These images are from the original published atlas:
Tenover, F. C., and J. V. Hirschmann. 1990. Interpretation of
Gram stains and other common microbiologic slide preparations.
The UpJohn Company, Kalamazoo, Mich. Permission granted to the
ASM MicrobeLibrary by Pfizer Inc.
This atlas was written to help clinicians,
microbiologists, and laboratory personnel identify organisms
in infected materials stained by techniques commonly used in
most clinical laboratories. Please refer to the atlas'
main page for more information and a guide to
all of the images.
Slide 1. Streptococcus pneumoniae
(“pneumococcus”)
This is a good, adequately decolorized,
sputum specimen with several neutrophils but no epithelial
cells. The predominant organisms are paired, slightly
elongated (“lancet-shaped”) gram-positive cocci. In sputum
specimens, pneumococci are usually paired but can be found as
single cocci or short chains of three or four organisms. The
halos visible around many of the cocci may be the
polysaccharide capsules of Streptococcus
pneumoniae.
Slide 2. Streptococcus agalactiae (group B
streptococcus)
Large, round, gram-positive cocci are found
singly and in pairs, chains, and clumps. The cocci are larger
and rounder than pneumococci, which rarely, if ever form
chains of more than four cocci in sputum. Various
nonpneumococcal streptococci cannot be differentiated by their
appearance on a Gram stain. When chains of streptococci
overlap, they can resemble clusters of staphylococci, making
differentiation of these two kinds of bacteria difficult.
Slide 3. Staphylococcus aureus
Numerous
gram-positive cocci, round and large, are visible as single
organisms, pairs, and grape-like clusters. The clusters
strongly suggest that the organisms are staphylococci. The red
strands of mucus in the background are common in good sputum
specimens.
Slide 4. Nocardia asteroides
Nocardia
asteroides are branching, beaded, gram-positive bacilli.
Actinomyces look the same, and Streptomyces
species are also long, branching gram-positive rods, but
usually are not beaded.
Slide 5. Nocardia asteroides
When stained with a
modified acid-fast technique, as this specimen is, most
Nocardia are acid fast, but Actinomyces and
Streptomyces species are not. The presence of
branching, red rods on the blue background confirms that the
organism is acid fast and thus most likely Nocardia.
See also:
Sputum Gram-Negative
Diplococci and Coccobacilli (4 images)
Sputum–Mixed
Organisms (2 images)
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