{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,11]],"date-time":"2026-10-11T16:19:49Z","timestamp":1791735589714,"version":"4.3.4"},"reference-count":56,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2024,1,4]],"date-time":"2024-01-04T00:00:00Z","timestamp":1704326400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Microbiol."],"abstract":"<jats:sec><jats:title>Introduction<\/jats:title><jats:p><jats:italic>Salmonella<\/jats:italic> infections have been intensely increasing and becoming a universal public health crisis. This study investigated the prevalence of <jats:italic>Salmonella<\/jats:italic> in organic and non-organic chickens and the antimicrobial resistance profiles and virulence genes (<jats:italic>inv<\/jats:italic>A, <jats:italic>pag<\/jats:italic>C, and <jats:italic>spv<\/jats:italic>C) in recovered <jats:italic>Salmonella<\/jats:italic> isolates.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Whole chicken carcasses [organic (<jats:italic>n<\/jats:italic> = 240) and non-organic (<jats:italic>n<\/jats:italic> = 240)] were obtained monthly for 1 year (<jats:italic>n<\/jats:italic> = 480) from a retail store on the Eastern Shore of Maryland. <jats:italic>Salmonella<\/jats:italic> isolation and identification were conducted by following the whole carcass enrichment method recommended by USDA-FSIS. Confirmed <jats:italic>Salmonella<\/jats:italic> isolates (organic <jats:italic>n<\/jats:italic> = 76; non-organic <jats:italic>n<\/jats:italic> = 137) were serotyped and tested for antibiotic susceptibility and virulence genes using standard methods.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Forty-nine percent (237\/480) of the carcasses were positive for <jats:italic>Salmonella<\/jats:italic>. Organic and non-organic positivity rates were 37.1 and 61.8%, respectively. A significantly higher <jats:italic>Salmonella<\/jats:italic> contamination was observed in non-organic chickens (<jats:italic>p<\/jats:italic> &amp;lt; 0.05). The most common serovars were <jats:italic>Salmonella<\/jats:italic> Kentucky (47%), <jats:italic>S. Infantis<\/jats:italic> (35%), <jats:italic>S<\/jats:italic>. Enteritidis (6%), <jats:italic>S<\/jats:italic>. <jats:italic>Typhimurium<\/jats:italic> (5%), and <jats:italic>S<\/jats:italic>. Blockley (4%). Isolates were frequently resistant to at least one antibiotic (91.24%) or multidrug resistant (45.54%). Resistance was observed to tetracycline (82.8%), minocycline (42.3%), nitrofurantoin (40.3%), cefazolin (38.3%), ampicillin (32.1%), and ceftriaxone (26%). All isolates were susceptible to fluoroquinolone, carbapenem, and glycylcycline. The majority of isolates (99.1%) possessed at least one of three virulence genes of concern and 4.2% tested positive for all three. Ninety-five, 89, and 6.6% of isolates contained <jats:italic>inv<\/jats:italic>A, <jats:italic>pag<\/jats:italic>C, and <jats:italic>spv<\/jats:italic>C genes, respectively. The <jats:italic>spv<\/jats:italic>C gene was not detected in serovars recovered from organic chickens though 92% and 82% of isolates were positive for <jats:italic>inv<\/jats:italic>A and <jats:italic>pag<\/jats:italic>C. The frequency of <jats:italic>Salmonella<\/jats:italic> recovered from non-organic chickens possessing <jats:italic>inv<\/jats:italic>A, <jats:italic>pag<\/jats:italic>C, and <jats:italic>spv<\/jats:italic>C genes were 97.1, 89.8, and 10.2%, respectively. Detection of <jats:italic>inv<\/jats:italic>A and <jats:italic>pag<\/jats:italic>C genes showed no significant difference (<jats:italic>p<\/jats:italic> &amp;gt; 0.05) between organic and non-organic chickens but a significantly higher <jats:italic>spv<\/jats:italic>C gene (<jats:italic>p<\/jats:italic> &amp;lt; 0.05) was detected in non-organic chickens due to the majority of <jats:italic>S<\/jats:italic>. Enteritidis (92.3%) exclusively recovered from non-organic chicken carried <jats:italic>spv<\/jats:italic>C gene.<\/jats:p><\/jats:sec><jats:sec><jats:title>Discussion<\/jats:title><jats:p>This study reveals a high prevalence of <jats:italic>Salmonella<\/jats:italic> in both organic and non-organic chickens, which exhibit resistance to vital antibiotics and carry virulence genes, thereby creating a potential risk of salmonellosis.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fmicb.2023.1272892","type":"journal-article","created":{"date-parts":[[2024,1,4]],"date-time":"2024-01-04T04:32:32Z","timestamp":1704342752000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":25,"title":["Prevalence and antibiotic resistance of Salmonella in organic and non-organic chickens on the Eastern Shore of Maryland, USA"],"prefix":"10.3389","volume":"14","author":[{"given":"Anuradha Jeewantha","family":"Punchihewage-Don","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jurgen","family":"Schwarz","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Abdirahman","family":"Diria","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"John","family":"Bowers","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Salina","family":"Parveen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2024,1,4]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"251","DOI":"10.1038\/nrmicro2312","article-title":"Call of the wild: Antibiotic resistance genes in natural environments.","volume":"8","author":"Allen","year":"2010","journal-title":"Nat. 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