Skip to main content

Microbiology

Sterile Technique

Sterile technique is a cornerstone of clinical microbiology, ensuring that the specimens we analyze are truly representative of the infection we’re trying to diagnose and aren’t contaminated by external sources

Importance

  • Preventing Contamination: The primary goal of sterile technique is to prevent the introduction of extraneous microorganisms into the specimen. Contamination can lead to false-positive results, misdiagnosis, and inappropriate treatment
  • Ensuring Specimen Integrity: Sterile technique helps maintain the integrity of the specimen, ensuring that the microorganisms present are truly representative of the infection being investigated
  • Patient Safety: Minimizing the risk of introducing opportunistic pathogens during specimen collection protects the patient from potential healthcare-associated infections (HAIs)
  • Accurate Diagnosis and Treatment: Reliable and accurate test results are essential for appropriate patient care. Sterile technique is a critical component of achieving accurate results

Key Principles of Sterile Technique

  • Sterile Equipment and Supplies
    • Use only sterile collection devices, containers, and transport media
    • Check packaging for integrity before use. Do not use if the packaging is damaged or expired
  • Hand Hygiene
    • Perform thorough handwashing with soap and water or use an alcohol-based hand rub before and after specimen collection
    • Adhere to established hand hygiene protocols
  • Personal Protective Equipment (PPE)
    • Wear appropriate PPE, such as gloves, gowns, and masks, to protect both the patient and the healthcare worker from exposure to infectious agents
  • Aseptic Technique
    • Avoid touching sterile surfaces or objects with non-sterile items
    • Minimize exposure of sterile areas to the air
    • When using sterile solutions, avoid contaminating the opening of the container
  • Skin Preparation
    • Thoroughly disinfect the patient’s skin at the collection site using an appropriate antiseptic solution (e.g., chlorhexidine, iodine)
    • Allow the antiseptic to dry completely before collecting the specimen
  • Specimen Handling
    • Collect the specimen directly into a sterile container or transport medium
    • Avoid contaminating the specimen during collection
    • Properly seal and label the specimen container immediately after collection

Specific Applications of Sterile Technique in Specimen Collection

  • Blood Cultures
    • Meticulous skin preparation is essential to prevent contamination with skin flora
    • Use sterile gloves and collection devices
    • Collect blood directly into sterile blood culture bottles
  • Urine Collection (Midstream Clean Catch)
    • Provide the patient with clear instructions on proper cleansing of the genital area
    • Collect the midstream portion of the urine into a sterile container
  • Cerebrospinal Fluid (CSF) Collection (Lumbar Puncture)
    • Strict sterile technique is essential to prevent the introduction of microorganisms into the central nervous system
    • Use sterile gloves, gowns, and masks
    • Thoroughly disinfect the patient’s skin at the puncture site
    • Collect CSF into sterile tubes
  • Wound Cultures
    • Clean the wound site with sterile saline to remove surface debris
    • Collect the specimen from the base of the wound using a sterile swab or needle aspirate
    • Avoid contaminating the swab with skin flora
  • Lower Respiratory Tract Specimens (Bronchoscopy/BAL)
    • Use sterile equipment and techniques during the procedure
    • Collect specimens directly into sterile containers

Step-by-Step Procedures and Considerations

While specific steps will vary depending on the type of specimen, here’s a general framework:

  1. Preparation
    • Review the test order and collection instructions
    • Gather all necessary sterile supplies and equipment
    • Verify the patient’s identity and explain the procedure
    • Perform hand hygiene and don appropriate PPE
  2. Patient Preparation
    • Position the patient comfortably
    • Identify the collection site
    • Prepare the skin according to established protocols (antiseptic solutions, drying time)
  3. Specimen Collection
    • Using sterile technique, collect the specimen directly into the appropriate container or transport medium
    • Avoid touching non-sterile surfaces or objects with the sterile collection device
    • Minimize the risk of contamination during collection
  4. Post-Collection
    • Properly seal and label the specimen container immediately after collection
    • Remove PPE and perform hand hygiene
    • Transport the specimen to the laboratory according to established protocols

Common Errors and How to Avoid Them

  • Inadequate Hand Hygiene: Skipping or rushing hand hygiene procedures
    • Solution: Emphasize the importance of thorough handwashing or using alcohol-based hand rubs. Provide accessible hand hygiene stations
  • Compromised Sterile Packaging: Using supplies with damaged or expired packaging
    • Solution: Always check the integrity of packaging before use. Discard any compromised items
  • Touching Sterile Surfaces: Contaminating sterile collection devices or containers
    • Solution: Reinforce the importance of avoiding contact with non-sterile surfaces. Use proper technique when handling sterile items
  • Inadequate Skin Preparation: Insufficiently disinfecting the patient’s skin
    • Solution: Follow established protocols for skin preparation, including the use of appropriate antiseptic solutions and adequate drying time
  • Improper Specimen Handling: Contaminating the specimen during collection or transfer
    • Solution: Train personnel on proper specimen handling techniques. Use appropriate collection devices and containers

Documentation and Quality Control

  • Documentation
    • Record the date and time of specimen collection, the type of specimen collected, and any relevant observations or deviations from standard procedure
  • Quality Control
    • Regularly monitor adherence to sterile technique protocols
    • Track contamination rates and investigate any trends or patterns
    • Provide ongoing training and education to personnel on sterile technique
    • Periodically review and update sterile technique protocols to ensure they are consistent with current best practices

Key Terms

  • Sterile Technique: A set of practices and procedures designed to minimize the risk of introducing microorganisms into a sterile environment or specimen
  • Aseptic Technique: A broader term that encompasses all measures taken to prevent contamination, including sterile technique, hand hygiene, and the use of PPE
  • Contamination: The introduction of unwanted microorganisms into a sterile environment or specimen
  • Antiseptic: A chemical agent used to kill or inhibit the growth of microorganisms on living tissue
  • Disinfectant: A chemical agent used to kill or inhibit the growth of microorganisms on inanimate objects
  • Personal Protective Equipment (PPE): Equipment worn to minimize exposure to hazards, including gloves, gowns, masks, and eye protection