# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 4574 | 0 | 1.0000 | Antibiotic resistance and microbial composition along the manufacturing process of Mozzarella di Bufala Campana. The use of antibiotics as growth promoters in livestock, banned in all EU member states in January 2006, has led to selection of antibiotic resistant strains within environmental bacteria, including gram-positive, non pathogenic bacteria that colonize the GI tract of humans and animals. In Italy and in other Mediterranean countries, fermented foods employing environmental bacteria pre-existing in the raw substrates, rather than industrial starters of defined genotype, represent a significant proportion of cheese and meat products carrying the official PDO designation (Protected Designation of Origin). Our study focused on the microbiological and molecular analysis of lactobacilli and of other lactic acid bacteria (LABs) isolated from the Italian PDO product water buffalo Mozzarella cheese, with the aim of identifying genes responsible for tetracycline, erythromycin and kanamycin resistance. We isolated over 500 LAB colonies from retail products, as well as from raw milk and natural whey starters employed in their production. Microbiological analysis showed that about 50% of these isolates were represented by lactobacilli, which were further characterized in terms of species and strain composition, as well as by determining phenotypic and genotypic antibiotic resistance. To overcome the limits of culture-dependent approaches that select only cultivable species, we have also extracted total DNA from the whole microbiome present in the cheese and investigated the presence of specific antibiotic resistance genes with molecular approaches. Genetic determinants of antibiotic resistance were identified almost exclusively in bacteria isolated from the raw, unprocessed substrates, while the final, marketed products did not contain phenotypically resistant lactobacilli, i.e. displaying MIC values above the microbiological breakpoint. Overall, our results suggest that the traditional procedures necessary for manufacturing of this typical cheese, such as high temperature treatments, lead to a final product with low bacterial counts, lower biodiversity and lack of significant presence of antibiotic resistant lactobacilli. | 2008 | 18990462 |
| 3664 | 1 | 0.9998 | Incidence of Staphylococcus aureus and analysis of associated bacterial communities on food industry surfaces. Biofilms are a common cause of food contamination with undesirable bacteria, such as pathogenic bacteria. Staphylococcus aureus is one of the major bacteria causing food-borne diseases in humans. A study designed to determine the presence of S. aureus on food contact surfaces in dairy, meat, and seafood environments and to identify coexisting microbiota has therefore been carried out. A total of 442 samples were collected, and the presence of S. aureus was confirmed in 6.1% of samples. Sixty-three S. aureus isolates were recovered and typed by random amplification of polymorphic DNA (RAPD). Profiles were clustered into four groups which were related to specific food environments. All isolates harbored some potential virulence factors such as enterotoxin production genes, biofilm formation-associated genes, antibiotic resistance, or lysogeny. PCR-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprints of bacterial communities coexisting with S. aureus revealed the presence of bacteria either involved in food spoilage or of concern for food safety in all food environments. Food industry surfaces could thus be a reservoir for S. aureus forming complex communities with undesirable bacteria in multispecies biofilms. Uneven microbiological conditions were found in each food sector, which indicates the need to improve hygienic conditions in food processing facilities, particularly the removal of bacterial biofilms, to enhance the safety of food products. | 2012 | 23023749 |
| 4674 | 2 | 0.9998 | Identification and Antimicrobial Resistance of Bacteria Isolated from Probiotic Products Used in Shrimp Culture. Probiotics are increasingly used in aquaculture to control diseases and improve feed digestion and pond water quality; however, little is known about the antimicrobial resistance properties of such probiotic bacteria and to what extent they may contribute to the development of bacterial resistance in aquaculture ponds. Concerns have been raised that the declared information on probiotic product labels are incorrect and information on bacterial composition are often missing. We therefore evaluated seven probiotics commonly used in Vietnamese shrimp culture for their bacterial species content, phenotypic antimicrobial resistance and associated transferable resistance genes. The bacterial species was established by 16S rRNA sequence analysis of 125 representative bacterial isolates. MIC testing was done for a range of antimicrobials and whole genome sequencing of six multiple antimicrobial resistant Bacillus spp. used to identify resistance genes and genetic elements associated with horizontal gene transfer. Thirteen bacterial species declared on the probiotic products could not be identified and 11 non-declared Bacillus spp. were identified. Although our culture-based isolation and identification may have missed a few bacterial species present in the tested products this would represent minor bias, but future studies may apply culture independent identification methods like pyro sequencing. Only 6/60 isolates were resistant to more than four antimicrobials and whole genome sequencing showed that they contained macrolide (ermD), tetracycline (tetL), phenicol (fexA) and trimethoprim (dfrD, dfrG and dfrK) resistance genes, but not known structures associated with horizontal gene transfer. Probiotic bacterial strains used in Vietnamese shrimp culture seem to contribute with very limited types and numbers of resistance genes compared to the naturally occurring bacterial species in aquaculture environments. Approval procedures of probiotic products must be strengthened through scientific-based efficacy trials and product labels should allow identification of individual bacterial strains and inform the farmer on specific purpose, dosage and correct application measures. | 2015 | 26147573 |
| 4678 | 3 | 0.9998 | Antimicrobial Susceptibility of Lactic Acid Bacteria Strains of Potential Use as Feed Additives - The Basic Safety and Usefulness Criterion. The spread of resistance to antibiotics is a major health concern worldwide due to the increasing rate of isolation of multidrug resistant pathogens hampering the treatment of infections. The food chain has been recognized as one of the key routes of antibiotic resistant bacteria transmission between animals and humans. Considering that lactic acid bacteria (LAB) could act as a reservoir of transferable antibiotic resistance genes, LAB strains intended to be used as feed additives should be monitored for their safety. Sixty-five LAB strains which might be potentially used as probiotic feed additives or silage inoculants, were assessed for susceptibility to eight clinically relevant antimicrobials by a minimum inhibitory concentration determination. Among antimicrobial resistant strains, a prevalence of selected genes associated with the acquired resistance was investigated. Nineteen LAB strains displayed phenotypic resistance to one antibiotic, and 15 strains were resistant to more than one of the tested antibiotics. The resistance to aminoglycosides and tetracyclines were the most prevalent and were found in 37 and 26% of the studied strains, respectively. Phenotypic resistance to other antimicrobials was found in single strains. Determinants related to resistance phenotypes were detected in 15 strains as follows, the aph(3″)-IIIa gene in 9 strains, the lnu(A) gene in three strains, the str(A)-str(B), erm(B), msr(C), and tet(M) genes in two strains and the tet(K) gene in one strain. The nucleotide sequences of the detected genes revealed homology to the sequences of the transmissible resistance genes found in lactic acid bacteria as well as pathogenic bacteria. Our study highlights that LAB may be a reservoir of antimicrobial resistance determinants, thus, the first and key step in considering the usefulness of LAB strains as feed additives should be an assessment of their antibiotic resistance. This safety criterion should always precede more complex studies, such as an assessment of adaptability of a strain or its beneficial effect on a host. These results would help in the selection of the best LAB strains for use as feed additives. Importantly, presented data can be useful for revising the current microbiological cut-off values within the genus Lactobacillus and Pediococcus. | 2021 | 34277757 |
| 6072 | 4 | 0.9998 | Bad to the bone? - Genomic analysis of Enterococcus isolates from diverse environments reveals that most are safe and display potential as food fermentation microorganisms. Enterococci comprise a group of lactic acid bacteria (LAB) with considerable potential to serve as food fermentation microorganisms. Unfortunately, enterococci have received a lot of negative attention, due to the occurrence of pathogenic and multidrug resistant strains. In this study, we used genomics to select safe candidates among the forty-four studied enterococcal isolates. The genomes of the forty-four strains were fully sequenced and assessed for presence of virulence and antibiotic resistance genes. Nineteen isolates belonging to the species Enterococcus lactis, Enterococcus faecium, Enterococcus durans, and Enterococcus thailandicus, were deemed safe from the genome analysis. The presence of secondary metabolite gene clusters for bacteriocins was assessed, and twelve candidates were found to secrete antimicrobial compounds effective against Listeria monocytogenes isolated from cheese and Staphylococcus aureus. Physiological characterization revealed nineteen industrial potentials; all strains grew well at 42 °C and acidified 1.5 hours faster than their mesophilic counterpart Lactococcus lactis, with which they share metabolism and flavor forming ability. We conclude that a large fraction of the examined enterococci were safe and could serve as excellent food fermentation microorganisms with inherent bioprotective abilities. | 2024 | 38552381 |
| 4639 | 5 | 0.9998 | Genomic 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. | 2023 | 37762186 |
| 4636 | 6 | 0.9998 | 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 |
| 3925 | 7 | 0.9998 | Evaluating 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. | 2025 | 39655960 |
| 3920 | 8 | 0.9998 | Antibiotic resistance in wild and commercial non-enterococcal Lactic Acid Bacteria and Bifidobacteria strains of dairy origin: An update. Antibiotic Resistance is a growing concern for public health and global economy. Lactic acid bacteria (LAB) involved in the production of dairy products and commonly present in the agro-zootechnical environment can act as reservoirs of antibiotic resistance genes, acquiring or transferring them to other microorganisms. The review focuses on LAB group of dairy origin (Lactobacillus, Lactococcus, Streptococcus, Leuconostoc, Pediococcus and Weissella) and Bifidobacterium genus, considering its large use in dairy industry. We have analyzed data in the last 25 years, highlighting atypical resistance, genetic traits correlated to antibiotic resistance and their ability to be transmitted to other microorganisms; comparative analysis of resistomes was also considered. Differences were observed among wild strains isolated from different regions because of authorized antibiotic use. Commercial strains belonging to Lactobacillus, Streptococcus and Bifidobacterium currently used for industrial dairy products are frequently resistant to gentamycin, kanamycin, chloramphenicol together with tetracycline. The presence of resistant wild LAB in raw milk products has been significantly reduced as a result of worldwide restrictions on the use of antibiotics in animal husbandry. Transmissible resistances are still present in industrial cultures, despite the great effort of starter industries in the process control and the safety screening of commercial cultures. | 2022 | 35287818 |
| 4580 | 9 | 0.9997 | Antimicrobial resistance of bacteria isolated from slaughtered and retail chickens in South Africa. Animal feed is increasingly being supplemented with antibiotics to decrease the risk of epidemics in animal husbandry. This practice could lead to the selection for antibiotic resistant micro-organisms. The aim of this study was to determine the level of antibiotic resistant bacteria present on retail and abattoir chicken. Staphylococci, Enterobacteriaceae, Salmonella and isolates from total aerobic plate count were tested for resistance to vancomycin, streptomycin, methicillin, tetracycline and gentamicin using the disc diffusion susceptibility test; resistance to penicillin was determined using oxacillin. Results from the antibiotic code profile indicated that many of the bacterial strains were displaying multiple antibiotic resistance (MAR). A larger proportion of resistance to most antibiotics, except for vancomycin, was displayed by the abattoir samples, therefore suggesting that the incidence of MAR pathogenic bacteria was also higher in the abattoir samples. This resistance spectrum of abattoir samples is a result of farmers adding low doses of antibiotics to livestock feed to improve feeding efficiency so that the animals need less food to reach marketable weight. The lower incidence of MAR pathogenic bacteria in the retail samples is a result of resistance genes being lost due to lack of selective pressure, or to the fact that the resistant flora are being replaced by more sensitive flora during processing. The use of subtherapeutic levels of antibiotics for prophylaxis and as growth promoters remains a concern as the laws of evolution dictate that microbes will eventually develop resistance to practically any antibiotic. Selective pressure exerted by widespread antimicrobial use is therefore the driving force in the development of antibiotic resistance. This study indicated that a large proportion of the bacterial flora on fresh chicken is resistant to a variety of antibiotics, and that resultant food-related infections will be more difficult to treat. | 1998 | 9633089 |
| 4675 | 10 | 0.9997 | Antibiotic Susceptibility Profiles of Pediococcus pentosaceus from Various Origins and Their Implications for the Safety Assessment of Strains with Food-Technology Applications. ABSTRACT: In the fight against the spread of antibiotic resistance, authorities usually require that strains "intentionally added into the food chain" be tested for their antibiotic susceptibility. This applies to strains used in starter or adjunct cultures for the production of fermented foods, such as many strains of Pediococcus pentosaceus. The European Food Safety Authority recommends testing strains for their antibiotic susceptibility based on both genomic and phenotypic approaches. Furthermore, it proposes a set of antibiotics to assess as well as a list of microbiological cutoffs (MCs), allowing classification of lactic acid bacteria as susceptible or resistant. Accurate MCs are essential not only to avoid false-negative strains, which may carry antibiotic resistance genes and remain unnoticed, but also to avoid false-positive strains, which may be discarded while screening potential candidates for food-technology applications. Because of relatively scarce data, MCs have been defined for the whole Pediococcus genus, although differences between species should be expected. In this study, we investigated the antibiotic susceptibility of 35 strains of P. pentosaceus isolated from various matrices in the past 70 yr. MICs were determined using a standard protocol, and MIC distributions were established. Phenotypic analyses were complemented with genome sequencing and by seeking known antibiotic resistance genes. The genomes of all the strains were free of known antibiotic resistance genes, but most displayed MICs above the currently defined MCs for chloramphenicol, and all showed excessive MICs for tetracycline. Based on the distributions, we calculated and proposed new MCs for chloramphenicol (16 instead of 4 mg/L) and tetracycline (256 instead of 8 mg/L). | 2021 | 33320937 |
| 4612 | 11 | 0.9997 | Assessment of tetracycline and erythromycin resistance transfer during sausage fermentation by culture-dependent and -independent methods. The food chain is considered one of the main routes of antibiotic resistance diffusion between animal and human population. The resistance to antimicrobial agents among enterococci could be related to the efficient exchange of transferable genetic elements. In this study a sausage model was used to evaluate the persistence of antibiotic resistant enterococci during meat fermentation and to assess horizontal gene transfer among bacteria involved in meat fermentation. Enterococcus faecalis OG1rf harbouring either pCF10 or pAMβ1 plasmid was used as donor strain. The analysis of population dynamics during fermentation confirmed that the human isolate E. faecalis OG1rf was able to colonize the meat ecosystem with similar growth kinetics to that of food origin enterococci and to transfer the mobile genetic elements coding for tetracycline and erythromycin resistances. Transconjugant strains were detected after only two days of fermentation and increased their numbers during ripening even in the absence of selective antibiotic pressure. By means of culture-dependent and -independent molecular techniques, transconjugant strains carrying both tetracycline and erythromycin resistance genes were identified in enterococci, pediococci, lactobacilli and staphylococci groups. Our results suggest that the sausage model provides a suitable environment for horizontal transfer of conjugative plasmids and antibiotic resistance genes among food microbiota. | 2012 | 22365347 |
| 4572 | 12 | 0.9997 | Effect of high pressure processing on changes in antibiotic resistance genes expression among strains from commercial starter cultures. This study analyzed the effect of high-pressure processing on the changes in resistance phenotype and expression of antibiotic resistance genes among strains from commercial starter cultures. After exposure to high pressure the expression of genes encoding resistance to aminoglycosides (aac(6')Ie-aph(2″)Ia and aph(3')-IIIa) decreased and the expression of genes encoding resistance to tetracyclines (tetM and tetW), ampicillin (blaZ) and chloramphenicol (cat) increased. Expression changes differed depending on the pressure variant chosen. The results obtained in the gene expression analysis correlated with the results of the phenotype patterns. To the best of the authors' knowledge, this is one of the first studies focused on changes in antibiotic resistance associated with a stress response among strains from commercial starter cultures. The results suggest that the food preservation techniques might affect the phenotype of antibiotic resistance among microorganisms that ultimately survive the process. This points to the need to verify strains used in the food industry for their antibiotic resistance as well as preservation parameters to prevent the further increase in antibiotic resistance in food borne strains. | 2023 | 36462825 |
| 3606 | 13 | 0.9997 | Presence of specific antibiotic (tet) resistance genes in infant faecal microbiota. The widespread use of antibiotics for medical and veterinary purposes has led to an increase of microbial resistance. The antibiotic resistance of pathogenic bacteria has been studied extensively. However, antibiotics are not only selective for pathogens: they also affect all members of the gut microbiota. These microorganisms may constitute a reservoir of genes carrying resistance to specific antibiotics. This study was designed to characterize the gut microbiota with regard to the presence of genes encoding tetracycline resistance proteins (tet) in the gut of healthy exclusively breast-fed infants and their mothers. For this purpose we determined the prevalence of genes encoding ribosomal protection proteins (tet M, tet W, tet O, tet S, tet T and tet B) by PCR and characterized the gut microbiota by FISH in stools of infants and their mothers. The gene tet M was found in all the breast-fed infants and their mothers. tet O was found in all of the mothers' samples, whilst only 35% of the infants harboured this gene. tet W was less frequently found (85% of the mothers and 13% of the infants). None of the other genes analysed was found in any sample. Our results suggest that genes carrying antibiotic resistance are common in the environment, as even healthy breast-fed infants with no direct or indirect previous exposure to antibiotics harbour these genes. | 2006 | 16965348 |
| 6074 | 14 | 0.9997 | Beneficial properties of lactic acid bacteria naturally present in dairy production. BACKGROUND: Consumers are increasingly demanding for natural and beneficial foods, in order to improve their health and well-being. Probiotics play an important role in such demand, and dairy foods are commonly used as vehicles for such bacteria, represented predominantly by lactic acid bacteria. Due to consumers demand, food industry is constantly looking for novel bacterial strains, leading to studies that aims the isolation and characterization of their beneficial features. This study aimed to characterize the naturally occurring lactic acid bacteria obtained from a dairy environment, in order to assess their potential use as probiotics. RESULTS: Preliminary screening and PCR analysis, based on 16S rRNA sequencing, were applied to select and identify 15 LAB strains from the genera Lactobacillus (n = 11), Pediococcus (n = 2) and Weissella (n = 2). All strains showed resistance to low pH and the evaluated bile salt concentrations in vitro. The API ZYM test characterized the enzymatic activity of the strains, and a high β-galactosidase activity was observed in 13 strains. All strains presented resistance to simulated gastric (3 h) and intestinal (4 h) conditions in vitro, the ability to auto- and co-aggregate with indicator microorganisms and a high cell surface hydrophobicity. Most of the strains were positive for map and EFTu beneficial genes. All strains exhibited strong deconjugation of bile salts in vitro and all assimilated lactose. CONCLUSIONS: The phenotypes exhibited in vitro and the presence of beneficial genes revealed the beneficial potential of the studied strains, demanding further analyses in a food matrix and in vivo to allow the development of a functional product, with health-related properties. | 2018 | 30567551 |
| 4575 | 15 | 0.9997 | Antimicrobial Resistance of Acetobacter and Komagataeibacter Species Originating from Vinegars. Consumers' preference towards healthy and novel foods dictates the production of organic unfiltered bottled vinegar that still contains acetic acid bacteria. After ingesting vinegar, the bacteria come into close contact with the human microbiota, creating the possibility of horizontal gene transfer, including genetic determinants for antibiotic resistance. Due to the global spread of antimicrobial resistance (AMR), we analyzed the AMR of Acetobacter and Komagataeibacter species originating mainly from vinegars. Six antibiotics from different structural groups and mechanisms of action were selected for testing. The AMR was assessed with the disk diffusion method using various growth media. Although the number of resistant strains differed among the growth media, 97.4%, 74.4%, 56.4%, and 33.3% of strains were resistant to trimethoprim, erythromycin, ciprofloxacin, and chloramphenicol, respectively, on all three media. Moreover, 17.9% and 53.8% of all strains were resistant to four and three antibiotics of different antimicrobial classes, respectively. We then looked for antimicrobial resistance genes in the genome sequences of the reference strains. The most common genetic determinant potentially involved in AMR encodes an efflux pump. Since these genes pass through the gastrointestinal tract and may be transferred to human microbiota, further experiments are needed to analyze the probability of this scenario in more detail. | 2022 | 35010733 |
| 2814 | 16 | 0.9997 | Fate of antimicrobial-resistant enterococci and staphylococci and resistance determinants in stored poultry litter. The use of antimicrobials in commercial broiler poultry production results in the presence of drug-resistant bacteria shed in the excreta of these birds. Because these wastes are largely land-disposed these pathogens can affect the surrounding environment and population. In this analysis, we characterized the survival of antimicrobial-resistant enterococci and staphylococci and resistance genes in poultry litter. Temperature, moisture, and pH were measured in the litter over a 120-day period from storage sheds at three conventional US broiler chicken farms, as well as colony-forming units of Enterococcus spp. and Staphylococcus spp. Selected isolates from each sampling event were tested for resistance to eight antimicrobials used in poultry feeds as well as the presence of resistance genes and mobile genetic elements. Temperatures greater than 60 degrees C were only intermittently observed in the core of the litter piles. Both antimicrobial-resistant enterococci and staphylococci, as well as resistance genes persisted throughout the 120-day study period. Resistance genes identified in the study include: erm(A), erm(B), erm (C), msr(A/B), msr(C), and vat(E). This study indicates that typical storage practices of poultry litter are insufficient for eliminating drug-resistant enterococci and staphylococci, which may then be released into the environment through land disposal. | 2009 | 19541298 |
| 5647 | 17 | 0.9997 | Resistance of bacterial isolates from poultry products to therapeutic veterinary antibiotics. Bacterial isolates from poultry products were tested for their susceptibility to 10 antibiotics commonly used in the therapeutic treatment of poultry. Bacteria were isolated from fresh whole broiler carcasses or from cut-up meat samples (breast with or without skin, wings, and thighs) that were either fresh or stored at 4 or 13 degrees C (temperatures relevant to poultry-processing facilities). The Biolog system was used to identify isolates, and a broth dilution method was used to determine the antibiotic resistance properties of both these isolates and complementary cultures from the American Type Culture Collection. The antibiotics to which the most resistance was noted were penicillin G, sulfadimethoxine, and erythromycin; the antibiotic to which the least resistance was noted was enrofloxacin. Individual isolates exhibited resistances to as many as six antibiotics, with the most common resistance pattern involving the resistance of gram-negative bacteria to penicillin G, sulfadimethoxine, and erythromycin. Differences in resistance patterns were noted among 18 gram-positive and 7 gram-negative bacteria, and comparisons were made between species within the same genus. The data obtained in this study provide a useful reference for the species and resistance properties of bacteria found on various raw poultry products, either fresh or stored at temperatures and for times relevant to commercial processing, storage, and distribution. The results of this study show that resistance to antibiotics used for the therapeutic treatment of poultry occurs in bacteria in the processing environment. | 2003 | 12540187 |
| 4679 | 18 | 0.9997 | Antimicrobial and Phylogenomic Characterization of Bacillus cereus Group Strains Isolated from Different Food Sources in Italy. Background:Bacillus cereus is a widespread environmental Gram-positive bacterium which is especially common in soil and dust. It produces two types of toxins that cause vomiting and diarrhea. At present, foodborne outbreaks due to Bacillus cereus group bacteria (especially Bacillus cereus sensu stricto) are rising, representing a serious problem in the agri-food supply chain. Methods: In this work, we analyzed 118 strains belonging to the Bacillus cereus group, isolated from several food sources, for which in vitro and in silico antibiotic resistance assessments were performed. Results: Many strains showed intermediate susceptibility to clindamycin, erythromycin, and tetracycline, suggesting an evolving acquisition of resistance against these antibiotics. Moreover, one strain showed intermediate resistance to meropenem, an antibiotic currently used to treat infections caused by Bacillus cereus. In addition to the phenotypic antimicrobial resistance profile, all strains were screened for the presence/absence of antimicrobial genes via whole-genome sequencing. There was inconsistency between the in vitro and in silico analyses, such as in the case of vancomycin, for which different isolates harbored resistance genes but, phenotypically, the same strains were sensitive. Conclusions: This would suggest that antibiotic resistance is a complex phenomenon due to a variety of genetic, epigenetic, and biochemical mechanisms. | 2024 | 39335071 |
| 3932 | 19 | 0.9997 | Acquired antibiotic resistance: are we born with it? The rapid emergence of antibiotic resistance (AR) is a major public health concern. Recent findings on the prevalence of food-borne antibiotic-resistant (ART) commensal bacteria in ready-to-consume food products suggested that daily food consumption likely serves as a major avenue for dissemination of ART bacteria from the food chain to human hosts. To properly assess the impact of various factors, including the food chain, on AR development in hosts, it is important to determine the baseline of ART bacteria in the human gastrointestinal (GI) tract. We thus examined the gut microbiota of 16 infant subjects, from the newborn stage to 1 year of age, who fed on breast milk and/or infant formula during the early stages of development and had no prior exposure to antibiotics. Predominant bacterial populations resistant to several antibiotics and multiple resistance genes were found in the infant GI tracts within the first week of age. Several ART population transitions were also observed in the absence of antibiotic exposure and dietary changes. Representative AR gene pools including tet(M), ermB, sul2, and bla(TEM) were detected in infant subjects. Enterococcus spp., Staphylococcus spp., Klebsiella spp., Streptococcus spp., and Escherichia coli/Shigella spp. were among the identified AR gene carriers. ART bacteria were not detected in the infant formula and infant foods examined, but small numbers of skin-associated ART bacteria were found in certain breast milk samples. The data suggest that the early development of AR in the human gut microbiota is independent of infants' exposure to antibiotics but is likely impacted by exposure to maternal and environmental microbes during and after delivery and that the ART population is significantly amplified within the host even in the absence of antibiotic selective pressure. | 2011 | 21821748 |