Reading Gram-stained Smears From Cultures

Authors: Betty Smith, MT(ASCP); Mary Ann Fiene, MSMT(ASCP); Rukhsana Evans, MSMT(ASCP)
Reviewers: Alexandru Casapu, MBA, MLS(ASCP)CM; Julie Ann West, PhD, MLS(ASCP)CM, SM(ASCP)CM
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Continuing Education Credits

P.A.C.E.® Contact Hours: 2 hour(s)

Florida Board of Clinical Laboratory Science CE Credit Hours

Florida Board of Clinical Laboratory Science CE - General (Microbiology/Mycology/Parasitology): 1.5 hour(s)

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This course explains how to intelligently evaluate and interpret gram stained smears from cultures. Good for clinical laboratory science students, cross training, and CE. Covers gram positive and gram negative bacilli; single, pair, chain, and tetrad cell arrangements; and reporting.

Objectives

  • Explain the importance of Gram-stained smears made from isolated colonies to the clinician.
  • Discuss the procedure for examination of smears made from cultures - concerning Gram stain reaction, shape of the organism, and arrangement of the cells.
  • Identify microorganisms as gram-positive or gram-negative and be able to describe their shape and cell arrangement.
  • Demonstrate ability to interpret Gram-stained smears made from cultures of various body sites, and report these smears appropriately.

Course Outline

  • Introduction to Reading Gram-stained Culture Smears
    • Culture, Isolation, and Identification of Microorganisms - Importance of the Gram Stain
    • All of the following are part of the microorganism identification process, except for which of the following?
    • True or False: A physician can use the information provided from a Gram-stained culture smear to help make a preliminary diagnosis and begin treatment.
  • General Aspects of Gram-stained Smears From Culture
    • Gram Stain
    • Procedure: Preparation of a Gram-stained Smear From Culture
    • Quality Control (QC)
    • Gram Stain Quality Control (QC) Organisms
    • Procedure: Examining the Smear
    • Which of the following is true of the Gram stain procedure?
    • Match each of the following Gram stain items/actions to the appropriate statement.
  • Organism Shapes in Gram-stained Culture Smears
    • Cocci and Rods
    • Variations in the Shape of Cocci
    • Variation in the Shape of Bacilli
    • Gram-Negative Rods (GNRs)
    • Which of the following terms can be used to describe cocci?
    • True or False: Bacilli can have tapered or rounded ends.
  • Arrangement of Organisms in Gram-stained Culture Smears
    • Cellular Arrangement
    • Single Cell Arrangement
    • Pair Cell Arrangement
    • Chain Cell Arrangement
    • Tetrad Cell Arrangement
    • Clusters of Gram-Positive Bacteria
    • Yeast Cells
    • When describing microorganisms seen on a Gram-stained smear, what do terms such as diplococci, tetrads, chains, and clusters describe?
  • Gram Stain Characteristics and Organisms Expected From Common Body Sites
    • Gram-positive Organisms Recovered From Culture
    • Images: Gram-positive Cocci (GPC) Recovered From Culture
    • Images: Gram-positive Rods (GPRs) Recovered From Culture
    • Gram-negative Organisms Recovered From Culture
    • Images: Gram-negative Organisms Recovered From Culture
    • Match the Gram stain characteristic to the organism it best describes:
    • Expected Pathogens From Common Body Sites/Specimens
    • Expected Pathogens From Common Body Sites/Specimens, continued...
    • Expected Pathogens From Common Body Sites/Specimens, continued...
  • Reporting Gram-stained Culture Smears
    • Gram-stained smears from Culture: Importance and Reporting
    • Select the correct choice for reporting.
    • Select the correct choice for reporting.
    • Select the correct choice for reporting.
    • Select the correct choice for reporting. Hint: This Gram stain was prepared on an aging culture. Focus on the organisms represented by the arrows.
    • Select the correct choice for reporting.
    • Select the correct choice for reporting.
    • Select the correct choice for reporting.
    • When performing a Gram stain from culture media, which of the following must always be reported for the organism?
    • True or False: The type of culture medium used to recover an organism does not have an effect on cellular arrangement.
  • Case Studies in Reading Gram-stained Smears From Cultures
    • This organism was recovered from the sputum of a patient with hospital-acquired pneumonia (HAP). Which of the options below would be used to describe the Gram-stained smear?
    • This organism is recovered from the blood culture of an immunocompromised patient. Which option below would be used to describe the Gram-stained smear?
    • This organism is recovered from the cerebrospinal fluid (CSF) of a child who attends daycare, following a severe ear infection. Which of the options below would be used to describe the Gram-stained smear?
    • This organism is recovered from the cervical culture of a female of childbearing age. Which of the options below would be used to describe the Gram-stained smear?
    • This organism is recovered from the joint fluid of a 28-year-old patient. Which of the options below would be used to describe the Gram-stained smear?
    • This organism is recovered from a wound culture. Which one of the options below would be used to describe the Gram-stained smear?
  • References
    • References

Additional Information

Level of Instruction: Basic

Intended Audience: Clinical laboratory science students, and medical technologists/technicians seeking review, cross-training, or continuing education opportunities. Also appropriate for medical students and pathology residents.

Course Description: This illustrated course covers the basics of reading Gram-stained smears from cultures, including interpretation of controls, reading, interpreting, and reporting Gram-stained culture smears. The course is illustrated with numerous images of actual culture Gram stains and contains many interactive quiz questions.

Author Credentials: This course was developed by Betty Smith MT (ASCP), Mary Ann Fiene, MSMT(ASCP), and Rukhsana Evans, MSMT(ASCP) and has been updated by Education Materials for Health Professionals, Inc.

Reviewer Information: Alexandru Casapu, MBA, MLS(ASCP)CM, PBTCM has over 20 years of experience as a medical laboratory scientist, section supervisor, and laboratory manager. He is the former Director of the Clinical Laboratory Technology Program at Georgia Piedmont Technical College. He is currently a Program Director at MediaLab, Inc. Alexandru holds BS degrees in Biology and Medical Technology from Clark Atlanta University and an MBA from the University of Georgia.
 
Reviewer Information: Dr. Julie Ann West is certified by the American Society for Clinical Pathology (ASCP) as a Medical Laboratory Scientist (MLS) and as a Specialist in Microbiology (SM). In addition, Dr. West has earned a PhD in Public Health - Epidemiology Specialization (emphasis on infectious disease) - and is Certified in Public Health (CPH) by the National Board of Public Health Examiners. Dr. West is experienced as a Technical Specialist, Safety Officer, Educator, and Lead in the Veterans Administration Healthcare System, and has prior experience as an Administrative Laboratory Director. 
 
About the Course: This course is part of a series of courses adapted for the web by MediaLab Inc. under license from Educational Materials for Health Professionals Inc. Dayton OH, 45420. Copyright EMHP. It has been reviewed and revised by MediaLab Solutions in February 2024.