Pseudomonadota is a major phylum of Gram-negative bacteria. Currently, they are considered the predominant phylum within the realm of bacteria. They are naturally found as pathogenic and free-living (non-parasitic) genera. The phylum comprises six classes Acidithiobacillia, Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Hydrogenophilia, and Zetaproteobacteria. The Pseudomonadota are widely diverse, with differences in morphology, metabolic processes, relevance to humans, and ecological influence.
Listeria monocytogenes is the species of pathogenic bacteria that causes the infection listeriosis. It is a facultative anaerobic bacterium, capable of surviving in the presence or absence of oxygen. It can grow and reproduce inside the host's cells and is one of the most virulent foodborne pathogens. Twenty to thirty percent of foodborne listeriosis infections in high-risk individuals may be fatal. In the European Union, listeriosis continues an upward trend that began in 2008, causing 2,161 confirmed cases and 210 reported deaths in 2014, 16% more than in 2013. In the EU, listeriosis mortality rates also are higher than those of other foodborne pathogens. Responsible for an estimated 1,600 illnesses and 260 deaths in the United States annually, listeriosis ranks third in total number of deaths among foodborne bacterial pathogens, with fatality rates exceeding even Salmonella spp. and Clostridium botulinum.
Listeria is a genus of bacteria that acts as an intracellular parasite in mammals. By 2024, 28 species had been identified. The genus is named in honour of the British pioneer of sterile surgery Joseph Lister. Listeria species are Gram-positive, rod-shaped, and facultatively anaerobic, and do not produce endospores.
Listeriosis is a bacterial infection most commonly caused by Listeria monocytogenes, although L. ivanovii and L. grayi have been reported in certain cases. Listeriosis can cause severe illness, including severe sepsis, meningitis, or encephalitis, sometimes resulting in lifelong harm and even death. Those at risk of severe illness are the elderly, fetuses, newborns and those who are immunocompromised. In pregnant women it may cause stillbirth or spontaneous abortion, and preterm birth is common. Listeriosis may cause mild, self-limiting gastroenteritis and fever in anyone.
The Bacillales are an order of Gram-positive bacteria, placed within the Bacillota. The Bacillales are the most productive order of the phylum Firmicutes. Representative genera include Bacillus, Listeria and Staphylococcus.
Listeriolysin O (LLO) is a hemolysin produced by the bacterium Listeria monocytogenes, the pathogen responsible for causing listeriosis. The toxin may be considered a virulence factor, since it is crucial for the virulence of L. monocytogenes.
Listeriosis is an infectious but not contagious disease caused by the bacterium Listeria monocytogenes, far more common in domestic animals, especially ruminants, than in human beings. It can also occur in feral animals—among others, game animals—as well as in poultry and other birds.
Pathogenic bacteria are bacteria that can cause disease. This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and are often beneficial but others can cause infectious diseases. The number of these pathogenic species in humans is estimated to be fewer than a hundred. By contrast, several thousand species are part of the gut flora present in the digestive tract.
Internalins are surface proteins found on Listeria monocytogenes. They exist in two known forms, InlA and InlB. They are used by the bacteria to invade mammalian cells via cadherins transmembrane proteins and Met receptors respectively. The exact role of these proteins and their invasiveness in vivo is not completely understood. In cultured cells, InlA is necessary to facilitate Listeria entry into human epithelial cells, while InlB is necessary for Listeria internalisation in several other cell types, including hepatocytes, fibroblasts, and epithelioid cells. Internalins are mainly surface-exposed virulence factors present in a number of Gram-positive bacteria whose role ranges from recognition of cellular receptors to aid in pathogen entry to escape from autophagy.
The 2008 Canadian listeriosis outbreak was a widespread outbreak of listeriosis in Canada linked to cold cuts from a Maple Leaf Foods plant in Toronto, Ontario. There were 57 total confirmed cases, resulting in 23 deaths.
Bacterial cellular morphologies are the shapes that are characteristic of various types of bacteria and often key to their identification. Their direct examination under a light microscope enables the classification of these bacteria.
The concept of a minimal infective dose (MID), also known as the infectious dose, has traditionally been used for infectious microorganisms that contaminate foods. MID was defined as the number of microorganisms ingested from which a pathology is observed in the consumer. For example, to cause gastrointestinal disorders, the food must contain more than 100,000 Salmonella per gram or 1000 per gram for salmonellosis. however, some viruses like DHBV( duck hepatitis B virus) need as low as 9.5 x 10(9) virus per milliliters to cause liver infections.To know the dose ingested, it is also necessary to know the mass of the portion. This may be calculated using the following formula:
The 2011 United States listeriosis outbreak was a widespread outbreak of Listeria monocytogenes food poisoning across 28 US states that resulted from contaminated cantaloupes linked to Jensen Farms of Holly, Colorado. As of the final report on August 27, 2012, there were 33 deaths and 147 total confirmed cases since the beginning of the first recorded case on July 31, 2011. It was the worst foodborne illness outbreak in the United States, measured by the number of deaths, since the Centers for Disease Control and Prevention began tracking outbreaks in the 1970s, or tied with the worst, an outbreak of listeria from cheese in 1985, depending on which CDC report is used.
Listeria virus P100 is a virus of the family Herelleviridae, genus Pecentumvirus.
Listeria ivanovii is a species of bacteria in the genus Listeria. The listeria are rod-shaped bacteria, do not produce spores, and become positively stained when subjected to Gram staining. Of the six bacteria species within the genus, L. ivanovii is one of the two pathogenic species. In 1955 Bulgaria, the first known isolation of this species was found from sheep. It behaves like L. monocytogenes, but is found almost exclusively in ruminants. The species is named in honor of Bulgarian microbiologist Ivan Ivanov. This species is facultatively anaerobic, which makes it possible for it to go through fermentation when there is oxygen depletion.
The 2018 Australian rockmelon listeriosis outbreak was an outbreak of Listeriosis, caused by the bacteria Listeria monocytogenes, later traced to rockmelon grown by Rombola Family Farms in the Riverina region of New South Wales, Australia.
Milk borne diseases are any diseases caused by consumption of milk or dairy products infected or contaminated by pathogens. Milk borne diseases are one of the recurrent foodborne illnesses—between 1993 and 2012 over 120 outbreaks related to raw milk were recorded in the US with approximately 1,900 illnesses and 140 hospitalisations. With rich nutrients essential for growth and development such as proteins, lipids, carbohydrates, and vitamins in milk, pathogenic microorganisms are well nourished and are capable of rapid cell division and extensive population growth in this favourable environment. Common pathogens include bacteria, viruses, fungi, and parasites and among them, bacterial infection is the leading cause of milk borne diseases.
Tartrolons are a group of boron-containing macrolide antibiotics discovered in 1994 from the culture broth of the myxobacterium Sorangium cellulosum. Two variants of tartrolons, A and B, were identified. Tartrolon B contains a boron atom, while tartrolon A does not.
