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Journal of Microbiology & Biology Education – Volume 8, 2007


Sixteen New Visual Resources


Two New Curriculum Resources

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©Ah American Society
    for Microbiology,
    Washington DC

Printable Version
Sputum Gram-Negative Diplococci and Coccobacilli
Resource Type: Visual: Image
Publication Date: 2/6/2007
Slide 1

Haemophilus influenzae (Enlarged view)
Slide 2

Moraxella (Branhamella) catarrhalis (Labeled view)
Slide 3

Neisseria meningitidis (Enlarged view)
Slide 4

Moraxella (Branhamella) catarrhalis (Enlarged view)
Rebecca Buxton (Corresponding Author)
Department of Pathology
University of Utah
Salt Lake City, Utah 84132

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. Haemophilus influenzae
These small, pleomorphic Gram-Negative bacteria range in shape from round (cocci) to short, thin rods (bacilli); hence the bacteria are called “coccobacilli.” In specimens from patients with pneumonia caused by Haemophilus influenzae, both neutrophils and bacteria are usually plentiful. However, if examination of the slide is not thorough, the coccobacilli may be inconspicuous in the background of pink-staining mucus. Other organisms, such as Eikenella corrodans or Bacteroides species, are also pleomorphic Gram-Negative coccobacilli; but they rarely cause pneumonia.

Slide 2. Haemophilus influenzae
Many coccobacilli are present in the cytoplasm of the neutrophils, a common site for Haemophilus influenzae in sputum stains. The examiner should always look carefully for organisms in white cells. (An alveolar macrophage is also present on this slide.)

Slide 3. Neisseria meningitidis
Numerous Gram-Negative diplococci are present, singly and in pairs. In patients with pneumonia, the respiratory pathogens most likely to have this appearance are Neisseria meningitidis or Moraxella (Branhamella) catarrhalis which look alike. Other Gram-Negative diplococci, such as commensal Neisseria species or Veillonella species, are rarely the sole or predominant organism in sputum smears of patients with pneumonia.

Slide 4. Moraxella (Branhamella) catarrhalis
Moraxella catarrhalis can cause pneumonia, especially in patients with alcoholism or chronic obstructive lung disease. This slide shows many Gram-Negative cocci, singly and in pairs. Like meningococci and Haemophilus influenzae, Moraxella catarrhalis is often visible within the cytoplasm of neutrophils.

See also:


Sputum GramPositive Bacterial Infections (5 images)

Sputum Gram-Negative Bacilli (5 images)

Sputum–Mixed Organisms (2 images)

Sputum–Mycobacteria (3 images)

Sputum–Unacceptable Specimens and Staining Artifacts (6 images)