Salmonella bongori

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Salmonella bongori
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Bacteria
Phylum: Pseudomonadota
Class: Gammaproteobacteria
Order: Enterobacterales
Family: Enterobacteriaceae
Genus: Salmonella
Species:
S. bongori
Binomial name
Salmonella bongori
(Le Minor et al. 1985) Reeves et al. 1989

Salmonella bongori is a pathogenic bacterium belonging to the genus Salmonella , and was earlier known as Salmonella subspecies V or S. enterica subsp. bongori or S. choleraesuis subsp. bongori. It is a Gram-negative, rod-shaped bacterium (bacillus), which causes a gastrointestinal disease called salmonellosis, characterized by cramping and diarrhoea. It is typically considered a microbe of cold-blooded animals, unlike other members of the genus, and is most frequently associated with reptiles. [1]

Contents

It was discovered in 1966 from a lizard in the city of Bongor, Chad, from which the specific name bongori was derived. [2] After decades of controversy in Salmonella nomenclature, it gained the species status in 2005. [3]

Pathogenicity and epidemiology

S. bongori is classically regarded as the Salmonella of lizards. However, discrete investigations contradict the notion of strict host-specificity, as reports emerged of occurrence in dogs and birds. [4] [5] In animals, unlike those of other Salmonella, infection is generally asymptomatic and does not cause discernible effects. However, infection of pet animals is associated with diarrhea. [5]

Further, human infections have been substantiated, with conclusive reports from Italy. The majority of these cases are among children less than 3 years old, who are more prone to oral contact with animal droppings. Symptoms are typified by diarrhoea with fever and acute enteritis. [6] The first observations, from Messina and Palermo, starting from late 1984, were followed by other cities in Sicily. [5] [7]

Origin and evolution

Originally S. bongori was considered to be a subspecies within the genus Salmonella. However, based on DNA similarity, all members of Salmonella are now grouped into only two species, namely S. bongori and S. enterica. [1] Species of Salmonella are closely related to E. coli and they are estimated to have diverged from a common ancestor about 100 million years ago; their genomes still display significant similarity, hence many functional identities. Many of the genes which are unique to Salmonella serovars, compared to E. coli, are found on large discrete genomic islands such as Salmonella pathogenicity islands (SPIs). [8] These Salmonella-specific functions include many genes for their virulence and characterize the divergence of S. enterica from S. bongori. For instance, the SPI-2 gene which encodes type III secretion systems present in S. enterica is absent in S. bongori. [9] Also, the virulence determinants, specifically effector proteins, are indicated to be more closely related to enteropathogenic E. coli because some of the gene are missing in S. enterica. [10]

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A pilus is a hair-like appendage found on the surface of many bacteria and archaea. The terms pilus and fimbria can be used interchangeably, although some researchers reserve the term pilus for the appendage required for bacterial conjugation. All conjugative pili are primarily composed of pilin – fibrous proteins, which are oligomeric.

<i>Escherichia coli</i> Enteric, rod-shaped, gram-negative bacterium

Escherichia coli ( ESH-ə-RIK-ee-ə KOH-ly) is a gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus Escherichia that is commonly found in the lower intestine of warm-blooded organisms. Most E. coli strains are harmless, but some serotypes such as EPEC, and ETEC are pathogenic and can cause serious food poisoning in their hosts, and are occasionally responsible for food contamination incidents that prompt product recalls. Most strains are part of the normal microbiota of the gut and are harmless or even beneficial to humans (although these strains tend to be less studied than the pathogenic ones). For example, some strains of E. coli benefit their hosts by producing vitamin K2 or by preventing the colonization of the intestine by pathogenic bacteria. These mutually beneficial relationships between E. coli and humans are a type of mutualistic biological relationship — where both the humans and the E. coli are benefitting each other. E. coli is expelled into the environment within fecal matter. The bacterium grows massively in fresh fecal matter under aerobic conditions for three days, but its numbers decline slowly afterwards.

<i>Salmonella</i> Genus of prokaryotes

Salmonella is a genus of rod-shaped (bacillus) gram-negative bacteria of the family Enterobacteriaceae. The two known species of Salmonella are Salmonella enterica and Salmonella bongori. S. enterica is the type species and is further divided into six subspecies that include over 2,600 serotypes. Salmonella was named after Daniel Elmer Salmon (1850–1914), an American veterinary surgeon.

<i>Salmonella enterica</i> Species of bacterium

Salmonella enterica is a rod-shaped, flagellate, facultative anaerobic, Gram-negative bacterium and a species of the genus Salmonella. It is divided into six subspecies, arizonae (IIIa), diarizonae (IIIb), houtenae (IV), salamae (II), indica (VI), and enterica (I). A number of its serovars are serious human pathogens; many of them are serovars of Salmonella enterica subsp. enterica.

<span class="mw-page-title-main">Serotype</span> Distinct variation within a species of bacteria or virus or among immune cells

A serotype or serovar is a distinct variation within a species of bacteria or virus or among immune cells of different individuals. These microorganisms, viruses, or cells are classified together based on their surface antigens, allowing the epidemiologic classification of organisms to a level below the species. A group of serovars with common antigens is called a serogroup or sometimes serocomplex.

In molecular genetics, a regulon is a group of genes that are regulated as a unit, generally controlled by the same regulatory gene that expresses a protein acting as a repressor or activator. This terminology is generally, although not exclusively, used in reference to prokaryotes, whose genomes are often organized into operons; the genes contained within a regulon are usually organized into more than one operon at disparate locations on the chromosome. Applied to eukaryotes, the term refers to any group of non-contiguous genes controlled by the same regulatory gene.

<span class="mw-page-title-main">C0343 RNA</span> Bacterial non-coding RNA

The C0343 RNA is a bacterial non-coding RNA of 74 nucleotides in length that is found between the ydaN and dbpA genes in the genomes of Escherichia coli and Shigella flexneri, Salmonella enterica and Salmonella typhimurium. This ncRNA was originally identified in E.coli using high-density oligonucleotide probe arrays (microarray). The function of this ncRNA is unknown.

<span class="mw-page-title-main">Hfq protein</span>

The Hfq protein encoded by the hfq gene was discovered in 1968 as an Escherichia coli host factor that was essential for replication of the bacteriophage Qβ. It is now clear that Hfq is an abundant bacterial RNA binding protein which has many important physiological roles that are usually mediated by interacting with Hfq binding sRNA.

<span class="mw-page-title-main">Leucine-responsive regulatory protein</span>

Leucine responsive protein, or Lrp, is a global regulator protein, meaning that it regulates the biosynthesis of leucine, as well as the other branched-chain amino acids, valine and isoleucine. In bacteria, it is encoded by the lrp gene.

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<i>Salmonella enterica <span style="font-style:normal;">subsp.</span> enterica</i> Subspecies of bacterium

Salmonella enterica subsp. enterica is a subspecies of Salmonella enterica, the rod-shaped, flagellated, aerobic, Gram-negative bacterium. Many of the pathogenic serovars of the S. enterica species are in this subspecies, including that responsible for typhoid.

<span class="mw-page-title-main">FourU thermometer</span> Class of non-coding RNAs in Salmonella

FourU thermometers are a class of non-coding RNA thermometers found in Salmonella. They are named 'FourU' due to the four highly conserved uridine nucleotides found directly opposite the Shine-Dalgarno sequence on hairpin II (pictured). RNA thermometers such as FourU control regulation of temperature via heat shock proteins in many prokaryotes. FourU thermometers are relatively small RNA molecules, only 57 nucleotides in length, and have a simple two-hairpin structure.

Bacterial small RNAs (bsRNA) are small RNAs produced by bacteria; they are 50- to 500-nucleotide non-coding RNA molecules, highly structured and containing several stem-loops. Numerous sRNAs have been identified using both computational analysis and laboratory-based techniques such as Northern blotting, microarrays and RNA-Seq in a number of bacterial species including Escherichia coli, the model pathogen Salmonella, the nitrogen-fixing alphaproteobacterium Sinorhizobium meliloti, marine cyanobacteria, Francisella tularensis, Streptococcus pyogenes, the pathogen Staphylococcus aureus, and the plant pathogen Xanthomonas oryzae pathovar oryzae. Bacterial sRNAs affect how genes are expressed within bacterial cells via interaction with mRNA or protein, and thus can affect a variety of bacterial functions like metabolism, virulence, environmental stress response, and structure.

<i>Escherichia coli</i> sRNA

Escherichia coli contains a number of small RNAs located in intergenic regions of its genome. The presence of at least 55 of these has been verified experimentally. 275 potential sRNA-encoding loci were identified computationally using the QRNA program. These loci will include false positives, so the number of sRNA genes in E. coli is likely to be less than 275. A computational screen based on promoter sequences recognised by the sigma factor sigma 70 and on Rho-independent terminators predicted 24 putative sRNA genes, 14 of these were verified experimentally by northern blotting. The experimentally verified sRNAs included the well characterised sRNAs RprA and RyhB. Many of the sRNAs identified in this screen, including RprA, RyhB, SraB and SraL, are only expressed in the stationary phase of bacterial cell growth. A screen for sRNA genes based on homology to Salmonella and Klebsiella identified 59 candidate sRNA genes. From this set of candidate genes, microarray analysis and northern blotting confirmed the existence of 17 previously undescribed sRNAs, many of which bind to the chaperone protein Hfq and regulate the translation of RpoS. UptR sRNA transcribed from the uptR gene is implicated in suppressing extracytoplasmic toxicity by reducing the amount of membrane-bound toxic hybrid protein.

Omptins are a family of bacterial proteases. They are aspartate proteases, which cleave peptides with the use of a water molecule. Found in the outer membrane of gram-negative enterobacteria such as Shigella flexneri, Yersinia pestis, Escherichia coli, and Salmonella enterica. Omptins consist of a widely conserved beta barrel spanning the membrane with 5 extracellular loops. These loops are responsible for the various substrate specificities. These proteases rely upon binding of lipopolysaccharide for activity.

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Yersiniabactin (Ybt) is a siderophore found in the pathogenic bacteria Yersinia pestis, Yersinia pseudotuberculosis, and Yersinia enterocolitica, as well as several strains of enterobacteria including enteropathogenic Escherichia coli and Salmonella enterica. Siderophores, compounds of low molecular mass with high affinities for ferric iron, are important virulence factors in pathogenic bacteria. Iron—an essential element for life used for such cellular processes as respiration and DNA replication—is extensively chelated by host proteins like lactoferrin and ferritin; thus, the pathogen produces molecules with an even higher affinity for Fe3+ than these proteins in order to acquire sufficient iron for growth. As a part of such an iron-uptake system, yersiniabactin plays an important role in pathogenicity of Y. pestis, Y. pseudotuberculosis, and Y. entercolitica.

<span class="mw-page-title-main">Bacterial DNA binding protein</span>

In molecular biology, bacterial DNA binding proteins are a family of small, usually basic proteins of about 90 residues that bind DNA and are known as histone-like proteins. Since bacterial binding proteins have a diversity of functions, it has been difficult to develop a common function for all of them. They are commonly referred to as histone-like and have many similar traits with the eukaryotic histone proteins. Eukaryotic histones package DNA to help it to fit in the nucleus, and they are known to be the most conserved proteins in nature. Examples include the HU protein in Escherichia coli, a dimer of closely related alpha and beta chains and in other bacteria can be a dimer of identical chains. HU-type proteins have been found in a variety of bacteria and archaea, and are also encoded in the chloroplast genome of some algae. The integration host factor (IHF), a dimer of closely related chains which is suggested to function in genetic recombination as well as in translational and transcriptional control is found in Enterobacteria and viral proteins including the African swine fever virus protein A104R.

<span class="mw-page-title-main">Cytolethal distending toxin</span>

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<span class="mw-page-title-main">Mark Achtman</span>

Mark Achtman FRS is Professor of Bacterial Population Genetics at Warwick Medical School, part of the University of Warwick in the UK.

<span class="mw-page-title-main">ZnuABC</span> Class of transport proteins

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