1/15/2024 0 Comments Xld plate![]() Organism tracing during a disease outbreak utilizes phage typing and serovar identification to distinguish isolates of the same serovar 6. These genes can enhance the bacterial host’s fitness either by producing toxins or by increasing the fitness of the host during infection 5. Prophages integrated into the host genome can encode genes that are not required for phage production instead, they can be of benefit to the host cell. coli and other members of Enterobacteriaceae 4. Particularly, phages as mobile genetic elements are found to be a source of genetic differences between avirulent and virulent strains of E. The role of temperate phages is critical for host adaptability during infection and for disease epidemiology. Salmonella harbors a wide variety of temperate phages in their genomes. It is important to study the factors responsible for host adaptability in different ecological niches. The prevalence of these serovars in the food chain leads to high chances of human infections 3. Most outbreaks are due to the consumption of contaminated livestock and food products 1, 2. Salmonella Typhimurium, a major foodborne pathogen with zoonotic potential is responsible for several outbreaks of salmonellosis in humans resulting in high levels of morbidity and economic losses. Our findings may contribute to understanding of origin of new temperate phages. Our study identifies BIS20 as a new species of genus Eganvirus temperate phages as its maximum nucleotide similarity is 82.4% with any phage in NCBI. We found strong evidence of recombination hotspot in tail fiber gene. ![]() Capsid genes were conserved however those associated with tail fiber formation and assembly were unique to all members of genus Eganvirus. Genome analysis indicates its similarity to Salmonella enterica serovar Senftenberg prophage (SEStP) sequence (Nucleotide similarity 87.7%) and Escherichia virus 186 (~ 82.4% nucleotide similarity). ![]() These ORFs have mosaic arrangement as indicated by its ORF similarity to various phages and prophages in NCBI. Phage BIS20 features 29,477-base pair (bp) linear DNA genome with 53% GC content and encodes for 37 putative ORFs. Despite being temperate BIS20 significantly slowed down the growth of host strain for 24 h as compared to control (P < 0.009). Phage BIS20 was viable only at biological pH and temperature ranges (pH7 and 37 ☌). It belongs to the subfamily Peduovirinae genus Eganvirus and infects Salmonella Typhimurium strain (SE-BS17 Acc. In this study, we characterized a novel temperate phage Salmonella phage BIS20 (BIS20) with unique tail fiber genes. Salmonella has one of the largest pools of temperate phages in its genome that possess evolutionary significance for pathogen. typhimurium, but they recovered significantly higher numbers than from XLD agar (P < 0.05).Salmonella enterica serovar Typhimurium is a foodborne pathogen causing occasional outbreaks of enteric infections in humans. No significant difference occurred among TSA, OV, and TAL (P > 0.05) for enumeration of heat-injured S. typhimurium with the TAL method was compared with TSA, XLD, and the traditional overlay method (OV pouring selective agar on top of resuscitated cells on TSA agar 3-4 h after incubation). The recovery rate for heat-injured (55 degrees C for 15 min) S. typhimurium started to produce a typical reaction (black color) and other microorganisms were inhibited by the selective agents. Once the selective agents diffused to the top part of the TAL, the resuscitated S. During the resuscitation of injured cells, the selective agents from XLD were diffused to the TSA top layer part. typhimurium repaired and started to grow in the TSA. During the first few hours of incubating the plate, the injured S. typhimurium from other bacteria in the sample, a thin agar layer (TAL) procedure was developed by overlaying 14 ml of nonselective medium (TSA) onto prepoured and solidified XLD medium in a 8.5 cm diameter Petri dish. typhimurium cells while providing selectivity of isolation of S. To facilitate recovery of heat-injured S. Xylose lysine decarboxylase (XLD) medium, a selective plating medium, can inhibit heat-injured Salmonella typhimurium from growing, whereas tryptic soy agar (TSA), a nonselective medium, does not.
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