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ARS Home » Plains Area » College Station, Texas » Southern Plains Agricultural Research Center » Food and Feed Safety Research » Research » Publications at this Location » Publication #378061

Research Project: Ecological Reservoirs and Intervention Strategies to Reduce Foodborne Pathogens in Cattle and Swine

Location: Food and Feed Safety Research

Title: Whole genome sequence of Aeromonas hydrophila CVM861 isolated from diarrheic neonatal swine

item Poole, Toni
item SCHLOSSER, WAYNE - Food Safety Inspection Service (FSIS)
item Anderson, Robin
item NORMAN, KERI - Texas A&M University
item Beier, Ross
item Nisbet, David

Submitted to: Microorganisms
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/21/2020
Publication Date: 10/24/2020
Citation: Poole, T.L., Schlosser, W.D., Anderson, R.C., Norman, K.N., Beier, R.C., Nisbet, D.J. 2020. Whole genome sequence of Aeromonas hydrophila CVM861 isolated from diarrheic neonatal swine. Microorganisms. 8(11). Article 1648.

Interpretive Summary: Bacteria that cause disease (pathogens) in humans and animals are becoming more resistant to antibiotics. This has produced public health concerns because diseases once thought largely under control are reappearing. To eliminate or minimize diseases, it is necessary to know where pathogens live and how they move through the environment. Members of the genus Aeromonas are bacteria that naturally live in water systems from sewage to water treatment systems. However, they have been identified throughout many environmental habitats. Some strains tolerate refrigerator temperatures and have been found on vegetables and meat, including ready-to-eat packaged meats. Since they are found on food, they have a pathway to cause foodborne diseases in people. Aeromonads naturally carry genes that cause severe disease (virulence genes). Aeromonas species are called opportunistic pathogens, meaning they can cause diseases when an individual’s immune system has been weakened, but they can also cause severe disease in normal healthy people. Some of the severe infections include, diarrhea, blood and heart infections, flesh-eating disease, and a blood disease that damages kidneys (hemolytic-uremic syndrome HUS). We found an Aeromonas hydrophila strain in neonatal piglets with diarrhea. This strain was named, CVM861 and was found to be resistant to many antibiotics when using standard testing. For this, reason the whole genome of CVM861was sequenced to determine the number of virulence genes, antibiotic resistance genes, and incompatibility plasmids the strain possessed. CVM861 contained 1 plasmid, 4 virulence genes and 14 resistance genes. This showed that an environment such as a swine farm may have a highly resistant pathogen that could easily spread resistance and virulence traits to other, more normal foodborne pathogens such as Escherichia coli or Salmonella.

Technical Abstract: Aeromonas hydrophila are ubiquitous in the environment and are highly distributed in aquatic habitats. They have long been known as fish pathogens but are opportunistic human pathogens. Aeromonas spp. have persisted through food processing safe-guards and have been isolated from fresh grocery vegetables, dairy, beef, pork, poultry products, and packaged ready-to-eat meats, thus providing an avenue to foodborne illness. A beta-hemolytic, putative Escherichia coli strain collected from diarrheic neonatal pigs in Oklahoma was subsequently identified as A. hydrophila, and designated, CVM861. Here we report the whole genome sequence of A. hydrophila CVM861, SRA accession number, SRR12574563; biosample number, SAMN1590692; and Genbank accession number, SRX9061579. The sequence data for CVM861 revealed 4 Aeromonas specific virulence genes: lipase (lip), hemolysin (hlyA), cytonic enterotoxin (ast), and phospholipid-cholesterolacyltransferase (GCAT). There were no alignments to any virulence genes in VirulenceFinder. CVM861 contained an E. coli kanamycin resistance plasmid identified as IncQ1_1__M28829. There were five aminoglycoside, three beta-lactam resistance genes, and one of each macrolide, phenicol, sulphonamide, tetracycline, and trimethoprim resistance genes, all with over 95% identity to genes in ResFinder. This shows that a rarely considered aquatic pathogen contributes to the resistome reservoir and may be capable of transferring resistance and virulence genes to other more prevalent foodborne strains such as E. coli or Salmonella in swine or other food production systems.