6 research outputs found
Phage Therapy an Effective Remedy Against Drug-Resistant Bugs and Hard to Treat Bacterial Infections-A Review
The injudicious use of antibiotics not only in medicine but also to promote the growth of farm animals has led to the development of antibiotic resistance against many bacterial diseases. One of the remedy against such drug resistant bacterial infections is the application of phage (Bacteriophage) therapy. Phage therapy involves using phages or their products as bioagents for the treatment or prophylaxis of bacterial infections. There are two types of phages based on their type of life cycle: the lytic and the lysogenic phages. Only the lytic phages are used in phage therapy, because of the disadvantages of lysogenic pahges (Superinfection immunity, lysogenic conversion, specialized transduction). Apart from live phages the phage byproducts like phage lysins can also be used specifically against certain bacterial infections. The reports indicate that appropriate administration of living phages can be used to treat lethal infectious diseases caused by bacteria, like Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, Salmonella spp. and Staphylococcus aureus etc. In the coming time the phage therapy will compensate for unavoidable complications of antimicrobial therapy, particularly the appearance of multidrug resistance bacteria (super bugs)
Data from: Recombinant production of a diffusible signal factor inhibits Salmonella invasion and animal carriage
Please cite as: Mudasir Ali Rather, Rimi Chowdhury, Paulina Pavinski Bitar, Craig Altier. (2023) Data from: Recombinant production of a diffusible signal factor inhibits Salmonella invasion and animal carriage. [dataset] Cornell University eCommons Repository. https://doi.org/10.7298/gv1c-b060These files contain data along with associated output from instrumentation supporting all results reported in Rather, et al. In Rather, et al., we found: The complex chemical environment of the intestine is defined largely by the metabolic products of the resident microbiota. Enteric pathogens, elegantly evolved to thrive in the gut, use these chemical products as signals to recognize specific niches and to promote their survival and virulence. Our previous work has shown that a specific class of quorum-sensing molecules found within the gut, termed diffusible signal factors (DSF), signals the repression of Salmonella tissue invasion, thus defining a means by which this pathogen recognizes its location and modulates virulence to optimize its survival. Here we determined whether the recombinant production of a DSF could reduce Salmonella virulence in vitro and in vivo. We found that the most potent repressor of Salmonella invasion, cis-2-hexadecenoic acid (c2-HDA), could be recombinantly produced in E. coli by the addition of a single exogenous gene encoding a fatty acid enoyl-CoA dehydratase/thioesterase, and that co-culture of the recombinant strain with Salmonella potently inhibited tissue invasion by repressing Salmonella genes required for this essential virulence function. Using the well characterized E. coli Nissle 1917 strain and a chicken infection model, we found that the recombinant DSF-producing strain could be stably maintained in the large intestine. Further, challenge studies demonstrated that this recombinant organism could significantly reduce Salmonella colonization of the cecum, the site of carriage in this animal species. These findings thus describe a plausible means by which Salmonella virulence may be affected in animals by in situ chemical manipulation of functions essential for colonization and virulence.This project was supported by Agriculture and Food Research Initiative Competitive Grant no. 2021-08162 from the USDA National Institute of Food and Agriculture, and by NIH/NIAID grant R01 AI162944-01 to C.A
Recombinant production of a diffusible signal factor inhibits Salmonella invasion and animal carriage
ABSTRACTThe complex chemical environment of the intestine is defined largely by the metabolic products of the resident microbiota. Enteric pathogens, elegantly evolved to thrive in the gut, use these chemical products as signals to recognize specific niches and to promote their survival and virulence. Our previous work has shown that a specific class of quorum-sensing molecules found within the gut, termed diffusible signal factors (DSF), signals the repression of Salmonella tissue invasion, thus defining a means by which this pathogen recognizes its location and modulates virulence to optimize its survival. Here, we determined whether the recombinant production of a DSF could reduce Salmonella virulence in vitro and in vivo. We found that the most potent repressor of Salmonella invasion, cis-2-hexadecenoic acid (c2-HDA), could be recombinantly produced in E. coli by the addition of a single exogenous gene encoding a fatty acid enoyl-CoA dehydratase/thioesterase and that co-culture of the recombinant strain with Salmonella potently inhibited tissue invasion by repressing Salmonella genes required for this essential virulence function. Using the well characterized E. coli Nissle 1917 strain and a chicken infection model, we found that the recombinant DSF-producing strain could be stably maintained in the large intestine. Further, challenge studies demonstrated that this recombinant organism could significantly reduce Salmonella colonization of the cecum, the site of carriage in this animal species. These findings thus describe a plausible means by which Salmonella virulence may be affected in animals by in situ chemical manipulation of functions essential for colonization and virulence
RNA Interference and its therapeutic applications
RNAi is a potent method, requiring only a few molecules of dsRNA per cell to silence the expression. Long molecules of double stranded RNA (dsRNA) trigger the process. The dsRNA comes from virus and transposon activity in natural RNAi process, while it can be injected in the cells in experimental processes. The strand of the dsRNA that is identical in sequence to a region in target mRNA molecule is called the sense strand, and the other strand which is complimentary is termed the antisense strand. An enzyme complex called DICER thought to be similar to RNAase III then recognizes dsRNA, and cuts it into roughly 22- nucleotide long fragments. These fragments termed siRNAs for “small interfering RNAs” remain in double stranded duplexes with very short 3' overhangs. However, only one of the two strands, known as the guide strand or antisense strand binds the argonaute protein of RNA-induced silencing complex (RISC) and target the complementary mRNA resulting gene silencing. The other anti-guide strand or passenger strand is degraded as a RISC substrate during the process of RISC activation. This form of RNAi is termed as post transcriptional gene silencing (PTGS); other forms are also thought to operate at the genomic or transcriptional level in some organisms. In mammals dsRNA longer than 30 base pairs induces a nonspecific antiviral response. This so-called interferon response results in a nonspecific arrest in translation and induction of apoptosis. This cascade induces a global non-specific suppression of translation, which in turn triggers apoptosis. Interestingly, dsRNAs less than 30 nt in length do not activate the antiviral response and specifically switched off genes in human cells without initiating the acute phase response. Thus these siRNAs are suitable for gene target validation and therapeutic applications in many species, including humans. [Vet. World 2011; 4(5.000): 225-229
Corrigendum to: Occurrence of Dog Bites and Rabies within Humans in Srinagar, Kashmir
Open garbage dumps and dog bites are major public health problems in the Kashmir region. In Srinagar city, there are more than 91,000 dogs, or about one dog for every 12 citizens. The mounting street dog population is leading to increasing fright in the city due to the fear of rabies. Although treatable, rabies can be deadly without access to vaccines and treatment. Unfortunately, Kashmir is experiencing a shortage of the anti-rabies vaccine. More than 80,000 dog bites and 20 deaths due to rabies were reported in the Kashmir valley in the period 2008–2012. We conducted our study of dog bites in Srinagar, which has a large stray dog population, perhaps due to mismanagement of garbage. We obtained our data from Shri Maharaja Hari Singh (SMHS) Hospital. We found that most dog bite victims were males aged 30–40 years presenting with category 3 bites to the legs. The majority of victims were bitten in the evening and reported to the hospital the same day. Most victims received immunoglobin treatment. We suggest that proper garbage control can help to curb the stray dog population in the area and thus reduce the incidence of rabies
Detection and sequencing of plasmid encoded tetracycline resistance determinants (tetA and tetB) from food–borne Bacillus cereus isolates
AbstractObjectiveTo investigate the detection and sequencing of plasmid encoded tetracycline resistance genes (tetA and tetB) from food-borne and standard strains of Bacillus cereus (B. cereus).MethodsA PCR was carried out to detect the tetracycline resistance genes (tetA and tetB) in food-borne B. cereus strains and the amplified products were sequenced.ResultsThe phenotypic resistance against tetracycline was observed in 39 of the 118 food-borne isolates and two reference strains (MTCC 430 and MTCC 1307) of B. cereus. Among the phenotypically resistant isolates, tetA was detected in 36 food-borne isolates and two reference strains (MTCC 430 and MTCC 1307), whereas, tetB was detected in 12 food-borne isolates and MTCC 1307 strain.ConclusionsA close association was therefore found between phenotypic resistance against tetracycline and presence of tetracycline resistance genes. The tetA and tetB gene fragments were amplified, purified and sequenced. The gene sequences of the isolates studied herein were found similar to tetA and tetB gene sequences of other bacteria available in NCBI. The occurrence of tetA and tetB genes in B. cereus indicate the horizontal transfer of antibiotic resistance determinants from other bacteria into B. cereus. The transfer of these resistant determinants to other potentially pathogenic bacteria may be a matter of great concern