A Study Of Airborne Bacterial Diversity In Washington D.C. Using Non-Culture Based Techniques

EPA Grant Number: MA916979
Title: A Study Of Airborne Bacterial Diversity In Washington D.C. Using Non-Culture Based Techniques
Investigators: Velez-Quinones, Maria A
Institution: Howard University
EPA Project Officer: Lee, Sonja
Project Period: September 1, 2008 through August 31, 2011
RFA: GRO Fellowships for Graduate Environmental Study (2008) RFA Text |  Recipients Lists
Research Category: Academic Fellowships


We may or may not know about the presence of microbes in every environment even in the air we breathe. Most of us use detergents and antimicrobial agents to eliminate microbes from kitchen counters, floors, bathrooms, and virtually anything we are in contact with. In some time of our life we have heard about bacterial organisms like Anthrax, Pneumonia, and Salmonella and their negative impacts in human health. On the other hand, not all of the microbes are bad, microbes like the ones we find in cheese and yogurt are known to help us during our digestion processes, equally many other microbes have positive impacts in health and food production. Even though, microorganisms are recognized to play a mayor role in the support and maintenance of life on Earth, many of them can be a mayor threat to the environment and human survival.


In the case of a disease caused by bacterial contamination of food, before any treatment is applied, the causing agent of the disease needs to be identified. With the correct identification of the bacteria a better treatment could be determined and a prevention plan could be establish to avoid global spread of the disease. In the past few decades, the identification of these bacteria has evolved from traditional techniques which involve culturing and multiple tests, to the use of genetic identification. The traditional techniques are very arduous and take days to weeks to be completed and the identification of the bacterial agent are rarely accurate. With increased knowledge of genetics, scientists have been able to extract the bacterial DNA (genetic code) directly from soil, water, and the human body for identification of the bacterial species. The implementation of these non-culture based genetic identification has permitted a fast and more accurate identification of bacterial species, which in the case of a disease will immediately lead to a prompt treatment response plan.

Expected Results:

Scientist have found that many microbes are able to be transported in the air and at this moment, only traditional techniques have been used to identify bacteria carried by the wind in indoor and outdoor environments. For our study we collected outdoor air samples in an urban area of Washington D.C. for a complete year. These samples will be used to develop a quick and original protocol to characterize bacteria carried in the air and identify them using a non-culture genomic identification technique. This technique will allow us to identify the bacterial species within the air without the time taken traditional identification tests. We believe this study will reveal a far higher variety of airborne bacteria than has been detected by culturing techniques. The overall goal is to catalog all the bacteria present in the air from one year of continuous air sample collection and try to detect, if any, seasonal variations within the bacterial species assuming the types of bacteria in the air might change depending of the season, weather and other environmental changes. This study can be used to predict an increase in the concentration of bacteria that can cause diseases like human respiratory infections, in the Washington, D.C. metro area and the environmental conditions that make suitable their presence at the site of collection.

Progress and Final Reports:

  • 2009
  • 2010
  • Final