Since the discovery of antibiotic therapies, the battle between humans and infectious diseases has never stopped. A number of drug-resistant bacterial strains are now appearing in the clinical field, and infectious diseases originating from these strains have become a major problem. Multidrug efflux pumps produce multidrug resistance by exporting antibiotics from cells. Genomic analysis has resulted in the identification of many genes which have been proposed as drug efflux pumps, and bacterial genome sequences have allowed us to identify the drug-resistant gene libraries of bacteria. In this review, we will first introduce the method to analyze all drug efflux pump genes by using genomic information. Next, we will discuss the regulation of drug efflux pumps. Furthermore, we will also introduce the roles of drug efflux pumps in virulence, which is an ongoing research area. Because drug efflux pumps have roles in bacterial multidrug resistance and virulence, we propose that drug efflux pumps have greater clinical relevance than is usually attributed to them.
We evaluated the effects of a tablet containing Bacillus natto and Lactobacillus acidophilus as probiotics supplemented with three stomachic herbs on human fecal microbiota. Six healthy subjects ingested 3 tablets, 3 times a day after meals for 10 days. Fecal samples were collected before and after the administration period, and 1 week post administration. As shown by the TGGE images, the density of the bands identified with Bifidobacterium increased in four cases. This increase was confirmed by real-time PCR. It was observed that the densities of the bands identified with Haemophilus decreased, Ruminococcus decreased, Clostridium colinum decreased, Acidaminococcus increased and Megamonas increased individually.