In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall.
Staphylococcus aureus is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often positive for catalase and nitrate reduction and is a facultative anaerobe that can grow without the need for oxygen. Although S. aureus usually acts as a commensal of the human microbiota, it can also become an opportunistic pathogen, being a common cause of skin infections including abscesses, respiratory infections such as sinusitis, and food poisoning. Pathogenic strains often promote infections by producing virulence factors such as potent protein toxins, and the expression of a cell-surface protein that binds and inactivates antibodies. S. aureus is one of the leading pathogens for deaths associated with antimicrobial resistance and the emergence of antibiotic-resistant strains, such as methicillin-resistant S. aureus (MRSA), is a worldwide problem in clinical medicine. Despite much research and development, no vaccine for S. aureus has been approved.
Methicillin-resistant Staphylococcus aureus (MRSA) is a group of gram-positive bacteria that are genetically distinct from other strains of Staphylococcus aureus. MRSA is responsible for several difficult-to-treat infections in humans. It caused more than 100,000 deaths worldwide attributable to antimicrobial resistance in 2019.
Staphylococcus lugdunensis is a coagulase-negative member of the genus Staphylococcus, consisting of Gram-positive bacteria with spherical cells that appear in clusters.
Staphylococcus epidermidis is a Gram-positive bacterium, and one of over 40 species belonging to the genus Staphylococcus. It is part of the normal human microbiota, typically the 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, patients with compromised immune systems are at risk of developing infection. These infections are generally 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.
mecA is a gene found in bacterial cells which allows them to be resistant to antibiotics such as methicillin, penicillin and other penicillin-like antibiotics.
Staphylococcus capitis is a coagulase-negative species (CoNS) of Staphylococcus. It is part of the normal flora of the skin of the human scalp, face, neck, scrotum, and ears and has been associated with prosthetic valve endocarditis, but is rarely associated with native valve infection.
Staphylococcus is a genus of Gram-positive bacteria in the family Staphylococcaceae from the order Bacillales. Under the microscope, they appear spherical (cocci), and form in grape-like clusters. Staphylococcus species are facultative anaerobic organisms.
Actinopolymorpha is a genus in the phylum Actinomycetota (Bacteria).
SCCmec, or staphylococcal cassette chromosome mec, is a mobile genetic element of Staphylococcus bacterial species. This genetic sequence includes the mecA gene coding for resistance to the antibiotic methicillin and is the only known way for Staphylococcus strains to spread the gene in the wild by horizontal gene transfer. SCCmec is a 21 to 60 kb long genetic element that confers broad-spectrum β-lactam resistance to MRSA. Moreover, additional genetic elements like Tn554, pT181, and pUB110 can be found in SCCmec, which have the capability to render resistance to various non-β-lactam drugs.
Staphylococcus simiae is a Gram-positive, coagulase-negative member of the bacterial genus Staphylococcus consisting of clustered cocci. This species was originally isolated from the gastrointestinal tract of South American squirrel monkeys, Saimiri sciureus, and found to be genetically similar to S. aureus, but more biochemically similar to S. piscifermentans. A draft genome of S. simiae was sequenced.
Staphylococcus rostri is a Gram-positive, coagulase-negative member of the bacterial genus Staphylococcus consisting of clustered cocci. This species was originally isolated from the noses of healthy pigs; the name is derived from the Latin rostrum or "the snout of a swine".
Staphylococcus microti is a Gram-positive, coagulase-negative member of the bacterial genus Staphylococcus consisting of clustered cocci. This species was originally isolated from viscera of the common vole, Microtus arvalis. It is genetically similar to Staphylococcus rostri.
Pseudoalteromonas phenolica is a marine bacterium species in the genus Pseudoalteromonas.
Staphylococcus intermedius is a Gram-positive, catalase positive member of the bacterial genus Staphylococcus consisting of clustered cocci. Strains of this species were originally isolated from the anterior nares of pigeons, dogs, cats, mink, and horses. Many of the isolated strains show coagulase activity. Clinical tests for detection of methicillin-resistant S. aureus may produce false positives by detecting S. intermedius, as this species shares some phenotypic traits with methicillin-resistant S. aureus strains. It has been theorized that S. intermedius has previously been misidentified as S. aureus in human dog bite wound infections, which is why molecular technologies such as MALDI-TOF and PCR are preferred in modern veterinary clinical microbiology laboratories for their more accurate identifications over biochemical tests. S. intermedius is largely phenotypically indiscriminate from Staphylococcus pseudintermedius and Staphylococcus delphini, and therefore the three organisms are considered to be included in the more general 'Staphylococcus intermedius group'.
Glutamyl endopeptidase is an extracellular bacterial serine protease of the glutamyl endopeptidase I family that was initially isolated from the Staphylococcus aureus strain V8. The protease is, hence, commonly referred to as "V8 protease", or alternatively SspA from its corresponding gene.
Staphylococcus pseudintermedius is a gram positive coccus bacteria of the genus Staphylococcus found worldwide. It is primarily a pathogen for domestic animals, but has been known to affect humans as well. S. pseudintermedius is an opportunistic pathogen that secretes immune modulating virulence factors, has many adhesion factors, and the potential to create biofilms, all of which help to determine the pathogenicity of the bacterium. Diagnoses of Staphylococcus pseudintermedius have traditionally been made using cytology, plating, and biochemical tests. More recently, molecular technologies like MALDI-TOF, DNA hybridization and PCR have become preferred over biochemical tests for their more rapid and accurate identifications. This includes the identification and diagnosis of antibiotic resistant strains.
Streptomyces pluripotens is a bacterium species from the genus of Streptomyces which has been isolated from mangrove soil from the Tanjung Lumpur river in Malaysia.
Staphylococcus argenteus are gram-positive cocci from the genus Staphylococcus which have been isolated from blood culture of a 55-year-old Indigenous Australian female in 2006 in Darwin, Northern Territory, Australia. The species is close related to S. aureus and the differentiation is challenging. Staphylococcus argenteus is cytotoxic to human cells due to high expression of alpha-hemolysin.
Accessory gene regulator (agr) is a complex 5 gene locus that is a global regulator of virulence in Staphylococcus aureus. It encodes a two-component transcriptional quorum-sensing (QS) system activated by an autoinducing, thiolactone-containing cyclic peptide (AIP).
