Integrate genome-based assessment of safety for probiotic strains: Bacillus coagulans GBI-30, 6086 as a case study. - Related Documents




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477601.0000Integrate genome-based assessment of safety for probiotic strains: Bacillus coagulans GBI-30, 6086 as a case study. Probiotics are microorganisms that confer beneficial effects on the host; nevertheless, before being allowed for human consumption, their safety must be verified with accurate protocols. In the genomic era, such procedures should take into account the genomic-based approaches. This study aims at assessing the safety traits of Bacillus coagulans GBI-30, 6086 integrating the most updated genomics-based procedures and conventional phenotypic assays. Special attention was paid to putative virulence factors (VF), antibiotic resistance (AR) genes and genes encoding enzymes responsible for harmful metabolites (i.e. biogenic amines, BAs). This probiotic strain was phenotypically resistant to streptomycin and kanamycin, although the genome analysis suggested that the AR-related genes were not easily transferrable to other bacteria, and no other genes with potential safety risks, such as those related to VF or BA production, were retrieved. Furthermore, no unstable elements that could potentially lead to genomic rearrangements were detected. Moreover, a workflow is proposed to allow the proper taxonomic identification of a microbial strain and the accurate evaluation of risk-related gene traits, combining whole genome sequencing analysis with updated bioinformatics tools and standard phenotypic assays. The workflow presented can be generalized as a guideline for the safety investigation of novel probiotic strains to help stakeholders (from scientists to manufacturers and consumers) to meet regulatory requirements and avoid misleading information.201626952108
422010.9998Whole genome sequencing for the risk assessment of probiotic lactic acid bacteria. Probiotic bacteria exhibit beneficial effects on human and/or animal health, and have been widely used in foods and fermented products for decades. Most probiotics consist of lactic acid bacteria (LAB), which are used in the production of various food products but have also been shown to have the ability to prevent certain diseases. With the expansion of applications for probiotic LAB, there is an increasing concern with regard to safety, as cases with adverse effects, i.e., severe infections, transfer of antimicrobial resistance genes, etc., can occur. Currently, in vitro assays remain the primary way to assess the properties of LAB. However, such methodologies are not meeting the needs of strain risk assessment on a high-throughput scale, in the context of the evolving concept of food safety. Analyzing the complete genetic information, including potential virulence genes and other determinants with a negative impact on health, allows for assessing the safe use of the product, for which whole-genome sequencing (WGS) of individual LAB strains can be employed. Genomic data can also be used to understand subtle differences in the strain level important for beneficial effects, or protect patents. Here, we propose that WGS-based bioinformatics analyses are an ideal and cost-effective approach for the initial in silico microbial risk evaluation, while the technique may also increase our understanding of LAB strains for food safety and probiotic property evaluation.202335694810
463720.9997What Differentiates Probiotic from Pathogenic Bacteria? The Genetic Mobility of Enterococcus faecium Offers New Molecular Insights. Enterococcus faecium is a lactic acid bacterium with applications in food engineering and nutrigenomics, including as starter cultures in fermented foods. To differentiate the E. faecium probiotic from pathogenic bacteria, physiological analyses are often used but they do not guarantee that a bacterial strain is not pathogenic. We report here new findings and an approach based on comparison of the genetic mobility of (1) probiotic, (2) pathogenic, and (3) nonpathogenic and non-probiotic strains, so as to differentiate probiotics, and inform their safe use. The region of the 16S ribosomal DNA (rDNA) genes of different E. faecium strains native to Pernambuco-Brazil was used with the GenBank query sequence. Complete genomes were selected and divided into three groups as noted above to identify the mobile genetic elements (MGEs) (transposase, integrase, conjugative transposon protein and phage) and antibiotic resistance genes (ARGs), and to undertake pan-genome analysis and multiple genome alignment. Differences in the number of MGEs were found in ARGs, in the presence and absence of the genes that differentiate E. faecium probiotics and pathogenic bacteria genetically. Our data suggest that genetic mobility appears to be informative in differentiating between probiotic and pathogenic strains. While the present findings are not necessarily applicable to all probiotics, they offer novel molecular insights to guide future research in nutrigenomics, clinical medicine, and food engineering on new ways to differentiate pathogenic from probiotic bacteria.202032762606
391930.9997Detection of antibiotic resistance in probiotics of dietary supplements. BACKGROUND: Probiotics are live microorganisms that confer nutrition- and health-promoting benefits if consumed in adequate amounts. Concomitant with the demand for natural approaches to maintaining health is an increase in inclusion of probiotics in food and health products. Since probiotic bacteria act as reservoir for antibiotic resistant determinants, the transfer of these genes to pathogens sharing the same intestinal habitat is thus conceivable considering the fact that dietary supplements contain high amounts of often heterogeneous populations of probiotics. Such events can confer pathogens protection against commonly-used drugs. Despite numerous reports of antibiotic resistant probiotics in food and biological sources, the antibiogram of probiotics from dietary supplements remained elusive. FINDINGS: Here, we screened five commercially available dietary supplements for resistance towards antibiotics of different classes. Probiotics of all batches of products were resistant towards vancomycin while batch-dependent resistance towards streptomycin, aztreonam, gentamycin and/or ciprofloxacin antibiotics was detected for probiotics of brands Bi and Bn, Bg, and L. Isolates of brand Cn was also resistant towards gentamycin, streptomycin and ciprofloxacin antibiotics. Additionally, we also report a discrepancy between the enumerated viable bacteria amounts and the claims of the manufacturers. CONCLUSIONS: This short report has highlighted the present of antibiotic resistance in probiotic bacteria from dietary supplements and therefore serves as a platform for further screenings and for in-depth characterization of the resistant determinants and the molecular machinery that confers the resistance.201526370532
463940.9997Genomic and Phenotypic Characterization of Mastitis-Causing Staphylococci and Probiotic Lactic Acid Bacteria Isolated from Raw Sheep's Milk. Dairy products play a crucial role in human nutrition as they provide essential nutrients. However, the presence of diverse microorganisms in these products can pose challenges to food safety and quality. Here, we provide a comprehensive molecular characterization of a diverse collection of lactic acid bacteria (LAB) and staphylococci isolated from raw sheep's milk. Whole-genome sequencing, phenotypic characterization, and bioinformatics were employed to gain insight into the genetic composition and functional attributes of these bacteria. Bioinformatics analysis revealed the presence of various genetic elements. Important toxin-related genes in staphylococci that contribute to their pathogenic potential were identified and confirmed using phenotypic assays, while adherence-related genes, which are essential for attachment to host tissues, surfaces in the dairy environment, and the creation of biofilms, were also present. Interestingly, the Staphylococcus aureus isolates belonged to sequence type 5, which largely consists of methicillin-susceptible isolates that have been involved in severe nosocomial infections. Although genes encoding methicillin resistance were not identified, multiple resistance genes (RGs) conferring resistance to aminoglycosides, macrolides, and fluroquinolones were found. In contrast, LAB had few inherently present RGs and no virulence genes, suggesting their likely safe status as food additives in dairy products. LAB were also richer in bacteriocins and carbohydrate-active enzymes, indicating their potential to suppress pathogens and effectively utilize carbohydrate substrates, respectively. Additionally, mobile genetic elements, present in both LAB and staphylococci, may facilitate the acquisition and dissemination of genetic traits, including RGs, virulence genes, and metabolic factors, with implications for food quality and public health. The molecular and phenotypic characterization presented herein contributes to the effort to mitigate risks and infections (e.g., mastitis) and enhance the safety and quality of milk and products thereof.202337762186
417850.9997Efficacy and food safety considerations of poultry competitive exclusion products. Competitive exclusion (CE) products are anaerobic cultures of bacteria that are applied to poultry hatchlings to establish a protective enteric microbiota that excludes intestinal colonization by human food-borne pathogens. For safety of the poultry flock and human consumers, the identities of bacteria in CE products need to be known. A CE product is a culture of intestinal contents from adult chickens. It may be microbiologically defined by analysis of bacteria isolated from the culture, but many bacteria are hard to reliably isolate, identify, and characterize with conventional techniques. Sequence analysis of 16S ribosomal RNA (rRNA) genes may be more reliable than conventional techniques to identify CE bacteria. Bacteria in CE products may contain antimicrobial drug resistance and virulence mechanisms that could be transferred to the enteric bacteria of the food animal and to the human consumer. Detection methods for specific antimicrobial drug resistance and virulence genes and the integrase genes of conjugative transposons, mostly utilizing PCR technology, are being developed that can be applied to assess these risks in CE bacteria. With improvements in efficacy, bacterial identification, and detection and control of the possible risks of gene transfer, CE product technology can be made a more effective food safety tool.200617039457
477560.9997Safety assessment of dairy microorganisms: the Lactobacillus genus. Lactobacilli are Gram positive rods belonging to the Lactic Acid Bacteria (LAB) group. Their phenotypic traits, such as each species' obligate/facultative, homo/heterofermentation abilities play a crucial role in souring raw milk and in the production of fermented dairy products such as cheese, yoghurt and fermented milk (including probiotics). An up to date safety analysis of these lactobacilli is needed to ensure consumer safety. Lactobacillus genus is a heterogeneous microbial group containing some 135 species and 27 subspecies, whose classification is constantly being reshuffled. With the recent use of advanced molecular methods it has been suggested that the extreme diversity of the Lactobacillus genomes would justify recognition of new subgeneric divisions. A combination of genotypic and phenotypic tests, for example DNA-based techniques and conventional carbohydrate tests, is required to determine species. Pulsed-Field gel Electrophoresis (PFGE) has been successfully applied to strains of dairy origin and is the most discriminatory and reproducible method for differentiating Lactobacillus strains. The bibliographical data support the hypothesis that the ingestion of Lactobacillus is not at all hazardous since lactobacillemia induced by food, particularly fermented dairy products, is extremely rare and only occurs in predisposed patients. Some metabolic features such as the possible production of biogenic amines in fermented products could generate undesirable adverse effects. A minority of starter and adjunct cultures and probiotic Lactobacillus strains may exceptionally show transferable antibiotic resistance. However, this may be underestimated as transferability studies are not systematic. We consider that transferable antibiotic resistance is the only relevant cause for caution and justifies performing antibiotic-susceptibility assays as these strains have the potential to serve as hosts of antibiotic-resistance genes, with the risk of transferring these genes to other bacteria. However, as a general rule, lactobacilli have a high natural resistance to many antibiotics, especially vancomycin, that is not transferable. Safety assessment requirements for Lactobacillus strains of technological interest should be limited to an antibiotic profile and a study to determine whether any antibiotic resistance(s) of medical interest detected is (or are) transferable. This agrees with the recent EFSA proposal suggesting attribution of a QPS status for 32 selected species of lactobacilli.200817889388
418170.9997The place of molecular genetic methods in the diagnostics of human pathogenic anaerobic bacteria. A minireview. Anaerobic infections are common and can cause diseases associated with severe morbidity, but are easily overlooked in clinical settings. Both the relatively small number of infections due to exogenous anaerobes and the much larger number of infections involving anaerobic species that are originally members of the normal flora, may lead to a life-threatening situation unless appropriate treatment is instituted. Special laboratory procedures are needed for the isolation, identification and susceptibility testing of this diverse group of bacteria. Since many anaerobes grow more slowly than the facultative or aerobic bacteria, and particularly since clinical specimens yielding anaerobic bacteria commonly contain several organisms and often very complex mixtures of aerobic and anaerobic bacteria, considerable time may elapse before the laboratory is able to provide a final report. Species definition based on phenotypic features is often time-consuming and is not always easy to carry out. Molecular genetic methods may help in the everyday clinical microbiological practice in laboratories dealing with the diagnostics of anaerobic infections. Methods have been introduced for species diagnostics, such as 16S rRNA PCR-RFLP profile determination, which can help to distinguish species of Bacteroides, Prevotella, Actinomyces, etc. that are otherwise difficult to differentiate. The use of DNA-DNA hybridization and the sequencing of special regions of the 16S rRNA have revealed fundamental taxonomic changes among anaerobic bacteria. Some anaerobic bacteria are extremely slow growing or not cultivatable at all. To detect them in special infections involving flora changes due to oral malignancy or periodontitis, for instance, a PCR-based hybridization technique is used. Molecular methods have demonstrated the spread of specific resistance genes among the most important anaerobic bacteria, the members of the Bacteroides genus. Their detection and investigation of the IS elements involved in their expression may facilitate following of the spread of antibiotic resistance among anaerobic bacteria involved in infections and in the normal flora members. Molecular methods (a search for toxin genes and ribotyping) may promote a better understanding of the pathogenic features of some anaerobic infections, such as the nosocomial diarrhoea caused by C. difficile and its spread in the hospital environment and the community. The investigation of toxin production at a molecular level helps in the detection of new toxin types. This mini-review surveys some of the results obtained by our group and others using molecular genetic methods in anaerobic diagnostics.200616956128
391880.9997Update on antibiotic resistance in foodborne Lactobacillus and Lactococcus species. Lactobacilli represent a major Lactic Acid Bacteria (LAB) component within the complex microbiota of fermented foods obtained from meat, dairy, and vegetable sources. Lactococci, on the other hand, are typical of milk and fermented dairy products, which in turn represent the vast majority of fermented foods. As is the case for all species originating from the environment, foodborne lactobacilli and lactococci consist of natural, uncharacterized strains, whose biodiversity depends on geographical origin, seasonality, animal feeding/plant growth conditions. Although a few species of opportunistic pathogens have been described, lactobacilli and lactococci are mostly non-pathogenic, Gram-positive bacteria displaying probiotic features. Since antibiotic resistant (AR) strains do not constitute an immediate threat to human health, scientific interest for detailed studies on AR genes in these species has been greatly hindered. However, increasing evidence points at a crucial role for foodborne LAB as reservoir of potentially transmissible AR genes, underlining the need for further, more detailed studies aimed at identifying possible strategies to avoid AR spread to pathogens through fermented food consumption. The availability of a growing number of sequenced bacterial genomes has been very helpful in identifying the presence/distribution of mobile elements associated with AR genes, but open questions and knowledge gaps still need to be filled, highlighting the need for systematic and datasharing approaches to implement both surveillance and mechanistic studies on transferability of AR genes. In the present review we report an update of the recent literature on AR in lactobacilli and lactococci following the 2006 EU-wide ban of the use of antibiotics as feed additives in animal farming, and we discuss the limits of the present knowledge in evaluating possible risks for human health.201324115946
422490.9997The Genus Enterococcus: Between Probiotic Potential and Safety Concerns-An Update. A considerable number of strains belonging to different species of Enterococcus are highly competitive due to their resistance to wide range of pH and temperature. Their competitiveness is also owed to their ability to produce bacteriocins recognized for their wide-range effectiveness on pathogenic and spoilage bacteria. Enterococcal bacteriocins have attracted great research interest as natural antimicrobial agents in the food industry, and as a potential drug candidate for replacing antibiotics in order to treat multiple drugs resistance pathogens. However, the prevalence of virulence factors and antibiotic-resistance genes and the ability to cause disease could compromise their application in food, human and animal health. From the current regulatory point of view, the genus Enterococcus is neither recommended for the QPS list nor have GRAS status. Although recent advances in molecular biology and the recommended methods for the safety evaluation of Enterococcus strains allowed the distinction between commensal and clinical clades, development of highly adapted methods and legislations are still required. In the present review, we evaluate some aspects of Enterococcus spp. related to their probiotic properties and safety concerns as well as the current and potential application in food systems and treatment of infections. The regulatory status of commensal Enterococcus candidates for food, feed, probiotic use, and recommended methods to assess and ensure their safety are also discussed.201830123208
4180100.9997Toward integrative genomics study of genetic resistance to Salmonella and Campylobacter intestinal colonization in fowl. Salmonella enterica serotypes Enteritidis and Typhimurium and Campylobacter jejuni are responsible for most cases of food poisoning in Europe. These bacteria do not cause severe disease symptoms in chicken, but they are easily propagated by symptomless chicken carriers which cannot be easily isolated. This animal tolerance is detrimental to food safety. In this particular case, increasing animal's resistance is not sufficient, since some animals considered as resistant are able to carry bacteria during several weeks without displaying disease symptoms. We review studies aimed at evaluating the resistance of chicken to Salmonella and Campylobacter intestinal colonization, either a few days or several weeks after infection. While studies of the genetic control of Campylobacter colonization are only beginning, mostly due to technical difficulties in infection protocols, genetic studies of Salmonella colonization have been conducted for now more than 20 years. They have initially reported an estimation of the genetic parameters associated with resistance to Salmonella colonization and are now aimed at identifying the genomic regions controlling variation of this trait in experimental lines and commercial populations. With the advent of high-throughput genomics, we are closer than ever to identify the true genes controlling resistance to Enterobacteria colonization in chicken. The comparison of genes involved in early resistance to intestinal colonization with genes controlling resistance to bacteria persistence several weeks after infection (i.e., carrier-state) should soon highlight the differences between the molecular mechanisms underlying those two distinct phenotypes. It will also be highly interesting to compare the genes or genomic regions controlling Campylobacter and Salmonella, in order to evaluate the feasibility of a selection conducted on both bacteria simultaneously.201223412643
4221110.9997Antibiotic resistance in probiotic bacteria. Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. The main probiotic bacteria are strains belonging to the genera Lactobacillus and Bifidobacterium, although other representatives, such as Bacillus or Escherichia coli strains, have also been used. Lactobacillus and Bifidobacterium are two common inhabitants of the human intestinal microbiota. Also, some species are used in food fermentation processes as starters, or as adjunct cultures in the food industry. With some exceptions, antibiotic resistance in these beneficial microbes does not constitute a safety concern in itself, when mutations or intrinsic resistance mechanisms are responsible for the resistance phenotype. In fact, some probiotic strains with intrinsic antibiotic resistance could be useful for restoring the gut microbiota after antibiotic treatment. However, specific antibiotic resistance determinants carried on mobile genetic elements, such as tetracycline resistance genes, are often detected in the typical probiotic genera, and constitute a reservoir of resistance for potential food or gut pathogens, thus representing a serious safety issue.201323882264
4673120.9997Whole-genome analysis of probiotic product isolates reveals the presence of genes related to antimicrobial resistance, virulence factors, and toxic metabolites, posing potential health risks. BACKGROUND: Safety issues of probiotic products have been reported frequently in recent years. Ten bacterial strains isolated from seven commercial probiotic products on market were evaluated for their safety, by whole-genome analysis. RESULTS: We found that the bacterial species of three probiotic products were incorrectly labeled. Furthermore, six probiotic product isolates (PPS) contained genes for the production of toxic metabolites, while another three strains contained virulence genes, which might pose a potential health risk. In addition, three of them have drug-resistance genes, among which two strains potentially displayed multidrug resistance. One isolate has in silico predicted transferable genes responsible for toxic metabolite production, and they could potentially transfer to human gut microflora or environmental bacteria. Isolates of Lactobacillus rhamnosus and Bifidobacterium animalis subsp. lactis are associated with low risk for human consumption. Based on a comparative genome analysis, we found that the isolated Enterococcus faecium TK-P5D clustered with a well-defined probiotic strain, while E. faecalis TK-P4B clustered with a pathogenic strain. CONCLUSIONS: Our work clearly illustrates that whole-genome analysis is a useful method to evaluate the quality and safety of probiotic products. Regulatory quality control and stringent regulations on probiotic products are needed to ensure safe consumption and protect human health.202133761872
4219130.9997Antibiotic resistance and virulence factors in lactobacilli: something to carefully consider. Lactobacilli are a ubiquitous bacteria, that includes many species commonly found as part of the human microbiota, take part in the natural food fermentation processes, are used as probiotics, and in the food sector as starter cultures or bio-protectors. Their wide use is dictated by a long history of safe employ, which has allowed them to be classified as GRAS (General Recognized As Safe) microorganisms by the US Food and Drug Administration (FDA) and QPS (Qualified Presumption of Safety) by the European Food Safety Authority (EFSA, 2007; EFSA, 2021). Despite their classification as safe microorganisms, several studies show that some members of Lactobacillus genus can cause, especially in individuals with previous pathological conditions, problems such as bacteremia, endocarditis, and peritonitis. In other cases, the presence of virulence genes and antibiotic resistance, and its potential transfer to pathogenic microorganisms constitute a risk to be considered. Consequently, their safety status was sometimes questioned, and it is, therefore, essential to carry out appropriate assessments before their use for any purposes. The following review focuses on the state of the art of studies on genes that confer virulence factors, including antibiotic resistance, reported in the literature within the lactobacilli, defining their genetic basis and related functions.202235082060
4636140.9997Functional screening of antibiotic resistance genes from a representative metagenomic library of food fermenting microbiota. Lactic acid bacteria (LAB) represent the predominant microbiota in fermented foods. Foodborne LAB have received increasing attention as potential reservoir of antibiotic resistance (AR) determinants, which may be horizontally transferred to opportunistic pathogens. We have previously reported isolation of AR LAB from the raw ingredients of a fermented cheese, while AR genes could be detected in the final, marketed product only by PCR amplification, thus pointing at the need for more sensitive microbial isolation techniques. We turned therefore to construction of a metagenomic library containing microbial DNA extracted directly from the food matrix. To maximize yield and purity and to ensure that genomic complexity of the library was representative of the original bacterial population, we defined a suitable protocol for total DNA extraction from cheese which can also be applied to other lipid-rich foods. Functional library screening on different antibiotics allowed recovery of ampicillin and kanamycin resistant clones originating from Streptococcus salivarius subsp. thermophilus and Lactobacillus helveticus genomes. We report molecular characterization of the cloned inserts, which were fully sequenced and shown to confer AR phenotype to recipient bacteria. We also show that metagenomics can be applied to food microbiota to identify underrepresented species carrying specific genes of interest.201425243126
4222150.9997Conjugal Transfer of Antibiotic Resistances in Lactobacillus spp. Lactic acid bacteria (LAB) are a heterogeneous group of bacteria which are Gram-positive, facultative anaerobes and non-motile, non-spore forming, with varied shapes from cocci to coccobacilli and bacilli. Lactobacillus is the largest and most widely used bacterial species amongst LAB in fermented foods and beverages. The genus is a common member of human gut microbiome. Several species are known to provide benefits to the human gut via synergistic interactions with the gut microbiome and their ability to survive the gut environment. This ability to confer positive health effects provide them a status of generally recognized as safe (GRAS) microorganisms. Due to their various beneficial characteristics, other factors such as their resistance acquisition were overlooked. Overuse of antibiotics has made certain bacteria develop resistance against these drugs. Antibiotic resistance was found to be acquired mainly through conjugation which is a type of lateral gene transfer. Several in vitro methods of conjugation have been discussed previously depending on their success to transfer resistance. In this review, we have addressed methods that are employed to study the transfer of resistance genes using the conjugation phenomenon in lactobacilli.202134076710
4177160.9997Statement on how to interpret the QPS qualification on 'acquired antimicrobial resistance genes'. The qualified presumption of safety (QPS) approach was developed to provide a regularly updated generic pre-evaluation of the safety of microorganisms intended for use in the food or feed chains. Safety concerns identified for a taxonomic unit (TU) are, where possible, confirmed at the species/strain or product level and reflected by 'qualifications' which should be assessed at strain and/or product level by EFSA's Scientific Panels. The generic qualification 'the strains should not harbour any acquired antimicrobial resistance (AMR) genes to clinically relevant antimicrobials' applies to all QPS bacterial TUs. The different EFSA risk assessment areas use the same approach to assess the qualification related to AMR genes. In this statement, the terms 'intrinsic' and 'acquired' AMR genes were defined for the purpose of EFSA's risk assessments, and they apply to bacteria used in the food and feed chains. A bioinformatic approach is proposed for demonstrating the 'intrinsic'/'acquired' nature of an AMR gene. All AMR genes that confer resistance towards 'critically important', 'highly important' and 'important' antimicrobials, as defined by the World Health Organisation (WHO), found as hits, need to be considered as hazards (for humans, animals and environment) and need further assessment. Genes identified as responsible for 'intrinsic' resistance could be considered as being of no concern in the frame of the EFSA risk assessment. 'Acquired' AMR genes resulting in a resistant phenotype should be considered as a concern. If the presence of the 'acquired' AMR gene is not leading to phenotypic resistance, further case-by-case assessment is necessary.202337915981
4730170.9997Antibiotic Resistance Carriage Causes a Lower Survivability Due to Stress Associated with High-Pressure Treatment among Strains from Starter Cultures. High-pressure processing is one of the most promising novel food preservation methods that is increasingly used in the food industry. Its biggest advantage is that it is a nonthermal method that ensures the microbiological safety of the product while maintaining other features, including nutritional value. If products made with starter cultures are subjected to high-pressure treatment, the process parameters should be selected so as not to eliminate all microorganisms in the product. The aim of the study was to investigate if carrying antibiotic resistance genes affects the survival of lactic acid bacteria (Lactococcus and the former Lactobacillus) strains during high-pressure treatment. Survival was assessed using the plate count method. It was shown that the strains carrying antibiotic resistance genes showed a lower survival to high pressure. This might be explained by the phenomenon of fitness cost, consisting in a reduced adaptation of antibiotic-resistant strains related to metabolic expenditure. The obtained results indicate the need for further research in this field and the need to select food processing parameters depending on the strains intentionally included in the food.202235681924
4339180.9997Overview of Virulence and Antibiotic Resistance in Campylobacter spp. Livestock Isolates. Campylobacter remains the most prevalent foodborne pathogen bacterium responsible for causing gastroenteritis worldwide. Specifically, this pathogen colonises a ubiquitous range of environments, from poultry, companion pets and livestock animals to humans. The bacterium is uniquely adaptable to various niches, leading to complicated gastroenteritis and, in some cases, difficult to treat due to elevated resistance to certain antibiotics. This increased resistance is currently detected via genomic, clinical or epidemiological studies, with the results highlighting worrying multi-drug resistant (MDR) profiles in many food and clinical isolates. The Campylobacter genome encodes a rich inventory of virulence factors offering the bacterium the ability to influence host immune defences, survive antimicrobials, form biofilms and ultimately boost its infection-inducing potential. The virulence traits responsible for inducing clinical signs are not sufficiently defined because several populations have ample virulence genes with physiological functions that reflect their pathogenicity differences as well as a complement of antimicrobial resistance (AMR) systems. Therefore, exhaustive knowledge of the virulence factors associated with Campylobacter is crucial for collecting molecular insights into the infectivity processes, which could pave the way for new therapeutical targets to combat and control the infection and mitigate the spread of MDR bacteria. This review provides an overview of the spread and prevalence of genetic determinants associated with virulence and antibiotic resistance from studies performed on livestock animals. In addition, we have investigated the relevant coincidental associations between the prevalence of the genes responsible for pathogenic virulence, horizontal gene transfer (HGT) and transmissibility of highly pathogenic Campylobacter strains.202336830312
3925190.9997Evaluating the health risk of probiotic supplements from the perspective of antimicrobial resistance. Antimicrobial resistance remains a public health threat. Probiotics harboring antimicrobial resistant genes (ARGs) have, in recent years, been considered a potential health risk. Studies conducted on probiotics from increasingly popular health supplements have raised the possibility of transmitting ARGs to commensals in the human gut, concomitantly establishing a reservoir of ARGs and risking acquisition by opportunistic pathogens. Building on our previous study that reported multiple antibiotic resistance in probiotics of health supplements, in this research, we have attempted to detect their ARGs that may account for resistant phenotypes. ARGs responsible for tetracycline, macrolide, aminoglycoside, and glycopeptide resistance were prevalent in probiotics. Through laboratory adaptive evolution studies, we also show that streptomycin-adapted probiotics gained resistance to erythromycin, tetracycline, and doxycycline more effectively than non-adapted ones. When co-incubated with Enterococcus faecalis, Escherichia coli, or Staphylococcus aureus on Caco-2 and/or HCT-116 cells, streptomycin resistance was transferred from the adapted probiotics to generate transconjugants at frequencies comparable to or higher than that of other studies conducted through filter mating. Consistently, ARGs conferring resistance to streptomycin (aadA) and erythromycin [erm(B)-1] were detected in E. coli and S. aureus transconjugants, respectively, after co-incubation with streptomycin-adapted probiotics on Caco-2 cells. aadA and erm(B)-1 were both detected in E. faecalis transconjugant after the same co-incubation on HCT-116 cells. Our data and future comparative genomics and metagenomics studies conducted on animal models and in healthy, immunocompromised, and/or antibiotic-treated human cohorts will contribute to a more comprehensive understanding of probiotic consumption, application, and safety. IMPORTANCE: Probiotics are becoming increasingly popular, with promising applications in food and medicine, but the risk of transferring ARGs to disease-causing bacteria has raised concerns. Our study detected ARGs in probiotics of health supplements conferring resistance to tetracycline, macrolide, aminoglycoside, and glycopeptide drugs. Streptomycin-adapted probiotics also gained resistance to other antibiotics more effectively than non-adapted ones. Importantly, we showed that streptomycin resistance could be transferred to other bacteria after co-incubation with probiotics on human intestinal cells. ARGs responsible for erythromycin and streptomycin resistance, which were initially absent in the recipient bacteria, were also detected in the transconjugants. Our data build the foundation for future studies that will be conducted on animal models and in humans and leveraging advanced metagenomics approaches to clarify the long-term health risk of probiotic consumption.202539655960