SALT LAKE CITY – Over the past two decades there has been a sharp rise in the number and severity of infections caused by the bacteria 艰难梭状芽胞杆菌 常缩写为 C. diff now the most common hospital acquired infection in the United States. But a new study suggests that the most routinely prescribed antibiotic is not the best treatment for severe cases. 弗吉尼亚州盐湖城医疗保健系统的科学家和 犹他大学医学院 报告患者病情严重 C. diff infection (CDI) were less likely to die when treated with the antibiotic vancomycin compared to the standard treatment of metronidazole. 研究结果将于2月11日在网上公布. 6 .在… Journal of the American Medical Association (JAMA) Internal Medicine 网站.
The Centers for Disease Control and Prevention (CDC) report that almost half a million Americans, 大多是65岁或以上, 2011年开发了CDI. 这些, 83,000 patients experienced recurrence of infection within 30 days of completing the standard course of antibiotics. "This is a very real problem that impacts the patients' quality of life,该研究的主要作者凡妮莎·史蒂文斯说, Ph.D., a research assistant professor in the department of internal medicine and an investigator at the IDEAS 2.退伍军人事务部的0中心. 除了, the study showed that there is up to a 20 percent chance of mortality within 30 days of a CDI diagnosis.
C. diff 不直接致病吗. The bacterium produces two chemicals that are toxic to the human body. These toxins work in concert to irritate the cells of the intestinal lining producing the symptoms associated with the illness. CDI的症状包括水样腹泻, 发热, 食欲不振, 恶心想吐, 还有腹部疼痛和压痛. 严重的病例与结肠炎症有关.
Current guidelines primarily recommend two antibiotics metronidazole or vancomycin to treat CDI. 而万古霉素是最初的治疗方法, the medical community has favored metronidazole for the past few decades, because it is less expensive and will limit vancomycin resistance in other hospital-acquired infections. The guidelines are based on small clinical trials carried out about 30 years ago.
"For many years the two antibiotics were considered to be equivalent in their ability to cure C. diff 并预防疾病复发，”史蒂文斯说. "Our work and several other studies show that this isn't always the case.在本期的 美国医学会内科杂志, the research team looked at the effectiveness of the two drugs by comparing the risk of mortality after treatment with these two antibiotics.
The investigators conducted the largest study to date by examining the data from more than 10,000 patients treated for CDI through the US Department of Veterans Affairs healthcare system from 2005 to 2012. A severe case of CDI was defined as a patient with an elevated white blood cell count or serum creatinine within four days of the CDI diagnosis. A mild to moderate case of CDI was defined as a patient with normal white blood cell counts and creatinine levels. About 35 percent of cases in this study were considered severe.
病人 with a severe case of CDI had lower mortality rates when treated with vancomycin compared to metronidazole (15.3%对19%.8%). The scientists calculated that only 25 patients with severe CDI would need to be treated with vancomycin to prevent one death. "That is a powerful, positive outcome for our patient's well-being,解释说 Stevens. She cautions that the researchers still do not understand how the choice of antibiotic affects mortality rates.
"Although antibiotics are one of the greatest miracles of modern medicine, there are still tremendous gaps in our knowledge about when and how to use them to give our patients the best health outcomes,解释说 迈克尔·鲁宾，硕士.D., Ph.D., an associate professor in internal medicine and an investigator at the VA Salt Lake City Health Care System.
"This research shows that if providers choose vancomycin over metronidazole to treat patients with severe CDI, it should result in a lower risk of death for those critically ill patients,鲁宾说。. This study showed that less than 15 percent of CDI patients, 包括重症病例, 收到了万古霉素.
The study results did not show a difference in the rate of the illness returning following either antibiotic treatment whether the initial illness was mild to moderate or severe. Nor did it show a difference for the rate of death following either antibiotic treatment for mild to moderate CDI cases.
Stevens cautions that the study was observational in nature and does not prove cause and effect of the drug. 除了, the study focused on patients that were primarily men; however, 过去的研究表明 C. diff 男性和女性的治疗结果相似.
根据史蒂文斯的说法, future work should balance the targeted application of vancomycin treatment, 特别是对于严重的CDI病例, with economic considerations and the consequences of antibiotic resistance. "The optimal way to move forward is to do decision analysis that allows us to weigh the pros and cons of the various treatment strategies,她说.
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The research was funded by the Department of Veterans Affairs, 退伍军人健康管理局, 研究与发展办公室, 卫生服务研究与发展.
除了史蒂文斯和鲁宾, 合著者包括理查德·尼尔森, 卡里姆埃塞俄比亚, Makoto琼斯, Lindsay Croft and Matthew Samore (University of Utah and the VA Salt Lake City Health Care System), Elyse Schwab-Daugherty和Kevin A. 布朗大学（安大略省公共卫生部和多伦多大学）, 汤姆·格林（犹他大学）, Melinda Neuhauser (VA Pharmacy Benefits Management 服务) and Peter Glassman and Matthew Bidwell Goetz (VA Greater Los Angeles Healthcare System).