Brief history of the taxonomy of Listeria<\/u><\/strong><\/p>\n

Introduction<\/u><\/strong><\/p>\n

Taxonomy is a scientific discipline pertaining to the classification, nomenclature, and identification of organisms. Organisms are classified or grouped based on shared characteristics, previously unknown strains are placed in known taxa and assigned names following set nomenclature standards. The naming of organisms dates back as early as the great philosopher Aristotle (384-322BC). Modern taxonomy is based on the principles established by the Swedish botanist, Carolus Linnaeus (1707-1778). He introduced binomial nomenclature for naming organisms and established the Linnaean classification system whereby organisms are ranked hierarchically at species, genus, family, order, class, phylum and kingdom levels.<\/p>\n

In the last few years, the taxonomy of the genus Listeria has undergone extensive modifications, mainly because of the now well-established DNA hybridisation techniques. Murray, Webb and Swann described Listeria monocytogenes<\/em> as the causative agent for sepsis in rodents in 1926 and they named it Bacterium <\/em>monocytogenes<\/em>because the infection was monocytotic (Liu, 2013<\/a>). <\/em>The following year, Pirie isolated a similar bacillus from the infected liver of the African jumping mice, the gerbils and named it Listerella <\/em>hepatolytica <\/em>(McLauchlin, 1987<\/a>). Up Until 1940, there was considerable confusion in the nomenclature of L. monocytogenes. J. H. Pirie (1940)<\/a> chose Listerella<\/em> as the generic name in honour of Lord Lister, the British surgeon who pioneered antiseptic surgery. However, this name had already been applied by Jahn in 1906 to a group of slime moulds (Mycetozoa<\/em>) (J. H. Pirie, 1940<\/a>). The generic name Bacterium<\/em> as applied by Murray and collaborators was undesirable because the organism does not possess the characteristics of this genus. The resolution of the Committee on Nomenclature, Third International Congress for Microbiology, New York, 1939, was that in all duplications of generic names, only the one first applied should be considered valid, invalidating the generic name proposed by Pirie, and thus he suggested the name Listeria<\/em> in 1940 (J. H. H. Pirie, 1940<\/a>). Listeria<\/em> was adopted in the sixth edition of Bergey\u2019s Manual of Determinative Bacteriology and approved by the Judicial Commission on Bacteriological Nomenclature and Taxonomy, and it is now the official genus name (Rocourt & Buchrieser, 2007<\/a>).<\/p>\n

Listeria<\/em> species known to date are as follows: L. monocytogenes<\/em> (J. H. Pirie, 1940<\/a>), Listeria <\/em>grayi<\/em>, Listeria<\/em> innocua<\/em>, Listeria <\/em>welshimeri<\/em>, Listeria <\/em>seeligeri<\/em>, Listeria <\/em>ivanovii<\/em> (Seeliger, Rocourt, Schrettenbrunner, Grimont, & Jones, 1984<\/a>), Listeria <\/em>marthii<\/em> (Graves et al., 2010<\/a>), Listeria <\/em>rocourtiae<\/em> (Leclercq et al., 2010<\/a>), Listeria <\/em>fleischmannii<\/em> (Bertsch et al., 2013<\/a>), Listeria <\/em>weihenstephanensis<\/em> (Lang Halter, Neuhaus, & Scherer, 2013<\/a>), Listeria <\/em>floridensis<\/em>, Listeria <\/em>aquatica<\/em>, Listeria <\/em>cornellensis<\/em>, Listeria <\/em>riparia<\/em> and Listeria <\/em>grandensis<\/em> (den Bakker et al., 2014<\/a>) and the recently published Listeria <\/em>booriae<\/em> and Listeria <\/em>newyorkensis<\/em> (Weller, Andrus, Wiedmann, & den Bakker, 2015<\/a>). Additionally, two subspecies have been identified within L. <\/em>ivanovii<\/em> [subsp. ivanovii<\/em> and subsp. londoniensis<\/em>, (Boerlin et al, 1992 cited in Weller et al. (2015)<\/a>], L<\/em>. grayi<\/em> [subsp. grayi<\/em> and subsp. murrayi<\/em>(Stuart & Welshimer, 1974<\/a>)], and L. <\/em>fleischmannii<\/em> [subsp. fleischmannii<\/em> and subsp. coloradonensis<\/em>, (den Bakker, Manuel, Fortes, Wiedmann, & Nightingale, 2013<\/a>)].<\/p>\n

Listeria<\/em> only had one species, L. monocytogenes<\/em>, for many years. It was only in 1948 that Listeria <\/em>denitrificans<\/em> was added, followed by L. <\/em>grayi<\/em> in 1966, L. <\/em>murrayi<\/em> in 1971, L. <\/em>innocua<\/em> in 1981, L. <\/em>welshimeri<\/em> and L<\/em>. seeligeri<\/em>in 1983 and L. <\/em>ivanovii<\/em> in 1985. The newer members of the species were all added post-2009. The species are named after famous scientists in the sciences field who were mainly involved in microbiology related studies. The newer species are mostly named after the places they were first isolated.<\/p>\n

Diversity<\/u><\/strong><\/p>\n

Listeria<\/em> species are ubiquitous, being found in most natural and urban environmental habitats. The wide distribution in the environment of the species isolated before 1985 is well documented. For example, the newly isolated species (2009 onwards) were from different environments as follows: L.<\/em> weihenstephanensis <\/em>was isolated from vegetation in a pond in Germany (Lang Halter et al., 2013). L.<\/em> rocourtiae<\/em>was isolated from processed lettuce in Austria (Leclercq et al., 2010). L. booriae<\/em> and L.<\/em> newyorkensis<\/em> were isolated from food processing environments in the USA (Weller et al., 2015). L.<\/em> floridensis, L. aquatica, L. cornellensis, L. riparia<\/em> and L. grandensis<\/em> were isolated from natural and agricultural environments in the USA (den Bakker et al., 2014). L. <\/em>fleischmannii<\/em> was isolated from cheeses in Switzerland and Germany (Bertsch et al., 2013). L. <\/em>marthii<\/em> was isolated from different natural environments in the USA (Graves et al., 2010). This clearly shows that the Listeria species is adapted to various environmental conditions and not confined to specific environments.<\/p>\n

The genus Listeria<\/em> is composed of short (0.5 \u2013 2 \u00b5m long), Gram-positive, non-sporulating, facultatively anaerobic rods that have a low G + C content. Cells are non-encapsulated exhibiting growth at temperatures ranging from 0 \u2013 45^{o<\/sup>C, and at pH 6 \u2013 9. Depending on the growing conditions, the cells can appear coccoid and motile. Listeria <\/em>species are catalase-positive and oxidative-negative. According to Schleifer & Kandler, 1972, cited in} Lang Halter et al. (2013)<\/a>, the cell walls contain meso-diaminopimelic acid variation A1\u03b3. When grown at 37^{o<\/sup>C, the major fatty acids are anteiso-C_{17:0<\/sub> and anteiso-C15:0<\/sub>. Menaquinones are the sole respiratory quinones as stated by Ludwig et al cited in}} Lang Halter et al. (2013)<\/a>.<\/p>\n

\u00a0<\/strong><\/p>\n

Pathogenicity<\/u><\/strong><\/p>\n

Three of the Listeria <\/em>species, that is, L. monocytogenes<\/em>, L. ivanovii<\/em> and L. <\/em>seeligeri<\/em> are haemolytic and harbour the Listeria <\/em>virulence gene cluster. Of these species, only L. monocytogenes<\/em> and L. ivanovii<\/em> are pathogenic to animals and humans, with L<\/em>. monocytogenes <\/em>expressing pathogenicity in humans and L. ivanovii<\/em> in ungulates (cattle and sheep). L. <\/em>seeligeri<\/em> is not pathogenic to humans even though it contains homologues of the virulence gene cluster (Lang Halter et al., 2013<\/a>). Although L. monocytogenes<\/em> is recognized as the causative agent of listeriosis in humans, rare cases of infection by L. <\/em>innocua<\/em>, L. ivanovii<\/em>, and L. <\/em>seeligeri<\/em> have also been reported (Magalh\u00e3es et al., 2014).<\/p>\n

Batz (2005), Gillespie (2010) and Painter (2013) cited in Weller et al. (2015)<\/a> stated that L. monocytogenes<\/em> poses a significant threat to public health and Scallan et al (2011) cited in Orsi and Wiedmann (2016)<\/a> mentioned that it is the third leading cause of foodborne deaths related to microbial contamination. It is the most commonly isolated member responsible for listeriosis (Leclercq et al., 2010<\/a>). Major outbreaks of food-borne listeriosis have been recorded in different parts of the industrialised world. This has raised grave concerns in relation to public health. L. monocytogenes<\/em> has been identified as the causative agent in all cases of human listeriosis. It mainly manifests in high-risk segments of the populations such as foetuses, neonates, infants, the elderly, pregnant women and immunocompromised people Farber and Peterkin, 1991 cited in Gormon and Phan-Thanh (1995). The ability of L. monocytogenes<\/em> strains to survive in conditions of temperatures as low as 4^{o<\/sup>C have made it a bacterium that is significant in the food processing sector especially in ready-to-eat foods.<\/p>\n}

Phylogeny<\/u><\/strong><\/p>\n

The relationship of Listeria<\/em> spp to other bacteria was relatively unclear until the 1970s. It only received recognition in in 1930 when it was incorporated in the tribe Kurthia<\/em> of the Corynebacteriaceae<\/em> family. In 1974, it was unclearly placed with Erysipelothrix <\/em>and Caryophanon<\/em> after the Lactobacillaceae <\/em>family. It was subsequently grouped with Lactobacillus<\/em>, Erysipelothrix<\/em>, Brochothrix<\/em>, Renibacterium<\/em>, Kurthia<\/em> and Caryophanon<\/em> in the section of \u201cregular, non-sporing Gram-positive rods\u201d in Bergey\u2019s Manual of Determinative Bacteriology <\/em>(Rocourt & Buchrieser, 2007<\/a>). <\/em><\/p>\n

Studies by Jones (1975) paved way for a broader understanding of the phylogenetic relationship between then known Listeria spp and various other genera. Wilkinson and Jones (1977) and Feresu and Jones (1988) cited in Rocourt and Buchrieser (2007)<\/a> carried out studies that progressively led to a phylogenetic refinement in the positioning of Listeria<\/em>. These works clearly distinguished Listeria<\/em> from other genera such as Erysipelothrix<\/em> and Brochothrix <\/em>thermosphacta<\/em> and its relatedness to Lactobacillus<\/em> and Streptococcus.<\/em> Based on these results, Wilkinson and Jones (1988) cited in Rocourt and Buchrieser (2007)<\/a> suggested that Listeria, Gemella, Brochothrix, Streptococcus<\/em> and Lactobacillus<\/em> be classified in the family Lactobacillaceae.<\/em><\/p>\n

Chemotaxonomic methods have shown that Listeria<\/em> spp belong to the low G + C percent DNA content (<55%) group of Gram-positive bacteria. Lipoteichoic acids isolated from L. monocytogenes<\/em> exhibit structural analogies with lipoteichoic acids from other bacteria. Rocourt and Buchrieser (2007)<\/a> suggested that they may be used as taxonomic markers. According to Ruhland and Fiedler (1987) cited in Rocourt and Buchrieser (2007), lipoteichoic acids imply biochemical consistency and their absence in Coryneform bacteria and presence in Bacillus, Staphylococcus, Streptococcus <\/em>and Lactobacillus<\/em> cements the grouping of Listeria<\/em> with the latter. Mara and Michalec (1977) cited in Rocourt and Buchrieser (2007) reported the absence of free mycolic acids in Listeria<\/em>. The presence of menaquinones corroborates relatedness of Listeria<\/em> and Brochothrix<\/em> albeit distance from lactobacilli (Rocourt & Buchrieser, 2007<\/a>).<\/p>\n

16S and 23S rRNA analysis of L. monocytogenes has elucidated the position of Listeria<\/em> with regard to the other genera of Gram-positive bacteria. Collins et al cited in Rocourt and Buchrieser (2007) deduced that Listeria<\/em> is remote from Lactobacillus<\/em> and should not be in the Lactobacillaceae<\/em> family and that the Listeria-Brochothrix<\/em> subline should be a different family, Listeriaceae.<\/em> 23S rRNA sequencing has affirmed the dissimilarities between Lactobacillus<\/em> and Listeria<\/em> and the similarities with Bacillus<\/em> and Staphylococcus <\/em>(<\/em>Rocourt & Buchrieser, 2007<\/em><\/a>)<\/em>.<\/p>\n

According to den Bakker et al. (2014)<\/a>, the species of the genus Listeria can be put into four clades by use of 16S rRNA gene and amino acid sequence phylogenies as follows:<\/p>\n

\n
1. L. monocytogenes<\/em> and related species (Listeria <\/em>sensu<\/em>stricto<\/em>: L. marthii, L. innocua, L. <\/em>welshimeri<\/em>, L. seeligeri, <\/em>and L. ivanovii<\/em>),<\/li>\n
2. L. rocourtiae, L. weihenstephanensis, L. cornellensis, L. grandensis and L. riparia,<\/li>\n
3. L. fleischmannii, L. floridensis<\/em> and L. aquatica<\/em>, and<\/li>\n
4. L. grayi<\/em>.<\/li>\n<\/ol>\n

   They also state that the L. rocourtiae<\/em> and L. grayi<\/em> clades are sister groups based on 16S rRNA gene sequence analysis.<\/p>\n

   Sensu<\/u><\/strong>stricto<\/u><\/strong> and <\/u><\/strong>sensu<\/u><\/strong>lato<\/u><\/strong><\/p>\n

   Chiara et al. (2015)<\/a> and Orsi and Wiedmann (2016)<\/a>\u00a0 categorised the species in the genus Listeria into two groups. Listeria<\/em> sensu stricto, comprising L. monocytogenes<\/em>, L. seeligeri, L. marthii, L. ivanovii, L<\/em>. welshimeri<\/em> and L. innocua <\/em>and Listeria<\/em> sensu lato, consisting of L. grayi <\/em>and all the other 10 remaining species.\u00a0 These researchers based their separation on the relatedness of the species to L. monocytogenes<\/em> which was the first Listeria<\/em> species to be classified and its importance to the food processing sector.<\/p>\n

   The members of this group of species are easily recognisable by the following characteristics. They can grow at temperatures as low as 4^{o<\/sup>C; motility at temperatures around 30o<\/sup>C; catalase-positive; unable to reduce nitrate to nitrite as well as showing a positive reaction to Voges-Proskauer test which gives an indication of the glucose fermenting ability via the butane diol pathway. All sensu stricto species are able to ferment D-arabitol, \u03b1-methyl D-glucoside, cellobiose, D-fructose, D-mannose, N-acetylglucosamine, maltose, and lactose but are unable to ferment inositol, L-arabinose, and D-mannitol (}Orsi & Wiedmann, 2016<\/a>). The species can be differentiated from each other based on standard biochemical tests. For example, L. marthii<\/em> is unique in its ability to ferment both D-mannitol and D-xylose but it is also the only sensu stricto unable to ferment sucrose.<\/p>\n

   The species in sensu lato have all been recently described and their distribution in the environment is yet to be comprehensively studied, except for L. grayi<\/em>. The sensu lato species are catalase-positive, non-capsulated, non-sporulating rods. The sensu lato species can be distinguished from the sensu stricto by standard biochemical tests as well. They are non-motile except for L. grayi. <\/em>Initial studies carried out by Lang Halter et al. (2013)<\/a>; Leclercq et al. (2010)<\/a> found the presence of motility in L. rocourtiae<\/em> and L. <\/em>weinhenstephanensis<\/em> but later studies found that they were non-motile. Weller et al. (2015)<\/a> carried out subsequent analyses that revealed the absence of motility in all sensu lato species at temperatures ranging from 4 to 37^{o<\/sup>C, except for L. grayi. <\/em><\/p>\n}

   L. grayi and L. murrayi<\/u><\/em><\/strong><\/p>\n

   The position of L. grayi<\/em> and L. murrayi<\/em> in the genus Listeria<\/em> has courted controversy for decades, with various suggestions having been proposed. Rocourt, Boerlin, Grimont, Jacquet, and Piffaretti (1992)<\/a> proposed that L. grayi<\/em> and L. murrayi<\/em> be assigned to a single taxon, L. grayi<\/em>, because based on the DNA-DNA hybridisation, multilocus enzyme electrophoresis, and rRNA restriction fragment length polymorphism techniques they used, they found a high level of relatedness between the two species. They share specific chemotaxonomic properties which allow for their distinction from the other Listeria <\/em>spp. They can only be distinguished from each other based on nitrate reduction data.<\/p>\n

   A high level of DNA-DNA homology was observed between L<\/em>. grayi<\/em> and L<\/em>. murrayi <\/em>by Stuart and Welshimer with a subsequent proposal that they should be classified in their own genus. However, they also discovered a low DNA relatedness between L. monocytogenes<\/em> and L. grayi<\/em> and L. murrayi<\/em>. They proposed the removal of L. grayi<\/em> and L. murrayi<\/em> and transfer to a new genus \u201cMurraya<\/em>\u201d as \u201cMurraya<\/em> grayi<\/em> subsp. grayi<\/em>\u201d and \u201cMurraya<\/em> grayi<\/em> subsp murrayi<\/em>\u201d (Stuart & Welshimer, 1974<\/a>).<\/p>\n

   Rocourt et al. (1992)<\/a> carried out studies to re-assess and re-evaluate the genomic relatedness between Listeria grayi<\/em> and Listeria murrayi<\/em> using DNA-DNA hybridisation, multilocus enzyme electrophoresis, and rRNA restriction fragment length polymorphism techniques. They concluded the species should be assigned a single genus, confirming the data published since 1973. They observed that there were high levels of similarity between the strains of these two species and suggested that they be assigned the name L. grayi<\/em>.<\/p>\n

   L. monocytogenes<\/u><\/em><\/strong><\/p>\n

   DNA-DNA hybridisations carried out by Stuart and Welshimeri in 1974 identified L. monocytogenes<\/em> as heterogenous. As they had only one labelled DNA in their collection, the total number of DNA hybridisation groups could not be ascertained. Further DNA hybridisation techniques discovered five DNA relatedness groups that had previously been identified as L. monocytogenes<\/em>. Genomic group 1 contained the type strain L. monocytogenes <\/em>(sensu stricto). Genomic group 2 contained haemolytic strains belonging to L. monocytogenes<\/em> serovar 5. Upon further investigation of the strains, using DNA-DNA hybridisation and rRNA gene restriction patterns, two subspecies L. ivanovii<\/em> subsp ivanovii<\/em> (ribose-positive) and L. ivanovii<\/em> subsp. londoniensis<\/em> (ribose-negative) were labelled. Genomic group 3 contained <\/a>non-haemolytic and non-pathogenic (for mice) strains corresponding to L. innocua. <\/em>Genomic group 4 contained non-haemolytic and non-pathogenic strains now known as L. <\/em>welshimeri<\/em>.\u00a0 Genomic group 5 included haemolytic and non-pathogenic strains and was subsequently named L. seeligeri <\/em>(<\/em>Rocourt & Buchrieser, 2007<\/a>)<\/em>.<\/em><\/p>\n

   L. ivanovii<\/u><\/em><\/strong><\/p>\n

   In 1975, Ivanov as cited in Seeliger et al. (1984)<\/a>, suggested the name Listeria <\/em>bulgarica<\/em> for what was then known as Listeria monocytogenes<\/em> serovar 5. In 1982, Seeliger et al cited in Seeliger et al. (1984)<\/a> recommended that L. monocytogenes<\/em> serovar 5 strains be recognised either as a subspecies perhaemolytica or as a distinct species which could be named either Listeria <\/em>perhaemolytica<\/em> or L<\/em>. ivanovii.<\/em> The authors were merely expressing their opinions but did not actually propose a name change for the species in question. Studies carried out showed that L. monocytogenes<\/em> serovar 5 was pathogenic for mice and was reported as the etiological agent of abortion in sheep by Macleod & Watt in 1974, cited in Seeliger et al. (1984)<\/a>. Thus, the name L. ivanovii<\/em> was proposed.<\/p>\n

   Listeria <\/u><\/em><\/strong>denitrificans<\/u><\/em><\/strong> \/ <\/u><\/em><\/strong>Jonesis<\/u><\/em><\/strong>denitrificans<\/u><\/em><\/strong><\/p>\n

   On the basis of DNA-DNA hybridization, DNA base composition, and determination of 16S rRNA cataloguing data and the results of numerous other chemotaxonomic studies, Listeria <\/em>denitrificans<\/em> was excluded from the genus and renamed Jonesia<\/em>denitrificans<\/em> (Boerlin, Rocourt, & Piffaretti, 1991<\/a>) (Stuart & Welshimer, 1973<\/a>). The results obtained confirmed that this species was not a member of the genus Listeria. L<\/em>. denitrificans<\/em> was found to be phylogenetically similar to sub-branches of the actinomycetes subdivision (Rocourt, Wehmeyer, & Stackebrandt, 1987<\/a>). Studies carried out later revealed that the closest relatives of Jonesia<\/em>were Dermobacter <\/em>hominis<\/em> and Brachybacterium <\/em>faicium<\/em> (Rocourt & Buchrieser, 2007<\/a>).<\/p>\n

   Conclusion<\/u><\/strong><\/p>\n

   Results from over 30 years of research demonstrated that Listeria is a robust taxon with clearly distinct characteristics from neighbouring taxa. Numerical studies, chemotaxonomy, rRNA and DNA sequencing analyses showed that it does not belong to the Coryneform<\/em> family of bacteria. The exact phylogenetic position is still debatable.<\/p>\n

   The identification of new Listeria<\/em> species and changes in the taxonomy of Listeria<\/em> can have considerable impacts on the food industry and test kit manufacturers. There is no doubt there will be a progressive evolution of taxonomic studies that will open new avenues in taxonomy.<\/p>\n

   Genomic studies are relevant and have revolutionised taxonomy. They offer a definitive classification, including that of previously unknown strains. The study of the pathogenic and non-pathogenic strains of Listeria<\/em> are being done to understand genome evolution and the evolution of virulence characteristics therein. The information obtained from such studies will allow for the development of genetic and genomic criteria for pathogenic strains, including the development of assays that specifically detect pathogenic Listeria <\/em>strains (Henk C. den Bakker et al., 2010). Pallen (2007) cited in Henk C. den Bakker et al. (2010) reiterates that an understanding of the genomic content of non-pathogenic strains of pathogenic species is necessary to understand the evolution of virulence-associated genes and to facilitate identification of putative virulence genes.<\/p>\n

   Bibliography<\/u><\/strong><\/p>\n

   <\/a>Bertsch, D., Rau, J., Eugster, M. R., Haug, M. C., Lawson, P. A., Lacroix, C., & Meile, L. (2013). Listeria fleischmannii sp. nov., isolated from cheese. International Journal of Systematic and Evolutionary Microbiology, 63<\/em>, 526-532.<\/p>\n

   <\/a>Boerlin, P., Rocourt, J., & Piffaretti, J.-C. (1991). Taxonomy of the genus Listeria by using multilocus enzyme electrophoresis. International Journal of Systematic and Evolutionary Microbiology, 41<\/em>(1), 59-64.<\/p>\n

   <\/a>Chiara, M., Caruso, M., D\u2019Erchia, A. M., Manzari, C., Fraccalvieri, R., Goffredo, E., . . . Parisi, A. (2015). Comparative Genomics of Listeria Sensu Lato: Genus-Wide Differences in Evolutionary Dynamics and the Progressive Gain of Complex, Potentially Pathogenicity-Related Traits through Lateral Gene Transfer. Genome Biology and Evolution, 7<\/em>(8), 2154-2172. doi:10.1093\/gbe\/evv131<\/p>\n

   <\/a>den Bakker, H. C., Manuel, C. S., Fortes, E. D., Wiedmann, M., & Nightingale, K. K. (2013). Genome sequencing identifies Listeria fleischmannii subsp. coloradonensis subsp. nov., isolated from a ranch. International Journal of Systematic and Evolutionary Microbiology, 63<\/em>, 3257-3268.<\/p>\n

   <\/a>den Bakker, H. C., Warchocki, S., Wright, E. M., Allred, A. F., Ahlstrom, C., Manuel, C. S., . . . Strawn, L. K. (2014). Listeria floridensis sp. nov., Listeria aquatica sp. nov., Listeria cornellensis sp. nov., Listeria riparia sp. nov. and Listeria grandensis sp. nov., from agricultural and natural environments. International Journal of Systematic and Evolutionary Microbiology, 64<\/em>, 1882-1889.<\/p>\n

   <\/a>Graves, L. M., Helsel, L. O., Steigerwalt, A. G., Morey, R. E., Daneshvar, M. I., Roof, S. E., . . . den Bakker, H. C. (2010). Listeria marthii sp. nov., isolated from the natural environment, Finger Lakes National Forest. International Journal of Systematic and Evolutionary Microbiology, 60<\/em>, 1280-1288.<\/p>\n

   <\/a>Lang Halter, E., Neuhaus, K., & Scherer, S. (2013). Listeria weihenstephanensis sp. nov., isolated from the water plant Lemna trisulca taken from a freshwater pond. International Journal of Systematic and Evolutionary Microbiology, 63<\/em>(2), 641-647. doi:doi:10.1099\/ijs.0.036830-0<\/p>\n

   <\/a>Leclercq, A., Clermont, D., Bizet, C., Grimont, P. A., Le Fleche-Mateos, A., Roche, S. M., . . . Lecuit, M. (2010). Listeria rocourtiae sp. nov. International Journal of Systematic and Evolutionary Microbiology, 60<\/em>, 2210-2214.<\/p>\n

   <\/a>Liu, D. (2013). Molecular Approaches to the Identification of Pathogenic and Nonpathogenic Listeriae. Microbiology Insights, 6<\/em>, 59-69. doi:10.4137\/MBI.S10880<\/p>\n

   <\/a>McLauchlin, J. (1987). Listeria monocytogenes, recent advances in the taxonomy and epidemiology of listeriosis in humans. Journal of Applied Bacteriology, 63<\/em>(1), 1-11. doi:10.1111\/j.1365-2672.1987.tb02411.x<\/p>\n

   <\/a>Orsi, R. H., & Wiedmann, M. (2016). Characteristics and distribution of Listeria spp., including Listeria species newly described since 2009. Applied Microbiology and Biotechnology, 100<\/em>(12), 5273-5287.<\/p>\n

   <\/a>Pirie, J. H. (1940). The genus listerella pirie. Science, 91<\/em>(2364), 383.<\/p>\n

   <\/a>Pirie, J. H. H. (1940). Listeria: Change of Name for a Genus Bacteria. Nature., 145<\/em>(3668), 264-264. doi:10.1038\/145264a0<\/p>\n

   <\/a>Rocourt, J., Boerlin, P., Grimont, F., Jacquet, C., & Piffaretti, J.-C. (1992). Assignment of Listeria grayi and Listeria murrayi to a single species, Listeria grayi, with a revised description of Listeria grayi. International Journal of Systematic and Evolutionary Microbiology, 42<\/em>(1), 171-174.<\/p>\n

   <\/a>Rocourt, J., & Buchrieser, C. (2007). The genus Listeria and Listeria monocytogenes: phylogenetic position, taxonomy, and identification.<\/p>\n

   <\/a>Rocourt, J., Wehmeyer, U., & Stackebrandt, E. (1987). Transfer of Listeria dentrificans to a New Genus, Jonesia gen. nov., as Jonesia denitrificans comb. nov. International Journal of Systematic and Evolutionary Microbiology, 37<\/em>(3), 266-270. doi:doi:10.1099\/00207713-37-3-266<\/p>\n

   <\/a>Seeliger, H. P., Rocourt, J., Schrettenbrunner, A., Grimont, P. A., & Jones, D. (1984). Notes: Listeria ivanovii sp. nov. International Journal of Systematic and Evolutionary Microbiology, 34<\/em>(3), 336-337.<\/p>\n

   <\/a>Stuart, S. E., & Welshimer, H. (1973). Intrageneric relatedness of Listeria Pirie. Int J Syst Bacteriol, 23<\/em>, 8-14.<\/p>\n

   <\/a>Stuart, S. E., & Welshimer, H. (1974). Taxonomic reexamination of Listeria Pirie and transfer of Listeria grayi and Listeria murrayi to a new genus, Murraya. International Journal of Systematic and Evolutionary Microbiology, 24<\/em>(2), 177-185.<\/p>\n

   <\/a>Weller, D., Andrus, A., Wiedmann, M., & den Bakker, H. C. (2015). Listeria booriae sp. nov. and Listeria newyorkensis sp. nov., from food processing environments in the USA. International Journal of Systematic and Evolutionary Microbiology, 65<\/em>, 286-292.<\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

   Brief history of the taxonomy of Listeria Introduction Taxonomy is a scientific discipline pertaining to the classification, nomenclature, and identification of organisms. Organisms are classified or grouped based on shared characteristics, previously unknown strains are placed in known taxa and assigned names following set nomenclature standards. The naming of organisms dates back as early as the great philosopher Aristotle (384-322BC). Modern taxonomy is based on […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[72666],"tags":[72709],"class_list":["post-249166","post","type-post","status-publish","format-standard","hentry","category-full-dissertations","tag-history-of-the-taxonomy-of-listeria"],"_links":{"self":[{"href":"https:\/\/glowriters.com\/wp-json\/wp\/v2\/posts\/249166"}],"collection":[{"href":"https:\/\/glowriters.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/glowriters.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/glowriters.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/glowriters.com\/wp-json\/wp\/v2\/comments?post=249166"}],"version-history":[{"count":0,"href":"https:\/\/glowriters.com\/wp-json\/wp\/v2\/posts\/249166\/revisions"}],"wp:attachment":[{"href":"https:\/\/glowriters.com\/wp-json\/wp\/v2\/media?parent=249166"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/glowriters.com\/wp-json\/wp\/v2\/categories?post=249166"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/glowriters.com\/wp-json\/wp\/v2\/tags?post=249166"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}