Microbiology (ACP Medicine)

Culture Specimen

Routinely Cultured for

Also Reported

Normal Flora

Throat

Group A p-hemolytic streptococci, pyogenic groups C and G p-hemolytic streptococci, Arcanobacterium haemolyticum

If a complete throat culture is requested, it will be examined for Haemophilus in-fluenzae, Staphylococcus aureus, Streptococcus pneumoniae, Neisseria meningitidis, and yeast

a-Hemolytic streptococci, nonhemolytic streptococci, diphtheroids, coagulase-negative staphylococci, saprophytic

Neisseria

Sputum

Pneumococci, H. influenzae, p-hemolytic streptococci, S. aureus, Moraxella (Branhamella) catarrhalis, Pseudomonas, Enterobacteriaceae, yeast

Presence or absence of normal throat flora

Carefully collected specimens should contain few or no normal throat flora

Urine

Aerobic bacteria and yeast: abundant, > 10⁵ colony-forming units/ml; moderate, 10⁴-10⁵ colony-forming units/ml

Few, 10³-10⁴ colony-forming units/ml; rare, 10²-10³ colony-forming units/ml; no growth, < 10² colony-forming units/ ml; these amounts may indicate clinicaly significant bacteriuria if accompanied by pyuria, clinical symptoms, or both

Carefully collected specimens should not contain mixed bacterial species (i.e., two or more of the following: lacto-bacilli, non-p-hemolytic streptococci, diphtheroids, coagulase-negative staphylococci, Gardnerella vaginalis)

Blood

Aerobic and anaerobic bacteria, yeasts

Growth in both bottles is usually more clinically significant than growth in a single bottle

None; aerobic and anaerobic diphthe-roids and coagulase-negative staphy-lococci are common contaminants

Cerebrospinal and other fluids

Aerobic and anaerobic bacteria; yeasts, including Cryptococcus

Any organism isolated

None

Feces

Enteric pathogens: Salmonella, Shigella, Campylobacter, Plesiomonas, and Aero-monas when predominant

Moderate or abundant yeast or S. aureus; presence or absence of normal gram-negative enteric flora; special cultures can be specifically requested for Yersi-nia, Vibrio cholerae, V. parahaemolyticus, or hemorrhagic (O157) strains of Esche-richia coli

Enterobacteriaceae, streptococci, Pseudo-monas, small numbers of staphylo-cocci, and yeast (and anaerobes that are not cultured routinely)

Wounds

Aerobic and anaerobic bacteria, yeasts

Cervical or vaginal

Gonococci, p-hemolytic streptococci, S. aureus, and G. vaginalis when predominant

Enteric gram-negative rods and Candida, if present in large numbers