gram + cocci Flashcards
- skin and soft tissue infections
- abscesses
- endocarditis
- sepsis
- gastroenteritis (food poisoning)
- pneumonia (rarely)
- toxic shock syndrome
Staphylococcus aureus diseases
- gram + cocci in clusters
- coagulase positive (if initial lab report reads coagulase negative Staphylococci, think S. epidermidis which is less likely to be pathogenic than S. aureus)
- most isolates produce beta-lactamase
Staphylococcus aureus characteristics
- found on human skin and in nose
- transmission is usually via the hands
Staphylococcus aureus habitat and transmission
- Gram stain AND Routine C and S
Staphylococcus aureus lab dx
Beware of hospital acquired methicillin resistant _____ as well as community acquired ____.
Staphylococcus aureus
- infections on prostheses
- intravascular catheter infections
Staphylococcus epidermidis diseases
- gram + cocci in clusters
- coagulase -
Staphylococcus epidermidis and Staphylococcus saprophyticus characteristics
- normal flora of skin and mucus membranes
Staphylococcus epidermidis habitat
UTI in young women (however, E. coli is more commonly the cause of UTIs)
Staphylococcus saprophyticus
suppurative (pus-producing) diseases
immunologic diseases
Streptococcus pyogenes (Group A strep) diseases
- gram + cocci in chains
- beta-hemolytic (hemolysis)
Streptococcus pyogenes (Group A strep) characteristics
- human throat and skin
- transmitted via respiratory droplets
Streptococcus pyogenes (Group A strep) habitat and transmission
- gram stain and culture
- when you suspect it to be the cause of pharyngitis, you can order a “strep screen” or rapid strep antigen test.
- when rheumatic fever or glomerulonephritis is suspected, the strep screen and throat C&S will be negative, so you’ll need to order anti-streptococcal antibody titers
Streptococcus pyogenes (Group A strep) lab dx
Rheumatic fever lab dx
anti-streptolysin O (ASO) identifies previous infection
Glomerulonephritis lab dx
streptococcal Dnase B ab
immunologic diseases for Streptococcus pyogenes (Group A strep)
- rheumatic fever
- glomerulonephritis
suppurative (pus-producing) diseases for Streptococcus pyogenes (Group A strep)
- pharyngitis (strep throat)
- cellulitis and erysipelas
- toxic shock syndrome
neonatal meningitis and sepsis
Streptococcus agalactiae (Group B strep) disease
- gram + cocci in chains
- beta hemolytic
Streptococcus agalactiae (Group B strep) characteristics
- habitat is the vagina
- transmission occurs during birth
Streptococcus agalactiae (Group B strep) habitat and transmission
Urinary tract and biliary tract infection are most common
Enterococcus faecalis disease
- gram + cocci in chains
- vancomycin-resistant enterococci (VRE) are important cause of nosocomial infections
Enterococcus faecalis characteristics
- habitat is the colon, urethra, and female genital tract can be colonized
- may enter bloodstream during GI or GU surgery
Enterococcus faecalis habitat and transmission
- gram stain AND culture
Enterococcus faecalis lab dx
Streptococcus agalactiae (Group B strep) lab dx
Streptococcus pneumoniae lab dx
Viridans Group Streptococci (S. mutans, S. sanguis, and others) lab dx
Most common are OM and sinusitis (mostly in children), and community-acquired pneumonia and meningitis (mostly adults)
Streptococcus pneumoniae diseases
- gram + “lancent-shaped” cocci in pairs (diplococci) or short chains
Streptococcus pneumoniae characteristics
- habitat is the human upper respiratory trat
- transmission is via respiratory droplets
Streptococcus pneumoniae habitat and transmission
endocarditis is the most important disease
Viridans Group Streptococci (S. mutans, S. sanguis, and others) disease
- gram + cocci in chains
Viridans Group Streptococci (S. mutans, S. sanguis, and others) characteristics
habitat is the human oropharynx
Viridans Group Streptococci (S. mutans, S. sanguis, and others) habitat
