Welcome to the Falkinham lab. We are located in Derring Hall, the home of the Department of Biological Sciences at Virginia Tech.
Since 1975, research in the Falkinham lab has focused on describing the epidemiology, ecology, physiology, and genetics of Nontuberculous Mycobacteria (NTM) in particular Mycobacterium avium and Mycobacterium intracellulare (the M. avium complex, MAC) and Mycobacterium abscessus (see NTM and MAC Epidemiology). NTM are environmental microbes that are responsible for life-threatening infections in AIDS patients, cervical lymph node infections in children, and pulmonary infections, particularly in slender, older women and individuals with cystic fibrosis. (www.ntminfo.com) The source of M. avium, M. intracellulare, M. abscessus, and other NTM infection is the environment. NTM, including M. avium, M. intracellulare, and M. abscessus have been recovered from natural waters, drinking waters, soils, potting mixes and peats, and aerosols and dusts. DNA fingerprinting has been used to show that M. avium, M. intracellulare, and M. abscessus isolates from environmental samples (e.g., water, pipe biofilms, and potting soils) that patients had been exposed, had the same DNA fingerprint as the isolate recovered from the patient. We have shown that M. avium isolates from shower water had the same DNA fingerprint as those from a patient with M. avium pulmonary disease (Falkinham et al., 2008). Water is not the only proven source of M. avium infection. DNA fingerprints from M. avium isolates recovered from aerosols of potting soils were identical to M. avium isolates recovered from patients who had worked with the soils (De Groote et al., 2007).
Just last year with financial support from the Nontuberculous Mycobacteria Information and Research, Inc. Foundation , we completed a study of NTM in household plumbing of patients with NTM pulmonary disease. Plumbing of 17 households of 37 NTM patients (46 %) was colonized with NTM belonging to the same species as that from the patient. Further, in 7 of the 17 households (41 %), the DNA fingerprint of at least one of the plumbing isolates was identical to that isolate from the patient (Falkinham, 2011). That data strongly supports the notion that households are a source of NTM infection.The continuing focus of NTM research in the lab is to identify the genetic and physiologic factors that permit their survival and growth in the environment. Below are listed current individual research projects.
A second project is in partnership with colleagues at the University of North Carolina - Greensboro (Dr. Nicolas Oberlies) and the Jordan University of Science and Technology (JUST) in Irbid, Jordan (Dr. Feras Alali). This research was initiated by a grant from the Fogarty Center of NIH through the Internation Cooperative Biodiversity Groups (ICBG) program. The research is focused on the identification of novel anti-microbial, anti-cancer, and anti-central nervous system (CNS) compounds produced by bacteria that can prey on other microorganisms. These bacteria, called Predators, can grow in laboratory medium but can also grow on other microorganisms as a sole source of nutrient. Some kill by attachment and introduction of antimicrobial compounds. The Falkinham lab is focusing on those Predators that produce extracellular antimicrobial compounds. This work led to the discovery of an antibiotic "Red Soil" from Jordan used by Jordanians to treat skin infections. The antibiotic activity of this soil is due to the presence of antimicrobial-producing bacteria whose growth is stimulated by the presence of other bacteria, in particular those causing skin infections such as Staphylococcus aureus. Upon encountering S. aureus, the antibiotic-producing bacteria in "Red Soil" are stimulated to grow and produce high concentrationsof antibiotics (Falkinham et al., 2005). Our natural product chemist colleagues at UNC-G and JUST have been identifying the anti-microbial, anti-cancer, and anti-CNS compounds. The research with Predator bacteria was initiated with a contract from Dominion BioSciences, Inc. and has led to the identification of a novel, broad-spectrum anti-fungal agent (i.e., burkholdines, Schmidt et al., 2010) for treating fungal diseases of crop and ornamental plants. Below are listed current individual research projects.
Out of our collaboration with Dr. Oberlies (UNC-G) and Dr. Allali (JUST) the lab developed the methods for measurement of antimicrobial activity of a variety of materials. That has led to our participation in antibiotic-design and development efforts with colleagues in the Virginia Tech Department of Chemistry. Current collaborations are with Dr. Richard Gandour and his students who have designed and synthesized dendritic amphiphiles; molecules with long fatty acid chains (C13-C30) that are soluble due to the presence of polar head groups. These studies are now being extended to identify the molecular basis for the activity of these antimicrobial dendritic amphiphiles. With Dr. Joe Merola and his student, George Karpin, we are carrying out structure-function studies of antimicrobial platinium group, transition metal complexes. We are currently developing the skills to measure the cytotoxicity of these two different, but highly active, series of novel antibiotics.
Right-click the image above to download the PowerPoint from a webinar Dr. Falkinham participated in on December 10, 2015!