50-525: L. aquatica L. booriae L. cornellensis L. costaricensis L. farberi L. fleischmannii L. floridensis L. goaensis L. grandensis L. grayi L. ilorinensis L. immobilis L. innocua L. ivanovii L. marthii L. monocytogenes L. newyorkensis L. riparia L. rocourtiae L. rustica L. seeligeri L. swaminathanii L. thailandensis L. valentina L. weihenstephanensis L. welshimeri Listeria
100-584: A mutualistic relationship with the human body, as it protects the host against potential invasions by pathogens , and in turn, the host provides a source of nutrients. Lactobacilli are among the most common probiotic found in food such as yogurt, and it is diverse in its application to maintain human well-being, as it can help treat diarrhea, vaginal infections, and skin disorders such as eczema. Lactobacilli are homofermentative , i.e. hexoses are metabolised by glycolysis to lactate as major end product, or heterofermentative, i.e. hexoses are metabolised by
150-535: A broad spectrum of carbohydrates. Most lentilactobacilli are environmental or plant-associated, metabolise agmatine and convert lactate and/or diols. L. senioris and L. kribbianus form an outgroup to the genus; both species were isolated from vertrebrates and may transition to a host-adapted lifestyle. The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature and
200-455: A food-contact safe sanitizer with increased duration of the sanitizing action. Keeping foods in the home refrigerated below 4 °C (39 °F) discourages bacterial growth. Unpasteurized dairy products may pose a risk. Heating of meats (including beef, pork, poultry, and seafood) to a sufficient internal temperature, typically 74 °C (165 °F), will kill the food-borne pathogen. Non-invasive listeriosis : bacteria are retained within
250-448: A larger scale. Recently, in the field of food preservation, experiments have been conducted to measure the survivability of Listeria in different commercial finishing waxes for citrus fruits. These waxes are typically applied to extend the expiration date of the citrus fruits and aid in preventing extensive damage. Researchers found that the temperatures used during the application of some of the finishing waxes practices were sufficient for
300-902: A marker to distinguish L. monocytogenes from other Listeria species, but it is not a definitive criterion. Further biochemical characterization may be necessary to distinguish between the different species of Listeria . Listeria monocytogenes is commonly found in soil, stream water, sewage, plants, and food . Listeria in soil can contaminate vegetables, and animals can be carriers. It has been found in uncooked meats, uncooked vegetables, fruits including cantaloupe and apples, pasteurized or unpasteurized milk and milk products, and processed foods. Pasteurization and sufficient cooking kill Listeria ; however, contamination may occur after cooking and before packaging. For example, meat-processing plants producing ready-to-eat foods, such as hot dogs and deli meats, must follow extensive sanitation policies and procedures to prevent Listeria contamination. Listeria
350-713: A nomadic lifestyle that ferment a wide range of carbohydrates; most species metabolise phenolic acids by esterase, decarboxylase and reductase activities. L. plantarum expresses pseudocatalase and nitrate reductase activities. Heterofermentative, vancomycin resistant, with large genome size, broad metabolic potential and unknown ecology. Heterofermentative, vancomycin resistant, mesophilic or psychrotrophic, aerotolerant, most strains ferment pentoses but not disaccharides. Heterofermentative, thermophilic, vancomycin resistant with two exceptions, Limosilactobacillus species are vertebrate host adapted and generally form exopolysaccharides from sucrose to support biofilm formation in
400-694: A nomadic lifestyle. Homofermentative, mesophilic free living and environmental lactobacilli. Many strains are psychrotrophic and grow below 8 °C. Homofermentative, vancomycin resistant, aerotolerant and psychrophilic. Homofermentative, vancomycin resistant, motile organisms growing in liquid, plant-associated habitats. Many liquorilactobacilli produce EPS from sucrose and degrade fructans with extracellular fructanases. Homofermentative, vancomycin resistant, most ligilactobacilli are host adapted and many strains are motile. Several strains of Ligilactobacillus express urease to withstand gastric acidity. Homofermentative, vancomycin resistant organisms with
450-460: A significant component of the human and animal microbiota at a number of body sites, such as the digestive system , and the female genital system . In women of European ancestry, Lactobacillus species are normally a major part of the vaginal microbiota . Lactobacillus forms biofilms in the vaginal and gut microbiota , allowing them to persist during harsh environmental conditions and maintain ample populations. Lactobacillus exhibits
500-496: A third fell ill but survived the disease. In September 2019, three deaths and a miscarriage were reported in the Netherlands after the consumption of listeria-infected deli meats produced by Offerman. Preventing listeriosis as a foodborne illness requires effective sanitation of food contact surfaces. Ethanol is an effective topical sanitizer against Listeria . Quaternary ammonium can be used in conjunction with alcohol as
550-513: A wealth of compound microsatellites in the coding region of the genome, which are imperfect and have variant motifs. Many lactobacilli also contain multiple plasmids. A recent study has revealed that plasmids encode the genes which are required for adaptation of lactobacilli to the given environment. The genus Lactobacillus comprises the following species: The genus Lactobacillus currently contains 44 species which are adapted to vertebrate hosts or to insects. In recent years, other members of
SECTION 10
#1732773029504600-509: A widespread one the US in 2024. Improperly handled cantaloupe was implicated in both the outbreak of listeriosis from Jensen Farms in Colorado in 2011 , and a similar listeriosis outbreak across eastern Australia in early 2018. 35 people died across these two outbreaks. The Australian company GMI Food Wholesalers was fined A$ 236,000 for providing L. monocytogenes -contaminated chicken wraps to
650-522: Is a Gram-positive , facultatively anaerobic, nonmotile, non- spore -forming rod-shaped species of bacteria. It is not pathogenic. It was discovered from running water in Florida , and was first described in 2014. Its name comes from Latin, "found in water, aquatic". Listeria aquatica is the only member of genus Listeria that can ferment maltose. It is also the only nonmotile Listeria that can ferment D-tagatose. This bacilli -related article
700-504: Is a genus of bacteria that acts as an intracellular parasite in mammals. As of 2024, 28 species have 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 . The major human pathogen in the genus is L. monocytogenes . Although L. monocytogenes has low infectivity, it
750-499: Is a stub . You can help Misplaced Pages by expanding it . Lactobacillus See text Lactobacillus is a genus of gram-positive , aerotolerant anaerobes or microaerophilic , rod-shaped, non- spore -forming bacteria . Until 2020, the genus Lactobacillus comprised over 260 phylogenetically, ecologically, and metabolically diverse species; a taxonomic revision of the genus assigned lactobacilli to 25 genera (see § Taxonomy below). Lactobacillus species constitute
800-613: Is critical to prevent bacteria from infecting the fetus ; antibiotics may be given to pregnant women even in non-invasive listeriosis. Mirena Nikolova, et al. , states that applying antibiotics is crucial during the third trimester because cell-mediated immunity is reduced during this time. Pfaff and Tillet say that listeriosis can cause long-term consequences—including meningitis, preterm labor, newborn sepsis, stillbirths—when contracted during pregnancy. Oral therapies in less severe cases may include amoxicillin or erythromycin . Higher doses may be given to pregnant women to ensure penetration of
850-501: Is further complicated by the fact that biofilms are highly resistant to many disinfectants. The detection of these biofilms was made much easier through the use of quantitative techniques such as plate counting and crystalline violet staining. Although the structures and components of these biofilms have been extensively studied, how they are formed at the molecular level remains a subject of contention. This uncertainty surrounding their formation complicates any methods to completely eradicate
900-479: Is hardy and can grow in a refrigerator temperature of 4 °C (39.2 °F) up to the human body temperature of 37 °C (98.6 °F). It is the usual cause of the relatively rare bacterial disease listeriosis , an infection caused by eating food contaminated with the bacteria. The overt form of the disease has a case-fatality rate of around 20–30%. Listeriosis can cause serious illness in pregnant women , newborns , adults with weakened immune systems and
950-609: Is most prevalent in the elderly, pregnant mothers, and patients infected with HIV. With improved healthcare leading to a growing elderly population and extended life expectancies for HIV infected patients, physicians are more likely to encounter this otherwise-rare infection (only seven per 1,000,000 healthy people are infected with virulent Listeria each year). Better understanding the cell biology of Listeria infections, including relevant virulence factors, may lead to better treatments for listeriosis and other intracytoplasmic parasite infections. In oncology, researchers are investigating
1000-505: Is optimal at 39 °C, and is controlled by a transcriptional activator, PrfA, whose expression is thermoregulated by the PrfA thermoregulator UTR element. At low temperatures, the PrfA transcript is not translated due to structural elements near the ribosome binding site. As the bacteria infect the host, the temperature of the host denatures the structure and allows translation initiation for
1050-406: Is responsible for listeriosis, a rare but potentially lethal foodborne illness . The case fatality rate for those with a severe form of infection may approach 25%. ( Salmonellosis , in comparison, has a mortality rate estimated at less than 1%.) Although L. monocytogenes has low infectivity, it is hardy and can grow in temperatures from a refrigerator temperature of 4 °C (39.2 °F) up to
SECTION 20
#17327730295041100-636: Is strain specific and acquired by lateral gene transfer. The genomes of lactobacilli are highly variable, ranging in size from 1.2 to 4.9 Mb ( megabases ). Accordingly, the number of protein-coding genes ranges from 1,267 to about 4,758 genes (in Fructilactobacillus sanfranciscensis and Lentilactobacillus parakefiri , respectively). Even within a single species there can be substantial variation. For instance, strains of L. crispatus have genome sizes ranging from 1.83 to 2.7 Mb, or 1,839 to 2,688 open reading frames . Lactobacillus contains
1150-1063: The Lactobacillaceae. Two websites inform on the assignment of species to the novel genera or species ( http://www.lactobacillus.uantwerpen.be/ ; http://www.lactobacillus.ualberta.ca/ ). Homofermentative with strain-specific ability to ferment pentoses, thermophilic, vancomycin-sensitive, adapted to vertebrate or insect hosts. Homofermentative, vancomycin sensitive, unknown ecology but likely host-adapted. Homofermentative, vancomycin sensitive, extracellular amylases are frequent, unknown ecology but likely host-adapted. Homofermentative, thermophilic, vancomycin resistant, small genome size, adapted to bees and bumblebees Homofermentative with strain- or species-specific ability to ferment pentoses, vancomycin resistant, unknown ecology, likely nomadic Homofermentative with strain- or species-specific ability to ferment pentoses, vancomycin resistant, unknown ecology. Homofermentative, aerotolerant and vancomycin resistant. Genome size, G+C content of
1200-876: The Listeria rocket and the process is repeated, perpetuating the infection. Once phagocytosed, the bacterium is never again extracellular: it is an intracellular parasite like S. flexneri , Rickettsia spp., and C. trachomatis . The Center for Science in the Public Interest has published a list of foods that have sometimes caused outbreaks of Listeria : hot dogs, deli meats, milk (even if pasteurized ), cheeses (particularly soft-ripened cheeses such as feta, Brie, Camembert, blue-veined, or Mexican-style queso blanco ), raw and cooked poultry, raw meats, ice cream, raw fruit, vegetables, and smoked fish. Cold-cut meats were implicated in an outbreak in Canada in 2008 and
1250-609: The Phosphoketolase pathway to lactate, CO 2 and acetate or ethanol as major end products. Most lactobacilli are aerotolerant and some species respire if heme and menaquinone are present in the growth medium. Aerotolerance of lactobacilli is manganese -dependent and has been explored (and explained) in Lactiplantibacillus plantarum (previously Lactobacillus plantarum ) . Lactobacilli generally do not require iron for growth. The Lactobacillaceae are
1300-412: The elderly , and may cause gastroenteritis in others who have been severely infected. The incubation period can vary from three to 70 days. The two main clinical manifestations are sepsis and meningitis , often complicated by encephalitis , a pathology unusual for bacterial infections. L. ivanovii is a pathogen of mammals , specifically ruminants , and rarely causes listeriosis in humans. In
1350-429: The macrophage 's polysaccharides . Other important adhesins are the internalins . Listeria uses internalin A and B to bind to cellular receptors. Internalin A binds to E-cadherin, while internalin B binds to the cell's Met receptors. If both of these receptors have a high enough affinity to Listeria ' s internalin A and B, then it will be able to invade the cell via an indirect zipper mechanism. Once phagocytosed,
1400-399: The umbilical cord and placenta . Infected pregnant women may receive ultrasound scans to monitor the health of the fetus. Asymptomatic patients who have been exposed to Listeria typically are not treated, but are informed of the signs and symptoms of the disease and advised to return for treatment if any develop. Some Listeria species are opportunistic pathogens: L. monocytogenes
1450-609: The airline Virgin Blue in 2011. Caramel apples have also been cited as a source of listerial infections which hospitalized 26 people, of whom five died. In 2019, the United Kingdom experienced nine cases of the disease, of which six were fatal, in an outbreak caused by contaminated meat (produced by North Country Cooked Meats) in hospital sandwiches. In 2019, two people in Australia died after probably eating smoked salmon and
1500-425: The bacterial migration to the host cell's outer membrane. Gelsolin, an actin filament severing protein, localizes at the tail of Listeria and accelerates the bacterium's motility. Once at the cell surface, the actin-propelled Listeria pushes against the cell's membrane to form protrusions called filopods or "rockets". The protrusions are guided by the cell's leading edge to contact adjacent cells, which then engulf
1550-418: The bacterium is encapsulated by the host cell's acidic phagolysosome organelle. Listeria , however, escapes the phagolysosome by lysing the vacuole's entire membrane with secreted hemolysin , now characterized as the exotoxin listeriolysin O . The bacteria then replicate inside the host cell's cytoplasm. Listeria must then navigate to the cell's periphery to spread the infection to other cells. Outside
Listeria - Misplaced Pages Continue
1600-472: The biofilms. However, it has been observed that certain antimicrobial agents such as bacteriophages and enzymes have made promising progress in the effort to eradicate the Listeria biofilm. The enzymes specifically have been noted to have the capability to disrupt specific chemical components of the biofilms, degrading them in the process. More research and development is needed to make these biofilm elimination processes more affordable and efficient to be used on
1650-416: The body, Listeria has flagellar -driven motility, sometimes described as a "tumbling motility". However, at 37 °C, flagella cease to develop and the bacterium instead usurps the host cell's cytoskeleton to move. Inventively, Listeria polymerizes an actin tail or "comet", from actin monomers in the host's cytoplasm with the promotion of virulence factor ActA. The comet forms in a polar manner and aids
1700-500: The digestive tract. Symptoms are mild, lasting only a few days and requiring only supportive care. Muscle pain and fever can be treated with over-the-counter pain relievers; diarrhea and gastroenteritis can be treated with over-the-counter medications. Invasive listeriosis : bacteria have spread to the bloodstream and central nervous system. Treatment includes intravenous delivery of high-dose antibiotics and hospital in-patient care of (probably) not less than two weeks stay, depending on
1750-546: The extent of the infection. Ampicillin , penicillin , or amoxicillin are typically administered for invasive listeriosis; gentamicin may be added in cases of patients with compromised immune systems. In cases of allergy to penicillin, trimethoprim-sulfamethoxazole , vancomycin , and fluoroquinolones may be used. For effective treatment the antibiotic must penetrate the host cell and bind to penicillin-binding protein 3 (PBP3). Cephalosporins are not effective for treating listeriosis. In cases of pregnancy, prompt treatment
1800-595: The family is Brochothrix . The first documented human case of listeriosis was in 1929, described by the Danish physician Aage Nyfeldt. The genus Listeria as of 2024 is known to contain 28 species, classified into two groups: sensu stricto and sensu lato . Listeria sensu strictu contains L. monocytogenes alongside nine other closely related species: L. cossartiae , L. farberi , L. immobilis , L. innocua , L. ivanovii , L. marthii , L. seeligeri , L. swaminathanii and L. welshimeri . Listeria sensu lato contains
1850-548: The genome and the source of the two species suggest a free-living lifestyle of the genus. Homofermentative, vancomycin resistant, aerotolerant. Schleiferilactobacillus spp. have a large genome size, ferment a wide range of carbohydrates, and spoil beer and dairy products by copious production of diacetyl. Homofermentative, vancomycin resistant, mesophilic or psychrotrophic organisms. Homofermentative, vancomycin resistant; many species ferment pentoses, and are resistant to oxidative stress. L. casei and related species have
1900-480: The genus Lactobacillus (formerly known as the Leuconostoc branch of Lactobacillus ) have been reclassified into the genera Atopobium , Carnobacterium , Weissella , Oenococcus , and Leuconostoc . The Pediococcus species P. dextrinicus has been reclassified as a Lapidilactobacillus dextrinicus and most lactobacilli were assigned to Paralactobacillus or one of the 23 novel genera of
1950-398: The growth of the bacteria is limited because the biofilm formation process is interrupted. Also, it increases the difficulty in the transportation of membranes. The results of the study have led the researchers to speculate that this specific strain, Lactobacillus plantarum can be used as a “natural bacteriostat” due to its disruptive qualities. Listeria aquatica Listeria aquatica
2000-575: The human body temperature of 37 °C (98.6 °F). Listeriosis may manifest as meningitis, and can affect newborns due to its ability to penetrate the endothelial layer of the placenta . Listeria uses the cellular machinery to move around inside the host cell. It induces directed polymerization of actin by the ActA transmembrane protein , thus pushing the bacterial cell around. Listeria monocytogenes , for example, encodes virulence genes that are thermoregulated . The expression of virulence factor
2050-402: The late 1920s, two groups of researchers independently identified L. monocytogenes from animal outbreaks, naming it Bacterium monocytogenes . They proposed the genus Listerella in honour of surgeon and early antiseptic advocate Joseph Lister , but that name was already in use for a slime mould and a protozoan . Eventually, the genus Listeria was proposed and accepted. The genus Listeria
Listeria - Misplaced Pages Continue
2100-403: The only family of the lactic acid bacteria (LAB) that includes homofermentative and heterofermentative organisms; in the Lactobacillaceae , homofermentative or heterofermentative metabolism is shared by all strains of a genus. Lactobacillus species are all homofermentative, do not express pyruvate formate lyase, and most species do not ferment pentoses. In L. crispatus , pentose metabolism
2150-418: The remaining 18 species: L. aquatica , L. booriae , L. cornellensis , L. costaricensis , L. fleischmannii , L. floridensis , L. goaensis , L. grandensis , L. grayi , L. ilorinensis , L. newyorkensis , L. portnoyi , L. riparia , L. rocourtiae , L. rustica , L. thailandensis , L. valentina and L. weihenstephanensis . Listeria dinitrificans , previously thought to be part of the genus Listeria ,
2200-419: The survival of Listeria . In some of the waxes, the bacteria were detected up to 135 days after they were initially contaminated. Acknowledging these results, the researchers have suggested that more insight is needed into how the ingredients come together to allow for the survival of Listeria , and possibly other microbial agents. In another study, scientists isolated a strain of Lactobacillus plantarum that
2250-966: The upper intestine of animals. Heterofermentative, vancomycin resistant, mesophilic, aerotolerant, small genome size. Fructilactobacilli are adapted to narrow ecological niches that relate to insects, flowers, or both. Heterofermentative, vancomycin resistant, grow in the pH range of 3–5; fermenting disaccharides and sugar alcohols but few hexoses and no pentoses. Heterofermentative, vancomycin resistant, small genome size, fermenting only few carbohydrates, adapted to bees and/or flowers. Heterofermentative, vancomycin resistant, mesophilic or psychrotrophic, metabolise agmatine, environmental or plant-associated lifestyle. Heterofermentative, vancomycin resistant, mesophilic or psychrotrophic, environmental or plant-associated lifestyle. Adapted to hexose-depleted habitats, most strains do not reduce fructose to mannitol but metabolize agmatine and diols. Heterofermentative, vancomycin resistant, mesophilic, fermenting
2300-409: The use of Listeria as a cancer vaccine, taking advantage of its "ability to induce potent innate and adaptive immunity" by activating gamma delta T cells . Researchers have also been investigating the continuous presence of Listeria in food processing plants. The bacteria’s presence has been partially attributed to the formation of biofilms . This increases the likelihood of food contamination and
2350-441: The virulence genes. The majority of Listeria bacteria are attacked by the immune system before they are able to cause infection . Those that escape the immune system's initial response, however, spread through intracellular mechanisms, which protects them from circulating immune factors (AMI). To invade, Listeria induces macrophage phagocytic uptake by displaying D-galactose in their teichoic acids that are then bound by
2400-413: Was able to completely eradicate a Listeria from a sample of sauerkraut. Through the use of transmission electron microscopy (TEM), the researchers were able to observe cell morphological changes. The isolated strain of Lactobacillus plantarum was observed to possess several antibacterial properties, capable of disrupting the cell structure of the Listeria sample and acting as a lethal agent. Specifically,
2450-483: Was classified in the family Corynebacteriaceae through the seventh edition (1957) of Bergey's Manual of Systematic Bacteriology . 16S rRNA cataloging studies demonstrated that L. monocytogenes is a distinct taxon within the Lactobacillus - Bacillus branch of the bacterial phylogeny constructed by Woese. In 2004 the genus was placed in the newly created family Listeriaceae , of which the only other genus in
2500-513: Was reclassified into the new genus Jonesia . All species within the genus Listeria are gram-positive , catalase -positive rods and do not produce endospores . Under the microscope, Listeria species appear as small rods, sometimes arranged in short chains. In direct smears, they may be coccoid , and can be mistaken for streptococci . Longer cells may resemble corynebacteria . Flagella are produced at room temperature, but not at 37 °C. Hemolytic activity on blood agar has been used as
#503496