 | It has been suggested that this article be merged into Bacterial cellular morphologies . (Discuss) Proposed since December 2023. |
A diplococcus (plural diplococci) is a round bacterium (a coccus) that typically occurs in the form of two joined cells.
Examples of gram-negative diplococci are Neisseria spp. and Moraxella catarrhalis. Examples of gram-positive diplococci are Streptococcus pneumoniae and Enterococcus spp. [1] [2] Presumably, diplococcus has been implicated in encephalitis lethargica. [3]
Phylum: Proteobacteria
Class: Betaproteobacteria
Order: Neisseriales
Family: Neisseriaceae
Genus:Neisseria
The genus Neisseria belongs to the family Neisseriaceae. This genus, Neisseria, is divided into more than ten different species, but most of them are gram negative and coccoid. The gram-negative, coccoid species include: Neisseria cinerea, Neisseria gonorrhoeae, Neisseria polysaccharea, Neisseria lactamica, Neisseria meningitidis, Neisseria mucosa, Neisseria oralis and Neisseria subflava. Of these Neisseria species, the most common, pathogenic species are N. meningitidis and N.gonorrhoeae. [4]
Phylum: Proteobacteria
Class: Gammaproteobacteria
Order: Pseudomonadales
Family: Moraxellaceae
Genus:Moraxella
The genus Moraxella belongs to the family Moraxellaceae. This genus, Moraxellaceae, comprises gram-negative coccobacilli bacteria: Moraxella lacunata, Moraxella atlantae, Moraxella boevrei, Moraxella bovis, Moraxella canis, Moraxella caprae, Moraxella caviae, Moraxella cuniculi, Moraxella equi, Moraxella lincolnii, Moraxella nonliquefaciens, Moraxella osloensis, Moraxella ovis and Moraxella saccharolytica, Moraxella pluranimalium. [5] However, only one has a morphology of diplococcus, Moraxella catarrhalis. M. catarrhalis is a salient pathogen contributing to infections in the human body. [6]
Phylum: Firmicutes
Class: Bacilli
Order: Lactobacillales
Family: Streptococcaceae
Genus: Streptococcus
Species:Streptococcus pneumoniae
The species Streptococcus pneumoniae belongs to the genus Streptococcus and the family Streptococcaceae. The genus Streptococcus has around 129 species and 23 subspecies [7] that benefit many microbiomes on the human body. There are many species that show non-pathogenic characteristics; however, there are some, like S. pneumoniae, that exhibit pathogenic characteristics in the human body. [8] [2]
Phylum: Firmicutes
Class: Bacilli
Order: Lactobacillales
Family: Enterococcaceae
Genus:Enterococcus
The genus Enterococcus belongs to the family Enterococcaceae. This genus is divided into 58 species and two subspecies. [9] These gram-positive, coccoid bacteria were once thought to be harmless to the human body. However, within the last ten years, there has been an influx of nosocomial pathogens originating from Enterococcus bacteria. [10] [2]
Many diplococci have species or strains that exhibit pathogenic characteristics. Examples of gram-negative pathogenic diplococci include N.gonorrhoeae and N. meningitidis. Examples of gram-positive pathogenic diplococci include Streptococcus pneumoniae and some species of Enterococcus bacteria.[ citation needed ]
Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is their cell envelopes, which consists of a thin peptidoglycan cell wall sandwiched between an inner (cytoplasmic) membrane and an outer membrane. These bacteria are found in all environments that support life on Earth.
Streptococcus is a genus of gram-positive coccus or spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales, in the phylum Bacillota. Cell division in streptococci occurs along a single axis, so as they grow, they tend to form pairs or chains that may appear bent or twisted. This differs from staphylococci, which divide along multiple axes, thereby generating irregular, grape-like clusters of cells. Most streptococci are oxidase-negative and catalase-negative, and many are facultative anaerobes.
The Bacillota are a phylum of bacteria, most of which have gram-positive cell wall structure. The renaming of phyla such as Firmicutes in 2021 remains controversial among microbiologists, many of whom continue to use the earlier names of long standing in the literature.
Neisseria is a large genus of bacteria that colonize the mucosal surfaces of many animals. Of the 11 species that colonize humans, only two are pathogens, N. meningitidis and N. gonorrhoeae.
A coccus is any bacterium or archaeon that has a spherical, ovoid, or generally round shape. Bacteria are categorized based on their shapes into three classes: cocci (spherical-shaped), bacillus (rod-shaped) and spiral. Coccus refers to the shape of the bacteria, and can contain multiple genera, such as staphylococci or streptococci. Cocci can grow in pairs, chains, or clusters, depending on their orientation and attachment during cell division. In contrast to many bacilli-shaped bacteria, most cocci bacteria do not have flagella and are non-motile.
The Neisseriaceae are a family of Pseudomonadota, within the Neisseriales order. While many organisms in the family are mammalian commensals or part of the normal flora, the genus Neisseria includes two important human pathogens, specifically those responsible for gonorrhea and many cases of meningitis. As a group, the Neisseriaceae are strictly aerobic and Gram-negative, occur mainly in pairs (diplococci), and typically do not have flagella.
Cefuroxime axetil, sold under the brand name Ceftin among others, is a second generation oral cephalosporin antibiotic.
Neisseria meningitidis, often referred to as the meningococcus, is a Gram-negative bacterium that can cause meningitis and other forms of meningococcal disease such as meningococcemia, a life-threatening sepsis. The bacterium is referred to as a coccus because it is round, and more specifically a diplococcus because of its tendency to form pairs.
Moraxella catarrhalis is a fastidious, nonmotile, Gram-negative, aerobic, oxidase-positive diplococcus that can cause infections of the respiratory system, middle ear, eye, central nervous system, and joints of humans. It causes the infection of the host cell by sticking to the host cell using trimeric autotransporter adhesins.
Moraxella is a genus of gram-negative bacteria in the family Moraxellaceae. It is named after the Swiss ophthalmologist Victor Morax. The organisms are short rods, coccobacilli, or as in the case of Moraxella catarrhalis, diplococci in morphology, with asaccharolytic, oxidase-positive, and catalase-positive properties. M. catarrhalis is the clinically most important species under this genus.
Cefodizime is a 3rd generation cephalosporin antibiotic with broad spectrum activity against aerobic gram positive and gram negative bacteria. Clinically, it has been shown to be effective against upper and lower respiratory tract infections, urinary tract infections, and gonorrhea. Cefodizime is a bactericidal antibiotic that targets penicillin-binding proteins (PBPs) 1A/B, 2, and 3 resulting in the eventual death of the bacterial cell. In vivo experimental models of infection showed that bacterial clearance by this drug is at least as effective compared with other 3rd generation cephalosporins. It has similar adverse effect profile to other 3rd generation cephalosporins as well, mainly being limited to gastrointestinal or dermatological side effects.
Non-fermenters are a taxonomically heterogeneous group of bacteria of the phylum Pseudomonadota that cannot catabolize glucose, and are thus unable to ferment. This does not necessarily exclude that species can catabolize other sugars or have anaerobiosis like fermenting bacteria.
IgA protease is an enzyme. This enzyme catalyses the following chemical reaction[reaction equation needed]
Neisseria flava is a bacterium belonging to a group of species under the genus Neisseria that is considered non-pathogenic. Along with its other members of the non-pathogenic group, Neisseria flava is often found in the upper respiratory tract surface in humans. On rare occasions, it can cause rheumatic heart disease and ventricular septal defect aortic insufficiency.
Moraxella nonliquefaciens is a Gram-negative bacterium in the genus Moraxella, which was isolated from the upper respiratory tract of humans. M. nonliquefaciens occasionally causes disease.
The NYC medium or GC medium agar is used for isolating Gonococci.
Neisseria flavescens was first isolated from cerebrospinal fluid in the midst of an epidemic meningitis outbreak in Chicago. These gram-negative, aerobic bacteria reside in the mucosal membranes of the upper respiratory tract, functioning as commensals. However, this species can also play a pathogenic role in immunocompromised and diabetic individuals. In rare cases, it has been linked to meningitis, pneumonia, empyema, endocarditis, and sepsis.
In bacteria, phasevarions mediate a coordinated change in the expression of multiple genes or proteins. This occurs via phase variation of a single DNA methyltransferase. Phase variation of methyltransferase expression results in differential methylation throughout the bacterial genome, leading to variable expression of multiple genes through epigenetic mechanisms.
Zoliflodacin is an experimental antibiotic that is being studied for the treatment of infection with Neisseria gonorrhoeae (gonorrhea). It has a novel mechanism of action which involves inhibition of bacterial type II topoisomerases. Zoliflodacin is being developed by Innoviva Specialty Therapeutics, and the drug has demonstrated clinical efficacy equivalent to ceftriaxone in Phase III clinical trials.
| Medical microbiology | |||||||
|---|---|---|---|---|---|---|---|
| Biochemistry and ecology |
| ||||||
| Shape | |||||||
| Structure |
| ||||||
| Taxonomy and evolution | |||||||
