AUTHOR=Tekedar Hasan C. , Arick Mark A. , Hsu Chuan-Yu , Thrash Adam , Blom Jochen , Lawrence Mark L. , Abdelhamed Hossam 

TITLE=Identification of Antimicrobial Resistance Determinants in Aeromonas veronii Strain MS-17-88 Recovered From Channel Catfish (Ictalurus punctatus)

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=10

YEAR=2020

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2020.00348

DOI=10.3389/fcimb.2020.00348

ISSN=2235-2988

ABSTRACT=<p><italic>Aeromonas veronii</italic> is a Gram-negative species ubiquitous in different aquatic environments and capable of causing a variety of diseases to a broad host range. <italic>Aeromonas</italic> species have the capability to carry and acquire antimicrobial resistance (AMR) elements, and currently multi-drug resistant (MDR) <italic>Aeromonas</italic> isolates are commonly found across the world. <italic>A. veronii</italic> strain MS-17-88 is a MDR strain isolated from catfish in the southeastern United States. The present study was undertaken to uncover the mechanism of resistance in MDR <italic>A. veronii</italic> strain MS-17-88 through the detection of genomic features. To achieve this, genomic DNA was extracted, sequenced, and assembled. The <italic>A. veronii</italic> strain MS-17-88 genome comprised 5,178,226-bp with 58.6% G+C, and it encoded several AMR elements, including <italic>imiS, ampS, mcr-7.1, mcr-3, catB2, catB7, catB1, floR, vat(F), tet(34), tet(35), tet(E), dfrA3</italic>, and <italic>tetR</italic>. The phylogeny and resistance profile of a large collection of <italic>A. veronii</italic> strains, including MS-17-88, were evaluated. Phylogenetic analysis showed a close relationship between MS-17-88 and strain Ae5 isolated from fish in China and ARB3 strain isolated from pond water in Japan, indicating a common ancestor of these strains. Analysis of phage elements revealed 58 intact, 63 incomplete, and 15 questionable phage elements among the 53 <italic>A. veronii</italic> genomes. The average phage element number is 2.56 per genome, and strain MS-17-88 is one of two strains having the maximum number of identified prophage elements (6 elements each). The profile of resistance against various antibiotics across the 53 <italic>A. veronii</italic> genomes revealed the presence of <italic>tet(34), mcr-7.1, mcr-3</italic>, and <italic>dfrA3</italic> in all genomes (100%). By comparison, <italic>sul1</italic> and <italic>sul2</italic> were detected in 7.5% and 1.8% of <italic>A. veronii</italic> genomes. Nearly 77% of strains carried <italic>tet(E)</italic>, and 7.5% of strains carried <italic>floR</italic>. This result suggested a low abundance and prevalence of sulfonamide and florfenicol resistance genes compared with tetracycline resistance among <italic>A. veronii</italic> strains. Overall, the present study provides insights into the resistance patterns among 53 <italic>A. veronii</italic> genomes, which can inform therapeutic options for fish affected by <italic>A. veronii</italic>.</p>