Sagnik Nag, Amity University, Kolkata
Listeria is a gram-positive bacterial intracellular parasite that causes Listeriosis i.e. a foodborne infection causing fever, muscle aches, and, in many people, diarrhoea. It can cause fatal illness during pregnancy and affect newborns, adults with weakened immune systems and the elderly. According to statistics, 1,700 people in the U.S. get listeriosis annually and nearly 270 die. Doctors diagnose listeriosis by learning that a person was associated with an outbreak of Listeria-contaminated diet or fluid. Listeriosis is generally analyzed when a bacterial culture accumulates. Most people spontaneously clear the disorder and require no medication, in contrast, health supervision experts should deal with patients with risk factors promptly with IV antibiotics. Listeria infection lasts approximately one week to roughly about six weeks, relying upon the stringency of the illness.
Since 2010, 13 of the 26 species were successfully identified and discovered in the genus listeria. Out of the 26 isolates, 25 samples were obtained from soil and one was from a freshwater source. The soil samples were collected from the eight U.S. states predominantly North Carolina, Florida, Texas, South Dakota, and Alabama.
Cornell University food scientists from the U.S. have surveyed the presence of the Listeria population on the agricultural soil and found out six novel relatives of the bacteria. The species identified in the research couldn’t be classified and categorised into pre-existing species of Listeria, thus they went under whole-genome sequencing (WGS) to enable additional characterization. The 27 species identified and discovered could be grouped into 5 distinct clusters using Whole-genome sequence-based average nucleotide identity blast (ANIb). The clusters showed <95 % similarity to each other and were identified as individual novel species of listeria. Out of the 5 clusters, 3 were identified as Listeria sensu stricto clade and the other 2 were identified as sensu lato. According to the scientific data, all the 5 novel clusters that were isolated were non-haemolytic and showed negative results for phosphatidylinositol-specific phospholipase C activity.
This discovery and research on the species will help the food facilities and help them to identify unknown growth niches that until now, may have been disregarded. Understanding and exploring the populations of listeria will save the commercial food world confusion and errors, as well as prevent contamination, explain erroneous trials and thwart foodborne pandemics.
The discovery of the novel species, L. immobilis, is closely related to L. monocytogenes, a well-known foodborne pathogen—and used as a crucial test in listeria detection methods. Peculiarly motility was thought to be common, but L. immobilis was found to lack the ability to move. Listeria monocytogenes can have a disastrous and grave pathogenic consequence on food processing factories and those units must be kept sterile. According to research and statistical data, Listeriosis has a mortality rate of 25% to 35%, even with a sufferer taking antibiotics. This finding effectively calls for a rewrite of the definitive identification procedures administered by food safety regulators. For more than 30 years, CDC has administered surveillance for Listeria infections to understand generously about the germ, how it results in disease, how it’s spread and additional evidence to ensure the public from the ailment. Each of the CDC networks surveying Listeria assists a distinct objective. Concurrently, they furnish an extensive perspective of listeriosis in the United States.
Also read: Campylobacter infection caused through sexual contact
Source:
https://phys.org/news/2021-05-scientists-species-listeria-food-safety.html
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