|
Hemolysis (microbiology)
Hemolysis is the breakdown of red blood cells. The ability of bacterial colonies to induce hemolysis when grown on blood agar is used to classify certain microorganisms. This is particularly useful in classifying streptococcal species. A substance that causes hemolysis is called a hemolysin. Types Alpha-hemolysis When alpha-hemolysis (α-hemolysis) is present, the agar under the colony is light and greenish. '' Streptococcus pneumoniae'' and a group of oral streptococci ( ''Streptococcus'' viridans or viridans streptococci) display alpha-hemolysis. This is sometimes called ''green hemolysis'' because of the color change in the agar. Other synonymous terms are ''incomplete hemolysis'' and ''partial hemolysis''. Alpha-hemolysis is caused by the bacteria's production of hydrogen peroxide, which oxidizes hemoglobin and produces the green oxidized derivative methemoglobin. Beta-hemolysis Beta-hemolysis (β-hemolysis), sometimes called ''complete hemolysis'', is a complete lysi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptococcal Hemolysis
''Streptococcus'' is a genus of gram-positive bacteria, gram-positive spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales (lactic acid bacteria), in the phylum Bacillota. Cell division in streptococci occurs along a single coordinate system, axis, thus when growing they tend to form pairs or chains, which may appear bent or twisted. This differs from Staphylococcus, staphylococci, which divide along multiple axes, thereby generating irregular, grape-like clusters of cell (biology), cells. Most streptococci are Oxidase test, oxidase-negative and Catalase#Clinical significance and application, catalase-negative, and many are facultative anaerobic organism, facultative anaerobes (capable of growth both aerobically and anaerobically). The term was coined in 1877 by Viennese surgeon Theodor Billroth, Albert Theodor Billroth (1829–1894), by combining the prefix "strepto-" (from ), together with the suffix "-coccus" (from Modern , from .) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptococcus Pyogenes
''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 (round cells) 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'' is thus also used. The species name is derived from Greek words meaning 'a chain' () of berries ( atiniz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Standard Serial Number
An International Standard Serial Number (ISSN) is an eight-digit to uniquely identify a periodical publication (periodical), such as a magazine. The ISSN is especially helpful in distinguishing between serials with the same title. ISSNs are used in ordering, cataloging, interlibrary loans, and other practices in connection with serial literature. The ISSN system was first drafted as an International Organization for Standardization (ISO) international standard in 1971 and published as ISO 3297 in 1975. ISO subcommittee TC 46/SC 9 is responsible for maintaining the standard. When a serial with the same content is published in more than one media type, a different ISSN is assigned to each media type. For example, many serials are published both in print and electronic media. The ISSN system refers to these types as print ISSN (p-ISSN) and electronic ISSN (e-ISSN). Consequently, as defined in ISO 3297:2007, every serial in the ISSN system is also assigned a linking ISSN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Object Identifier
A digital object identifier (DOI) is a persistent identifier or handle used to uniquely identify various objects, standardized by the International Organization for Standardization (ISO). DOIs are an implementation of the Handle System; they also fit within the URI system ( Uniform Resource Identifier). They are widely used to identify academic, professional, and government information, such as journal articles, research reports, data sets, and official publications. A DOI aims to resolve to its target, the information object to which the DOI refers. This is achieved by binding the DOI to metadata about the object, such as a URL where the object is located. Thus, by being actionable and interoperable, a DOI differs from ISBNs or ISRCs which are identifiers only. The DOI system uses the indecs Content Model to represent metadata. The DOI for a document remains fixed over the lifetime of the document, whereas its location and other metadata may change. Referring to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
McGraw Hill
McGraw Hill is an American education science company that provides educational content, software, and services for students and educators across various levels—from K-12 to higher education and professional settings. They produce textbooks, digital learning tools, and adaptive technology to enhance learning experiences and outcomes. It is one of the "big three" educational publishers along with Houghton Mifflin Harcourt and Pearson Education. McGraw Hill also publishes reference and trade publications for the medical, business, and engineering professions. Formerly a division of The McGraw Hill Companies (later renamed McGraw Hill Financial, now S&P Global), McGraw Hill Education was divested and acquired by Apollo Global Management in March 2013 for $2.4 billion in cash. McGraw Hill was sold in 2021 to Platinum Equity for $4.5 billion. History McGraw Hill was founded in 1888, when James H. McGraw, co-founder of McGraw Hill, purchased the ''American Journal of Railwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vibrio Cholerae
''Vibrio cholerae'' is a species of Gram-negative bacteria, Gram-negative, Facultative anaerobic organism, facultative anaerobe and Vibrio, comma-shaped bacteria. The bacteria naturally live in Brackish water, brackish or saltwater where they attach themselves easily to the chitin-containing shells of crabs, shrimp, and other shellfish. Some strains of ''V. cholerae'' are pathogenic to humans and cause a deadly disease called cholera, which can be derived from the consumption of undercooked or raw marine life species or drinking contaminated water. ''V. cholerae'' was first described by Félix-Archimède Pouchet in 1849 as some kind of protozoa. Filippo Pacini correctly identified it as a bacterium and from him, the scientific name is adopted. The bacterium as the cause of cholera was discovered by Robert Koch in 1884. Sambhu Nath De isolated the cholera toxin and demonstrated the toxin as the cause of cholera in 1959. The bacterium has a flagellum (a tail like structure) at one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Staphylococcus Epidermidis
''Staphylococcus epidermidis'' is a Gram-positive bacterium, and one of over 40 species belonging to the genus ''Staphylococcus''. It is part of the human flora, normal human microbiota, typically the skin flora, skin microbiota, and less commonly the mucosal microbiota and also found in marine sponges. It is a facultative anaerobic bacteria. Although ''S. epidermidis'' is not usually Pathogenic bacteria, pathogenic, patients with compromised immune systems are at risk of developing infection. These infections are generally Hospital-acquired infection, hospital-acquired. ''S. epidermidis'' is a particular concern for people with catheters or other surgical implants because it is known to form biofilms that grow on these devices. Being part of the normal skin microbiota, ''S. epidermidis'' is a frequent contaminant of specimens sent to the diagnostic laboratory. Some strains of ''S. epidermidis'' are highly salt tolerant and commonly found in marine environments. S.I. Paul et al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Staphylococcus Saprophyticus
''Staphylococcus saprophyticus'' is a Gram-positive coccus belonging to the genus ''Staphylococcus''. ''S. saprophyticus'' is a common cause of community-acquired urinary tract infections. History ''Staphylococcus saprophyticus'' was not recognized as a cause of urinary tract infections until the early 1970s, more than 10 years after its original demonstration in urine specimens. Prior to this, the presence of coagulase-negative staphylococci (CoNS) in urine specimens was dismissed as contamination. Epidemiology and pathogenesis In humans, ''S. saprophyticus'' is found in the normal flora of the female genital tract and perineum. It has been isolated from other sources, too, including meat and cheese products, vegetables, the environment, and human and animal gastrointestinal tracts. ''S. saprophyticus'' causes 10–20% of urinary tract infections (UTIs). In females 17–27 years old, it is the second-most common cause of community-acquired UTIs, after ''Escherichia coli''. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enterococcus Faecalis
''Enterococcus faecalis'' – formerly classified as part of the group D '' Streptococcus,'' is a Gram-positive, commensal bacterium naturally inhabiting the gastrointestinal tracts of humans. Like other species in the genus '' Enterococcus'', ''E. faecalis'' is found in healthy humans and can be used as a probiotic. The probiotic strains such as Symbioflor1 and EF-2001 are characterized by the lack of specific genes related to drug resistance and pathogenesis. Despite its commensal role, ''E. faecalis'' is an opportunistic pathogen capable of causing severe infections, especially in the nosocomial (hospital) settings. ''Enterococcus'' spp. is among the leading causes of healthcare-associated infections ranging from endocarditis to urinary tract infections (UTIs). Hospital-acquired UTIs are associated with catheterization because catheters provide an ideal surface for biofilm formation, allowing ''E. faecalis'' to adhere, persist, and evade both the immune response and antibiot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clostridium Perfringens
''Clostridium perfringens'' (formerly known as ''C. welchii'', or ''Bacillus welchii'') is a Gram-positive, bacillus (rod-shaped), anaerobic, spore-forming pathogenic bacterium of the genus '' Clostridium''. ''C. perfringens'' is ever-present in nature and can be found as a normal component of decaying vegetation, marine sediment, the intestinal tract of humans and other vertebrates, insects, and soil. It has the shortest reported generation time of any organism at 6.3 minutes in thioglycolate medium. ''Clostridium perfringens'' is one of the most common causes of food poisoning in the United States, alongside norovirus, ''Salmonella'', '' Campylobacter'', and ''Staphylococcus aureus''. However, it can sometimes be ingested and cause no harm. Infections induced by ''C. perfringens'' are associated with tissue necrosis, bacteremia, emphysematous cholecystitis, and gas gangrene, which is also known as clostridial myonecrosis. The specific name, ''perfringens,'' is derived ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Listeria Monocytogenes
''Listeria monocytogenes'' is the species of pathogenic bacteria that causes the infection listeriosis. It is a facultative anaerobic bacterium, capable of surviving in the presence or absence of oxygen. It can grow and reproduce inside the host's cells and is one of the most virulent foodborne pathogens. Twenty to thirty percent of foodborne listeriosis infections in high-risk individuals may be fatal. In the European Union, listeriosis continues an upward trend that began in 2008, causing 2,161 confirmed cases and 210 reported deaths in 2014, 16% more than in 2013. In the EU, listeriosis mortality rates also are higher than those of other foodborne pathogens. Responsible for an estimated 1,600 illnesses and 260 deaths in the United States annually, listeriosis ranks third in total number of deaths among foodborne bacterial pathogens, with fatality rates exceeding even ''Salmonella'' spp. and ''Clostridium botulinum''. Named for Joseph Lister, ''Listeria monocytogenes'' is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CAMP Test
The CAMP test (Christie–Atkins–Munch-Petersen) is a test to identify group B β-hemolytic streptococci ('' Streptococcus agalactiae'') based on their formation of a substance, CAMP factor, that enlarges the area of hemolysis formed by the β- hemolysin elaborated from ''Staphylococcus aureus''. CAMP factor Although the test is usually used to identify group B streptococcus, there is some evidence that the CAMP factor gene is present in several groups of streptococci, including group A. A similar factor has been identified in '' Bartonella henselae''. Uses The CAMP test can be used to identify '' Streptococcus agalactiae''. Though not strongly beta-hemolytic on its own, group B strep presents with wedge-shaped colonies in the presence of ''Staphylococcus aureus''. It can also be used to identify ''Listeria monocytogenes'' which produces a positive CAMP reaction. Setup # Streak a beta-lysin–producing strain of ''aureus'' down the center of a sheep blood agar plate. # Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
