Aerobic and Facultatively Anaerobic Gram-Positive Cocci

Aerobic and Facultatively Anaerobic Gram-Positive Cocci

Last Updated on January 13, 2020 by Sagar Aryal

Enterococcus faecalis and Enterococcus faecium

Clinical Features

Urinary tract infections, peritonitis, bacteremia, endocarditis

Virulence Factors

Relatively avirulent

Aerobic and Facultatively Anaerobic Gram-Positive Cocci

Staphylococcus aureus

Clinical Features

Suppurative infections: impetigo, folliculitis, furuncles, carbuncles, wounds

Disseminated infections: bacteremia, endocarditis, pneumonia, empyema, osteomyelitis, septic arthritis

Toxin-mediated infections: toxic shock syndrome, scalded skin syndrome, food poisoning

Virulence Factors

Possess thick peptidoglycan layer, capsule, protein A, various toxins (cytotoxins, exfoliative toxins, enterotoxins, toxic shock syndrome toxin, Panton- Valentine leukocidin) and hydrolytic enzymes

Staphylococcus, coagulase-negative

Clinical Features

Wound infections, urinary tract infections, catheter and shunt infections, prosthetic device infections

Virulence Factors

Possess thick peptidoglycan layer and loose polysaccharide slime layer; Staphylococcus saprophyticus
produces high concentrations of urease

Streptococcus pyogenes (group A)

Clinical Features

Suppurative infections: pharyngitis, scarlet fever, sinusitis, skin and softtissue infection (impetigo,
erysipelas, cellulitis, necrotizing fasciitis), toxic shock–like syndrome; bacteremia

Nonsuppurative infections: rheumatic fever, glomerulonephritis

Virulence Factors

Capsule, M protein, M-like protein, F protein, pyrogenic exotoxins, streptolysin S and O, streptokinase,
deoxyribonuclease, C5a peptidase

Streptococcus agalactiae (group B)

Clinical Features

Neonatal disease (early onset, late onset): bacteremia, pneumonia, meningitis; postpartum endometritis, wound infection, skin and soft-tissue infection, urinary tract infections, pneumonia

Virulence Factors

Similar to group A but no capsule

Viridans streptococci

Clinical Features

Abscess formation; septicemia in neutropenic patients; subacute endocarditis; odontogenic infections; dental caries

Virulence Factors

Relatively avirulent

Streptococcus pneumoniae

Clinical Features

Pneumonia, sinusitis, otitis media, meningitis, bacteremia, endocarditis, spontaneous bacterial peritonitis, septic arthritis

Virulence Factors

Polysaccharide capsule; teichoic acid; immunoglobulin A protease; pneumolysin O

Aerobic and Facultatively Anaerobic Gram-Positive Cocci

5 thoughts on “Aerobic and Facultatively Anaerobic Gram-Positive Cocci”

Leave a Comment