Bacillus subtilis (1000X). This is an example of a typical
streptobacillus. Note the clear endospores inside the chains of cells.
B. subtilis is a common inhabitant of soil and is thermoduric (can
withstand high temperatures). Some strains of this species produce the
antibiotic bacitracin, a cell wall inhibitor used as a topical chemotheraputic
Staphylococcus aureus (1000X). This is a organism which exhibits
the typical staphylococcus (grape-like cluster) arrangement of cells.
S. aureus is a halotolerant (salt tolerant) organism associated
with the nasal mucosa of mammals which has both benign and pathogenic strains.
Illnesses associated with this organism include toxic shock syndrome (TSS),
scalded skin syndrome in infants, intoxication-based gastroenteritis, pimples,
boils, and other inflammations. It is a nosocomial (hospital-borne)
agent of infection.
epidermidis (1000X). Another staphylococcus, though this organism
is a nonpathogenic normal microflora component of the skin. Like
S. aureus, it is a halotolerant microorganism.
luteus (1000X). This soil and air-borne contaminant of media
forms groups of two to four cocci, is catalase positive like the staphylococci,
and forms distinct yellow pigmented colonies which are circular with entire
Corynebacterium xerosis (1000X). This slightly curved rod is a normal flora component of the skin of mammals which has arrangements of two, fours, V formations or palisades. This species does not form spores and is commonly referred to by the generic term "diptheroid", which is based on its relation to C. diptheriae, the etiologic agent of diptheria.
pyogenes (1000X). This streptococcus is an inhabitant of the
oral cavities of mammals and is the etiologic agent of with strep throat
(pharyngitis), Scarlet fever, Erysipelas, Pneumonia, bacteremia, necrotizing
fasciaitis (IGAS; Invasive Group A Streptococcus), and other systemic infections.
pneumoniae (1000X). This streptococcus is a major agent of bacterial
pneumonia. The pathogenic strains form capsules which can be visuallized
with a capsule stain.
Enterococcus faecalis (1000X). This enterococcus is a normal flora inhabitant of the gastrointestinal tract of mammals, and is an opportunistic pathogen associated with pyogenic infections. Recently, strains of vancomycin resistant enterococci have begun to appear which are probably spread by the nosocomial route.