Comparative genomics of transport proteins in seven Bacteroides species

Abstract

The communities of beneficial bacteria that live in our intestines, the gut microbiome, are important for the development and function of the immune system. Bacteroides species make up a significant fraction of the human gut microbiome, and can be probiotic and pathogenic, depending upon various genetic and environmental factors. These can cause disease conditions such as intra-abdominal sepsis, appendicitis, bacteremia, endocarditis, pericarditis, skin infections, brain abscesses and meningitis. In this study, we identify the transport systems and predict their substrates within seven Bacteroides species, all shown to be probiotic; however, four of them (B. thetaiotaomicron, B. vulgatus, B. ovatus, B. fragilis) can be pathogenic (probiotic and pathogenic; PAP), while B. cellulosilyticus, B. salanitronis and B. dorei are believed to play only probiotic roles (only probiotic; OP). The transport system characteristics of the four PAP and three OP strains were identified and tabulated, and results were compared among the seven strains, and with E. coli and Salmonella strains. The Bacteroides strains studied contain similarities and differences in the numbers and types of transport proteins tabulated, but both OP and PAP strains contain similar outer membrane carbohydrate receptors, pore-forming toxins and protein secretion systems, the similarities were noteworthy, but these Bacteroides strains showed striking differences with probiotic and pathogenic enteric bacteria, particularly with respect to their high affinity outer membrane receptors and auxiliary proteins involved in complex carbohydrate utilization. The results reveal striking similarities between the PAP and OP species of Bacteroides, and suggest that OP species may possess currently unrecognized pathogenic potential.

Evaluation of Gentamicin Exposure Effects on Human gut Microbiota using the Simulator of Human Intestinal Microbial Ecosystem (SHIME)

“…Moreover, pathways related to human diseases (such as cancer, infectious diseases, metabolic diseases, and neurosurgical diseases) are positively correlated with the abundance of Klebsiella found in this study were also supported by several other studies [49][50][51][52][53]. For Bacteroides, a common probiotic, the decrease of this kind of probiotic may cause dysbiosis of gut microbiota and leads to human health problem [54][55][56][57]. There are some other studies showed that Bacteroides intrinsically carries tetracycline and aminoglycoside resistance genes [58][59][60].…”

Effect of cinnamon essential oil on gut microbiota in the mouse model of dextran sodium sulfate‐induced colitis

“…Kanwal et al also observed similar trends, in which the levels of Bacteroidaceae family and Bacteroides genus were increased in mice treated with antibiotics (clindamycin and metronidazole). To our knowledge, Bacteroides contain both probiotic and potentially pathogenic species . On the one hand, Bacteroides with beneficial effects, such as B. vulgatus and B. dorei , could suppress the proinflammatory response by ameliorating endotoxemia and gut microbiota lipopolysaccharide levels in atherosclerosis‐prone mice .…”

Lipopolysaccharide-stimulated, NF-kB-, miRNA-146a- and miRNA-155-mediated molecular-genetic communication between the human gastrointestinal tract microbiome and the brain

“…The vast majority of all GI-tract microbiota consists of Gram-negative anaerobic bacteria, and Bacteroidetes species represent the most abundant Gram-negative anaerobes, outnumbering Escherichia coli in abundance by about 100 to 1 [3][4][5][6][7][8]14,15,[61][62][63][64]. Certain strains of Bacteroidetes species such as Bacteroides fragilis (B. fragilis), as a normal commensal microbe of the human GI-tract, are thought to be ordinarily beneficial to human health due to their multiple capabilities: (i) to biosynthesize useful metabolic co-factors and products such as polysaccharides, transport proteins, volatile fatty acids and other nutrients [9,14,47,62,74]; (ii) to cleave dietary fiber into digestible short-chain fatty acids (SCFAs) that include acetate, propionate, and butyrate [9,38,63,74]; (iii) to function in the maintenance, development and homeostasis of the host immune system [14,47,62,74,79]; (iv) to support immunomodulation and protection against pathogens including potentially pathogenic GI tract bacteria [9,14,29,63,79]; and (v) to support glucose homeostasis [8,9,13,63,69,72]. Conversely, when enterotoxigenic strains of B. fragilis or their array of secretory neurotoxins leak through normally protective biophysiological-mucosal barriers they can cause substantial inflammatory pathology sys-temically that can contribute to significant mortality and morbidity…”