# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 4774 | 0 | 1.0000 | Are antimicrobial resistance genes key targets to detect genetically modified microorganisms in fermentation products? As genetically modified microorganisms (GMM), commonly used by the food and feed industry to produce additives, enzymes and flavourings, are frequently harbouring antimicrobial resistance (AMR) genes as selection markers, health and environmental concerns were consequently raised. For this reason, the interest of the competent authorities to control such microbial fermentation products has strongly increased, especially since several recent accidental contaminations of unauthorized GMM, or associated recombinant DNA, in bacterial fermentation products intended for the European food and feed chain. However, no global screening strategy is currently available in enforcement laboratories to assess the presence of GMM harbouring AMR genes and/or the presence of full-length AMR genes. Moreover, the confidentiality of the related GMM dossiers strongly hampers the development of methods to perform such control. To overcome this issue, an analysis of related publicly available patents was performed in this study to identify all reported AMR genes. On this basis, the aminoglycoside adenyltransferase (aadD) gene, conferring a resistance to both kanamycin and neomycin, was identified as a key target to cover a large spectrum of GM bacteria. A real-time PCR method to screen for its potential presence as well as a nested-PCR method associated with a sequencing analysis to assess its full-length were developed to target this aadD gene. The performance of these new methods were successfully evaluated in terms of specificity, sensitivity and applicability, allowing their easy implementation in enforcement laboratories. Moreover, the integration of these newly developed methods to our very recently proposed strategy, initially targeting GMM carrying a chloramphenicol resistance gene, allows to drastically increase the detection spectrum of GM bacteria producing fermentation food and feed products. The data generated by the proposed strategy represents therefore a crucial support for the competent authorities, especially to evaluate potential risks for the food and feed safety. | 2020 | 32622259 |
| 4220 | 1 | 0.9997 | Whole 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. | 2023 | 35694810 |
| 4181 | 2 | 0.9997 | The 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. | 2006 | 16956128 |
| 4178 | 3 | 0.9996 | Efficacy 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. | 2006 | 17039457 |
| 4776 | 4 | 0.9996 | Integrate 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. | 2016 | 26952108 |
| 4177 | 5 | 0.9996 | Statement 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. | 2023 | 37915981 |
| 4296 | 6 | 0.9996 | Twenty-first century molecular methods for analyzing antimicrobial resistance in surface waters to support One Health assessments. Antimicrobial resistance (AMR) in the environment is a growing global health concern, especially the dissemination of AMR into surface waters due to human and agricultural inputs. Within recent years, research has focused on trying to understand the impact of AMR in surface waters on human, agricultural and ecological health (One Health). While surface water quality assessments and surveillance of AMR have historically utilized culture-based methods, culturing bacteria has limitations due to difficulty in isolating environmental bacteria and the need for a priori information about the bacteria for selective isolation. The use of molecular techniques to analyze AMR at the genetic level has helped to overcome the difficulties with culture-based techniques since they do not require advance knowledge of the bacterial population and can analyze uncultivable environmental bacteria. The aim of this review is to provide an overview of common contemporary molecular methods available for analyzing AMR in surface waters, which include high throughput real-time polymerase chain reaction (HT-qPCR), metagenomics, and whole genome sequencing. This review will also feature how these methods may provide information on human and animal health risks. HT-qPCR works at the nanoliter scale, requires only a small amount of DNA, and can analyze numerous gene targets simultaneously, but may lack in analytical sensitivity and the ability to optimize individual assays compared to conventional qPCR. Metagenomics offers more detailed genomic information and taxonomic resolution than PCR by sequencing all the microbial genomes within a sample. Its open format allows for the discovery of new antibiotic resistance genes; however, the quantity of DNA necessary for this technique can be a limiting factor for surface water samples that typically have low numbers of bacteria per sample volume. Whole genome sequencing provides the complete genomic profile of a single environmental isolate and can identify all genetic elements that may confer AMR. However, a main disadvantage of this technique is that it only provides information about one bacterial isolate and is challenging to utilize for community analysis. While these contemporary techniques can quickly provide a vast array of information about AMR in surface waters, one technique does not fully characterize AMR nor its potential risks to human, animal, or ecological health. Rather, a combination of techniques (including both molecular- and culture-based) are necessary to fully understand AMR in surface waters from a One Health perspective. | 2021 | 33774111 |
| 3918 | 7 | 0.9996 | Update 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. | 2013 | 24115946 |
| 4637 | 8 | 0.9996 | What 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. | 2020 | 32762606 |
| 4225 | 9 | 0.9996 | Safety aspects and implications of regulation of probiotic bacteria in food and food supplements. The application of living bacteria as probiotics in food or food supplements requires a careful safety assessment. This review summarizes key issues concerning the safety aspects of bacteria added to particular products marketed for improvement of general health or treatment of (post)infectious symptoms. The bacteria used in such products should be completely safe; however, it can be challenging to provide evidence for absence of all virulence properties. In some cases, virulence factors have been detected in probiotic bacterial strains, and the implications of these traits for safety assessments are discussed. Horizontal gene transfer can result in acquisition of virulence genes or antimicrobial resistance in probiotic bacteria. Antimicrobial resistance in these bacteria can possibly aid the spread of undesired resistance in intestinal bacterial populations. The relative risk of such gene transfers is considered. The generation of complete bacterial genome sequences can both resolve and create safety issues. Current practices of safety assessment procedures in the United States and the European Union are briefly reviewed and a future outlook is provided. | 2008 | 18724773 |
| 3825 | 10 | 0.9996 | Lack of detectable DNA uptake by transformation of selected recipients in mono-associated rats. BACKGROUND: An important concern revealed in the public discussion of the use of genetically modified (GM) plants for human consumption, is the potential transfer of DNA from these plants to bacteria present in the gastrointestinal tract. Especially, there is a concern that antibiotic resistance genes used for the construction of GM plants end up in pathogenic bacteria, eventually leading to untreatable disease. FINDINGS: Three different bacterial species (Escherichia coli, Bacillus subtilis, Streptococcus gordonii), all natural inhabitants of the food and intestinal tract environment were used as recipients for uptake of DNA. As source of DNA both plasmid and genomic DNA from GM plants were used in in vitro and in vivo transformation studies. Mono-associated rats, creating a worst-case scenario, did not give rise to any detectable transfer of DNA. CONCLUSION: Although we were unable to detect any transformation events in our experiment, it cannot be ruled out that this could happen in the GI tract. However, since several steps are required before expression of plant-derived DNA in intestinal bacteria, we believe this is unlikely, and antibiotic resistance development in this environment is more in danger by the massive use of antibiotics than the consumption of GM food harbouring antibiotic resistance genes. | 2010 | 20193062 |
| 9405 | 11 | 0.9996 | Functional Metagenomic Screening for Antimicrobial Resistance in the Oral Microbiome. A large proportion of bacteria, from a multitude of environments, are not yet able to be grown in the laboratory, and therefore microbiological and molecular biological investigations of these bacteria are challenging. A way to circumvent this challenge is to analyze the metagenome, the entire collection of DNA molecules that can be isolated from a particular environment or sample. This collection of DNA molecules can be sequenced and assembled to determine what is present and infer functional potential, or used as a PCR template to detect known target DNA and potentially unknown regions of DNA nearby those targets; however assigning functions to new or conserved hypothetical, functionally cryptic, genes is difficult. Functional metagenomics allows researchers to determine which genes are responsible for selectable phenotypes, such as resistance to antimicrobials and metabolic capabilities, without the prerequisite needs to grow the bacteria containing those genes or to already know which genes are of interest. It is estimated that a third of the resident species of the human oral cavity is not yet cultivable and, together with the ease of sample acquisition, makes this metagenome particularly suited to functional metagenomic studies. Here we describe the methodology related to the collection of saliva samples, extraction of metagenomic DNA, construction of metagenomic libraries, as well as the description of functional assays that have previously led to the identification of new genes conferring antimicrobial resistance. | 2021 | 34410638 |
| 4216 | 12 | 0.9996 | Antimicrobial Resistance in the Food Chain in the European Union. Consumers require safety foods but without losing enough supply and low prices. Food concerns about antimicrobial residues and antimicrobial-resistant (AMR) bacteria are not usually appropriately separated and could be perceived as the same problem. The monitoring of residues of antimicrobials in animal food is well established at different levels (farm, slaughterhouse, and industry), and it is preceded by the legislation of veterinary medicines where maximum residues limits are required for medicines to be used in food animal. Following the strategy of the World Health Organization, one of the proposed measures consists in controlling the use of critical antibiotics. The European Union surveillance program currently includes the animal species with the highest meat production (pigs, chickens, turkeys, and cattle) and the food derived from them, investigating antimicrobial resistance of zoonotic (Salmonella and Campylobacter) and indicator (Escherichia coli and enterococci) bacteria. AMR mechanisms encoded by genes have a greater impact on transfer than mutations. Sometimes these genes are found in mobile genetic elements such as plasmids, transposons, or integrons, capable of passing from one bacterium to another by horizontal transfer. It is important to know that depending on how the resistance mechanism is transferred, the power of dissemination is different. By vertical transfer of the resistance gene, whatever its origin, will be transmitted to the following generations. In the case of horizontal transfer, the resistance gene moves to neighboring bacteria and therefore the range of resistance can be much greater. | 2018 | 30077219 |
| 4219 | 13 | 0.9996 | Antibiotic 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. | 2022 | 35082060 |
| 9918 | 14 | 0.9996 | Linking plasmid-based beta-lactamases to their bacterial hosts using single-cell fusion PCR. The horizonal transfer of plasmid-encoded genes allows bacteria to adapt to constantly shifting environmental pressures, bestowing functional advantages to their bacterial hosts such as antibiotic resistance, metal resistance, virulence factors, and polysaccharide utilization. However, common molecular methods such as short- and long-read sequencing of microbiomes cannot associate extrachromosomal plasmids with the genome of the host bacterium. Alternative methods to link plasmids to host bacteria are either laborious, expensive, or prone to contamination. Here we present the One-step Isolation and Lysis PCR (OIL-PCR) method, which molecularly links plasmid-encoded genes with the bacterial 16S rRNA gene via fusion PCR performed within an emulsion. After validating this method, we apply it to identify the bacterial hosts of three clinically relevant beta-lactamases within the gut microbiomes of neutropenic patients, as they are particularly vulnerable multidrug-resistant infections. We successfully detect the known association of a multi-drug resistant plasmid with Klebsiella pneumoniae, as well as the novel associations of two low-abundance genera, Romboutsia and Agathobacter. Further investigation with OIL-PCR confirmed that our detection of Romboutsia is due to its physical association with Klebsiella as opposed to directly harboring the beta-lactamase genes. Here we put forth a robust, accessible, and high-throughput platform for sensitively surveying the bacterial hosts of mobile genes, as well as detecting physical bacterial associations such as those occurring within biofilms and complex microbial communities. | 2021 | 34282723 |
| 4791 | 15 | 0.9996 | Detection of tetracycline resistance genes by PCR methods. Rapid, accurate, and sensitive determination of antibiotic resistance profiles of various human and animal pathogens becomes a vital prerequisite for successful therapeutic intervention in the face of the increased occurrences of drug-resistant bacterial infections. The current methods, which are dependent on cultivation of pathogens and phenotypic expression of antibiotic resistance, usually require excessive time, special microbiological equipment, and qualified personnel. However, even with all these requisites, for example, no bacteria can be grown from more than 80% of all clinical samples sent to clinical microbiology laboratories. Besides the cultivation limitations, the cultivation-based determination of an antibiotic resistance profile lacks the genotypic information, which is essential for understanding the epidemiology and routes of transmission of antibiotic resistance genes. These genes often reside on mobile genetic elements and can move freely between commensal and pathogenic microbiota, occurring even between taxonomically distant clinical and environmental microbiota. Therefore, development of genotyping methods for detection of antibiotic resistance genes is highly desirable for fast, accurate, and sensitive detection of antibiotic resistance genes in a broad range of pathogenic and commensal bacteria in both clinical and environmental samples. As a model for our studies we have chosen the genes conferring resistance to tetracyclines. Tetracyclines belong to a family of broad-spectrum antibiotics that include tetracycline, chlortetracycline, oxytetracycline, demeclocycline, methacycline, doxycycline, minocycline, and a number of other semisynthetic derivatives. These antibiotics inhibit protein synthesis in Gram-positive and Gram-negative bacteria by preventing the binding of aminoacyl-tRNA molecules to the 30S ribosomal subunit. The antibiotics of this group were introduced in the late 1950s and since then have been widely used in clinical and veterinary medicine, as well as for prophylaxis and growth promotion in food animals. Because of the possible misuse and overuse of these drugs, resistance to this class of antibiotics is widespread among many clinical isolates, thus limiting the utility of tetracyclines in treating infections. Despite this shortcoming, antibiotics of this class still remain in the active arsenal for dermatologists to treat skin infections such as acne and rosacea. | 2004 | 15156014 |
| 9656 | 16 | 0.9996 | Use of sequence barcodes for tracking horizontal gene transfer of antimicrobial resistance genes in a microbial community. One of the most important knowledge gaps in the antimicrobial resistance crisis is the lack of understanding regarding how genes spread from their environmental origins to bacteria pathogenic to humans. In this study our aim was to create a system that allows the conduction of experiments in laboratory settings that mimic the complexity of natural communities with multiple resistance genes and mobile genetic elements circulating at the same time. Here we report a new sequence-based barcode system that allows simultaneous tracking of the spread of antimicrobial resistance genes from multiple genetic origins. We tested this concept with an experiment in which we added an antimicrobial resistance gene to different genetic environments in alive and dead donors and let the gene spread naturally in an artificial microbial community under different environmental conditions to provide examples of factors that can be investigated. We used emulsion, paired-isolation, and concatenation polymerase chain reaction to detect the new gene carriers and metagenomic analysis to see changes in the genetic environment. We observed the genes moving and were able to recognise the barcode from the gene sequences, thus validating the idea of barcode use. We also saw that temperature and gene origin had effects on the number of new host species. Our results confirmed that our system worked and can be further developed for more complicated experiments. | 2025 | 40800620 |
| 4222 | 17 | 0.9996 | Conjugal 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. | 2021 | 34076710 |
| 4636 | 18 | 0.9996 | Functional 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. | 2014 | 25243126 |
| 5099 | 19 | 0.9996 | A machine learning-based strategy to elucidate the identification of antibiotic resistance in bacteria. Microorganisms, crucial for environmental equilibrium, could be destructive, resulting in detrimental pathophysiology to the human host. Moreover, with the emergence of antibiotic resistance (ABR), the microbial communities pose the century's largest public health challenges in terms of effective treatment strategies. Furthermore, given the large diversity and number of known bacterial strains, describing treatment choices for infected patients using experimental methodologies is time-consuming. An alternative technique, gaining popularity as sequencing prices fall and technology advances, is to use bacterial genotype rather than phenotype to determine ABR. Complementing machine learning into clinical practice provides a data-driven platform for categorization and interpretation of bacterial datasets. In the present study, k-mers were generated from nucleotide sequences of pathogenic bacteria resistant to antibiotics. Subsequently, they were clustered into groups of bacteria sharing similar genomic features using the Affinity propagation algorithm with a Silhouette coefficient of 0.82. Thereafter, a prediction model based on Random Forest algorithm was developed to explore the prediction capability of the k-mers. It yielded an overall specificity of 0.99 and a sensitivity of 0.98. Additionally, the genes and ABR drivers related to the k-mers were identified to explore their biological relevance. Furthermore, a multilayer perceptron model with a hamming loss of 0.05 was built to classify the bacterial strains into resistant and non-resistant strains against various antibiotics. Segregating pathogenic bacteria based on genomic similarities could be a valuable approach for assessing the severity of diseases caused by new bacterial strains. Utilization of this strategy could aid in enhancing our understanding of ABR patterns, paving the way for more informed and effective treatment options. | 2024 | 39816256 |