Water supply and feed as sources of antimicrobial-resistant Enterococcus spp. in aquacultures of rainbow trout (Oncorhyncus mykiss), Portugal. - Related Documents




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281601.0000Water supply and feed as sources of antimicrobial-resistant Enterococcus spp. in aquacultures of rainbow trout (Oncorhyncus mykiss), Portugal. The role of European fish farms in the spread of antimicrobial-resistance in the environment and food chain, as well as possible sources of their contamination by clinically relevant antimicrobial-resistance bacteria is scarcely known. This study aimed to assess the contribution of Portuguese rural trout farms on dispersion of Enterococcus with antimicrobial-resistance and putative virulence genes in the environment and food chain, as well as to identify farms contamination sources. We also assessed the presence of Enterococcus with low-levels of antimicrobial-resistance using epidemiological cut-offs (ECOFFs). Enterococcus spp. (n=391) from water/sediment recovered upstream, within and downstream trout tanks, feed, trout (2 aquacultures; no antibiotic use) and marketed trout (8 supermarkets) showed variable resistance to tetracycline, erythromycin, ciprofloxacin, chloramphenicol, quinupristin-dalfopristin, nitrofurantoin or aminoglycosides. Antimicrobial-resistance rates were similar among upstream, within and downstream trout tank samples (P>0.05), positioning water-supplying aquacultures as a source of multidrug-resistant (MDR) strains. Nevertheless, predominance of MDR E. faecium in feed, trout tanks and trout comparing to upstream samples, suggests feed as an additional aquaculture contamination source. The observation of E. faecium and E. faecalis susceptible to ampicillin and gentamicin by clinical breakpoints but with low-levels of resistance to those antimicrobials by ECOFFs breakpoints is of concern, as they might evolve throughout secondary genetic events to resistance levels with human clinical impact. Multiple MDR clones carrying copper tolerance (tcrB/cueO), putative virulence or other genes often associated with clinical strains (e.g. E. faecium with IS16/ptsD/sgrA) were observed, some in distinct samples (e.g. upstream and within trout tanks). They included major human and animal Enterococcus lineages, suggesting human and non-aquatic animal origins. The results highlight the need to define the maximum acceptance level of antimicrobial-resistance genes/bacteria to assess water quality and to monitor antimicrobial-resistance strains on feed, essential requirements to maintain a sustainable aquaculture production.201829996407
564610.9998Dispersion and persistence of antimicrobial resistance genes among Staphylococcus spp. and Mammaliicoccus spp. isolated along a swine manure treatment plant. Staphylococcus spp. and Mammaliicoccus spp. colonize the skin and mucosa of humans and other animals and are responsible for several opportunistic infections. Staphylococci antibiotic resistance may be present in the environment due to the spread of treated and untreated manure from the livestock industry due to antibiotic use to disease control or growth promoter. In this work, we analyzed the species distribution and antimicrobial susceptibility of Staphylococcus and Mammaliicoccus species along different sites of a swine manure treatment plant from Southeastern Brazil. Bacterial colonies were obtained on mannitol salt agar, selected after catalase test and Gram staining, and finally identified by mass spectrometry and sequencing of the tuf gene. According to the results, S.cohnii and S. simulans were the most prevalent species. Antibiotic resistance test revealed that several strains were resistant to multiple drugs, with high levels of chloramphenicol resistance (98%), followed by erythromycin (79%), tetracycline (73%), gentamicin (46%), ciprofloxacin (42%), cefoxitin (18%), sulfamethoxazole + trimethoprim (12%), and linezolid (4%). In addition, gene detection by PCR showed that all strains carried at least 2 resistance genes and one of them carried all 11 genes investigated. Using the GTG(5)-PCR approach, a high genetic similarity was observed between some strains that were isolated from different points of the treatment plant. Although some were seemingly identical, differences in their resistance phenotype and genotype suggest horizontal gene transfer. The presence of resistant bacteria and resistance genes along the treatment system highlights the potential risk of contamination by people in direct contact with these animals and the soil since the effluent is used as a biofertilizer in the surrounding environment.202336515883
281720.9998Characterization of antibiotic resistant enterococci isolated from untreated waters for human consumption in Portugal. Untreated drinking water is frequently overlooked as a source of antibiotic resistance in developed countries. To gain further insight on this topic, we isolated the indicator bacteria Enterococcus spp. from water samples collected in wells, fountains and natural springs supplying different communities across Portugal, and characterized their antibiotic resistance profile with both phenotypic and genetic approaches. We found various rates of resistance to seven antibiotic families. Over 50% of the isolates were resistant to at least ciprofloxacin, tetracyclines or quinupristin-dalfopristin and 57% were multidrug resistant to ≥3 antibiotics from different families. Multiple enterococcal species (E. faecalis, E. faecium, E. hirae, E. casseliflavus and other Enterococcus spp) from different water samples harbored genes encoding resistance to tetracyclines, erythromycin or gentamicin [tet(M)-46%, tet(L)-14%, tet(S)-5%, erm(B)-22%, aac(6´)-Ie-aph(2″)-12%] and putative virulence factors [gel-28%, asa1-16%]. The present study positions untreated drinking water within the spectrum of ecological niches that may be reservoirs of or vehicles for antibiotic resistant enterococci/genes. These findings are worthy of attention as spread of antibiotic resistant enterococci to humans and animals through water ingestion cannot be dismissed.201121145609
339730.9998Characterization of antibiotic resistance in commensal bacteria from an aquaculture ecosystem. The objective of the study was to improve the understanding of antibiotic resistance (AR) ecology through characterization of antibiotic-resistant commensal isolates associated with an aquaculture production system. A total of 4767 isolates non-susceptible to sulfamethoxazole/trimethoprim (Sul/Tri), tetracycline (Tet), erythromycin (Erm), or cefotaxime (Ctx), originated from fish, feed, and environmental samples of an aquaculture farm with no known history of antibiotic applications were examined. Close to 80% of the isolates exhibited multi-drug resistance in media containing the corresponding antibiotics, and representative AR genes were detected in various isolates by PCR, with feed isolates had the highest positive rate detected. Identified AR gene carriers involved 18 bacterial genera. Selected AR genes led to acquired resistance in other bacteria by transformation. The AR traits in many isolates were stable in the absence of selective pressure. AR-rich feed and possibly environmental factors may contribute to AR in the aquaculture ecosystem. For minimum inhibitory concentration test, brain heart infusion medium was found more suitable for majority of the bacteria examined than cation-adjusted Mueller Hinton broth, with latter being the recommended medium for clinical isolates by standard protocol. The data indicated a need to update the methodology due to genetic diversity of microbiota for better understanding of the AR ecology.201526441859
554340.9998Antimicrobial resistance in bacteria isolated from aquaculture sources in Australia. AIMS: To carry out a preliminary assessment of the occurrence of resistance to antimicrobials in bacteria that has been isolated from a variety of aquaculture species and environments in Australia. METHOD AND RESULTS: A total of 100 Gram-negative (Vibrio spp. and Aeromonas spp. predominantly) and four Gram-positive bacteria isolated from farmed fish, crustaceans and water from crab larval rearing tanks were obtained from diagnostic laboratories from different parts of Australia. All the isolates were tested for sensitivity to 19 antibiotics and Minimal Inhibitory Concentrations were determined by the agar dilution method. Plasmid DNA was isolated by the alkali lysis method. Resistance to ampicillin, amoxycillin, cephalexin and erythromycin was widespread; resistance to oxytetracycline, tetracycline, nalidixic acid and sulfonamides was common but resistance to chloramphenicol, florfenicol, ceftiofur, cephalothin, cefoperazone, oxolinic acid, gentamicin, kanamycin and trimethoprim was less common. All strains were susceptible to ciprofloxacin. Multiple resistance was also observed and 74.4% of resistant isolates had between one and ten plasmids with sizes ranging 2-51 kbp. CONCLUSIONS: No antibiotics are registered for use in aquaculture in Australia but these results suggest that there has been significant off-label use. SIGNIFICANCE AND IMPACT OF STUDY: Transfer of antibiotic resistant bacteria to humans via the food chain is a significant health concern. In comparison with studies on terrestrial food producing animals, there are fewer studies on antibiotic resistance in bacteria from aquaculture enterprises and this study provides further support to the view that there is the risk of transfer of resistant bacteria to humans from consumption of aquaculture products. From the Australian perspective, although there are no products registered for use in aquaculture, antimicrobial resistance is present in isolates from aquaculture and aquaculture environments.200616630011
281950.9998Prevalence of Antibiotic-Resistant Lactobacilli in Sepsis Patients with Long-Term Antibiotic Therapy. Lactobacilli are the most common probiotic bacteria found in the human gut microbiota, and the presence of acquired antibiotic resistance determinants carried on mobile genetic elements must be screened due to safety concerns. Unnecessary and inappropriate antibiotic therapy, as well as ingested antibiotic resistance bacteria (originating from food or food products), influence the abundance of antibiotic resistance genes in human guts, with serious clinical consequences. The current study looked into the antibiotic resistance of lactobacilli isolated from the guts of sepsis patients on long-term antibiotic therapy. The broth microdilution method was used to investigate the minimum inhibitory concentrations (MICs) of antibiotics such as imipenem, meropenem, erythromycin, tetracycline, cefepime, ciprofloxacin, and gentamycin, and the molecular genetic basis of resistance was studied based on the MIC values. The isolates were phenotypically resistant to tetracycline (20%), fluoroquinolone (20%), and macrolide (5%). Following that, resistance genes for tetracycline [tet(L), tet(O), tet(K), and tet(M)], macrolide [erm(B) and erm(C)], and beta-lactams [bla(CMY)] were investigated. Tetracycline or macrolide resistance genes were not found in the isolates, and only one isolate possessed the bla(CMY) resistance gene. The findings suggested that tetracycline and macrolide resistance may be linked to other resistance genes that were not investigated in this study. Because tetracyclines, fluoroquinolones, and macrolides are commonly used in clinics and animals, there has been concern about the spread of resistance in humans. If acquired antibiotic resistance is passed down through mobile genetic elements, it may serve as a reservoir of resistance for gut pathogens and other microbiome environments.202236088413
282360.9998Microbial occurrence and antibiotic resistance in ready-to-go food items. Foodborne pathogens, such as Escherichia coli, and Salmonella, are commonly prevalent in contaminated food products seen through annual food recalls. Excessive use of antibiotics through the past few decades has led to a multitude of antibiotic resistant bacteria, including foodborne pathogens. We investigated microbial occurrence and their antibiotics resistances in ready-to-go food items, i.e. canned food, bagged food, and baby food. A total of 112 isolates were isolated from varying food items, and 21 of these isolates were identified through 16S rRNA sequencing revealing Bacillus sp., Staphylococcus sp. and Micrococcus sp. Bagged food items showed the most microbial diversity as well as the largest colony forming unit (log 20-25 CFU/g). Isolates showed antibiotic resistance to ampicillin, streptomycin, chloramphenicol, and kanamycin at concentrations of 100, 500, and 1000 µg/mL. 57% isolates were ampicillin resistance followed by kanamycin (26%). A variety of microorganisms present in ready-to-go food items may not be pathogenic, however their occurrence and multiple antibiotic resistance (MAR) poses risk of transferring their genes to foodborne pathogens.201830042576
559870.9998Antibiotic Resistance in Lactic Acid Bacteria from Dairy Products in Northern Italy. Background: The spread of antibiotic resistance genes (ARGs) from the food chain is a significant public health concern. Dairy products from raw milk containing lactic acid bacteria (LAB) resistant to antimicrobials may serve as vectors for the transfer of resistance to commensal or potentially pathogenic bacteria in the human gut. Detecting ARGs in dairy products and milk is, therefore, crucial and could aid in the development of strategies to mitigate resistance dissemination through the food chain. Objectives: This study aimed to determine the presence of ARGs and assess the antibiotic susceptibility of LAB strains isolated from dairy products made from raw milk. Methods: Fifty-four LAB strains were isolated from 41 dairy samples and were tested for antimicrobial susceptibility using broth microdilution to determine Minimal Inhibitory Concentration (MIC). Moreover, the presence of resistance genes related to tetracyclines, beta-lactams, quinolones, and erythromycin was examined using six multiplex PCR assays. Results: Lactobacillus spp. and Leuconostoc spp. strains exhibited a high level of resistance to vancomycin (93-100%). Low-level resistance (4.2-20%) was observed in Lactococcus spp. and Lactobacillus spp. strains against tetracycline. Additionally, Lactococcus spp. strains showed resistance to trimethoprim/sulfamethoxazole, erythromycin, and clindamycin. Twenty-two out of 54 LAB strains (40.7%) carried at least one antibiotic resistance gene, and five of these were multidrug-resistant. Genes associated with acquired resistance to tetracycline were commonly detected, with tetK being the most frequent determinant. Conclusions: This study demonstrated that LABs in dairy products can act as reservoirs for ARGs, potentially contributing to the horizontal transfer of resistance within microbial communities in food and consumers. These findings highlight the need for the ongoing surveillance of antibiotic resistance in LAB and the implementation of control measures to minimize the dissemination of resistance through dairy products.202540298519
282080.9998Direct detection of antibiotic resistance genes in specimens of chicken and pork meat. Antibiotic resistance (AR) in bacteria, a major threat to human health, has emerged in the last few decades as a consequence of the selective pressure exerted by the widespread use of antibiotics in medicine, agriculture and veterinary practice and as growth promoters in animal husbandry. The frequency of 11 genes [tet(M), tet(O), tet(K), erm(A), erm(B), erm(C), vanA, vanB, aac (6')-Ie aph (2'')-Ia, mecA, blaZ] encoding resistance to some antibiotics widely used in clinical practice was analysed in raw pork and chicken meat and in fermented sausages as well as in faecal samples from the relevant farm animals using a molecular approach based on PCR amplification of bacterial DNA directly extracted from specimens. Some of the 11 AR genes were highly prevalent, the largest number being detected in chicken meat and pig faeces. The genes found most frequently in meat were tet(K) and erm(B); vanB and mecA were the least represented. All 11 determinants were detected in faecal samples except mecA, which was found only in chicken faeces. erm(B) and erm(C) were detected in all faecal samples. The frequency of AR genes was not appreciably different in meat compared to faecal specimens of the relevant animal except for vanB, which was more prevalent in faeces. Our findings suggest that AR genes are highly prevalent in food-associated bacteria and that AR contamination is likely related to breeding rather than processing techniques. Finally, the cultivation-independent molecular method used in this work to determine the prevalence of AR genes in foods proved to be a rapid and reliable alternative to traditional tools.200717005283
554190.9998Molecular characterization and antimicrobial resistance profile of fecal contaminants and spoilage bacteria that emerge in rainbow trout (Oncorhynchus mykiss) farms. Fecal contaminants are a major public concern that directly affect human health in the fish production industry. In this study, we aimed to determine the fecal coliform, spoilage bacteria, and antimicrobial-resistant bacterial contamination in rainbow trout (Oncorhynchus mykiss) farms. Fish were sampled from rainbow trout farms that have a high production capacity and are established on spring water, stream water, and dammed lakes in six different regions of Turkey. A total of seven Enterobacter subspecies, two strains of Pseudomonas spp., and one isolate each of Morganella and Stenotrophomonas were characterized based on biochemical and molecular methods, including the 16S rRNA and gyrB housekeeping gene regions. The sequencing results obtained from the 16S rRNA and gyrB gene regions were deposited in the GenBank database and compared with isolates from different countries, which were registered in the database. Resistance to 10 different antimicrobial compounds was determined using the broth microdilution method, and molecular resistance genes against florfenicol, tetracycline, and sulfamethoxazole were identified by PCR. All detected resistance genes were confirmed by sequencing analyses. E. cloacae, E. asburiae, Pseudomonas spp., S. maltophilia, and M. psychrotolerans were identified using the gyrB housekeeping gene, while isolates showed different biochemical characteristics. All isolates were found to be phenotypically resistant to sulfamethoxazole, and some isolates were resistant to tetracycline, florfenicol, amoxicillin, and doxycycline; the resistance genes of these isolates included floR, tetC, tetD, and tetE. We showed that fecal coliforms, spoilage bacteria, and antimicrobial resistant bacteria were present in farmed rainbow trout, and they pose a threat for human health and must be controlled in the farming stage of fish production.201931106106
2849100.9998Antibiotic-resistant bacteria and gut microbiome communities associated with wild-caught shrimp from the United States versus imported farm-raised retail shrimp. In the United States, farm-raised shrimp accounts for ~ 80% of the market share. Farmed shrimp are cultivated as monoculture and are susceptible to infections. The aquaculture industry is dependent on the application of antibiotics for disease prevention, resulting in the selection of antibiotic-resistant bacteria. We aimed to characterize the prevalence of antibiotic-resistant bacteria and gut microbiome communities in commercially available shrimp. Thirty-one raw and cooked shrimp samples were purchased from supermarkets in Florida and Georgia (U.S.) between March-September 2019. The samples were processed for the isolation of antibiotic-resistant bacteria, and isolates were characterized using an array of molecular and antibiotic susceptibility tests. Aerobic plate counts of the cooked samples (n = 13) varied from < 25 to 6.2 log CFU/g. Isolates obtained (n = 110) were spread across 18 genera, comprised of coliforms and opportunistic pathogens. Interestingly, isolates from cooked shrimp showed higher resistance towards chloramphenicol (18.6%) and tetracycline (20%), while those from raw shrimp exhibited low levels of resistance towards nalidixic acid (10%) and tetracycline (8.2%). Compared to wild-caught shrimp, the imported farm-raised shrimp harbored distinct gut microbiota communities and a higher prevalence of antibiotic-resistance genes in their gut. The presence of antibiotic-resistant strains in cooked shrimps calls for change in processing for their mitigation.202133558614
1924110.9998Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes. The development and spread of antibiotic resistance (AR) through microbiota associated with freshwater bodies is a major global health concern. In the present study, freshwater samples were collected and analyzed with respect to the total bacterial diversity and AR genes (ARGs) using both conventional culture-based techniques and a high-throughput culture-independent metagenomic approach. This paper presents a systematic protocol for the enumeration of the total and antibiotic-resistant culturable bacteria from freshwater samples and the determination of phenotypic and genotypic resistance in the culturable isolates. Further, we report the use of whole metagenomic analysis of the total metagenomic DNA extracted from the freshwater sample for the identification of the overall bacterial diversity, including non-culturable bacteria, and the identification of the total pool of different ARGs (resistome) in the water body. Following these detailed protocols, we observed a high antibiotic-resistant bacteria load in the range of 9.6 × 10(5)-1.2 × 10(9) CFU/mL. Most isolates were resistant to the multiple tested antibiotics, including cefotaxime, ampicillin, levofloxacin, chloramphenicol, ceftriaxone, gentamicin, neomycin, trimethoprim, and ciprofloxacin, with multiple antibiotic resistance (MAR) indexes of ≥0.2, indicating high levels of resistance in the isolates. The 16S rRNA sequencing identified potential human pathogens, such as Klebsiella pneumoniae, and opportunistic bacteria, such as Comamonas spp., Micrococcus spp., Arthrobacter spp., and Aeromonas spp. The molecular characterization of the isolates showed the presence of various ARGs, such as blaTEM, blaCTX-M (β-lactams), aadA, aac (6')-Ib (aminoglycosides), and dfr1 (trimethoprims), which was also confirmed by the whole metagenomic DNA analysis. A high prevalence of other ARGs encoding for antibiotic efflux pumps-mtrA, macB, mdtA, acrD, β-lactamases-SMB-1, VIM-20, ccrA, ampC, blaZ, the chloramphenicol acetyltransferase gene catB10, and the rifampicin resistance gene rphB-was also detected in the metagenomic DNA. With the help of the protocols discussed in this study, we confirmed the presence of waterborne MAR bacteria with diverse AR phenotypic and genotypic traits. Thus, whole metagenomic DNA analysis can be used as a complementary technique to conventional culture-based techniques to determine the overall AR status of a water body.202336939224
5545120.9998Healthy broilers disseminate antibiotic resistance in response to tetracycline input in feed concentrates. Wide varieties of antibiotics are used in poultry farms to improve the growth and also to control the infection in broiler chicken. To identify the seriousness of the same in the poultry sector, current study has been designed to analyze the presence of tetracycline in poultry feed and also the tetracycline resistance among the bacteria released through the excreta of poultry. In the study, 27 bacteria belonging to the Escherichiacoli and Klebsiellapneumoniae. were isolated from the faecal samples collected from five different farms. Antibiotic susceptibility analysis showed 77% of E. coli and 100% of the K. pneumoniae. to be resistant to tetracycline. Further, molecular screening for tetA and tetB genes showed 85.18% of isolates to have tetA and 22.22% with tetB. The presence of tetracycline in collected feed samples was also analysed quantitatively by Liquid chromatography-mass spectrometry (LC-MS). Here, three out of five feed samples were found to be positive for tetracycline. The study showed a direct correlation between the antibiotic supplemented feed and the emergence of antimicrobial resistance among the intestinal microflora. The results of the study indicate the need for strict control over antibiotic use in animal feed to limit the rapid evolution and spread of antimicrobial resistance.202033039593
5644130.9997Identification and Characterization of Antibiotic-Resistant, Gram-Negative Bacteria Isolated from Korean Fresh Produce and Agricultural Environment. The consumption of fresh produce and fruits has increased over the last few years as a result of increasing consumer awareness of healthy lifestyles. Several studies have shown that fresh produces and fruits could be potential sources of human pathogens and antibiotic-resistant bacteria. In this study, 248 strains were isolated from lettuce and surrounding soil samples, and 202 single isolates selected by the random amplified polymorphic DNA (RAPD) fingerprinting method were further characterized. From 202 strains, 184 (91.2%) could be identified based on 16S rRNA gene sequencing, while 18 isolates (8.9%) could not be unequivocally identified. A total of 133 (69.3%) and 105 (54.7%) strains showed a resistance phenotype to ampicillin and cefoxitin, respectively, while resistance to gentamicin, tobramycin, ciprofloxacin, and tetracycline occurred only at low incidences. A closer investigation of selected strains by whole genome sequencing showed that seven of the fifteen sequenced strains did not possess any genes related to acquired antibiotic resistance. In addition, only one strain possessed potentially transferable antibiotic resistance genes together with plasmid-related sequences. Therefore, this study indicates that there is a low possibility of transferring antibiotic resistance by potential pathogenic enterobacteria via fresh produce in Korea. However, with regards to public health and consumer safety, fresh produce should nevertheless be continuously monitored to detect the occurrence of foodborne pathogens and to hinder the transfer of antibiotic resistance genes potentially present in these bacteria.202337317216
2821140.9997Antibiotic resistant enterococci and staphylococci isolated from flies collected near confined poultry feeding operations. Use of antibiotics as feed additives in poultry production has been linked to the presence of antibiotic resistant bacteria in farm workers, consumer poultry products and the environs of confined poultry operations. There are concerns that these resistant bacteria may be transferred to communities near these operations; however, environmental pathways of exposure are not well documented. We assessed the prevalence of antibiotic resistant enterococci and staphylococci in stored poultry litter and flies collected near broiler chicken houses. Drug resistant enterococci and staphylococci were isolated from flies caught near confined poultry feeding operations in the summer of 2006. Susceptibility testing was conducted on isolates using antibiotics selected on the basis of their importance to human medicine and use in poultry production. Resistant isolates were then screened for genetic determinants of antibiotic resistance. A total of 142 enterococcal isolates and 144 staphylococcal isolates from both fly and poultry litter samples were identified. Resistance genes erm(B), erm(A), msr(C), msr(A/B) and mobile genetic elements associated with the conjugative transposon Tn916, were found in isolates recovered from both poultry litter and flies. Erm(B) was the most common resistance gene in enterococci, while erm(A) was the most common in staphylococci. We report that flies collected near broiler poultry operations may be involved in the spread of drug resistant bacteria from these operations and may increase the potential for human exposure to drug resistant bacteria.200919157515
2818150.9997Tetracycline resistance associated with commensal bacteria from representative ready-to-consume deli and restaurant foods. Proper knowledge of antibiotic resistance (AR) dissemination is essential for effective mitigation. This study examined the profiles of tetracycline-resistant (Tetr) commensal bacteria from representative ready-to-consume food samples from salad bars at local grocery stores and restaurants. Out of 900 Tetr isolates examined, 158 (17.6%) carried one or more of tetM, tetL, tetS, and tetK genes by conventional PCR, 28 harbored more than one Tetr determinants. The most prevalent genotype was tetM, which was detected in 70.9% of the AR gene carriers, followed by tetL (31.6%), tetS (13.9%), and tetK (2.5%). Identified AR gene carriers included Enterococcus, Lactococcus, Staphylococcus, Brochothrix, Carnobacterium, Stenotrophomonas, Pseudomonas, and Sphingobacterium, by 16S rRNA gene sequence analysis. AR determinants were successfully transmitted, and led to resistance in Streptococcus mutans via natural gene transformation and Enterococcus faecalis via electroporation, suggesting the functionality and mobility of the AR genes from the food commensal bacteria. In addition, the AR traits in many isolates are quite stable, even in the absence of the selective pressure. The identification of new commensal carriers for representative AR genes revealed the involvement of a broad spectrum of bacteria in the horizontal transmission of AR genes. Meanwhile, the spectrum of the antibiotic-resistant bacteria differed from the spectrum of the total bacteria (by denaturing gradient gel electrophoresis) associated with the food items. Our data revealed a common avenue in AR exposure and will assist in proper risk assessment and the development of comprehensive mitigation strategies to effectively combat AR.201021067672
5647160.9997Resistance 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.200312540187
5905170.9997Characterization of Antibiotic Resistance Genes from Lactobacillus Isolated from Traditional Dairy Products. Lactobacilli are widely used as starter cultures or probiotics in yoghurt, cheese, beer, wine, pickles, preserved food, and silage. They are generally recognized as safe (GRAS). However, recent studies have shown that some lactic acid bacteria (LAB) strains carry antibiotic resistance genes and are resistant to antibiotics. Some of them may even transfer their intrinsic antibiotic resistance genes to other LAB or pathogens via horizontal gene transfer, thus threatening human health. A total of 33 Lactobacillus strains was isolated from fermented milk collected from different areas of China. We analyzed (1) their levels of antibiotic resistance using a standardized dilution method, (2) their antibiotic resistance gene profiles by polymerase chain reaction (PCR) using gene-specific primers, and (3) the transferability of some of the detected resistance markers by a filter mating assay. All Lactobacillus strains were found to be resistant to vancomycin, but susceptible to gentamicin, linezolid, neomycin, erythromycin, and clindamycin. Their susceptibilities to tetracycline, kanamycin, ciprofloxacin, streptomycin, quinupristin/dalfopristin, trimethoprim, ampicillin, rifampicin, and chloramphenicol was different. Results from our PCR analysis revealed 19 vancomycin, 10 ciprofloxacin, and 1 tetracycline-resistant bacteria that carried the van(X), van(E), gyr(A), and tet(M) genes, respectively. Finally, no transferal of the monitored antibiotic resistance genes was observed in the filter mating assay. Taken together, our study generated the antibiotic resistance profiles of some milk-originated lactobacilli isolates and preliminarily assessed their risk of transferring antibiotic gene to other bacteria. The study may provide important data concerning the safe use of LAB.201728182844
2865180.9997Antibiotic resistance in soil and water environments. Seven locations were screened for antibiotic-resistant bacteria using a modified agar dilution technique. Isolates resistant to high levels of antibiotics were screened for r plasmids. Low-level resistance (25 micro g x ml(-1)) was widespread for ampicillin, penicillin, tetracycline, vancomycin and streptomycin but not for kanamycin. Resistant populations dropped sharply at high antibiotic levels, suggesting that intrinsic non-emergent mechanisms were responsible for the multiple drug resistance exhibited at low doses. Dairy farm manure contained significantly (P < 0.01) more (%) resistant bacteria than the other sites. Bacteria isolated from a dairy water canal, a lake by a hospital and a residential garden (fertilized by farm manure) displayed resistance frequencies of 77, 75 and 70%, respectively. Incidence of tetracycline resistance was most prevalent at 47-89% of total bacteria. Out of 200 representative isolates analyzed, Pseudomonas, Enterococcus-like bacteria, Enterobacter and Burkholderia species constituted the dominant reservoirs of resistance at high drug levels (50-170 micro g x ml(-1)). Plasmids were detected in only 29% (58) of these bacteria with tetracycline resistance accounting for 65% of the plasmid pool. Overall, resistance trends correlated to the abundance and type of bacterial species present in the habitat. Environmental reservoirs of resistance include opportunistic pathogens and constitute some public health concern.200212396530
1926190.9997Whole genome sequencing revealed high occurrence of antimicrobial resistance genes in bacteria isolated from poultry manure. BACKGROUND: Global demand for food has driven expansion and intensification of livestock production, particularly in developing nations where antibiotic use is often routine. Waste from poultry production, including manure, is commonly utilized as fertilizers in agroecosystems, risking environmental contamination with potentially zoonotic bacteria and antimicrobial resistance genes (ARGs). METHODS: Here, 33 bacterial isolates were recovered from broiler (n = 17) and layer (n = 16) chicken manure by aerobic culture using Luria Bertani agar. Antimicrobial susceptibility testing (AST) was performed using disc diffusion method. MALDI-ToF and 16S rRNA sequencing were used to identify and compare a subset of antibiotic-resistant isolates (n = 13). Comparison of whole genome sequence assemblies and phenotypic assays were used to assess capacity for biofilm formation, heavy metal tolerance and virulence. RESULTS: AST by disc diffusion revealed all isolates were resistant to a minimum of three antibiotics, with resistance to ampicillin, co-trimoxazole, fluoroquinolones, tetracyclines, streptomycin, rifampicin and/or chloramphenicol detected. Stutzerimonas sp. and Acinetobacter sp. were the common genera observed in this study. Genome sequencing of each selected isolate revealed carriage of multiple ARGs capable of conferring resistance to many antimicrobials commonly employed in poultry production and human medicine, including tetracyclines, quinolones, macrolides, sulfonamide and cephalosporins. CONCLUSIONS: The high occurrence of ARGs in studied bacterial isolates confirms that poultry manure could act as a source of genetic material that could be transferred to commensal microbiota and opportunistic pathogens of humans. Understanding the complex resistome interplay between humans, animals, and the environment requires a One Health approach, with implications for agricultural settings and public health.202539880102