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.
A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular polymeric substances (EPSs). The cells within the biofilm produce the EPS components, which are typically a polymeric conglomeration of extracellular polysaccharides, proteins, lipids and DNA. Because they have three-dimensional structure and represent a community lifestyle for microorganisms, they have been metaphorically described as "cities for microbes".
Streptococcus pyogenes is a species of Gram-positive, aerotolerant bacteria in the genus Streptococcus. These bacteria are extracellular, and made up of non-motile and non-sporing cocci that tend to link in chains. They are clinically important for humans, as they are an infrequent, but usually pathogenic, part of the skin microbiota that can cause Group A streptococcal infection. S. pyogenes is the predominant species harboring the Lancefield group A antigen, and is often called group A Streptococcus (GAS). However, both Streptococcus dysgalactiae and the Streptococcus anginosus group can possess group A antigen as well. Group A streptococci, when grown on blood agar, typically produce small (2–3 mm) zones of beta-hemolysis, a complete destruction of red blood cells. The name group A (beta-hemolytic) Streptococcus (GABHS) is thus also used.
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.
Streptococcus mutans is a facultatively anaerobic, gram-positive coccus commonly found in the human oral cavity and is a significant contributor to tooth decay. It is part of the "streptococci", an informal general name for all species in the genus Streptococcus. The microbe was first described by James Kilian Clarke in 1924.
Ceftazidime, sold under the brand name Fortaz among others, is a third-generation cephalosporin antibiotic useful for the treatment of a number of bacterial infections. Specifically it is used for joint infections, meningitis, pneumonia, sepsis, urinary tract infections, malignant otitis externa, Pseudomonas aeruginosa infection, and vibrio infection. It is given by injection into a vein, muscle, or eye.
Pseudomonas aeruginosa is a common encapsulated, Gram-negative, aerobic–facultatively anaerobic, rod-shaped bacterium that can cause disease in plants and animals, including humans. A species of considerable medical importance, P. aeruginosa is a multidrug resistant pathogen recognized for its ubiquity, its intrinsically advanced antibiotic resistance mechanisms, and its association with serious illnesses – hospital-acquired infections such as ventilator-associated pneumonia and various sepsis syndromes.
Peptostreptococcus is a genus of anaerobic, Gram-positive, non-spore forming bacteria. The cells are small, spherical, and can occur in short chains, in pairs or individually. They typically move using cilia. Peptostreptococcus are slow-growing bacteria with increasing resistance to antimicrobial drugs. Peptostreptococcus is a normal inhabitant of the healthy lower reproductive tract of women.
Isocitrate lyase, or ICL, is an enzyme in the glyoxylate cycle that catalyzes the cleavage of isocitrate to succinate and glyoxylate. Together with malate synthase, it bypasses the two decarboxylation steps of the tricarboxylic acid cycle and is used by bacteria, fungi, and plants.
In enzymology, a malate synthase (EC 2.3.3.9) is an enzyme that catalyzes the chemical reaction
Streptococcus dysgalactiae is a gram positive, beta-haemolytic, coccal bacterium belonging to the family Streptococcaceae. It is capable of infecting both humans and animals, but is most frequently encountered as a commensal of the alimentary tract, genital tract, or less commonly, as a part of the skin flora. The clinical manifestations in human disease range from superficial skin-infections and tonsillitis, to severe necrotising fasciitis and bacteraemia. The incidence of invasive disease has been reported to be rising. Several different animal species are susceptible to infection by S. dysgalactiae, but bovine mastitis and infectious arthritis in lambs have been most frequently reported.
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.
Perianal cellulitis, also known as perianitis or perianal streptococcal dermatitis, is a bacterial infection affecting the lower layers of the skin (cellulitis) around the anus. It presents as bright redness in the skin and can be accompanied by pain, difficulty defecating, itching, and bleeding. This disease is considered a complicated skin and soft tissue infection (cSSTI) because of the involvement of the deeper soft tissues.
The lung microbiota is the pulmonary microbial community consisting of a complex variety of microorganisms found in the lower respiratory tract particularly on the mucous layer and the epithelial surfaces. These microorganisms include bacteria, fungi, viruses and bacteriophages. The bacterial part of the microbiota has been more closely studied. It consists of a core of nine genera: Prevotella, Sphingomonas, Pseudomonas, Acinetobacter, Fusobacterium, Megasphaera, Veillonella, Staphylococcus, and Streptococcus. They are aerobes as well as anaerobes and aerotolerant bacteria. The microbial communities are highly variable in particular individuals and compose of about 140 distinct families. The bronchial tree for instance contains a mean of 2000 bacterial genomes per cm2 surface. The harmful or potentially harmful bacteria are also detected routinely in respiratory specimens. The most significant are Moraxella catarrhalis, Haemophilus influenzae, and Streptococcus pneumoniae. They are known to cause respiratory disorders under particular conditions namely if the human immune system is impaired. The mechanism by which they persist in the lower airways in healthy individuals is unknown.
Rothia mucilaginosa is a Gram-positive, coagulase-negative, encapsulated, non-spore-forming and non-motile coccus, present in clusters, tetrads or pairs that is a part of the normal oropharyngeal flora. Belonging to the family Micrococcaceae, it was first isolated from the mucous membrane of the cheek and gingiva. It is an oral commensal, that has been linked to causing severe bacteremia in immunocompromised patients. This bacterium has also been shown to form biofilms, similar to that of Pseudomonas aeruginosa. R. mucilaginosa is a cohabitant in the lower airways of patients with chronic lung diseases such as bronchiectasis, however has been shown to elicit anti-inflammatory effects.
Twitching motility is a form of crawling bacterial motility used to move over surfaces. Twitching is mediated by the activity of hair-like filaments called type IV pili which extend from the cell's exterior, bind to surrounding solid substrates, and retract, pulling the cell forwards in a manner similar to the action of a grappling hook. The name twitching motility is derived from the characteristic jerky and irregular motions of individual cells when viewed under the microscope. It has been observed in many bacterial species, but is most well studied in Pseudomonas aeruginosa, Neisseria gonorrhoeae and Myxococcus xanthus. Active movement mediated by the twitching system has been shown to be an important component of the pathogenic mechanisms of several species.
Laurence G. Rahme is an American microbiologist who is Professor of Surgery and Microbiology at Harvard Medical School (HMS). At Massachusetts General Hospital (MGH) she also holds the title of Director of the Molecular Surgical Laboratory as a microbiologist in the Department of Surgery and Molecular Biology. Additionally, she holds a Senior Scientific Staff position at Shriners Hospitals for Children-Boston.
In microbiology, colonial morphology refers to the visual appearance of bacterial or fungal colonies on an agar plate. Examining colonial morphology is the first step in the identification of an unknown microbe. The systematic assessment of the colonies' appearance, focusing on aspects like size, shape, colour, opacity, and consistency, provides clues to the identity of the organism, allowing microbiologists to select appropriate tests to provide a definitive identification.
Alain Ange-Marie Filloux is a French/British microbiologist who is a Professor of Molecular Microbiology at Imperial College London. His research looks at the chronic infection of Pseudomonas aeruginosa, a Gram-negative bacterium that causes nosocomial infections in people who are immunocompromised and a deadly threat for cystic fibrosis patients.
Kalai Mathee is a professor at Florida International University, joint editor-in-chief of the Journal of Medical Microbiology, and an elected fellow of the American Academy of Microbiology. She is known for her research on bacterial infections caused by Pseudomonas aeruginosa.
