The mobile gene cassette carrying tetracycline resistance genes in Aeromonas veronii strain Ah5S-24 isolated from catfish pond sediments shows similarity with a cassette found in other environmental and foodborne bacteria

Abstract

Aeromonas veronii is a Gram-negative bacterium ubiquitously found in aquatic environments. It is a foodborne pathogen that causes diarrhea in humans and hemorrhagic septicemia in fish. In the present study, we used whole-genome sequencing (WGS) to evaluate the presence of antimicrobial resistance (AMR) and virulence genes found in A. veronii Ah5S-24 isolated from catfish pond sediments in South-East, United States. We found cphA4, dfrA3, mcr-7.1, valF, blaFOX-7, and blaOXA-12 resistance genes encoded in the chromosome of A. veronii Ah5S-24. We also found the tetracycline tet(E) and tetR genes placed next to the IS5/IS1182 transposase, integrase, and hypothetical proteins that formed as a genetic structure or transposon designated as IS5/IS1182/hp/tet(E)/tetR/hp. BLAST analysis showed that a similar mobile gene cassette (MGC) existed in chromosomes of other bacteria species such as Vibrio parahaemolyticus isolated from retail fish at markets, Aeromonas caviae from human stool and Aeromonas media from a sewage bioreactor. In addition, the IS5/IS1182/hp/tet(E)/tetR/hp cassette was also found in the plasmid of Vibrio alginolyticus isolated from shrimp. As for virulence genes, we found the tap type IV pili (tapA and tapY), polar flagellae (flgA and flgN), lateral flagellae (ifgA and IfgL), and fimbriae (pefC and pefD) genes responsible for motility and adherence. We also found the hemolysin genes (hylII, hylA, and TSH), aerA toxin, biofilm formation, and quorum sensing (LuxS, mshA, and mshQ) genes. However, there were no MGCs encoding virulence genes found in A. veronii AhS5-24. Thus, our findings show that MGCs could play a vital role in the spread of AMR genes between chromosomes and plasmids among bacteria in aquatic environments. Overall, our findings are suggesting that MGCs encoding AMR genes could play a vital role in the spread of resistance acquired from high usage of antimicrobials in aquaculture to animals and humans.

Antimicrobial resistance in aeromonads and new therapies targeting quorum sensing

“…veronii MALDI-TOF* and 16 s rRNA sequencing Cephamycin, cephalosporin, amoxicillin, tetracycline cphA4 , vatF mcr-7 . 1 , bla FOX-7 , bla OXA-12 , tetE , tetR In vitro susceptibility (disk diffusion) and WGS analysis USA Dubey et al ( 2023 ) Aeromonas spp . Vitek-2 and MALDI-TOF* Ampicillin, ciprofloxacin, florfenicol, chloramphenicol, tetracycline, trimethoprim-sulfamethoxazole, gentamicin, colistin bla KPC-2 , bla NDM-1 , bla VIM-1 mcr-3 , tmexCD-toprJ In vitro susceptibility (microdilution) and WGS analysis China Wu et al ( 2023 ) Included are studies describing emerging AMR genes or trends in Aeromonas (both clinical or environmental) which were unique for the given year or geographical region during the time of publication.…”

“…veronii isolated from catfish ponds in the South-Eastern USA was found to harbor tetracycline resistance gene on a MGE, similar to ones found in Vibrio parahaemolyticus and other Aeromonas spp. isolated from human stool (Dubey et al 2023 ). When 66 Aeromonas isolates [ A .…”

Molecular characterization of Listeria monocytogenes strains isolated from imported food in China from 14 countries/regions, 2003-2018

“…The pathogenicity of foodborne bacteria is closely associated with their antibiotic resistance and virulence ( Banerji et al., 2021 ; Dubey et al., 2023 ). Strains that exhibit a strong antibiotic resistance can survive in unfavorable growth environments ( Dharmasena et al., 2021 ).…”

“…Strains that exhibit a strong antibiotic resistance can survive in unfavorable growth environments ( Dharmasena et al., 2021 ). Besides, highly virulent strains can lead to more severe disease ( Dubey et al., 2023 ). Accordingly, the antibiotic resistance and virulence of bacteria are mainly determined by the antibiotic resistance or pathogenic genes.…”