CAP Pro Course - Microbiology - Organism Detection and Differentiation Using the Gram Stain

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Author: Hallee Waye, BS, MLS (ASCP)CM
Reviewer: Alexandru Casapu, MBA, MLS(ASCP)CM, PBTCM

Continuing Education Credits

Objectives

  • Describe and differentiate the procedures used to prepare and perform Gram stains both manually and using an automated stainer.
  • Discuss proper frequency and performance of quality control for Gram stain reagents.
  • Interpret and identify bacterial and non-bacterial elements on direct gram-stained smears to evaluate specimen quality when appropriate, provide preliminary identification of organisms, and guide culture workup.
  • Differentiate artifacts/questionable elements and identify significant findings seen on gram-stained smears.
  • Defend the need for stat preparations and timely, accurate reporting of gram-stained smears, including the specimens and/or the organism types for which this is optimal.

Course Outline

  • Describe and differentiate the procedures used to prepare and perform Gram stains both manually and using an automated stainer.
      • Principle of the Gram Stain
      • Information Provided by a Gram Stain
      • Preparation of a Clinical Specimen or Culture Isolate for Gram Stain
      • Gram Stain Procedure
      • When interpreting an appropriately stained Gram stain slide, a bacterium that is able to retain the primary stain will exhibit what color?
      • How many organisms per g or mL must be present for a Gram stain to be positive for a bacterium or fungal organism?
      • Which of the following statements about microscope use when interpreting Gram stains is true?
      • While working on the set-up bench in the microbiology laboratory, you receive 1000 mL of a pleural fluid specimen that is yellow and clear. You would ...
      • Which description of the Gram stain process is true?
  • Discuss proper frequency and performance of quality control for Gram stain reagents.
      • Producing Quality Gram Stains
      • Appropriate Quality Control (QC) Slides for Reagent Testing and Competency Testing of Personnel Performing Gram Stains
      • Troubleshooting Problem Gram Stains
      • At a minimum, how frequently must Gram stain QC be performed?
      • When interpreting a Gram stain, there is not much observed on the slide, even though the fluid is described in the laboratory information system (LIS)...
      • While reviewing Gram stain smears, everything on the slide appears pink/red, as shown in the image. What is the most likely cause of this problem and...
      • An expectorated sputum sample is received in the laboratory for routine culture. The image shows a field representative of the smear. What score shoul...
  • Interpret and identify bacterial and non-bacterial elements on direct gram-stained smears to evaluate specimen quality when appropriate, provide preliminary identification of organisms, and guide culture workup.
      • Evaluating the Quality of Respiratory Samples
      • Sputum Gram Stain Findings
      • Urine Screens
      • Non-Bacterial Elements Encountered on Gram-Stained Smears
      • Pathogens Commonly Encountered on Gram Stains by Site/Specimen
      • Pathogens Commonly Encountered on Gram Stains by Site/Specimen, continued
      • Gram Stain Results: Interpretation and Quantitation
      • When interpreting a Gram stain from a sputum specimen, contamination from the oral cavity is suspected. Which of the following cells if increased woul...
      • Which of the following items, when found on a Gram stain, is not an indicator of pathology?
      • This image is representative of the predominant organism observed on the original Gram stain from a cerebrospinal fluid specimen. What is the most lik...
      • This image is representative of an average 1000X oil immersion field on a urine Gram stain. How should this be reported to the physician?
      • A lower respiratory sample is received for a routine aerobic culture, but the specimen type is missing on the sample and the requisition. When you cal...
      • When performing a Gram stain, bacterial cells inside of a phagocytic cell may be seen. Which of the following cell types is not phagocytic?
      • While reviewing a sputum Gram stain, you see fields that are comparable to the image on the right. What infection is most likely indicated by this Gra...
  • Differentiate artifacts/questionable elements and identify significant findings seen on gram-stained smears.
      • Artifacts/Questionable Elements Observed on Gram Stains
      • Significant Gram Stain Findings: Intracellular Organisms
      • Possible Outcomes Suggested by Gram Stain Appearance or Recovery in Certain Specimens
      • Which of the following may be indicated by Charcot-Leyden crystals in a respiratory specimen?
      • Small, pale gram-negative coccobacilli are seen intracellularly in a cerebrospinal fluid. What organism does this most likely indicate?
      • What is the identity of the artifact in the image to the right?
      • The large structure in the image to the right was seen on a respiratory Gram stain. What is the structure and when is it typically seen?
  • Defend the need for stat preparations and timely, accurate reporting of gram-stained smears, including the specimens and/or the organism types for which this is optimal.
      • Specimens for Which Stat Gram Stains are Necessary or Optimum
      • Gram Stain Reporting
      • Timely Reporting of Direct Gram Stains
      • Gram Stain Results From Culture Isolates: When Preliminary Reports are Warranted Before Identification is Complete
      • Which of the following sources would not require a stat Gram stain?
      • Which of the following pieces of information must be reported in a direct specimen Gram stain?
  • References
      • References

Additional Information

Level of Instruction: Intermediate
Intended Audience: This program is designed as an educational and training tool for MLS, MT, and MLT personnel, medical laboratory science students and interns, pathology residents, and practicing pathologists.
Author Information: Hallee Waye, BS, MLS (ASCP)CM, has over 10 years of experience as a medical laboratory scientist. She has clinical experience in blood bank, microbiology, chemistry, hematology, urinalysis, and coagulation. She currently works as a clinical microbiologist and MLS Program Director for the Parkview School of Medical Laboratory Science in Pueblo, CO. She obtained her bachelor’s degree in microbiology from Colorado State University, attended the Colorado Center for Medical Laboratory Science to obtain her professional certificate in medical laboratory science, and completed her master’s degree in clinical laboratory science at the University of Texas Rio Grande Valley.
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 Clinical Laboratory Technology Program at Georgia Piedmont Technical College. He is currently a Program Director at MediaLab, Inc. Alex holds BS degrees in Biology and Medical Technology from Clark Atlanta University and an MBA from the University of Georgia.

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