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  8. Ashraf Khan
  1. Science & Research (NCTR)

Ashraf Khan Ph.D.

Senior Biomedical Research and Biological Product Assessment Service (SBRBPAS) Expert — Division of Microbiology

Headshot of Dr. Ashraf Khan

Ashraf Khan, Ph.D.
(870) 543-7121
NCTRResearch@fda.hhs.gov  

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 About  |  Publications  |  Lab Member

Background

Dr. Ashraf Khan is a Senior Biomedical Research and Biological Product Assessment Service (SBRBPAS) expert in the Division of Microbiology at FDA’s National Center for Toxicological Research (NCTR). Dr. Khan earned Master of Science and Ph.D. degrees in biochemistry and microbiology from Aligarh Muslim University, Aligarh, India, and the Central Drug Research Institute, Lucknow, India, where his research focused on the regulation of cholera toxin by plasmid. Dr. Khan worked as a postdoctoral fellow in the Department of Biological Sciences at Oakland University on genetic pathways for biodegradation of polychlorinated biphenyls by Pseudomonas species. Dr. Khan then worked as an assistant professor at Oakland University in Rochester Hills, Michigan, where he taught medical microbiology and genetics. In 1992, Dr. Khan joined NCTR’s Division of Microbiology as a research microbiologist and since then he has worked on projects in food safety, antimicrobial-resistance mechanisms, method development, environmental biotechnology, and microbial genetics of foodborne pathogens. Dr. Khan has authored several book chapters and technical reports, and more than 118 peer-reviewed papers. He is also an editor and reviewer for several peer-reviewed journals. Dr. Khan is serving as an adjunct professor in the Department of Biological Sciences at the University of Arkansas at Little Rock, Arkansas. Dr. Khan also serves on the FDA Bacterial Detection and ID TAG Review Committee and the FDA Microbiological Method Validation Subcommittee. Dr Khan has also served as an FDA Science Forum Organizing Committee member, FDA Scientific Achievement Awards Committee member, and reviewer for the Office of Chief Scientist’s Challenge Grant.
 

Research Interests

Dr. Khan’s research addresses emerging issues in food safety, pathogen detection, antimicrobial resistance, and heavy metal resistance. Dr. Khan’s research has focused on three major areas: 

  • Researching food safety and microbial contamination of FDA-regulated products that include working to understand factors that contribute to the development and dissemination of antimicrobial resistance (AMR) and virulence phenotypes in enteric and other bacterial pathogens
  • Developing and utilizing molecular genetics and bioinformatics approaches to characterize bacterial pathogens
  • Developing rapid molecular techniques to identify foodborne pathogens from FDA-regulated products and to improve risk assessments of priority of xenobiotics by utilizing multi-omics approaches to understand the fate of xenobiotics in environment

His research projects at NCTR include:

  • Analyzing the function of efflux pump genes and their regulation in heavy metal and multidrug-resistant Salmonella enterica and Escherichia coli
  • Characterizing structural and regulatory genes responsible for antibiotic resistance, their role in low-level resistance (low minimum inhibitory concentration [MICs]), and their synergy with other resistance mechanisms (increased MICs) by analyzing efflux pump inhibition using efflux pump inhibitors
  • Whole-genome sequencing of multidrug-resistant Salmonella species isolated from food, environmental sources, and clinical sources
  • Multi-laboratory validation of isolation and identification of non-tuberculous Mycobacteria associated with tattoo-related skin infections
  • Developing a cultural method for the detection of foodborne pathogens
     

Professional Societies Membership

American Society for Microbiology
Member
1988 — Present
 

Selected Publications

Draft Genome Sequences of Nine Non-O157 Shiga Toxin-Producing Escherichia coli in Ready-to-Eat Food from Supermarkets in Argentina.
Alotaibi K., Hikal A.F., Kidon S., Zhang G., and Khan A. A.
Microbiology Resource Announcements. 2023, 12(11): e00429-23. 10.1128/MRA.00429-23.

Draft Genome Sequences of 14 Fluoroquinolone-Resistant Escherichia coli Isolates from Imported Shrimp.
Alotaibi K., Revollo J., Sung K., Miranda J.A., Khan S., Khan A.A., Nawaz M.
Microbiology Resource Announcements. 2023, https://doi.org/10.1128/mra.01116-22.

Prevalence and Molecular Characterization of Shiga-Toxin Producing Escherichia coli from Food and Clinical Samples.
Alotaibi K. and Khan A.A.
Pathogens. 2023, 12(11):1302. 10.3390/pathogens12111302.

Microbial Genetics and Clonal Dissemination of Salmonella enterica Serotype Javiana Isolated from Human Populations in Arkansas, USA.
Sanad Y.M., Aljahdali N.H., Khajanchi B.K., Nayak R., Khan A.A., and Foley S.L.
Pathogens. 2022, 11(10),1192. https://doi.org/10.3390/pathogens11101192.

Draft Genome Sequences of Tetracycline-Resistant Shiga Toxin-Producing Escherichia coli Isolates from Food.
Alotaibi K., Hu L., Revollo J., Han J., Zhang G., and Khan A.A.
Microbiology Resource Announcements. 2022, 11(7) e00218-22. https://doi.org/10.1128%2Fmra.00218-22.

Antimicrobial Resistance and Related Gene Analysis of Salmonella from Egg and Chicken Sources by Whole-Genome Sequencing.
Hu L., Guojie C., Brown E., Allard M., Ma L., Khan A.A., and Zhang G. 
Poultry Science. 2020, 99:7076-83.

Analysis of Enterotoxigenic Bacillus cereus Strains from Dried Foods Using Whole Genome Sequencing, Ulti-Locus Sequence Analysis and Toxin Gene Prevalence and Distribution Using Endpoint PCR Analysis.
Carter L., Chase H., Gieseker C., Hasbrouck N., Stine C., Khan A.A., Ewing L., Tall B., and Gopinath G.
Int J Food Microbiol. 2018, 284:31-39.

Draft Genome Sequences of Ciprofloxacin-Resistant Salmonella enterica Strains with Multiple-Antibiotic Resistance, Isolated from Imported Foods.
Khan A.A., Khajanchi B.K., Khan S.A., Elkins C.A., and Foley S.L.
Genome Announc. 2017, 5(45).

Isolation and Characterization of Antimicrobial-Resistant Nontyphoidal Salmonella enterica serovars from Imported Food Products.
Bae D., Kweon O., and Khan A.A.
J Food Prot. 2016, 79(8):1348-54.

Characterization of Extended-Spectrum Beta-Lactamase (ESBL) Producing Non-Typhoidal Salmonella (NTS) from Imported Food Products.
Bae D., Cheng C., and Khan A.
Int J Food Microbiol. 2015, 214:12-7.

Detection and Functionality of the CdtB, PltA, and PltB from Salmonella enterica Serovar Javiana.
Mezal E., Bae D., and Khan A.
Pathog Dis. 2014, 72(2):95-103.

The Sub-Species Characterization and Antimicrobial Resistance of Listeria monocytogenes Isolated from Domestic and Imported Food Products from 2004 to 2011.
Bae D., Mezal E., Smiley R., Cheng C., and Khan A.
Food Res Int. 2014, 64;656-63.

Isolation and Molecular Characterization of Salmonella enterica Serovar Enteritidis from Poultry House and Clinical Samples During 2010.
Mezal E., Sabol A., Khan M., Ali N., Stefanova R., and Khan A.
Food Microbiol. 2014, 38;67-74.

The tetA Gene Decreases Tigecycline Sensitivity of Salmonella enterica Isolates.
Akiyama T., Presedo J., and Khan A.
Int J Antimicrob Agents. 2013, 42(2):133-40.

Isolation and Characterization of Small qnrS1-Carrying Plasmids from Imported Seafood Isolates of Salmonella enterica that are Highly Similar to Plasmids of Clinical Isolates.
Akiyama T. and Khan A.
FEMS Immunol Med Microbiol. 2012, 64(3):429-32.

Molecular Characterization of Strains of Fluoroquinolone-Resistant Salmonella enterica Serovar Schwarzengrund Carrying Multidrug Resistance Isolated from Imported Foods.
Akiyama T. and Khan A.
J Antimicrob Chemother. 2012, 67(1):101-10.

Molecular Characterization of Salmonella enterica Serovar Saintpaul Isolated from Imported Seafood, Pepper, Environmental and Clinical Samples.
Akiyama T., Khan A., Cheng C., and Stefanova R.
Food Microbiol. 2011, 28(6):1124-8.

Identification and Characterization of Class 1 Integron Resistance Gene Cassettes Among Salmonella Strains Isolated from Imported Seafood.
Khan A., Ponce E., Nawaz M., Cheng C., Khan J., and West C.
Appl Environ Microbiol. 2009, 75(4):1192-6.

Occurrence of Non-O157 Shiga Toxin-Producing Escherichia coli in Ready-to-Eat Food from Supermarkets in Argentina.
Balague C., Khan A., Fernandez L., Redolfi A., Aquili V., Voltattorni P., Hofer C., Ebner G., Duenas S., and Cerniglia C.
Food Microbiol. 2006, 23(3):307-13.

Classification of a Polycyclic Aromatic Hydrocarbon-Metabolizing Bacterium, Mycobacterium sp. Strain PYR-1, as Mycobacterium vanbaalenii sp. nov.
Khan A., Kim S., Paine D., and Cerniglia C.
Int J Syst Evol Microbiol. 2002, 52(Pt 6):1997-2002.

Characterization of United States Outbreak Isolates of Vibrio parahaemolyticus Using Enterobacterial Repetitive Intergenic Consensus (ERIC) PCR and Development of a Rapid PCR Method for Detection of O3:K6 Isolates.
Khan A., McCarthy S., Wang R., and Cerniglia C.
FEMS Microbiol Lett. 2002, 206(2):209-14.
 

Lab Member

Contact information for all lab members:
(870) 543-7121
NCTRResearch@fda.hhs.gov  

Ahmed Hikal, Ph.D.
Postdoctoral Fellow

Contact Information
Ashraf Khan
(870) 543-7121
Expertise
Expertise
Approach
Domain
Technology & Discipline
Toxicology
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