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P2-128 Phylogenomic Analyses of Efflux Pump Complexes in the Foodborne Pathogen Cronobacter spp. Using DNA Microarray Analysis Combined with Sequenced-based Bioinformatics Demonstrates the Presence of Species-Specific Orthologues.

Tuesday, July 11, 2017
Exhibit Hall (Tampa Convention Center)
Flavia Negrete , U.S. Food and Drug Administration , Laurel , MD
Jayanthi Gangiredla , U.S. Food and Drug Administration , Laurel , MD
Samantha Finkelstein , U.S. Food and Drug Administration , Laurel , MD
Isha Patel , U.S. Food and Drug Administration , Laurel , MD
Hannah Chase , U.S. Food and Drug Administration , Laurel , MD
ChaeYoon Lee , U.S. Food and Drug Administration , Laurel , MD
HyeJin Jeong , U.S. Food and Drug Administration , Laurel , MD
Ben Tall , U.S. Food and Drug Administration , Laurel , MD
Gopal Gopinath , U.S. Food and Drug Administration , Laurel , MD
Introduction: Cronobacter spp. cause disease in humans of all ages, but is most noted for causing infantile foodborne outbreaks. Microorganisms express a wide range of transmembrane complexes known as efflux pumps (EPs) that influence their survival under stressful growth conditions.  Additionally, through active efflux EPs are also involved in antimicrobial resistance to a variety of antibiotics, disinfectants, and preservatives. To date very little is known about EPs among Cronobacterspp.

Purpose: This project employed both microarray analysis (MA) and whole genomic sequencing (WGS) in an effort to provide a deeper understanding of the phylogeny of EPs found among Cronobacterspp.

Methods: One hundred thirty-nine Cronobacter strains were analyzed using a previously described pan-genomic DNA microarray which contained 37 EP probe sets representing 13 different EPs.  Using the microarray annotations for these genes, gene sequences for three of these EPs, namely, kefA (a potassium efflux system), a resistance/nodulation/division (RND) EP gene, and cmeB (a tranporter) were bioinformatically captured by searching a local database of previously sequenced Cronobactergenomes.  Phylogenetic analysis of these sequences was conducted using the Maximum Composite Likelihood method in Genomics CLC and MEGA7.

Results: MA revealed that the prevalence of the 37 efflux pumps followed evolutionary species lines which were previously noted.  WGS analysis of sequences for kefA, the RND EP, and cmeB, supported this phylogenetic relationship found by MA.

Significance: Understanding the genomic landscape of EPs among Cronobacter spp. is essential for future studies designed to identify mechanisms used by Cronobacter spp. to survive and persist under stressful growth conditions. The results reported here demonstrate that Cronobacter species have at least 37 efflux pumps and that all of the species possess species-specific orthologues; that these genes most probably arose from a common hypothetical ancestor; and their identification is critical for reliable prediction of gene function.

Back to: Poster Session 2 – Food Chemical Hazards and Food Allergens, Food Toxicology, Meat, Poultry and Eggs, Epidemiology, Retail and Food Service Safety, Communication Outreach and Education, Molecular Analytics, Genomics and Microbiome, Laboratory and Detection Methods, and Dairy
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