General Flashcards
Is widely distributed in the external environment. It may be found in 20 to 40% of the anterior nares of human adults. It also colonizes the skin, particularly in intertriginous areas such as the groin and axilla, and may be found in the vaginal canal
Staphylococcus aureus epidemiology
Was discovered more than 100 years ago by Hans Christian Gram. Crystal violet-primary stain. Gram’s iodine-mordant to fix the dye. GP Bacteria retain the dye in cell wall. Acid alcohol-decolorizer. GN bacteria stain red Safranin-counterstain.
The Gram stain
Is a basic fluorochrome dye that binds nonspecifically to nucleic acids, proteins, polysaccharides, and glycosaminoglycans. Useful in demonstrating bacteria in specimens where concentrations may be low.
Acridine orange
Catalase, Coagulase, Dnase, PYR, Nonmotile, Salt tolerance all +
Staphylococcus aureus
Drug of choice for Staphylococcus aureus, Strep pneumo
Penicillin and cephalosporin (1st generation)
the most frequently isolated coagulase-negative staphylococci from human sources
Staphylococcus epidermidis
Does not ferment mannitol, produces alkaline phosphatase, produces positive reactions for acetoin (Voges Proskauer), reduces nitrates to nitrites, and hydrolyzes urea. Acid is produced from maltose, fructose, sucrose, and mannose.
S. epidermidis
Drug of choice for Staphylococcus epidermidis
Penicillin
Has a particular predilection for causing urinary tract infections in young, healthy, sexually active females.
Staphylococcus saprophyticus
Has its natural habitat as part of the normal nasal and skin flora of various domestic animals, including dogs, cats, and horses. It is the most common coagulase-positive Staphylococcus species recovered from the skin of dogs.
Staphylococcus intermedius
Resistance to novobiocin is a key feature used in the presumptive identification of
S. saprophyticus
among the most commonly recovered bacterial species in the clinical laboratory. It is the cause of classic streptococcal pharyngitis, colloquially known as “strep throat.”
Streptococcus pyogenes
Poststreptococcal diseases
include scarlet fever, rheumatic fever, endocarditis, and nephritis.
Poststreptococcal diseases
include scarlet fever, rheumatic fever, endocarditis, and nephritis.
Small transparent colonies/wide zone of beta hemolysis. ID-Low conc of bacitracin (0.04 μg)/PYR +.
Group A streptococci
Group B-specific antigen. Metabolism is fermentative with lactic acid produced as the chief end product. Narrow zone of beta hemolysis. + cAMP reaction/ hydrolyzes NA hippurate
Streptococcus agalactiae
Infections include meningitis, pneumonia, polynephritis, sepsis including endocarditis/in women, puerperal infection assctd w/ abortion and premature labor. Neonatal sepsis and meningitis
Streptococcus agalactiae (Group B)
Drugs of choice for Streptococcus pyogenes
Penicillin, ampicillin, cephalosporin 1st gen, erythromycin
Drugs of choice for Streptococcus agalactiae
Penicillin, ampicillin, carbenicillin, cephalosporin 1st gen, erythromycin
Group for 2 species: S. bovis and S. equi. ID by + esculin hydrolysis in bile-esculin agar and by the inability to grow in 6.5% sodium chloride
Group D streptococci
Can be divided into one of 83 different capsular serotypes(Latex agg, coagg, or the Neufeld quellung rxn)3, 4, 14, and 19, are particularly virulent. The capsular material prevents phagocytosis and killing by the host phagocytic cells.
Strep pnuemo
Alpha hemolytic and smooth, moist, or mucoid/”checker piece” appearance/ susceptibile to either bile or ethylhydrocupreine hydrochloride (Optochin)
Strep pnuemo
Lobar type pneumonia and bacterial meningitis in adults, infants, and toddlers. Diabetes and alcoholism are common conditions predisposing to serious pneumococcal infections.
Strep pnuemo
Lobar type pneumonia and bacterial meningitis in adults, infants, and toddlers. Diabetes and alcoholism are common conditions predisposing to serious pneumococcal infections.
Strep pnuemo