Brenneman Karen E, Gonzales Amanda, Roland Kenneth L, Curtiss Roy
The Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA.
Present address - 23andMe, Inc, 1390 Shorebird Way, Mountain View, CA, 94043, USA.
BMC Microbiol. 2015 Mar 29;15:76. doi: 10.1186/s12866-015-0409-5.
To be effective, orally administered live Salmonella vaccines must first survive their encounter with the low pH environment of the stomach. To enhance survival, an antacid is often given to neutralize the acidic environment of the stomach just prior to or concomitant with administration of the vaccine. One drawback of this approach, from the perspective of the clinical trial volunteer, is that the taste of a bicarbonate-based acid neutralization system can be unpleasant. Thus, we explored an alternative method that would be at least as effective as bicarbonate and with a potentially more acceptable taste. Because ingestion of protein can rapidly buffer stomach pH, we examined the possibility that the protein-rich Ensure® Nutrition shakes would be effective alternatives to bicarbonate.
We tested one Salmonella enterica serovar Typhimurium and three Salmonella Typhi vaccine strains and found that all strains survived equally well when incubated in either Ensure® or bicarbonate. In a low gastric pH mouse model, Ensure® worked as well or better than bicarbonate to enhance survival through the intestinal tract, although neither agent enhanced the survival of the S. Typhi test strain possessing a rpoS mutation.
Our data show that a protein-rich drink such as Ensure® Nutrition shakes can serve as an alternative to bicarbonate for reducing gastric pH prior to administration of a live Salmonella vaccine.
为了发挥效力，口服的活沙门氏菌疫苗首先必须在与胃的低pH环境接触时存活下来。为提高存活率，通常在接种疫苗之前或同时给予抗酸剂以中和胃的酸性环境。从临床试验志愿者的角度来看，这种方法的一个缺点是基于碳酸氢盐的酸中和系统的味道可能令人不适。因此，我们探索了一种替代方法，其效果至少与碳酸氢盐相同，且味道可能更容易接受。由于摄入蛋白质可迅速缓冲胃pH值，我们研究了富含蛋白质的安素®营养奶昔作为碳酸氢盐有效替代品的可能性。
我们测试了一株肠炎沙门氏菌鼠伤寒血清型菌株和三株伤寒沙门氏菌疫苗菌株，发现所有菌株在安素®或碳酸氢盐中孵育时存活情况相同。在低胃pH值小鼠模型中，安素®在提高肠道存活率方面与碳酸氢盐效果相当或更好，尽管两种制剂均未提高具有rpoS突变的伤寒沙门氏菌测试菌株的存活率。
我们的数据表明，在接种活沙门氏菌疫苗之前，富含蛋白质的饮料如安素®营养奶昔可作为碳酸氢盐的替代品用于降低胃pH值。
