Occurrence and Multidrug Resistance in Strains of <i>Listeria monocytogenes</i> Recovered from the Anaerobic Co-Digestion Sludge Contained in a Single Stage Steel Biodigester: Implications for Antimicrobial Stewardship

<i>L. monocytogenes</i> is a zoonotic foodborne pathogen with inherent adaptability to tolerate environmental and physiological stresses, thereby causing severe disease outbreaks. Antibiotic resistant foodborne pathogens are a challenge to the food industry. A total of 18 samples were po...

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Main Authors: Christy Echakachi Manyi-Loh, Anthony Ifeanyin Okoh, Ryk Lues
Format: Article
Language:English
Published: MDPI AG 2023-03-01
Series:Microorganisms
Subjects:
Online Access:https://www.mdpi.com/2076-2607/11/3/725
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author Christy Echakachi Manyi-Loh
Anthony Ifeanyin Okoh
Ryk Lues
author_facet Christy Echakachi Manyi-Loh
Anthony Ifeanyin Okoh
Ryk Lues
author_sort Christy Echakachi Manyi-Loh
collection DOAJ
description <i>L. monocytogenes</i> is a zoonotic foodborne pathogen with inherent adaptability to tolerate environmental and physiological stresses, thereby causing severe disease outbreaks. Antibiotic resistant foodborne pathogens are a challenge to the food industry. A total of 18 samples were pooled from a bio-digester co-digesting swine manure/pinewood sawdust, and evaluated for the occurrence of bacterium plus total viable counts using the spread plate method. The recovered bacterial isolates were presumptively identified by growth on selective medium and confirmed by biochemical characterisation, leading to the isolation of 43 <i>L</i>. <i>monocytogenes</i>. The isolates were characterized based on their susceptibility to antibiotics via the Kirby-Bauer disc diffusion technique against a panel of 14 antibiotics. Equally, the multiple antibiotic resistance (MAR) index was calculated, and MAR phenotypes generated. The bacterial counts were between 10<sup>2</sup> and10<sup>4</sup> cfu/mL. Complete susceptibility (100%) was demonstrated to ampicillin, gentamicin and sulfamethoxazole, which are the drugs of choice in the treatment of listeriosis. In addition, intermediate sensitivity occurred at 25.58% to cefotaxime, and the highest resistance (51.16%) was exhibited against nalidixic acid. The MAR index ranged from 0 to 0.71. Overall, 41.86% of the Listeria isolates displayed multidrug resistance, with 18 different MAR phenotypes, demonstrating CIP, E, C, TET, AUG, S, CTX, NA, AML, NI as the greatest MAR phenotype. It can be concluded that the isolates yielding MAR > 0.2 originated from the farm, where antibiotics had been in routine use. Therefore, strict monitoring of antibiotics use in the farm is crucial to mitigate further increase in antibiotic resistance amongst these bacterial isolates.
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spelling doaj.art-e0ad75dd544c4e6bade0ddbc559649932023-12-01T01:23:50ZengMDPI AGMicroorganisms2076-26072023-03-0111372510.3390/microorganisms11030725Occurrence and Multidrug Resistance in Strains of <i>Listeria monocytogenes</i> Recovered from the Anaerobic Co-Digestion Sludge Contained in a Single Stage Steel Biodigester: Implications for Antimicrobial StewardshipChristy Echakachi Manyi-Loh0Anthony Ifeanyin Okoh1Ryk Lues2Centre of Applied Food Sustainability and Biotechnology (CAFSaB), Central University of Technology, Bloemfontein 9301, South AfricaSAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice 5700, South AfricaCentre of Applied Food Sustainability and Biotechnology (CAFSaB), Central University of Technology, Bloemfontein 9301, South Africa<i>L. monocytogenes</i> is a zoonotic foodborne pathogen with inherent adaptability to tolerate environmental and physiological stresses, thereby causing severe disease outbreaks. Antibiotic resistant foodborne pathogens are a challenge to the food industry. A total of 18 samples were pooled from a bio-digester co-digesting swine manure/pinewood sawdust, and evaluated for the occurrence of bacterium plus total viable counts using the spread plate method. The recovered bacterial isolates were presumptively identified by growth on selective medium and confirmed by biochemical characterisation, leading to the isolation of 43 <i>L</i>. <i>monocytogenes</i>. The isolates were characterized based on their susceptibility to antibiotics via the Kirby-Bauer disc diffusion technique against a panel of 14 antibiotics. Equally, the multiple antibiotic resistance (MAR) index was calculated, and MAR phenotypes generated. The bacterial counts were between 10<sup>2</sup> and10<sup>4</sup> cfu/mL. Complete susceptibility (100%) was demonstrated to ampicillin, gentamicin and sulfamethoxazole, which are the drugs of choice in the treatment of listeriosis. In addition, intermediate sensitivity occurred at 25.58% to cefotaxime, and the highest resistance (51.16%) was exhibited against nalidixic acid. The MAR index ranged from 0 to 0.71. Overall, 41.86% of the Listeria isolates displayed multidrug resistance, with 18 different MAR phenotypes, demonstrating CIP, E, C, TET, AUG, S, CTX, NA, AML, NI as the greatest MAR phenotype. It can be concluded that the isolates yielding MAR > 0.2 originated from the farm, where antibiotics had been in routine use. Therefore, strict monitoring of antibiotics use in the farm is crucial to mitigate further increase in antibiotic resistance amongst these bacterial isolates.https://www.mdpi.com/2076-2607/11/3/725anaerobic co-digestionswine manure/pine wood sawdust<i>Listeria</i> speciesantibiotic resistancemultiple antibiotic resistance (MAR) index
spellingShingle Christy Echakachi Manyi-Loh
Anthony Ifeanyin Okoh
Ryk Lues
Occurrence and Multidrug Resistance in Strains of <i>Listeria monocytogenes</i> Recovered from the Anaerobic Co-Digestion Sludge Contained in a Single Stage Steel Biodigester: Implications for Antimicrobial Stewardship
Microorganisms
anaerobic co-digestion
swine manure/pine wood sawdust
<i>Listeria</i> species
antibiotic resistance
multiple antibiotic resistance (MAR) index
title Occurrence and Multidrug Resistance in Strains of <i>Listeria monocytogenes</i> Recovered from the Anaerobic Co-Digestion Sludge Contained in a Single Stage Steel Biodigester: Implications for Antimicrobial Stewardship
title_full Occurrence and Multidrug Resistance in Strains of <i>Listeria monocytogenes</i> Recovered from the Anaerobic Co-Digestion Sludge Contained in a Single Stage Steel Biodigester: Implications for Antimicrobial Stewardship
title_fullStr Occurrence and Multidrug Resistance in Strains of <i>Listeria monocytogenes</i> Recovered from the Anaerobic Co-Digestion Sludge Contained in a Single Stage Steel Biodigester: Implications for Antimicrobial Stewardship
title_full_unstemmed Occurrence and Multidrug Resistance in Strains of <i>Listeria monocytogenes</i> Recovered from the Anaerobic Co-Digestion Sludge Contained in a Single Stage Steel Biodigester: Implications for Antimicrobial Stewardship
title_short Occurrence and Multidrug Resistance in Strains of <i>Listeria monocytogenes</i> Recovered from the Anaerobic Co-Digestion Sludge Contained in a Single Stage Steel Biodigester: Implications for Antimicrobial Stewardship
title_sort occurrence and multidrug resistance in strains of i listeria monocytogenes i recovered from the anaerobic co digestion sludge contained in a single stage steel biodigester implications for antimicrobial stewardship
topic anaerobic co-digestion
swine manure/pine wood sawdust
<i>Listeria</i> species
antibiotic resistance
multiple antibiotic resistance (MAR) index
url https://www.mdpi.com/2076-2607/11/3/725
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