Table 8.3.

Gram-positive infections and causative organisms

Gram-positive infections	Pathogenic strains	Diseases and symptoms	Morphology
Pneumococcal infections	Streptococcus pneumoniae	Otitis media, acute purulent rhinosinusitis, pneumonia, meningitis	Grows in chain
Staphylococcal infections	Streptococcus aureus	Toxin- and non-toxin-mediated infections, surgical wound infections, primary bacteremia	Forms grapelike clusters
Streptococcal infections	Group A Streptococcus pyogenes	Pharyngitis, post-infectious symptoms of acute rheumatic fever, and glomerulonephritis	Spherical to ovoid, grow in chains
	Group B Streptococcus agalactiae	Bacterial sepsis, meningitis in newborns, endometritis, and fever in parturient females
Enterococci (group D streptococci)	Enterococcus faecalis, E. faecium	Urinary tract infections, nosocomial bacteremia, endocarditis
Corynebacterial infections	Corynebacterium diphtheriae	Nasopharyngeal and skin infections, toxin causes systemic toxicity, myocarditis, polyneuropathy	Club-shaped bacillary appearance forming clusters
Listeria	Listeria monocytogenes	Food-borne pathogen, causes serious infections in immunocompromised individuals	Rod shaped
Clostridial infections	Clostridium tetani	Tetanus: neurologic disorder, increased muscle tone, and spasms due to tetanospasmin (toxin)	Resembles tennis racket
	Clostridium botulinum	Botulism: paralytic disease due to neurotoxins, proceeds with cranial nerve involvement
	Clostridium perfringens	Gas gangrene (bacteremia) due to active tissue and enterotoxins