Research Microbiologist — Division of Microbiology

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

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 About  |  Publications  |  Lab Member

Background

Dr. Saeed Khan received his Ph.D. from Banaras Hindu University, India in 1989 and postdoctoral training in the Department of Biochemistry at the University of Texas Health Science Center at San Antonio. He joined the Division of Microbiology at the National Center for Toxicological Research (NCTR) in 1997 as a visiting scientist and is currently serving as a research microbiologist. Dr. Khan recently finished a study that was funded by the Collaborative Opportunities for Research Excellence in Science (CORES) and developed in collaboration with FDA’s Center for Drug Evaluation and Research (CDER) and Center for Devices and Radiological Health (CDRH) that involved studying the susceptibility of mice to Listeria infection after a prolonged exposure of mice to silver, gold, and silica nanoparticles. Currently, Dr. Khan is working on a project that involves whole genome sequencing and proteomic approaches to identify genetic markers associated with virulence and biofilm formation in human clinical methicillin-resistant Staphylococcus aureus (MRSA) isolates. Earlier, Dr. Khan’s work on Bacillus anthracis that was funded by the Department of Homeland Security-USDA/FSIS was lauded by FDA and included in the FDA’s Food Protection Plan in 2008. It was also chosen by the American Society for Microbiology and the American Chemical Society (ACS) for press releases. Throughout his tenure at NCTR, he has received several FDA and NCTR awards, including the recent NCTR Director’s Award for Excellence in Laboratory Sciences and an FDA Award for Leveraging and Collaboration.

He has also served as a panel member on the FDA Science Genomics Symposium and an invited speaker at the both the FDA Center for Veterinary Medicine-sponsored General Public Meeting and the National Antibiotic Resistance Monitoring System (NARMS) meeting. He was invited by the Animal Plant and Fisheries Quarantine and Inspection Agency, Government of Korea, to present several talks on the isolation of different foodborne pathogens. Dr. Khan has also fostered a cooperative relationship between NCTR and the Higher Education Commission of Pakistan (HECP). Dr. Khan has also received several requests from the organizers of international meetings to be an invited speaker and he serves as an editorial board member for various journals.

Research Interests

Dr. Khan’s research interests and expertise include microbial physiology phages, and molecular biology of host-pathogen interactions, gene-expression studies, antimicrobial resistance, and genome comparisons. Dr. Khan uses state-of-the-art molecular tools to study host-pathogen interactions, gene-expression analysis, and antimicrobial-resistance genes in foodborne, animal, and human clinical isolates. He uses biochemical, molecular, and whole genome sequencing techniques to characterize bacterial isolates from different ecological niches. He also uses the real--time PCR analysis to study the expression of efflux pump and antimicrobial resistance genes and developed quantitative multiplex PCR assays to detect multiple antimicrobial resistance markers. He uses sequencing tools to study the mutations in genes responsible for fluoroquinolone resistance in bacteria from a variety of sources and also uses the next generation sequencing for several multidrug-resistant human clinical staphylococcal and enterococcal isolates. Currently, Dr. Khan is studying the differences among MRSA isolates that produce biofilms and carry a multitude of virulence and antimicrobial resistance factors, persistence of infection, survivability, diversity, and virulence using the whole genome sequencing techniques, proteomic profiles, and adhesion assays. Other projects that he is working in collaboration with scientists in the Division of Microbiology involve the mechanism of biofilm formation by S. aureus and uropathogenic E. coli. The research goals include understanding the mechanism of antimicrobial resistance, virulence, pathogenicity, and genetic evolution with a scope of developing countermeasure and mitigation strategies to control the spread of multidrug-resistant bacteria and help the Agency in making science-based prudent decisions for regulatory needs. 

Professional Societies/National and International Groups

American Society for Microbiology
Member
1997 – Present 

Arkansas Biotechnology Association
Member
1997 – Present 
 
Escherichia coli Coalition Group
Member
2010 – Present 

International Association for Food Protection
Member
2012 – Present
 

Selected Publications

Genotypic Characterization of Clinical Isolates of Staphylococcus aureus from Pakistan. 
Khan S., Marasa B., Sung K., and Nawaz M. 
Pathogens. 2021, 10, 918.

Dynamic Adaptive Response of Pseudomonas aeruginosa to Clindamycin/Rifampicin-Impregnated Catheters. 
Sung K., Chon J.W., Kweon O., Nho S., Kim S.J., Park M., Paredes A., Lim J.H., Khan S., Phillips K.S., and Cerniglia C.E. 
Antibiotics. 2021, 10(7), 752.

Molecular Typing of β-lactamase and Tetracycline Resistant Escherichia coli Strains Isolated from Imported Shrimp. 
Khan S., Campbell M., Khan A., Sung K., Altaibi K., Khan S., and Nawaz M. 
Journal of Bacteriology and Mycology. 2019, 6(3):1102.

Prevalence, Toxin Gene Profile, Antibiotic Resistance, and Molecular Characterization of Clostridium perfringens from Diarrheic and Non-Diarrheic Dogs in Korea.
Chon J., Seo K., Bae D., Park J., Khan S., and Sung K.
J Vet Sci. 2018, 19(3):368-374. doi: 10.4142/jvs.2018.19.3.368.

Investigating the Susceptibility of Mice to A Bacterial Challenge after Intravenous Exposure to Durable Nanoparticles.
Khan S., Zhang Q., Marasa B., Sung K., Cerniglia C., Ingle T., Jones M., Paredes A., Tobin G., Bancos S., Weaver J., Goering P., Howard P., Patri A., and Tyner K.
Nanomedicine (Lond). 2017, 12(17):2097-2111. doi: 10.2217/nnm-2017-0176.

Evaluating the Potential of Gold, Silver, and Silica Nanoparticles to Saturate Mononuclear Phagocytic System Tissues Under Repeat Dosing Conditions.
Weaver J., Tobin G., Ingle T., Bancos S., Stevens D., Rouse R., Howard K., Goodwin D., Knapton A., Li X., Shea K., Stewart S., Xu L., Goering P., Zhang Q., Howard P., Collins J., Khan S., Sung K., and Tyner K.
Part Fibre Toxicol. 2017, 14(1):25. doi: 10.1186/s12989-017-0206-4.

Diversity of Clostridium Perfringens Isolates from Various Sources and Prevalence of Conjugative Plasmids.
Rafii F., Park M., Steven M., Foley L., Nayak R., Glenn J., Songer J., Seibel M., Khan S., Alejandro P., and David W.
Anaerobe. 2016, 38:25-35.

Draft Genome Sequence of Multidrug-resistant Enterococcus faecium Clinical Isolate VRE3, ST16, with Novel Structural Arrangement of Tn1546.
Khan S., Sung K., Marasa B., Min S., Kweon O., Nawaz M., and Cerniglia C.
Genome Announc. 2015, 3(4): e00871-15.

Draft Genome Sequence of a Methicillin-Resistant Staphylococcus aureus ST1413 Strain for Studying Genetic Mechanisms of Antibiotic Resistance.
Bernard S., Revollo J., lram S., Sung K., Xu J., and Khan S.
Genome Announc. 2014, 2(2): e00162-14.

Molecular Characterization of Fluoroquinolone-Resistant Aeromonas spp. Isolated from Imported Shrimp.
Shakir Z., Khan S., Sung K., Khare S., Khan A., Steele R., and Nawaz M.
Appl Environ Microbiol. 2012, 78(22):8137-41.

A Transcriptomic Expression Array, PCR and Disk Diffusion Analysis of Antimicrobial Resistance Genes in Multidrug-Resistant Bacteria.
Khan S., Sung K., and Nawaz M.
Agriculture, Food and Anal Bacteriol. 2011, 1(2):123-39.

Lysozyme as a Barrier to Growth of Bacillus anthracis Strain Sterne in Liquid Egg White, Milk and Beef.
Sung K., Khan S., Nawaz M., Cerniglia C., Tamplin M., Phillips R., and Kelley L.
Food Microbiol. 2011, 28(6):1231-4.

Detection of aacA-aphD, qacEδ1, marA, floR, and tetA Genes from Multidrug-Resistant Bacteria: Comparative Analysis of Real-Time Multiplex PCR Assays Using EvaGreen® and SYBR® Green I Dyes.
Khan S., Sung K., and Nawaz M.
Mol Cell Probes. 2011, 25(2-3):78-86.

Detection and Characterization of Virulence Genes and Integrons in Aeromonas veronii Isolated from Catfish. 
Nawaz M., Khan S., Khan A., Sung K., Quynhtien T., Kerdahi K., and Steele R.
Food Microbiol. 2010, 27(3):327-31.

The Survivability of Bacillus anthracis in Processed Liquid Eggs.
Khan S., Sung K., Nawaz M., Cerniglia C., Tamplin M., Phillips R. and Kelly L.
Food Microbiol. 2009, 26(2):123-7.

Genetic Diversity of Tn1546-Like Elements in Clinical Isolates of Vancomycin-Resistant Enterococci.
Sung K., Khan S., and Nawaz M.
Int J Antimicrob Agents. 2008, 31(6):549-54.

Heteroresistance to Vancomycin and Novel Point Mutations in Tn1546 of Enterococcus faecium ATCC 51559.
Khan S., Sung K., and Nawaz M.
Int J Antimicrob Agents. 2008, 31(1): 27-36.

Direct In-Gel Hybridization of DNA with Digoxigenin-Labeled Probes. In Protocols for Nucleic Acid Analysis by Nonradioactive Probes.
Khan S. and Nawaz M.
Methods Mol Biol. 2007, 353:93-103.

Characterization of Class 1 Integron Resistance Gene Cassettes in Salmonella enterica Serovars Oslo and Bareily from Imported Seafood.
Khan A., Cheng C., Van K., West C., Nawaz M., and Khan S.
J Antimicrob Chemother. 2006, 58(6):1308-10.

Molecular Characterization of Multidrug-Resistant Enterococcus spp. from Poultry and Dairy Farms: Detection of Virulence and Vancomycin Resistance Gene Markers by PCR.
Khan S., Nawaz M., Khan A., Hopper S., Jones R., and Cerniglia C.
Mol Cell Probes. 2005, 19(1):27-34.
 

Lab Member

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

Kidon Sung, Ph.D.
Staff Fellow

Miseon Park, Ph.D.      
Staff Fellow