Singhi Sunit C, Baranwal A
Department of Pediatrics, Advanced Pediatrics Center, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Indian J Pediatr. 2008 Jun;75(6):621-7. doi: 10.1007/s12098-008-0119-1. Epub 2008 Aug 31.
Probiotics are "live microbes which when administered in adequate amounts confer a health benefit to the host" (FAO/WHO joint group). Their potential role in bio-ecological modification of pathological internal milieu of the critically ill is under evaluation. Probiotics are available as single microbial strain (e.g., Bacillus clausii, Lactobacillus) or as a mix of multiple strains of Lactobacillus (acidophilus, sporogenes, lactis, reuteri RC-14, GG, and L. plantarum 299v), Bifidobacterium (bifidum, longum, infantis), Streptococcus (thermophillus, lactis, fecalis), Saccharomyces boulardii etc. Lactobacilli and Bifidobacteria are gram-positive, anaerobic, lactic acid bacteria. These are normal inhabitant of human gut and colonize the colon better than others. Critical illness and its treatment create hostile environment in the gut and alters the micro flora favoring growth of pathogens. Therapy with probiotics is an effort to reduce or eliminate potential pathogens and toxins, to release nutrients, antioxidants, growth factors and coagulation factors, to stimulate gut motility and to modulate innate and adaptive immune defense mechanisms via the normalization of altered gut flora. Scientific evidence shows that use of probiotics is effective in prevention and therapy of antibiotic associated diarrhea. However, available probiotics strains in currently used doses do not provide much needed early benefits, and need long-term administration to have clinically beneficial effects (viz, a reduction in rate of infection, severe sepsis, ICU stay, ventilation days and mortality) in critically ill surgical and trauma patients. Possibly, available strains do not adhere to intestinal mucosa early, or may require higher dose than what is used. Gap exists in our knowledge regarding mechanisms of action of different probiotics, most effective strains--single or multiple, cost effectiveness, risk-benefit potential, optimum dose, frequency and duration of treatment etc. More information is needed on safety profile of probiotics in immunocompromised state of the critically ill in view of rare reports of fungemia and sepsis and a trend toward possible increase in nosocomial infection. At present, despite theoretical potential benefits, available evidence is not conclusive to recommend probiotics for routine use in the critically ill.
益生菌是“给予足够数量时能给宿主带来健康益处的活微生物”（粮农组织/世卫组织联合小组）。它们在对危重症患者病理性内环境进行生物生态调节方面的潜在作用正在评估中。益生菌有单一微生物菌株形式（如克劳氏芽孢杆菌、乳酸杆菌），或多种乳酸杆菌菌株（嗜酸乳杆菌、产芽孢乳杆菌、乳酸乳杆菌、罗伊氏乳杆菌RC - 14、GG和植物乳杆菌299v）、双歧杆菌（双歧双歧杆菌、长双歧杆菌、婴儿双歧杆菌）、链球菌（嗜热链球菌、乳酸链球菌、粪链球菌）、布拉酵母菌等的混合形式。乳酸杆菌和双歧杆菌是革兰氏阳性厌氧菌，是人类肠道的正常居民，比其他菌更易在结肠定殖。危重症及其治疗在肠道内创造了不利环境，改变了微生物群落，有利于病原体生长。使用益生菌进行治疗旨在减少或消除潜在病原体和毒素，释放营养物质、抗氧化剂、生长因子和凝血因子，刺激肠道蠕动，并通过使改变的肠道菌群正常化来调节固有免疫和适应性免疫防御机制。科学证据表明，使用益生菌对抗生素相关性腹泻的预防和治疗有效。然而，目前使用剂量的现有益生菌菌株不能提供急需的早期益处，需要长期给药才能对危重症外科和创伤患者产生临床有益效果（即降低感染率、严重脓毒症发生率、重症监护病房住院时间、通气天数和死亡率）。可能是现有菌株不能早期黏附于肠黏膜，或者可能需要比所用剂量更高的剂量。我们对不同益生菌的作用机制、最有效的菌株——单一菌株或多种菌株、成本效益、风险效益潜力、最佳剂量、治疗频率和持续时间等方面的认识存在差距。鉴于有罕见的真菌血症和脓毒症报告以及医院感染可能增加的趋势，对于危重症免疫功能低下状态下益生菌的安全性概况需要更多信息。目前，尽管有理论上的潜在益处，但现有证据并不确凿，不足以推荐在危重症患者中常规使用益生菌。
