医生在腹泻患者先前接受过抗生素治疗时都进行艰难梭菌检测。应针对所有医生开展更多教育项目，告知他们艰难梭菌在接受抗菌或化疗药物治疗患者中作为重要肠道病原体的作用。
