Tips for Aseptic Technique in the Laboratory -- An Introduction to Aseptic Technique (Part 1 of 4)

Cara N. Wilder, Ph.D.

When working in a microbiology laboratory, aseptic technique is fundamental to the success and safety of an experiment.  Generally, aseptic techniques are procedures or processes performed by scientists under sterile conditions to ensure that microbial contaminants do not harm colleagues and are not introduced into sterile solutions, supplies, or experimental cultures.  To minimize the possibility of microbial contamination, ATCC recommends the following practices listed below.  Additional information on risk assessment and precautions can be found in the Center for Disease Control (CDC) publication "Biosafety in Microbiological and Biomedical Laboratories, (BMBL)" at http://www.cdc.gov/biosafety/publications/bmbl5/BMBL.pdf. 

The unsafe practice of mouth-pipetting
Photo Provider: CDC/Dr. David Sencer

What to Avoid

• Obtaining microbial strains from colleagues
• Excessive subculturing of microbial strains
• Eating or drinking in the laboratory
• Handling contact lenses and cosmetics in the lab
• Mouth-pipetting media or cultures
• Pouring media
• Sharing media and reagents with colleagues
• Leaving cultures and agar plates exposed to the environment

   

What to Do

• Obtain microbial strains from an authenticated, trusted source
• Wear proper protective clothing
• Disinfect your work space before and after use
• Wash hands before and after handling any microbial cultures
• Work in a biosafety cabinet
• Use sterilized media, equipment, and reagents
• Sanitize the outer surface of reagents before use
• Transfer media and reagents using sterile pipettes
• Locate and use biosafety hazard waste-bins and sharps containers closest to you
• Sterilize and discard all microbial waste in accordance to appropriate biosafety standards
• Handle one culture at a time
• Clean up all spills immediately and properly disinfect the surrounding area

Additional information on aseptic technique will be further discussed in subsequent installments:
Tips for Aseptic Technique in the Laboratory -- Handling Microbial Cultures and Media (Part 2 of 4)
Tips for Aseptic Technique in the Laboratory -- Personal Protection and Cleanliness (Part 3 of 4)
Tips for Aseptic Technique in the Laboratory -- Biosafety Cabinets (Part 4 of 4)

Walking the fine line between cleanliness and sterility -- When is the time for aseptic technique?

Cara N. Wilder, Ph.D.

Photo provider: CDC/Kimberly Smith, Christine Ford

From the time we are very young, we are taught the aphorism "cleanliness is next to godliness".  Even now, we are bombarded by media advertising disinfecting wipes, anti-microbial soaps, and anti-bacterial hand-gels to sterilize every aspect of our daily life.  However, is this idea always the best policy for establishing a healthy lifestyle?  When is the time for aseptic technique versus general cleanliness?

Aseptic technique refers to the processes or procedures that are performed under sterile conditions.  Under these conditions, your equipment or local environment should be free of pathogenic microorganisms.  These techniques are routinely employed in both medical and laboratory environments where contamination with pathogenic microorganisms can result in hazardous conditions.  Aseptic techniques are also commonly used on a regular basis while dressing minor injuries or for the prevention of viral transmission during seasonal cold and flu epidemics.  But, how should we handle the daily messes, dirt, and grime that we come in contact with?  When does creating a sterile environment adversely affect your health?

Early childhood is when most individuals begin to interact with their environment and learn how to walk, speak, and develop proper eating and cleaning habits.  This critical stage in life is also when the immune system begins to develop and become the first line of defense against invading microorganisms.  It is at this developmental juncture where it is crucial that an individual is exposed to the vast array of naturally occurring microorganisms in the environment in order to not only establish a healthy microbial flora, but to enhance the maturation of the immune system.  

In medicine, the hygiene hypothesis states that the lack of early childhood exposure to environmental microorganisms increases the susceptibility to allergic disease via suppressing the natural development of the immune system.  In a recent study (Hanski et al., PNAS 2012), this concept was further advanced by the idea that "reduced contact of people with natural environmental features and biodiversity, including environmental microbiota, leads to inadequate stimulation of immunoregulatory circuits".  In this study, the allergic disposition (atopic sensitization) was analyzed in a random sample of adolescents living in a heterogeneous region.  They found that as compared to healthy individuals, atopic teens had lower environmental biodiversity in their surroundings in addition to significantly lower genetic diversity of gammaproteobacteria within their skin microflora.  These results correlated with the expression of IL-10, a key anti-inflammatory cytokine involved in immunological tolerance.  Generally, IL-10 expression was positively related with the abundance of gammaproteobacteria localized on the skin of healthy individuals.  Overall, these results suggest that environmental biodiversity, the human microbiome, and the human immune system are complex interwoven systems whose interactions are crucial for overall health and general well-being.  These results also suggest that the lack of environmental biodiversity is strongly associated with the development of allergies.

All in all, life can get a little messy -- what is important is how you deal with the mess.  Sometimes, a little dirt can go a long way.   

The intersection between Microbiology and society

Cara N. Wilder, Ph.D.

Billions of years ago, after the formation and natural development of primitive Earth, prokaryotic life evolved from the primordial ooze.  These ancient microbes survived in Earth’s anaerobic atmospheric conditions, thriving in this primeval, toxic environment.  Over time, the evolution of cyanobacteria led to the generation of life-sustaining oxygen via the hydrolysis of water during photosynthesis.  This microbial production of oxygen paved the way for the emergence of humans and the diverse group of animal species we see today.

The development and maintenance of life as we know it would not have been possible without the evolution and current presence of microorganisms.  It is because of the high reverence for microbial life harbored by scientists at ATCC, that for over 85 years this organization has been a leading innovator in microbial scientific discovery and a trusted resource of microbiological materials.  Our mission at ATCC is to acquire, authenticate, preserve, develop and distribute biological materials, information, technology, intellectual property and standards for the advancement and application of scientific knowledge. 

It is ATCC’s hope that this forum will serve as an intersection between Microbiology and society as a means to promote knowledge, the exchange of ideas, and interaction between scientists.  We hope to ignite an interest in budding scientists and fuel the passion and microbial veneration in mature microbiologists.  For as we know, microbes were here long before the emergence of humans and they will continue to thrive long after we are gone.  So in the meantime, we should try to get to know them a little better!