Epidemiology and Molecular Pathogenesis of Antimicrobial Resistance and Virulence for Foodborne Pathogens

A special issue of Pathogens (ISSN 2076-0817). This special issue belongs to the section "Epidemiology of Infectious Diseases".

Deadline for manuscript submissions: closed (29 February 2024) | Viewed by 24451

Special Issue Editors

Department of Agriculture, School of Agriculture, Fisheries, and Human Sciences, University of Arkansas, Pine Bluff, AR 71601, USA
Interests: veterinary preventive medicine; molecular epidemiology; One Health; food safety; antimicrobial resistance; virulence; zoonotic diseases
National Center for Toxicological Research, Jefferson, AR, USA
Interests: salmonella plasmid biology; molecular genetics; food microbiology; cell biology
Special Issues, Collections and Topics in MDPI journals
Department of Biological Science, The University of Tulsa, Tulsa, OK, USA
Interests: molecular microbiology of foodborne bacterial pathogens; molecular mechanisms of antimicrobial and heavy metals resistance; molecular characterization of bacterial plasmids; bacterial genomics and transcriptomics; secondary metabolites and diversity of actinomycetes
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Foodborne diseases are an important public health problem worldwide and have an important impact on trade, travel, and development. Foodborne disease globally is still not under control and outbreaks can cause health and economic losses. The causes are unhygienic practices in food production, harvesting, and preparation. There are several foodborne pathogens causing diseases, among which the significant ones are Campylobacter, Nontyphoidal salmonella, Shiga toxin-producing Escherichia coli, Colostredium and Listeria.

These foodborne agents can enter the food chain through multiple sources, some of which could be through cross contamination during food production or processing. Moreover, most agents can be transmitted via routes other than food, including water, farm animals, pets, and/or humans. Determining the source of foodborne infections could be challenging because of the incubation period after exposure to infection, and the most recently consumed food may mistakenly get suspected. In addition, source tracking of the foodborne causative agent might be difficult due to unavailability of the suspected food source for further analysis. Thus, molecular typing of agents isolated from cases spread over a wide geographic area is another way to determine the source of foodborne infection.

Furthermore, emergence of antimicrobial resistance (AMR) is a serious global public health threat as well as a threat to animal health and food safety. There are diverse mechanisms that promote drug resistance. It is known that the use of sub-therapeutic doses of antibiotics in humans or food producing animals promotes mutations of some chromosomal genes. Also, the horizontal transfer of resistance genes as groups (“cassettes”) or plasmids makes the spread of resistance to different bacterial genera possible, among which there could be pathogens. Further molecular characterization studies and whole genomic sequence analysis of variable foodborne pathogens to identify their plasmid content and assess antimicrobial resistance and virulence factors should help lead toward a better understanding of the mechanisms of AMR and virulence factors.

With the development and wide application of whole genome sequencing (WGS) in recent studies over the last decade, there have been many advances in the understanding of microbial genetics. However, futher epidemiological and molecular pathogensis studies are still warranted to develop a better understanding of the natural history of different foodborn pathogens and their virulence and AMR mechanisms.

Despite the several published research studies to investigate foodborne outbreaks as well as the implemented intervention strategies to control them, many people are still getting sick and more outbreaks are happening. To learn how to prevent similar outbreaks from happening in the future, further studies are imperative to assess in depth and to determine the steps and trends necessary to contain future outbreaks.

This Special Issue will cover a wide range of topics focusing on epidemiology and molecular pathogensis of AMR and the virulence of different foodborne pathogens. The aim is to help to enhance current knowledge of these pathogens and their respective diseases.

All types of articles will be considered for publication, including short reports, primary research articles, and reviews.

We look forward to your contribution.

Dr. Yasser Sanad
Dr. Steven Foley
Guest Editors
Dr. Mohamed K. Fakhr
Co-Guest Editor

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Pathogens is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Salmonella
  • Campylobacter
  • Listeria
  • Verbrio
  • Eschrishia coli
  • STEC
  • Colostredium
  • antimicrobial resistance
  • virulence
  • plasmids
  • invasion
  • persistence
  • Whole Genome Sequences (WGS)
  • molecular epidemiology
  • epidemiology

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Published Papers (11 papers)

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Research

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12 pages, 803 KiB  
Article
Antifungal Susceptibility of Saccharomyces cerevisiae Isolated from Clinical Specimens
by Aleksandra Górzyńska, Kamila Kondracka, Agnieszka Korzeniowska-Kowal and Urszula Nawrot
Pathogens 2024, 13(3), 248; https://0-doi-org.brum.beds.ac.uk/10.3390/pathogens13030248 - 14 Mar 2024
Viewed by 576
Abstract
(1) Background: Despite being considered a non-pathogenic yeast, recently, a growing occurrence of Saccharomyces cerevisiae infections has been noted. There is little knowledge about the drug susceptibility of this species. Therefore, the objective of this research was to expand it and determine the [...] Read more.
(1) Background: Despite being considered a non-pathogenic yeast, recently, a growing occurrence of Saccharomyces cerevisiae infections has been noted. There is little knowledge about the drug susceptibility of this species. Therefore, the objective of this research was to expand it and determine the drug susceptibility profile of a local collection of clinical isolates of this species. (2) Methods: This study contained 55 clinical isolates identified as Saccharomyces cerevisiae using the MALDI-TOF method. The susceptibility of Saccharomyces cerevisiae was tested to 10 antifungals (amphotericin B, flucytosine, fluconazole, voriconazole, posaconazole, micafungin, anidulafungin, caspofungin, and itraconazole) using MICRONAUT-AT tests and manogepix, a new drug, using the microdilution method according to EUCAST. (3) Results: Overall, most strains were classified as sensitive to amphotericin B and flucytosine (MIC ranges of ≤0.03–1 and ≤0.06–0.125, respectively) and also to echinocandins. However, five isolates expressed high MIC values for all of the tested azoles, indicating cross-resistance. The MIC range for manogepix was 0.001–0.125 mg/L, with an MIC50 of 0.03 mg/L and an MIC90 of 0.06 mg/L. (4) Conclusions: The occurrence of resistance to azoles may be a concerning problem and therefore should be investigated further. However, the new antifungal manogepix appears to be an interesting new therapeutic option for treating such infections. Full article
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18 pages, 3443 KiB  
Article
Epidemiological Data and Antimicrobial Resistance of Campylobacter spp. in Portugal from 13 Years of Surveillance
by Andreia Duarte, Luísa Pereira, Maria-Leonor Lemos, Miguel Pinto, João Carlos Rodrigues, Rui Matias, Andrea Santos, PTCampyNet and Mónica Oleastro
Pathogens 2024, 13(2), 147; https://0-doi-org.brum.beds.ac.uk/10.3390/pathogens13020147 - 06 Feb 2024
Viewed by 1508
Abstract
This study extensively analyzed campylobacteriosis surveillance in Portugal from 2009 to 2021, aiming to investigate demographic shifts, seasonal variations, and antimicrobial resistance (AMR) within Campylobacter isolates. Surveillance network and sentinel laboratory-based system data revealed a substantial under-notification of campylobacteriosis cases, suggesting an underestimated [...] Read more.
This study extensively analyzed campylobacteriosis surveillance in Portugal from 2009 to 2021, aiming to investigate demographic shifts, seasonal variations, and antimicrobial resistance (AMR) within Campylobacter isolates. Surveillance network and sentinel laboratory-based system data revealed a substantial under-notification of campylobacteriosis cases, suggesting an underestimated disease burden. Notification rates exhibited a paradigm shift, with a notable prevalence among the pediatric population, particularly in children aged 1–4 years, diverging from European reports. Additionally, an emerging trend of Campylobacter infections in younger adults (15–44 years) was observed. The study unveiled a unique seasonal distribution of cases, defying typical summer peaks seen elsewhere. AMR analysis revealed high resistance to ciprofloxacin and tetracycline, in both C. jejuni (93.7% and 79.2%, respectively) and C. coli (96.5% and 93.2%, respectively), stable throughout the studied period (2013–2021). C. coli exhibited significantly higher resistance to erythromycin, gentamicin, ampicillin and ertapenem compared to C. jejuni (p < 0.001). Multilocus Sequence Typing (MLST) data demonstrated the distribution of resistance markers across diverse sequence types, challenging the notion of a clonal origin for multidrug-resistant isolates. In conclusion, the study highlights the need for enhanced surveillance and raises concerns about alarming AMR levels, recommending the implementation of whole-genome sequencing (WGS)-based surveillance for a deeper comprehension of disease patterns and an evolving AMR landscape. Full article
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11 pages, 875 KiB  
Article
Prevalence and Molecular Characterization of Shiga Toxin-Producing Escherichia coli from Food and Clinical Samples
by Khulud Alotaibi and Ashraf A. Khan
Pathogens 2023, 12(11), 1302; https://0-doi-org.brum.beds.ac.uk/10.3390/pathogens12111302 - 31 Oct 2023
Viewed by 1186
Abstract
Shiga toxin-producing Escherichia coli (STEC) is one of the most prominent food-borne pathogens in humans. The current study aims to detect and to analyze the virulence factors, antibiotic resistance, and plasmid profiles for forty-six STEC strains, isolated from clinical and food strains. Pulsed-field [...] Read more.
Shiga toxin-producing Escherichia coli (STEC) is one of the most prominent food-borne pathogens in humans. The current study aims to detect and to analyze the virulence factors, antibiotic resistance, and plasmid profiles for forty-six STEC strains, isolated from clinical and food strains. Pulsed-field gel electrophoresis (PFGE) was used to determine the genetic relatedness between different serotypes and sources of samples. The clinical samples were found to be resistant to Nb (100%), Tet (100%), Amp (20%), SXT (15%), and Kan (15%) antibiotics. In contrast, the food strains were found to be resistant to Nb (100%), Tet (33%), Amp (16.6%), and SXT (16.6%) antibiotics. The PFGE typing of the forty-six isolates was grouped into more than ten clusters, each with a similarity between 30% and 70%. Most of the isolates were found positive for more than five virulence genes (eae, hlyA, stx1, stx2, stx2f, stx2c, stx2e, stx2, nelB, pagC, sen, toxB, irp, efa, and efa1). All the isolates carried different sizes of the plasmids. The isolates were analyzed for plasmid replicon type by PCR, and 72.5% of the clinical isolates were found to contain X replicon-type plasmid, 50% of the clinical isolates contained FIB replicon-type plasmid, and 17.5% of the clinical isolates contained Y replicon-type plasmid. Three clinical isolates contained both I1 and Hi1 replicon-type plasmid. Only two food isolates contained B/O and W replicon-type plasmid. These results indicate that STEC strains have diverse clonal populations among food and clinical strains that are resistant to several antimicrobials. In conclusion, our findings indicate that food isolates of STEC strains harbor virulence, antimicrobial resistance, plasmid replicon typing determinants like those of other STEC strains from clinical strains. These results suggest that these strains are unique and may contribute to the virulence of the isolates. Therefore, surveillance and characterization of STEC strains can provide useful information about the prevalence of STEC in food and clinical sources. Furthermore, it will help to identify STEC serotypes that are highly pathogenic to humans and may emerge as a threat to public health. Full article
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21 pages, 3955 KiB  
Article
Comparative Genomics Reveal the Utilization Ability of Variable Carbohydrates as Key Genetic Features of Listeria Pathogens in Their Pathogenic Lifestyles
by Qunfeng Lu, Xiaoying Zhu, Qinqin Long, Xueli Yi, Anni Yang, Xidai Long and Demin Cao
Pathogens 2022, 11(12), 1430; https://0-doi-org.brum.beds.ac.uk/10.3390/pathogens11121430 - 28 Nov 2022
Cited by 1 | Viewed by 1232
Abstract
Background: L. monocytogenes and L. ivanovii, the only two pathogens of Listeria, can survive in various environments, having different pathogenic characteristics. However, the genetic basis of their excellent adaptability and differences in pathogenicity has still not been completely elucidated. Methods: We [...] Read more.
Background: L. monocytogenes and L. ivanovii, the only two pathogens of Listeria, can survive in various environments, having different pathogenic characteristics. However, the genetic basis of their excellent adaptability and differences in pathogenicity has still not been completely elucidated. Methods: We performed a comparative genomic analysis based on 275 L. monocytogenes, 10 L. ivanovii, and 22 non-pathogenic Listeria strains. Results: Core/pan-genome analysis revealed that 975 gene families were conserved in all the studied strains. Additionally, 204, 242, and 756 gene families existed uniquely in L. monocytogenes, L. ivanovii, and both, respectively. Functional annotation partially verified that these unique gene families were closely related to their adaptability and pathogenicity. Moreover, the protein–protein interaction (PPI) network analysis of these unique gene sets showed that plenty of carbohydrate transport systems and energy metabolism enzymes were clustered in the networks. Interestingly, ethanolamine-metabolic-process-related proteins were significantly enriched in the PPI network of the unique genes of the Listeria pathogens, which can be understood as a determining factor of their pathogenicity. Conclusions: The utilization capacity of multiple carbon sources of Listeria pathogens, especially ethanolamine, is the key genetic basis for their ability to adapt to various environments and pathogenic lifestyles. Full article
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18 pages, 4612 KiB  
Article
Microbial Genetics and Clonal Dissemination of Salmonella enterica Serotype Javiana Isolated from Human Populations in Arkansas, USA
by Yasser M. Sanad, Nesreen H. Aljahdali, Bijay K. Khajanchi, Rajesh Nayak, Ashraf Khan and Steven L. Foley
Pathogens 2022, 11(10), 1192; https://0-doi-org.brum.beds.ac.uk/10.3390/pathogens11101192 - 16 Oct 2022
Viewed by 1969
Abstract
Salmonella is estimated to cause over a million infections and ~400 deaths annually in the U.S. Salmonella enterica serotype Javiana strains (n = 409) that predominantly originated from the State of Arkansas over a six-year period (2003 to 2008) were studied. This period [...] Read more.
Salmonella is estimated to cause over a million infections and ~400 deaths annually in the U.S. Salmonella enterica serotype Javiana strains (n = 409) that predominantly originated from the State of Arkansas over a six-year period (2003 to 2008) were studied. This period coincided with a rapid rise in the incidence of S. Javiana infections in the U.S. Children under the age of 10 displayed the highest prevalence of S. Javiana infections, regardless of sex or year of detection. Antimicrobial susceptibility to 15 different antimicrobials was assessed and 92% (n = 375) were resistant to at least one of the antimicrobials. Approximately 89% of the isolates were resistant to sulfisoxazole alone and 3% (n = 11) were resistant to different antimicrobials, including gentamicin, ciprofloxacin or ceftiofur. The pulsed-field gel electrophoresis (PFGE) analyses assessed the genotypic diversity and distribution of S. Javiana strains using XbaI restriction. Nine major clusters were identified and isolates from each group were digested with the restriction enzyme AvrII. Isolates with identical profiles of XbaI and AvrII were found to be disseminated in human populations. These distinct “types” of S. Javiana were persistent in human populations for multiple years. A subset of isolates (n = 19) with unique resistance phenotypes underwent plasmid and incompatibility (Inc) type analyses and the isolates resistant to more than one antimicrobial harbored multiple plasmids (<3 to 165 kb). Furthermore, these strains possessed 14 virulence genes, including pagC, cdtB, and iroN. The whole genome sequences (WGS) of 18 isolates that mostly originated from Arkansas from 2003 to 2011 were compared with isolates collected from different areas in the U.S. in 1999, indicating the perseverance of S. Javiana in disseminating antimicrobial resistance and virulence genes. Full article
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15 pages, 1809 KiB  
Article
Analysis of Sanitizer Rotation on the Susceptibility, Biofilm Forming Ability and Caco-2 Cell Adhesion and Invasion of Listeria
by Md Asfakur Rahman, Nirakar Sahoo and Veerachandra Yemmireddy
Pathogens 2022, 11(9), 961; https://0-doi-org.brum.beds.ac.uk/10.3390/pathogens11090961 - 24 Aug 2022
Cited by 1 | Viewed by 1609
Abstract
The purpose of this study was to determine the effect of sanitizer use conditions on the susceptibility, biofilm forming ability and pathogenicity of Listeria monocytogenes. Two different strains of L. monocytogenes and a non-pathogenic L. innocua were exposed to sodium hypochlorite, [...] Read more.
The purpose of this study was to determine the effect of sanitizer use conditions on the susceptibility, biofilm forming ability and pathogenicity of Listeria monocytogenes. Two different strains of L. monocytogenes and a non-pathogenic L. innocua were exposed to sodium hypochlorite, benzalkonium chloride and peroxyacetic acid at different concentrations (4 to 512 ppm) and treatment times (30 s to 5 min), respectively. Under the tested conditions, no significant difference (p > 0.05) in reduction was observed among the three tested sanitizers. A reduction of 1 to 8 log CFU/mL was observed depending upon the sanitizer concentration and treatment times. The survived cells at the highest sublethal concentration and treatment time of a particular sanitizer upon re-exposure to the same or different sanitizer showed either no change or increased susceptibility when compared to parent strains. Upon repeated exposure to sanitizers at progressively increasing concentrations from 1 to 128 ppm, L. innocua was able to survive concentrations of up to 32 ppm benzalkonium chloride and 64 ppm peroxyacetic acid treatments, respectively. At the tested sub-lethal concentrations, no significant difference (p > 0.05) in biofilm formation was observed among the tested strains. Caco-2 interaction with L. innocua showed a reduction in invasion ability with sublethal concentrations of sanitizers. Full article
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14 pages, 1197 KiB  
Article
Genotyping and Antimicrobial Susceptibility of Clostridium perfringens and Clostridioides difficile in Camel Minced Meat
by Mahmoud Fayez, Waleed R. El-Ghareeb, Ahmed Elmoslemany, Saleem J. Alsunaini, Mohamed Alkafafy, Othman M. Alzahrani, Samy F. Mahmoud and Ibrahim Elsohaby
Pathogens 2021, 10(12), 1640; https://0-doi-org.brum.beds.ac.uk/10.3390/pathogens10121640 - 19 Dec 2021
Cited by 8 | Viewed by 3690
Abstract
The present study aimed to determine the occurrence, genotypes, and antimicrobial resistance of Clostridium perfringens (C. perfringens) and Clostridioides difficile (C. difficile) in camel minced meat samples collected from small butcher shops and supermarkets in Al-Ahsa Governorate, Saudi Arabia. [...] Read more.
The present study aimed to determine the occurrence, genotypes, and antimicrobial resistance of Clostridium perfringens (C. perfringens) and Clostridioides difficile (C. difficile) in camel minced meat samples collected from small butcher shops and supermarkets in Al-Ahsa Governorate, Saudi Arabia. A total of 100 camel minced meat samples were randomly collected from small butcher’s shops (n = 50) and supermarkets (n = 50) in Al-Ahsa Governorate, Saudi Arabia. C. perfringens and C. difficile were isolated and identified using the VITEK-2 compact system and 16S rRNA gene amplification. Genotypes, toxin genes, and antimicrobial susceptibility of the isolates were determined. Moreover, ELISA was used to detect C. perfringens and C. difficile toxins. C. perfringens and C. difficile were isolated from 14% and 4% of the tested minced meat samples, respectively. Out of the 14 C. perfringens isolates, type A (64.3%), type B (7.1%), type C (21.5%), and type D (7.1%) were detected. However, out of the four C. difficile isolates, three (75%) were type A+B+ and one (25%) was type AB+. None of the C. perfringens or C. difficile toxins were identified using ELISA. C. perfringens and C. difficile isolates exhibited a high rate of resistance to tetracycline (56% and 75%, respectively). However, all isolates were susceptible to amoxicillin-clavulanate. Multidrug resistance was observed in three (21.4%) C. perfringens and one (25%) C. difficile isolates. In conclusion, camel minced meat was contaminated with C. perfringens and C. difficile, which present a potential risk of food poisoning. The majority of the isolates were resistant to at least one antimicrobial, and some isolates were multidrug-resistant. Therefore, food safety standards and frequent inspections of abattoirs, small butcher shops, and supermarkets should be enforced. Full article
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17 pages, 1580 KiB  
Article
Genotypic Characterization of Clinical Isolates of Staphylococcus aureus from Pakistan
by Saeed Khan, Bernard S. Marasa, Kidon Sung and Mohamed Nawaz
Pathogens 2021, 10(8), 918; https://0-doi-org.brum.beds.ac.uk/10.3390/pathogens10080918 - 21 Jul 2021
Cited by 7 | Viewed by 2915
Abstract
In this study, we compared pulsed-field gel electrophoretic (PFGE), multilocus sequence typing (MLST), Staphylococcal cassette chromosome mec (SCCmec), spa typing, and virulence gene profiles of 19 Panton–Valentine leucocidin (PVL)-positive, multidrug-, and methicillin-resistant clinical Staphylococcus aureus (MRSA) isolates obtained from a hospital [...] Read more.
In this study, we compared pulsed-field gel electrophoretic (PFGE), multilocus sequence typing (MLST), Staphylococcal cassette chromosome mec (SCCmec), spa typing, and virulence gene profiles of 19 Panton–Valentine leucocidin (PVL)-positive, multidrug-, and methicillin-resistant clinical Staphylococcus aureus (MRSA) isolates obtained from a hospital intensive care unit in Pakistan. The isolates exhibited 10 pulsotypes, contained eight adhesin genes (bbp, clfA, clfB, cna, fnbA, fnbB, map-eap, and spa), 10 toxin genes (hla, hlb, hld, hlg, pvl, sed, see, seg, seh, and tst), and two other virulence genes (cfb, v8) that were commonly present in all isolates. The spa-typing indicated seven known spa types (t030, t064, t138, t314, t987, t1509, and t5414) and three novel spa types. MLST analysis indicated eight ST types (ST8, ST15, ST30, ST239, ST291, ST503, ST772, and ST1413). All isolates belonged to the agr group 1. Most of the isolates possessed SCCmec type III, but some isolates had it in combination with types SCCmec IV and V. The presence of multidrug-resistant MRSA isolates in Pakistan indicates poor hygienic conditions, overuse of antibiotics, and a lack of rational antibiotic therapy that have led to the evolution and development of hypervirulent MRSA clones. The study warrants development of a robust epidemiological screening program and adoption of effective measures to stop their spread in hospitals and the community. Full article
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16 pages, 11676 KiB  
Article
Occurrence, Antimicrobial Resistance, and Molecular Characterization of Campylobacter spp. in Intensive Pig Production in South Africa
by Viwe Sithole, Daniel Gyamfi Amoako, Akebe Luther King Abia, Keith Perrett, Linda A. Bester and Sabiha Y. Essack
Pathogens 2021, 10(4), 439; https://doi.org/10.3390/pathogens10040439 - 07 Apr 2021
Cited by 15 | Viewed by 2461
Abstract
Campylobacter spp. are among the leading foodborne pathogens, causing campylobacteriosis, a zoonotic infection that results in bacterial gastroenteritis and diarrheal disease in animals and humans. This study investigated the molecular epidemiology of antibiotic-resistant Campylobacter spp. isolated across the farm-to-fork-continuum in an intensive pig [...] Read more.
Campylobacter spp. are among the leading foodborne pathogens, causing campylobacteriosis, a zoonotic infection that results in bacterial gastroenteritis and diarrheal disease in animals and humans. This study investigated the molecular epidemiology of antibiotic-resistant Campylobacter spp. isolated across the farm-to-fork-continuum in an intensive pig production system in South Africa. Following ethical approval, samples were collected over sixteen weeks from selected critical points (farm, transport, abattoir, and retail) using a farm-to-fork sampling approach according to WHO-AGISAR guidelines. Overall, 520 samples were investigated for the presence of Campylobacter spp., which were putatively identified using selective media with identity and speciation confirmed by polymerase chain reaction (PCR) of specific genes. Resistance profiles were ascertained by the Kirby–Bauer disk diffusion method. Antibiotic resistance and virulence genes were identified using PCR and DNA sequencing. Clonal relatedness was determined using ERIC-PCR. Altogether, 378/520 (72.7%) samples were positive for Campylobacter spp., with Campylobacter coli being the predominant species (73.3%), followed by Campylobacter jejuni (17.7%); 8.9% of the isolates were classified as “other spp”. Relatively high resistance was observed in C. coli and C. jejuni to erythromycin (89% and 99%), streptomycin (87% and 93%), tetracycline (82% and 96%), ampicillin (69% and 85%), and ciprofloxacin (53% and 67%), respectively. Multidrug resistance (MDR) was noted in 330 of the 378 (87.3%) isolates. The antibiotic resistance genes observed were tetO (74.6%), blaOXA-61 (2.9%), and cmeB (11.1%), accounting for the resistance to tetracycline and ampicillin. The membrane efflux pump (cmeB), conferring resistance to multiple antibiotics, was also detected in most resistant isolates. Chromosomal mutations in gyrA (Thr-86-Ile) and 23S rRNA (A2075G and A2074C) genes, conferring quinolone and erythromycin resistance, respectively, were also found. Of the virulence genes tested, ciaB, dnaJ, pldA, cdtA, cdtB, cdtC, and cadF were detected in 48.6%, 61.1%, 17.4%, 67.4%, 19.3%, 51%, and 5% of all Campylobacter isolates, respectively. Clonal analysis revealed that isolates along the continuum were highly diverse, with isolates from the same sampling points belonging to the same major ERIC-types. The study showed relatively high resistance to antibiotics commonly used in intensive pig production in South Africa with some evidence, albeit minimal, of transmission across the farm-to-fork continuum. This, together with the virulence profiles present in Campylobacter spp., presents a challenge to food safety and a potential risk to human health, necessitating routine surveillance, antibiotic stewardship, and comprehensive biosecurity in intensive pig production. Full article
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Review

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19 pages, 1429 KiB  
Review
Antimicrobial Effects of Plant-Based Supplements on Gut Microbial Diversity in Small Ruminants
by Ian K. Daniel, Obadiah M. Njue and Yasser M. Sanad
Pathogens 2024, 13(1), 31; https://0-doi-org.brum.beds.ac.uk/10.3390/pathogens13010031 - 29 Dec 2023
Viewed by 1039
Abstract
Every year in the United States, approximately 48 million people are affected by bacterial illnesses that are transmitted through food, leading to 3000 fatalities. These illnesses typically stem from food animals and their by-products, which may harbor dangerous pathogens like Salmonella enterica, [...] Read more.
Every year in the United States, approximately 48 million people are affected by bacterial illnesses that are transmitted through food, leading to 3000 fatalities. These illnesses typically stem from food animals and their by-products, which may harbor dangerous pathogens like Salmonella enterica, Listeria monocytogenes, enterohemorrhagic Escherichia coli O157:H7, and Campylobacter jejuni. Factors that contribute to contamination include manure used as a soil amendment, exposure to polluted irrigation water, and contact with animals. To improve food safety, researchers are studying pre-slaughter intervention methods to eliminate bacterial contamination in live animals. While small ruminants are vital to global agriculture and income generation for small farms, traditional feeding practices involve supplements and antibiotics to boost performance, which contributes to antibiotic resistance. Hence, researchers are looking for friendly bacterial strains that enhance both animal and human health without impacting livestock productivity. The global trend is to minimize the use of antibiotics as feed supplements, with many countries prohibiting or limiting their use. The aim of this review is to provide a comprehensive insight on the antioxidant capabilities, therapeutic attributes, and applications of bioactive compounds derived from sweet potato tops (SPTs), rice bran (RB) and radish tops (RTs). This overview provides an insight on plant parts that are abundant in antioxidant and prebiotic effects and could be used as value-added products in animal feed and pharmaceutical applications. This review was based on previous findings that supplementation of basal diets with natural supplements represents a multifaceted intervention that will become highly important over time. By remarkably reducing the burden of foodborne pathogens, they apply to multiple species, are cheap, do not require withdrawal periods, and can be applied at any time in food animal production. Full article
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25 pages, 4705 KiB  
Review
Transcriptional Regulation of the Multiple Resistance Mechanisms in Salmonella—A Review
by Michał Wójcicki, Olga Świder, Kamila J. Daniluk, Paulina Średnicka, Monika Akimowicz, Marek Ł. Roszko, Barbara Sokołowska and Edyta Juszczuk-Kubiak
Pathogens 2021, 10(7), 801; https://0-doi-org.brum.beds.ac.uk/10.3390/pathogens10070801 - 24 Jun 2021
Cited by 16 | Viewed by 4576
Abstract
The widespread use of antibiotics, especially those with a broad spectrum of activity, has resulted in the development of multidrug resistance in many strains of bacteria, including Salmonella. Salmonella is among the most prevalent causes of intoxication due to the consumption of [...] Read more.
The widespread use of antibiotics, especially those with a broad spectrum of activity, has resulted in the development of multidrug resistance in many strains of bacteria, including Salmonella. Salmonella is among the most prevalent causes of intoxication due to the consumption of contaminated food and water. Salmonellosis caused by this pathogen is pharmacologically treated using antibiotics such as fluoroquinolones, ceftriaxone, and azithromycin. This foodborne pathogen developed several molecular mechanisms of resistance both on the level of global and local transcription modulators. The increasing rate of antibiotic resistance in Salmonella poses a significant global concern, and an improved understanding of the multidrug resistance mechanisms in Salmonella is essential for choosing the suitable antibiotic for the treatment of infections. In this review, we summarized the current knowledge of molecular mechanisms that control gene expression related to antibiotic resistance of Salmonella strains. We characterized regulators acting as transcription activators and repressors, as well as two-component signal transduction systems. We also discuss the background of the molecular mechanisms of the resistance to metals, regulators of multidrug resistance to antibiotics, global regulators of the LysR family, as well as regulators of histone-like proteins. Full article
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