Occurrence and Molecular Characterization of Multidrug-Resistant Vegetable-Borne <i>Listeria monocytogenes</i> Isolates
Fresh vegetables play a significant role in the human diet. However, ready-to-eat (RTE) vegetables have been associated with increasing foodborne outbreaks including <i>L. monocytogenes</i>, which is a common human pathogen associated with foodborne infections resulting in listeriosis. T...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-10-01
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| Series: | Antibiotics |
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| Online Access: | https://www.mdpi.com/2079-6382/11/10/1353 |
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| author | Zizipho Ntshanka Temitope C. Ekundayo Erika M. du Plessis Lise Korsten Anthony I. Okoh |
| author_facet | Zizipho Ntshanka Temitope C. Ekundayo Erika M. du Plessis Lise Korsten Anthony I. Okoh |
| author_sort | Zizipho Ntshanka |
| collection | DOAJ |
| description | Fresh vegetables play a significant role in the human diet. However, ready-to-eat (RTE) vegetables have been associated with increasing foodborne outbreaks including <i>L. monocytogenes</i>, which is a common human pathogen associated with foodborne infections resulting in listeriosis. This study aims to assess the resistance of vegetable-borne <i>L. monocytogenes</i> to antibiotics. <i>L. monocytogenes</i> was isolated and molecularly characterized using polymerase chain reaction (PCR) from 17 RTE vegetable samples. The confirmed <i>L. monocytogenes</i> was further assessed for phenotypic and genotypic antibiotic resistance using the disc diffusion test and PCR primers targeting six antibiotic classes and thirty-one related antibiotic resistance genes (ARGs), respectively. The results revealed that <i>Listeria</i> counts ranged from 1.60 to 3.44 log<sub>10</sub> CFU/g in the samples. The isolates exhibited high resistance against penicillin G, erythromycin, vancomycin, tetracycline, trimethoprim-sulfamethoxazole, and nitrofurantoin among the 108 isolates tested. A total of 71 multiple antibiotic resistance (MAR) phenotypes were observed in the isolates, which ranged from resistance to 3 to 13 antibiotics. The MAR index was ˃0.2 in 97% of the isolates. Some of the highly detected ARG subtypes included <i>SulI</i> (100%), TEM (76.9%), <i>tetA</i> (59%), and <i>tetM</i> (54.7%). The findings show a high occurrence of multidrug-resistant <i>L. monocytogenes</i> and clinical ARGs in fresh vegetables, which constitutes an immediate danger for the health security of the public. |
| first_indexed | 2024-03-09T20:50:41Z |
| format | Article |
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| institution | Directory Open Access Journal |
| issn | 2079-6382 |
| language | English |
| last_indexed | 2024-03-09T20:50:41Z |
| publishDate | 2022-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Antibiotics |
| spelling | doaj.art-73403066f87846378b79945f156e56a72023-11-23T22:35:03ZengMDPI AGAntibiotics2079-63822022-10-011110135310.3390/antibiotics11101353Occurrence and Molecular Characterization of Multidrug-Resistant Vegetable-Borne <i>Listeria monocytogenes</i> IsolatesZizipho Ntshanka0Temitope C. Ekundayo1Erika M. du Plessis2Lise Korsten3Anthony I. Okoh4SAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice 5700, South AfricaSAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice 5700, South AfricaDepartment of Plant and Soil Sciences, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria 0002, South AfricaDepartment of Plant and Soil Sciences, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria 0002, South AfricaSAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice 5700, South AfricaFresh vegetables play a significant role in the human diet. However, ready-to-eat (RTE) vegetables have been associated with increasing foodborne outbreaks including <i>L. monocytogenes</i>, which is a common human pathogen associated with foodborne infections resulting in listeriosis. This study aims to assess the resistance of vegetable-borne <i>L. monocytogenes</i> to antibiotics. <i>L. monocytogenes</i> was isolated and molecularly characterized using polymerase chain reaction (PCR) from 17 RTE vegetable samples. The confirmed <i>L. monocytogenes</i> was further assessed for phenotypic and genotypic antibiotic resistance using the disc diffusion test and PCR primers targeting six antibiotic classes and thirty-one related antibiotic resistance genes (ARGs), respectively. The results revealed that <i>Listeria</i> counts ranged from 1.60 to 3.44 log<sub>10</sub> CFU/g in the samples. The isolates exhibited high resistance against penicillin G, erythromycin, vancomycin, tetracycline, trimethoprim-sulfamethoxazole, and nitrofurantoin among the 108 isolates tested. A total of 71 multiple antibiotic resistance (MAR) phenotypes were observed in the isolates, which ranged from resistance to 3 to 13 antibiotics. The MAR index was ˃0.2 in 97% of the isolates. Some of the highly detected ARG subtypes included <i>SulI</i> (100%), TEM (76.9%), <i>tetA</i> (59%), and <i>tetM</i> (54.7%). The findings show a high occurrence of multidrug-resistant <i>L. monocytogenes</i> and clinical ARGs in fresh vegetables, which constitutes an immediate danger for the health security of the public.https://www.mdpi.com/2079-6382/11/10/1353vegetableantibiotic resistance genemultidrug-resistantmultiple antibiotic resistance (MAR) indexriskpublic health |
| spellingShingle | Zizipho Ntshanka Temitope C. Ekundayo Erika M. du Plessis Lise Korsten Anthony I. Okoh Occurrence and Molecular Characterization of Multidrug-Resistant Vegetable-Borne <i>Listeria monocytogenes</i> Isolates Antibiotics vegetable antibiotic resistance gene multidrug-resistant multiple antibiotic resistance (MAR) index risk public health |
| title | Occurrence and Molecular Characterization of Multidrug-Resistant Vegetable-Borne <i>Listeria monocytogenes</i> Isolates |
| title_full | Occurrence and Molecular Characterization of Multidrug-Resistant Vegetable-Borne <i>Listeria monocytogenes</i> Isolates |
| title_fullStr | Occurrence and Molecular Characterization of Multidrug-Resistant Vegetable-Borne <i>Listeria monocytogenes</i> Isolates |
| title_full_unstemmed | Occurrence and Molecular Characterization of Multidrug-Resistant Vegetable-Borne <i>Listeria monocytogenes</i> Isolates |
| title_short | Occurrence and Molecular Characterization of Multidrug-Resistant Vegetable-Borne <i>Listeria monocytogenes</i> Isolates |
| title_sort | occurrence and molecular characterization of multidrug resistant vegetable borne i listeria monocytogenes i isolates |
| topic | vegetable antibiotic resistance gene multidrug-resistant multiple antibiotic resistance (MAR) index risk public health |
| url | https://www.mdpi.com/2079-6382/11/10/1353 |
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