Table 1.

Operational Classification of Bacterial Isolates

Category	Organisms
Absolute pathogens	Staphylococcus aureus, Streptococcus pneumoniae, yeast species, Streptococcus (groups A and B), Salmonella, Shigella, Haemophilus influenzae, Neisseria meningitidis, Mycobacterium, Campylobacter, Listeria
Possible pathogens	Abiotrophia, Acinetobacter, Actinomyces, alpha (viridans) Streptococcus, Streptococcus anginosus, Capnocytophaga, Citrobacter, Enterobacteriaceae, Enterococcus, nonfermenting gram-negative rods
Common contaminants	Bacillus, Coryneform bacteria, gram-positive rods or gram-positive cocci (unidentified), Kocuria, Leuconostoc, Lactobacillus, Moraxella, Neisseria (not meningitidis or gonorrheae), Rothia, coagulase-negative Staphylococcus