Classification
Gram-positive
bacteria
Bacteria
Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases.
Bacteriology: Overview:
Most
bacteria
Bacteria
Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases.
Bacteriology: Overview can be classified according to a lab procedure called Gram staining.
Bacteria with cell walls that have a thick layer of peptidoglycan retain the crystal violet stain utilized in Gram staining but are not affected by the safranin counterstain. These
bacteria
Bacteria
Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases.
Bacteriology: Overview appear as purple-blue on the stain, indicating that they are gram positive. The
bacteria
Bacteria
Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases.
Bacteriology: Overview can be further classified according to morphology (branching filaments, bacilli, and cocci in clusters or chains) and their ability to grow in the presence of oxygen (aerobic versus anaerobic). The cocci can also be further identified. Staphylococci can be narrowed down on the basis of the presence of the enzyme coagulase and on their sensitivity to the antibiotic novobiocin. Streptococci are grown on blood agar and classified on the basis of which form of hemolysis they employ (α, β, or γ). Streptococci are further narrowed on the basis of their response to the pyrrolidonyl-β-naphthylamide (PYR) test, their sensitivity to specific antimicrobials (optochin and bacitracin), and their ability to grow on sodium chloride (NaCl) media.
General Characteristics and Epidemiology
Basic features of Staphylococcus
- Gram-positive cocci
- Grow in clusters
- Resemble a cluster of grapes
- Nonmotile
- Non-spore-forming
- Aerobic and facultative anaerobic
- Catalase-positive:
- An enzyme that cleaves hydrogen peroxide → water and oxygen
- Distinguishing feature from streptococci (which are catalase-negative)
Digitally-colorized scanning electron microscopic image under 10,000X magnification of Staphylococcus aureus:
Notice these cocci resemble a “cluster of grapes.”
Clinically relevant species
The clinically relevant species can be classified based on the presence (or absence) of coagulase:
- Coagulase-positive staphylococci: S. aureus
- Coagulase-negative staphylococci (CoNS) species (often grouped together):
- S. epidermidis
- S. saprophyticus
- Infrequent pathogens (list is not exhaustive):
- S. lugdunensis
- S. hominis
- S. capitis
- S. haemolyticus
Distinguishing features
| Species | Coagulase | Blood agar | Mannitol salt agar | Novobiocin* sensitivity |
|---|---|---|---|---|
| S. aureus | Positive | Beta-hemolysis | Yellow colonies | Sensitive |
| S. epidermidis | Negative | Nonhemolytic | Pink or red colonies | Sensitive |
| S. saprophyticus | Negative | Nonhemolytic | Yellow colonies | Resistant |
Methicillin-resistant Staphylococcus aureus (MRSA):
Coagulase-positive S. aureus ferments mannitol (red), producing yellow colonies on mannitol salt agar plates.
Epidemiology
- S. aureus:
- Colonizes approximately 30% of the general population
- Major cause of community-acquired and nosocomial infections
- S. epidermidis:
- Most commonly identified Staphylococcus species from human skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Structure and Function of the Skin
- Common cause of nosocomial bacteremia
- S. saprophyticus: common cause of urinary tract infections Urinary tract infections Urinary tract infections (UTIs) represent a wide spectrum of diseases, from self-limiting simple cystitis to severe pyelonephritis that can result in sepsis and death. Urinary tract infections are most commonly caused by Escherichia coli, but may also be caused by other bacteria and fungi. Urinary Tract Infections (UTIs) in sexually active young women
Pathogenesis
Reservoir
Staphylococcus species are part of the normal human flora:
- Nasal mucosa
- Respiratory tract
- Skin
- GI tract
- Genitourinary tract (S. saprophyticus)
Transmission
Staphylococcus aureus can be transmitted via aerosols and contact with:
- Infected individuals
- Bodily fluids
- Contaminated objects
Risk factors
Risk factors for severe Staphylococcus infection include:
- Hospitalization
- Surgery
- Outpatient procedures (e.g., dialysis Dialysis Renal replacement therapy refers to dialysis and/or kidney transplantation. Dialysis is a procedure by which toxins and excess water are removed from the circulation. Hemodialysis and peritoneal dialysis (PD) are the two types of dialysis, and their primary difference is the location of the filtration process (external to the body in hemodialysis versus inside the body for PD). Overview and Types of Dialysis)
- Implanted or prosthetic material:
- Pacemakers/defibrillators
- Intravascular catheters
- Urethral catheters
- Surgical implants
- Prosthetic valves
- Immunocompromised individuals
- Nursing home stays
- Injection drug use
Virulence factors
Common to most staphylococci:
- Deoxyribonuclease (DNase): depolymerizes DNA DNA The molecule DNA is the repository of heritable genetic information. In humans, DNA is contained in 23 chromosome pairs within the nucleus. The molecule provides the basic template for replication of genetic information, RNA transcription, and protein biosynthesis to promote cellular function and survival. DNA Types and Structure, a component of neutrophil extracellular traps → ↓ pus viscosity
- Fibrinolysin Fibrinolysin A product of the lysis of plasminogen (profibrinolysin) by plasminogen activators. It is composed of two polypeptide chains, light (b) and heavy (a), with a molecular weight of 75, 000. It is the major proteolytic enzyme involved in blood clot retraction or the lysis of fibrin and quickly inactivated by antiplasmins. Hemostasis: lyses fibrin walls used to keep an infection contained → aids AIDS Chronic HIV infection and depletion of CD4 cells eventually results in acquired immunodeficiency syndrome (AIDS), which can be diagnosed by the presence of certain opportunistic diseases called AIDS-defining conditions. These conditions include a wide spectrum of bacterial, viral, fungal, and parasitic infections as well as several malignancies and generalized conditions. HIV Infection and AIDS in spread
- Proteases: degrade proteins of target cells, such as components of the:
- Extracellular matrix (ECM)
- Innate immune system Innate immune system Innate immunity, the 1st protective layer of defense, is a system that recognizes threatening microbes, distinguishes self-tissues from pathogens, and subsequently eliminates the foreign invaders. The response is nonspecific and uses different layers of protection: barriers such as the skin, pattern recognition receptors (PRRs) as well as circulating proteins, and immune cells that help eliminate the microbe. Cells of the Innate Immune System
- Biofilm:
- An extracellular polysaccharide matrix that encases the bacteria Bacteria Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology: Overview after attaching to foreign material
- Functions as a protective barrier against antibiotics and the host immune system
Staphylococcus aureus:
- Hyaluronidase:
- Splits hyaluronic acid
- Makes it easier for pathogen invasion into the tissues
- Lipase and hydrolase:
- Degrade lipids Lipids Lipids are a diverse group of hydrophobic organic molecules, which include fats, oils, sterols, and waxes. Fatty Acids and Lipids
- Used for invasion
- Hemolysins and leukocidins: causes target cell death Cell death Injurious stimuli trigger the process of cellular adaptation, whereby cells respond to withstand the harmful changes in their environment. Overwhelmed adaptive mechanisms lead to cell injury. Mild stimuli produce reversible injury. If the stimulus is severe or persistent, injury becomes irreversible. Apoptosis is programmed cell death, a mechanism with both physiologic and pathologic effects. Cell Injury and Death, including red blood cells and immune cells
- Clumping factor A:
- Binds fibrinogen and other proteins
- Causes bacteria Bacteria Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology: Overview clumping in plasma
- Particularly important in the pathogenesis of endocarditis Endocarditis Endocarditis is an inflammatory disease involving the inner lining (endometrium) of the heart, most commonly affecting the cardiac valves. Both infectious and noninfectious etiologies lead to vegetations on the valve leaflets. Patients may present with nonspecific symptoms such as fever and fatigue. Endocarditis and endovascular infections
- Coagulase:
- Converts fibrinogen to fibrin to form a wall around the local area of infection (pseudocapsule)
- Promotes abscess formation
- Exfoliative toxins A and B:
- Exotoxins
- Cause
SSSS
SSSS
Staphylococcal scalded skin syndrome (SSSS), also known as Ritter disease and staphylococcal epidermal necrolysis, is a toxin-mediated condition caused by Staphylococcus aureus. The exfoliative toxin produced disseminates and cleaves desmoglein 1 in the epidermis, causing separation and detachment of the skin.
Staphylococcal Scalded Skin Syndrome (SSSS)
- Cleave desmoglein Desmoglein A group of desmosomal cadherins with cytoplasmic tails that resemble those of classical cadherins. Cell Junctions-1 complex in the stratum granulosum
- Disrupt keratinocyte-to-keratinocyte adhesion
- Cause separation and detachment of the superficial epidermis
- Superantigens:
- Includes the exotoxins:
- Toxic shock syndrome toxin type-1 (TSST-1)
- Enterotoxin B
- Cause
toxic shock syndrome
Toxic Shock Syndrome
Toxic shock syndrome (TSS) is an acute, multi-systemic disease caused by the toxin-producing bacteria, Staphylococcus aureus and Streptococcus pyogenes. Staphylococcal TSS is more common and associated with tampons and nasal packing.
Toxic Shock Syndrome (
TSS
TSS
Toxic shock syndrome (TSS) is an acute, multi-systemic disease caused by the toxin-producing bacteria, Staphylococcus aureus and Streptococcus pyogenes. Staphylococcal TSS is more common and associated with tampons and nasal packing.
Toxic Shock Syndrome):
- Bind to MHC class II on antigen-presenting cells → cross-links with the β region of the T cell receptor (TCR)
- Stimulates T cell activation and an exaggerated cytokine release
- Results in an excessive inflammatory response
- Includes the exotoxins:
- Other enterotoxins:
- Heat stable exotoxins
- Mode of action unknown
- Can cause gastroenteritis Gastroenteritis Gastroenteritis is inflammation of the stomach and intestines, commonly caused by infections from bacteria, viruses, or parasites. Transmission may be foodborne, fecal-oral, or through animal contact. Common clinical features include abdominal pain, diarrhea, vomiting, fever, and dehydration. Gastroenteritis (food poisoning)
CoNS:
- Adhesins: aid CoNS adhesion to host cells
- Urease:
- Produced by S. saprophyticus
- Hydrolyzes urea → C02 and ammonia Ammonia A colorless alkaline gas. It is formed in the body during decomposition of organic materials during a large number of metabolically important reactions. Note that the aqueous form of ammonia is referred to as ammonium hydroxide. Physiology of Acid-Base Balance → ↑ urine pH
- Makes it particularly virulent within the urinary tract
Pathophysiology of staphylococcal scalded skin syndrome Staphylococcal Scalded Skin Syndrome Staphylococcal scalded skin syndrome (SSSS), also known as Ritter disease and staphylococcal epidermal necrolysis, is a toxin-mediated condition caused by Staphylococcus aureus. The exfoliative toxin produced disseminates and cleaves desmoglein 1 in the epidermis, causing separation and detachment of the skin. Staphylococcal Scalded Skin Syndrome (SSSS):
Image by Lecturio.
Exfoliative toxin cleaves desmoglein Desmoglein A group of desmosomal cadherins with cytoplasmic tails that resemble those of classical cadherins. Cell Junctions (Dsg) 1, disrupting the cell-to-cell adhesion of the stratum granulosum. This detachment of the superficial epidermis causes bullae formation and desquamation.
Superantigens bind to MHC class II T cell receptors (TCRs), which stimulate an exaggerated cytokine release and inflammatory response. This includes toxic shock syndrome Toxic Shock Syndrome Toxic shock syndrome (TSS) is an acute, multi-systemic disease caused by the toxin-producing bacteria, Staphylococcus aureus and Streptococcus pyogenes. Staphylococcal TSS is more common and associated with tampons and nasal packing. Toxic Shock Syndrome toxin type-1 (TSST-1), which can be produced by Staphylococcus aureus.
Image by Lecturio.
Diseases Caused by S. aureus
Infections
Staphylococcus aureus can cause a wide range of infections, including (but not limited to):
- Skin and soft tissue infections
- Folliculitis
- Impetigo Impetigo Impetigo is a highly contagious superficial bacterial infection typically caused by Staphylococcus aureus (most common) and Streptococcus pyogenes. Impetigo most commonly presents in children aged 2 to 5 years with lesions that evolve from papules to vesicles to pustules, which eventually break down to form characteristic "honey-colored" crusts. Impetigo
- Cellulitis
- Abscess
- Necrotizing fasciitis Necrotizing fasciitis Necrotizing fasciitis is a life-threatening infection that causes rapid destruction and necrosis of the fascia and subcutaneous tissues. Patients may present with significant pain out of proportion to the presenting symptoms and rapidly progressive erythema of the affected area. Necrotizing Fasciitis
- Surgical wound infection
- Bloodstream infection → can seed infections in other tissues
- Infective
endocarditis
Endocarditis
Endocarditis is an inflammatory disease involving the inner lining (endometrium) of the heart, most commonly affecting the cardiac valves. Both infectious and noninfectious etiologies lead to vegetations on the valve leaflets. Patients may present with nonspecific symptoms such as fever and fatigue.
Endocarditis (IE)
- Leads to cardiac valve vegetations
- Can release septic emboli → embolic complications and/or metastatic infection
- S. aureus is associated with acute, rapidly progressive infection.
-
Pneumonia
Pneumonia
Pneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy.
Pneumonia
- S. aureus notably causes secondary bacterial pneumonia in individuals with influenza Influenza Influenza viruses are members of the Orthomyxoviridae family and the causative organisms of influenza, a highly contagious febrile respiratory disease. There are 3 primary influenza viruses (A, B, and C) and various subtypes, which are classified based on their virulent surface antigens, hemagglutinin (HA) and neuraminidase (NA). Influenza typically presents with a fever, myalgia, headache, and symptoms of an upper respiratory infection. Influenza Viruses/Influenza.
- Complications:
- Necrotizing infection → tissue destruction → lung cavitation
- Lung abscess
- Empyema
- Septic arthritis Septic arthritis Septic arthritis is an infection of the joint due to direct inoculation, contiguous extension, or hematogenous spread of infectious organisms into the joint space. This process causes an acute, inflammatory, monoarticular arthritis. Septic Arthritis
- Osteomyelitis
- Infection of the bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Structure of Bones
- Can be due to hematogenous or nonhematogenous spread
- Medical device infections, such as:
- IV catheters
- Prosthetic valves
- Prosthetic joints
- Pacemakers
Crusted, nonbullous impetigo on the upper extremity of a pediatric patient
Image: “Diagnosis of Atopic Dermatitis Atopic Dermatitis Atopic dermatitis, also known as eczema, is a chronic, relapsing, pruritic, inflammatory skin disease that occurs more frequently in children, although adults can also be affected. The condition is often associated with elevated serum levels of IgE and a personal or family history of atopy. Skin dryness, erythema, oozing, crusting, and lichenification are present. Atopic Dermatitis (Eczema): Mimics, Overlaps, and Complications” by Siegfried EC, Hebert AA. License: CC BY 4.0
Cutaneous abscess caused by MRSA
Image: “Cutaneous abscess MRSA” by CDC/Bruno Coignard, M.D. License: Public Domain
Lower extremity with areas of necrosis, erythema, and bullous changes, commonly seen in necrotizing fasciitis.
Image: “ Necrotizing fasciitis Necrotizing fasciitis Necrotizing fasciitis is a life-threatening infection that causes rapid destruction and necrosis of the fascia and subcutaneous tissues. Patients may present with significant pain out of proportion to the presenting symptoms and rapidly progressive erythema of the affected area. Necrotizing Fasciitis left leg Leg The lower leg, or just "leg" in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg” by Piotr Smuszkiewicz, Iwona Trojanowska and Hanna Tomczak. License: CC BY 2.0
Bacterial endocarditis Endocarditis Endocarditis is an inflammatory disease involving the inner lining (endometrium) of the heart, most commonly affecting the cardiac valves. Both infectious and noninfectious etiologies lead to vegetations on the valve leaflets. Patients may present with nonspecific symptoms such as fever and fatigue. Endocarditis: obstruction of the pulmonic valve of a heart by a bacterial vegetation, seen here during autopsy
Image: “Bacterial endocarditis Endocarditis Endocarditis is an inflammatory disease involving the inner lining (endometrium) of the heart, most commonly affecting the cardiac valves. Both infectious and noninfectious etiologies lead to vegetations on the valve leaflets. Patients may present with nonspecific symptoms such as fever and fatigue. Endocarditis” by CDC/ Dr. Sellers. License: Public Domain
Toxin-mediated diseases
| Disease | Exotoxin | Clinical presentation |
|---|---|---|
| SSSS SSSS Staphylococcal scalded skin syndrome (SSSS), also known as Ritter disease and staphylococcal epidermal necrolysis, is a toxin-mediated condition caused by Staphylococcus aureus. The exfoliative toxin produced disseminates and cleaves desmoglein 1 in the epidermis, causing separation and detachment of the skin. Staphylococcal Scalded Skin Syndrome (SSSS) | Exfoliative toxins A and B |
|
| Toxic shock syndrome ( TSS TSS Toxic shock syndrome (TSS) is an acute, multi-systemic disease caused by the toxin-producing bacteria, Staphylococcus aureus and Streptococcus pyogenes. Staphylococcal TSS is more common and associated with tampons and nasal packing. Toxic Shock Syndrome) | Toxic shock syndrome toxin type-1 (TSST-1) Enterotoxin B |
|
| Gastroenteritis | Enterotoxins |
|
Staphylococcal scalded skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Structure and Function of the Skin syndrome in a newborn Newborn A neonate, or newborn, is defined as a child less than 28 days old. A thorough physical examination should be performed within the first 24 hours of life to identify abnormalities and improve outcomes by offering timely treatment. Physical Examination of the Newborn:
Image: “Staphylococcal Scalded Skin Syndrome in Neonate” by Kouakou K, Dainguy ME, Kassi K. License: CC BY 3.0
This image shows diffuse erythema, bullae formation, and skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Structure and Function of the Skin peeling.
Morbilliform rash from toxic shock syndrome Toxic Shock Syndrome Toxic shock syndrome (TSS) is an acute, multi-systemic disease caused by the toxin-producing bacteria, Staphylococcus aureus and Streptococcus pyogenes. Staphylococcal TSS is more common and associated with tampons and nasal packing. Toxic Shock Syndrome ( TSS TSS Toxic shock syndrome (TSS) is an acute, multi-systemic disease caused by the toxin-producing bacteria, Staphylococcus aureus and Streptococcus pyogenes. Staphylococcal TSS is more common and associated with tampons and nasal packing. Toxic Shock Syndrome)
Image: “Morbilliform rash (resembling measles Measles Measles (also known as rubeola) is caused by a single-stranded, linear, negative-sense RNA virus of the family Paramyxoviridae. It is highly contagious and spreads by respiratory droplets or direct-contact transmission from an infected person. Typically a disease of childhood, measles classically starts with cough, coryza, and conjunctivitis, followed by a maculopapular rash. Measles Virus) resulting from toxic shock syndrome Toxic Shock Syndrome Toxic shock syndrome (TSS) is an acute, multi-systemic disease caused by the toxin-producing bacteria, Staphylococcus aureus and Streptococcus pyogenes. Staphylococcal TSS is more common and associated with tampons and nasal packing. Toxic Shock Syndrome” by Centers for Disease Control and Prevention. License: Public Domain
Diseases Caused by CoNS
Coagulase-negative staphylococci can cause many of the same conditions as S. aureus. Notable infections include:
- Medical device infections (particularly S. epidermidis)
- IV catheters
- Prosthetic valves
- Pacemakers
- Prosthetic joints
- CNS shunts
- Breast implants
- Surgical wound infection
- IE (native and prosthetic valve)
- Osteomyelitis
- UTIs (particularly S. saprophyticus)
Antibiotics and Resistance
Antibiotic susceptibility
Staphylococcus species can develop antibiotic resistance, and identification of susceptibility is necessary for adequate treatment. Species are often designated as:
- Methicillin-sensitive
- Methicillin-resistant
- Vancomycin-resistant
Mechanism of resistance
- Methicillin: penicillin-binding protein (PBP)-mediated resistance
- Mutations in the PBPs (encoded by mecA gene) → ↓ affinity of penicillins Penicillins Beta-lactam antibiotics contain a beta-lactam ring as a part of their chemical structure. Drugs in this class include penicillin G and V, penicillinase-sensitive and penicillinase-resistant penicillins, cephalosporins, carbapenems, and aztreonam. Penicillins to the PBP
- Despite the mutations, these PBPs are still able to produce a cell wall.
- Vancomycin: alteration in peptidoglycan synthesis
- Conferred by vanA gene (on plasmid)
- Acquired from vancomycin-resistant Enterococcus Enterococcus Enterococcus is a genus of oval-shaped gram-positive cocci that are arranged in pairs or short chains. Distinguishing factors include optochin resistance and the presence of pyrrolidonyl arylamidase (PYR) and Lancefield D antigen. Enterococcus is part of the normal flora of the human GI tract. Enterococcus (VRE)
- Alters the D-alanyl-D-alanine peptidoglycan target to D-alanyl-D-lactate or D-alanyl-D-serine → poor glycopeptide binding and no disruption of cell wall synthesis
Penicillin-binding protein (PBP) forms cross-linked bridges between adjacent peptidoglycan chains during bacterial cell wall synthesis. A beta-lactam antibiotic irreversibly binds to and inhibits the PBP, preventing it from forming new cross-links. This effectively inhibits further cell wall synthesis, which ultimately leads to cell death Cell death Injurious stimuli trigger the process of cellular adaptation, whereby cells respond to withstand the harmful changes in their environment. Overwhelmed adaptive mechanisms lead to cell injury. Mild stimuli produce reversible injury. If the stimulus is severe or persistent, injury becomes irreversible. Apoptosis is programmed cell death, a mechanism with both physiologic and pathologic effects. Cell Injury and Death. Alterations in PBP are what confer staphylococcal resistance to penicillin antibiotics, such as methicillin.
Image by Lecturio. License: CC BY-NC-SA 4.0
Vancomycin resistance:
Image by Lecturio.
Synthesis of D-alanyl-D-lactate on peptidoglycan precursors in the cell wall causes poor binding with vancomycin, thus reducing the effectiveness of the antibiotic.
Antibiotic choices
The agent of choice and duration of treatment for Staphylococcus infection depends on the body area affected, the severity of infection, and the antibiotic sensitivity of the strain.
| Strain | Antibiotic |
|---|---|
| MSSA and CoNS |
|
| MRSA |
|
| VRSA |
|
References
- Carroll, KC, & Hobden, JA. (2015). The staphylococci. In Brooks, JE, et al. (Eds.), Jawetz, Melnick, & Adelberg’s Medical Microbiology. (27th ed). [VitalSource Bookshelf 9.4.3].
- Centers for Disease Control and Prevention. (2020). Staphylococcus aureus in Healthcare Settings. https://www.cdc.gov/hai/organisms/staph.html
- Fowler, VG, & Holland, TL. Clinical approach to Staphylococcus aureus bacteremia in adults. UpToDate. Retrieved May 13, 2021, from https://www.uptodate.com/contents/clinical-approach-to-staphylococcus-aureus-bacteremia-in-adults
- Tufariello, JM, & Lowy, FD. Infection due to coagulase-negative staphylococci: Epidemiology, microbiology, and pathogenesis. UpToDate. Retrieved May 14, 2021, from https://www.uptodate.com/contents/infection-due-to-coagulase-negative-staphylococci-epidemiology-microbiology-and-pathogenesis
- Chu, VH. Staphylococcal toxic shock syndrome. UpToDate. Retrieved May 19, 2021, from https://www.uptodate.com/contents/staphylococcal-toxic-shock-syndrome
- McMahon, P. Staphylococcal scalded skin syndrome. UpToDate. Retrieved May 19, 2021, from https://www.uptodate.com/contents/staphylococcal-scalded-skin-syndrome
- Cong, Y, Yang, S, & Rao, X. (2020). Vancomycin-resistant Staphylococcus aureus infections: A review of case updating and clinical features. Journal of Advanced Research. 21:169-176. https://www.sciencedirect.com/science/article/pii/S2090123219301638
- Gardete, S, & Tomasz, A. (2014). Mechanism of vancomycin resistance in Staphylococcus aureus. The Journal of Clinical Investigation. 124(7):2836-40. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4071404/
- Moreillon, P, et al. (1995). Rose of Staphylococcus aureus coagulase and clumping factor in pathogenesis of experimental endocarditis. Infection and Immunity. 63(12):4738-43. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC173679/
- Vandenesch, F, Lina, G, & Henry, T. (2012). Staphylococcus aureus hemolysins, bicomponent leukocidins, and cytolytic peptides: A redundant arsenal of membrane-damaging virulence factors? Frontiers in Cellular and Infection Microbiology. 2:12. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3417661/
