commensal bacterium
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Author(s):  
Yeong-Sik Hong ◽  
Dong-Hyun Jung ◽  
Won-Hyong Chung ◽  
Young-Do Nam ◽  
Ye-Jin Kim ◽  
...  

2022 ◽  
Vol XXVII (156) ◽  
pp. 32-43
Author(s):  
Mirella Tomaz Soares ◽  
Gerson Nakazato ◽  
Renata K. T. Kobayaski ◽  
Marcelo de Souza Zanutto

While diseases in humans seem to be an isolated concern, many are caused by zoonotic agents. The increasingly close contact between pets and their guardians must be considered, and investigations related to pathogens that are frequently found in humans and other animals must be carried out. Escherichia coli, in addition to being a commensal bacterium found in the intestinal tract of many animals, is one of the most frequent causes of several bacterial infections. Recent studies indicate that contact between humans and animals could contribute to the transmission between species of E. coli strains that produce extended-spectrum β-lactamases (ESBL) and AmpC-type lactamases, which are antimicrobial-resistant (multi-resistant). However, more studies are needed for these assumption to be confirmed. This review addresses the zoonotic potential of E. coli based on research related to the finding of pathogenic strains in animals and humans.


2021 ◽  
Author(s):  
Naoki Hayashi ◽  
Yong Lai ◽  
Mark Mimee ◽  
Timothy K Lu

Sophisticated gene circuits built by synthetic biology can enable bacteria to sense their environment and respond predictably. Biosensing bacteria can potentially probe the human gut microbiome to prevent, diagnose, or treat disease. To provide robust biocontainment for engineered bacteria, we devised a Cas9-assisted auxotrophic biocontainment system combining thymidine auxotrophy, an Engineered Riboregulator (ER) for controlled gene expression, and a CRISPR Device (CD). The CD prevents the engineered bacteria from acquiring thyA via horizontal gene transfer, which would disrupt the biocontainment system, and inhibits the spread of genetic elements by killing bacteria harboring the gene cassette. This system tunably controlled gene expression in the human gut commensal bacterium Bacteroides thetaiotaomicron, prevented escape from thymidine auxotrophy, and blocked transgene dissemination for at least 10 days. These capabilities were validated in vitro and in vivo. This biocontainment system exemplifies a powerful strategy for bringing genetically engineered microorganisms safely into biomedicine.


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Alan M O'Neill ◽  
Kate A Worthing ◽  
Nikhil Kulkarni ◽  
Fengwu Li ◽  
Teruaki Nakatsuji ◽  
...  

Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is an important emerging zoonotic pathogen that causes severe skin infections. To combat infections from drug-resistant bacteria, the transplantation of commensal antimicrobial bacteria as a therapeutic has shown clinical promise. We screened a collection of diverse staphylococcus species from domestic dogs and cats for antimicrobial activity against MRSP. A unique strain (S. felis C4) was isolated from feline skin that inhibited MRSP and multiple gram-positive pathogens. Whole genome sequencing and mass spectrometry revealed several secreted antimicrobials including a thiopeptide bacteriocin micrococcin P1 and phenol-soluble modulin beta (PSMβ) peptides that exhibited antimicrobial and anti-inflammatory activity. Fluorescence and electron microscopy revealed that S. felis antimicrobials inhibited translation and disrupted bacterial but not eukaryotic cell membranes. Competition experiments in mice showed that S. felis significantly reduced MRSP skin colonization and an antimicrobial extract from S. felis significantly reduced necrotic skin injury from MRSP infection. These findings indicate a feline commensal bacterium that could be utilized in bacteriotherapy against difficult-to-treat animal and human skin infections.


2021 ◽  
Vol 12 ◽  
Author(s):  
Jing Shao ◽  
Zhaocheng Li ◽  
Yanping Gao ◽  
Kairui Zhao ◽  
Minling Lin ◽  
...  

Ulcerative colitis (UC) is considered an immune disease, which is related to the dysbiosis of intestinal microbiota and disorders of the host immune system and metabolism. Sophora flavescens Aiton has been used for the clinical treatment of UC in China and East Asia for thousands of years. It has many traditional prescriptions and modern preparations, and its curative effects are definite. We are the first to report that the flavonoids in Sophora flavescens (S. flavescens) Aiton EtOAc extract (SFE) could potentially attenuate the dextran sodium sulfate–induced UC in mice, which changed the current understanding of considering alkaloids as the only anti-UC pharmacological substances of S. flavescens Aiton. Based on the 16S rRNA gene sequencing and metabolomic analysis, it was found that the anti-UC effects of SFE were due to the regulation of gut microbiota, reversing the abnormal metabolisms, and regulation of the short-chain fatty acids synthesis. Notably, according to the interaction networks of specific bacteria and “bacteria and metabolites” co-expression network, the SFE could enrich the abundance of the commensal bacterium Lactobacillus, Roseburia, norank_f__Muribaculaceae, Anaerotruncus, Candidatus_Saccharimona, and Parasutterella, which are proposed as potentially beneficial bacteria, thereby playing vital roles in the treatment of UC.


2021 ◽  
Author(s):  
Kenta Nakazono ◽  
Mi Nguyen-Tra Le ◽  
Miki Kawada-Matsuo ◽  
Noy Kimheang ◽  
Junzo Hisatsune ◽  
...  

AbstractStaphylococcus epidermidis is a commensal bacterium in humans. To persist in the bacterial flora of the host, some bacteria produce antibacterial factors such as the antimicrobial peptides known as bacteriocins. In this study, we tried to isolate bacteriocin-producing S. epidermidis strains. Among 150 S. epidermidis isolates from the oral cavities of 287 volunteers, we detected two bacteriocin-producing strains, KSE56 and KSE650. Complete genome sequences of the two strains confirmed that they carried the epidermin-harbouring plasmid pEpi56 and the nukacin IVK45-like- harbouring plasmid pNuk650. The amino acid sequence of epidermin from KSE56 was identical to the previously reported sequence, but the epidermin synthesis-related genes were partially different. The prepeptide amino acid sequences of nukacin KSE650 and nukacin IVK45 showed one mismatch, but both mature peptides were entirely similar. pNuk650 was larger and had an additional seven ORFs compared to pIVK45. We then investigated the antibacterial activity of the two strains against several skin and oral bacteria and found their different activity patterns. In conclusion, we report the complete sequences of 2 plasmids coding for bacteriocins from S. epidermidis, which were partially different from those previously reported. Furthermore, this is the first report to show the complete sequence of an epidermin-carrying plasmid, pEpi56.


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