Petschow B W, Batema R P, Talbott R D, Ford L L
Bristol-Myers Squibb Co., Mead Johnson Research Centre, Evansville, IN 47721, USA.
J Med Microbiol. 1998 May;47(5):383-9. doi: 10.1099/00222615-47-5-383.
Although a number of studies have shown that various free fatty acids (FFAs) and monoacylglycerides (MGs) have bactericidal properties in vitro, the role of these compounds in vivo has not been determined. This study evaluated the antibacterial properties of medium-chain MGs and FFAs for different bacterial enteropathogens with an in-vitro bacterial killing assay and an in-vivo model of intestinal colonisation. Incubation of test bacteria with medium-chain MGs for 4 h led to 100-10,000-fold reductions in numbers of viable cells of Vibrio cholerae, Salmonella typhi, Shigella sonnei and enterotoxigenic Escherichia coli (ETEC). Lauric acid was the only medium-chain FFA to show comparable in-vitro bactericidal activity. The ability of dietary MGs to reduce or eliminate bacterial colonisation of the intestinal tract was evaluated in mice that were predisposed to bacterial colonisation by treatment with streptomycin (STR+). Mice were treated with streptomycin, challenged intragastrically with V. cholerae or ETEC, and given monocaprin (C10:0 MG) either concurrently or as part of the daily diet. Control mice given STR+ without MGs and challenged with V. cholerae or ETEC showed high numbers of challenged bacteria in gastrointestinal contents by 1 h after administration. Concurrent administration of V. cholerae and C10:0 MG (2.5 mg/ml) caused > 1000-fold reduction in numbers of V. cholerae recovered from the gastrointestinal tracts of STR+ mice. Concurrent administration of C10:0 MG with ETEC did not cause a reduction in the number of viable ETEC present in the intestinal tract of STR+ mice. Administration of C10:0 MG in the diet had no effect on the number of viable V. cholerae or ETEC associated with caecal or ileal tissue of STR+ mice when C10:0 MG in the diet was started 1 day before, the same day, or 2 days after bacterial challenge. Collectively, these results suggested that dietary MGs may prevent intestinal colonisation by bacterial enteropathogens if administered at the time of exposure, but have little effect on established intestinal infections.
尽管多项研究表明，多种游离脂肪酸（FFA）和单酰甘油（MG）在体外具有杀菌特性，但这些化合物在体内的作用尚未确定。本研究通过体外细菌杀伤试验和肠道定植的体内模型，评估了中链MG和FFA对不同肠道致病菌的抗菌特性。将测试细菌与中链MG孵育4小时后，霍乱弧菌、伤寒沙门氏菌、宋内志贺氏菌和产肠毒素大肠杆菌（ETEC）的活细胞数量减少了100至10000倍。月桂酸是唯一显示出类似体外杀菌活性的中链FFA。在通过链霉素（STR+）处理而易于发生细菌定植的小鼠中，评估了膳食MG减少或消除肠道细菌定植的能力。小鼠用链霉素处理，经口给予霍乱弧菌或ETEC进行攻击，并同时或作为日常饮食的一部分给予单癸酸甘油酯（C10:0 MG）。给予STR+但未给予MG并经霍乱弧菌或ETEC攻击的对照小鼠，在给药后1小时，胃肠道内容物中可见大量攻击细菌。同时给予霍乱弧菌和C10:0 MG（2.5 mg/ml），使从STR+小鼠胃肠道中回收的霍乱弧菌数量减少了1000倍以上。同时给予C10:0 MG和ETEC，并未使STR+小鼠肠道中存在的活ETEC数量减少。当在细菌攻击前1天、当天或2天开始在饮食中给予C10:0 MG时，饮食中给予C10:0 MG对与STR+小鼠盲肠或回肠组织相关的活霍乱弧菌或ETEC数量没有影响。总体而言，这些结果表明，如果在接触时给予膳食MG，可能会预防肠道致病菌的肠道定植，但对已确立的肠道感染几乎没有影响。
