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MSphere 2016The effects of animal agriculture on the spread of antibiotic resistance (AR) are cross-cutting and thus require a multidisciplinary perspective. Here we use ecological,...
The effects of animal agriculture on the spread of antibiotic resistance (AR) are cross-cutting and thus require a multidisciplinary perspective. Here we use ecological, epidemiological, and ethnographic methods to examine populations of Escherichia coli circulating in the production poultry farming environment versus the domestic environment in rural Ecuador, where small-scale poultry production employing nontherapeutic antibiotics is increasingly common. We sampled 262 "production birds" (commercially raised broiler chickens and laying hens) and 455 "household birds" (raised for domestic use) and household and coop environmental samples from 17 villages between 2010 and 2013. We analyzed data on zones of inhibition from Kirby-Bauer tests, rather than established clinical breakpoints for AR, to distinguish between populations of organisms. We saw significantly higher levels of AR in bacteria from production versus household birds; resistance to either amoxicillin-clavulanate, cephalothin, cefotaxime, and gentamicin was found in 52.8% of production bird isolates and 16% of household ones. A strain jointly resistant to the 4 drugs was exclusive to a subset of isolates from production birds (7.6%) and coop surfaces (6.5%) and was associated with a particular purchase site. The prevalence of AR in production birds declined with bird age (P < 0.01 for all antibiotics tested except tetracycline, sulfisoxazole, and trimethoprim-sulfamethoxazole). Farming status did not impact AR in domestic environments at the household or village level. Our results suggest that AR associated with small-scale poultry farming is present in the immediate production environment and likely originates from sources outside the study area. These outside sources might be a better place to target control efforts than local management practices. IMPORTANCE In developing countries, small-scale poultry farming employing antibiotics as growth promoters is being advanced as an inexpensive source of protein and income. Here, we present the results of a large ecoepidemiological study examining patterns of antibiotic resistance (AR) in E. coli isolates from small-scale poultry production environments versus domestic environments in rural Ecuador, where such backyard poultry operations have become established over the past decade. Our previous research in the region suggests that introduction of AR bacteria through travel and commerce may be an important source of AR in villages of this region. This report extends the prior analysis by examining small-scale production chicken farming as a potential source of resistant strains. Our results suggest that AR strains associated with poultry production likely originate from sources outside the study area and that these outside sources might be a better place to target control efforts than local management practices.
PubMed: 27303705
DOI: 10.1128/mSphere.00021-15 -
Journal of Food Protection Dec 2013This study was conducted to investigate antimicrobial resistance profiles of Escherichia coli isolates from broiler chickens in Alberta, Canada. Cecal contents of...
This study was conducted to investigate antimicrobial resistance profiles of Escherichia coli isolates from broiler chickens in Alberta, Canada. Cecal contents of broiler chickens from 24 flocks were collected at slaughter between January and March 2005 for culture and antimicrobial susceptibility testing against a panel of 15 antimicrobials using a broth microdilution technique. Of 600 E. coli isolates tested, 475 (79.2%) were resistant to one or more antimicrobials, 326 (54.3%) were resistant to three or more antimicrobials, 65 (10.8%) were resistant to five or more antimicrobials, and 15 (2.5%) were resistant to seven or more antimicrobials. The most common resistance was to tetracycline (69.2%), followed by streptomycin (48.2%), kanamycin (40.3%), and sulfisoxazole (38.0%). None of the E. coli isolates were resistant to amikacin, ceftriaxone, or ciprofloxacin. Of the isolates that were resistant to two or more antimicrobials, the most common multidrug resistance patterns were streptomycinte-tracycline (44.0%), streptomycin-sulfisoxazole-tetracycline (30.7%), and kanamycin-streptomycin-sulfisoxazole-tetracycline (23.5%). Resistance to tetracycline and kanamycin (odds ratio = 46.7, P = 0.0001) was highly associated, followed by resistance to streptomycin and sulfisoxazole (odds ratio = 12.0, P = 0.0001), and streptomycin and tetracycline (odds ratio = 10.3, P = 0.0001). The flock level prevalence of resistance varied from 16.7% for chloramphenicol to 100.0% for ampicillin, streptomycin, sulfisoxazole, and tetracycline. The results of this study provided baseline information on antimicrobial susceptibility of E. coli isolates of broiler chickens at slaughter in Alberta, which can serve as a bench mark for future research.
Topics: Alberta; Animals; Anti-Bacterial Agents; Chickens; Colony Count, Microbial; Consumer Product Safety; Dose-Response Relationship, Drug; Drug Resistance, Bacterial; Drug Resistance, Multiple, Bacterial; Escherichia coli; Food Contamination; Humans; Microbial Sensitivity Tests; Prevalence
PubMed: 24290680
DOI: 10.4315/0362-028X.JFP-13-203 -
Canadian Journal of Veterinary Research... Apr 2019The objectives of this study were to describe the frequency of antimicrobial resistance (AMR) in and spp. isolates in fecal samples from beef cow-calf herds and to...
The objectives of this study were to describe the frequency of antimicrobial resistance (AMR) in and spp. isolates in fecal samples from beef cow-calf herds and to examine the associations between herd management practices, reported antimicrobial use, and AMR. Baseline prevalence data are needed to evaluate the effectiveness of antimicrobial stewardship programs. A pooled fecal sample, representing 20 cows, was collected from each of 107 herds during pregnancy testing. In the 305 recovered isolates (maximum 3 per herd), resistance to ≥ 1 antimicrobial was identified in 12 isolates [4%, 95% confidence interval (CI): 2% to 7%] from 105 herds (11%, 95% CI: 7% to 19%). The most common resistances identified in isolates were to tetracycline (3%) and to both streptomycin and sulfisoxazole (3%). Only 1 isolate was resistant to an antimicrobial of very high importance to human health - amoxicillin/clavulanic acid. However, 2 isolates had intermediate susceptibility to ciprofloxacin. Resistance to 1 antimicrobial was identified in 16 of 87 spp. isolates (18%, 95% CI: 11% to 28%) from 87 herds. Resistance to tetracycline was reported in 15% of spp. isolates and to nalidixic acid in 3.4%. Herds in which cows were treated with florfenicol were more likely to have resistance to ≥ 2 antimicrobials (OR 7.1, 95% CI: 1.1 to 57, = 0.03). Herds with calf mortality of > 5% were more likely to have with resistance to streptomycin and sulfisoxazole [odds ratio (OR): 7.8, = 0.03]. The results of this study are consistent with previous reports from western Canada and provide a starting point for designing an ongoing antimicrobial surveillance program.
Topics: Alberta; Animals; Anti-Bacterial Agents; Cattle; Drug Resistance, Bacterial; Drug Utilization; Escherichia coli; Feces; Female; Manitoba; Microbial Sensitivity Tests; Saskatchewan
PubMed: 31097869
DOI: No ID Found -
Antimicrobial Agents and Chemotherapy Aug 1995Forty-four sulfa drugs were screened against crude preparations of recombinant Pneumocystis carinii dihydropteroate synthetase. The apparent Michaelis-Menten constants... (Comparative Study)
Comparative Study
Forty-four sulfa drugs were screened against crude preparations of recombinant Pneumocystis carinii dihydropteroate synthetase. The apparent Michaelis-Menten constants (Km) for p-aminobenzoic acid and 7,8-dihydro-6-hydroxymethylpterin pyrophosphate were 0.34 +/- 0.02 and 2.50 +/- 0.71 microM, respectively. Several sulfa drugs, including sulfathiazole, sulfachlorpyridazine, sulfamethoxypyridazine, and sulfathiourea, inhibited dihydropteroate synthetase approximately as well as sulfamethoxazole, as determined by the concentrations which cause 50% inhibition and/or by Ki. For all sulfones and sulfonamides tested, unsubstituted p-amino groups were necessary for activity, and sulfonamides containing an N1-heterocyclic substituent were found to be the most effective inhibitors. Folate biosynthesis in isolated intact P. carinii was approximately equally sensitive to inhibition by sulfamethoxazole, sulfachlorpyridazine, sulfamethoxypyridazine, sulfisoxazole, and sulfathiazole. Two of these drugs, sulfamethoxypyridazine and sulfisoxazole, are known to be less toxic than sulfamethoxazole and should be further evaluated for the treatment of P. carinii pneumonia.
Topics: Animals; Anti-Infective Agents; Dihydropteroate Synthase; Folic Acid; Kinetics; Lung; Male; Pneumocystis; Pneumocystis Infections; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Structure-Activity Relationship; Sulfonamides
PubMed: 7486915
DOI: 10.1128/AAC.39.8.1756 -
Revue Scientifique Et Technique... Dec 2019Antibiotics used in animals may be found in food of animal origin and pose a risk to human health. The aim of this study was to screen for antibiotic residues in broiler...
Antibiotics used in animals may be found in food of animal origin and pose a risk to human health. The aim of this study was to screen for antibiotic residues in broiler chickens and milk. Two hundred and twenty-one samples were collected (71 samples of chicken breast meat, 117 samples of raw cow's milk and 33 samples of raw goat's milk). The chicken meat samples underwent a microbiological analysis, followed by a physical/chemical analysis using high-performance liquid chromatography (HPLC). The milk samples were screened using a commercial microbiological test, followed by a further test for residues of beta-lactams and tetracyclines. For chicken meat, 32.39% of the samples were positive, with 56.52% of these samples containing aminoglycosides, 52.17% containing sulphonamides, 30.43% containing beta-lactams and/or tetracyclines and 21.73% containing macrolides. The concentrations of amoxicillin, penicillin G, erythromycin and sulfisoxazole exceeded the maximum residue limits laid down in European regulations in 28.57%, 85.71%, 80% and 91.66% of samples, respectively. The results of the test on milk showed that 12.6% of samples were contaminated by inhibiting substances. Betalactams and tetracyclines were present in 26.32% and 15.79% of the samples analysed, respectively. These results indicate that the contamination of chicken meat and milk is due to non-compliance with administration procedures and inappropiate use of antibiotics.
Topics: Algeria; Animals; Anti-Bacterial Agents; Cattle; Chickens; Drug Residues; Female; Food Contamination; Humans; Meat; Milk
PubMed: 32286562
DOI: 10.20506/rst.38.3.3031 -
The Journal of Antimicrobial... Aug 2015The objective of this study was to determine the distribution and genetic basis of trimethoprim resistance in Actinobacillus pleuropneumoniae isolates from pigs in...
OBJECTIVES
The objective of this study was to determine the distribution and genetic basis of trimethoprim resistance in Actinobacillus pleuropneumoniae isolates from pigs in England.
METHODS
Clinical isolates collected between 1998 and 2011 were tested for resistance to trimethoprim and sulphonamide. The genetic basis of trimethoprim resistance was determined by shotgun WGS analysis and the subsequent isolation and sequencing of plasmids.
RESULTS
A total of 16 (out of 106) A. pleuropneumoniae isolates were resistant to both trimethoprim (MIC >32 mg/L) and sulfisoxazole (MIC ≥256 mg/L), and a further 32 were resistant only to sulfisoxazole (MIC ≥256 mg/L). Genome sequence data for the trimethoprim-resistant isolates revealed the presence of the dfrA14 dihydrofolate reductase gene. The distribution of plasmid sequences in multiple contigs suggested the presence of two distinct dfrA14-containing plasmids in different isolates, which was confirmed by plasmid isolation and sequencing. Both plasmids encoded mobilization genes, the sulphonamide resistance gene sul2, as well as dfrA14 inserted into strA, a streptomycin-resistance-associated gene, although the gene order differed between the two plasmids. One of the plasmids further encoded the strB streptomycin-resistance-associated gene.
CONCLUSIONS
This is the first description of mobilizable plasmids conferring trimethoprim resistance in A. pleuropneumoniae and, to our knowledge, the first report of dfrA14 in any member of the Pasteurellaceae. The identification of dfrA14 conferring trimethoprim resistance in A. pleuropneumoniae isolates will facilitate PCR screens for resistance to this important antimicrobial.
Topics: Actinobacillus Infections; Actinobacillus pleuropneumoniae; Animals; Anti-Infective Agents; England; Genome, Bacterial; Microbial Sensitivity Tests; Molecular Sequence Data; Plasmids; Sequence Analysis, DNA; Sulfisoxazole; Swine; Swine Diseases; Tetrahydrofolate Dehydrogenase; Trimethoprim; Trimethoprim Resistance
PubMed: 25957382
DOI: 10.1093/jac/dkv121 -
Microorganisms Jun 2020This study aimed to compare antimicrobial resistance (AMR) in extended-spectrum cephalosporin-resistant and generic from a One Health continuum of the beef production...
A One Health Comparative Assessment of Antimicrobial Resistance in Generic and Extended-Spectrum Cephalosporin-Resistant from Beef Production, Sewage and Clinical Settings.
This study aimed to compare antimicrobial resistance (AMR) in extended-spectrum cephalosporin-resistant and generic from a One Health continuum of the beef production system in Alberta, Canada. A total of 705 extended-spectrum cephalosporin-resistant (ESC) were obtained from: cattle feces (CFeces, = 382), catch basins (CBasins, = 137), surrounding streams (SStreams, = 59), beef processing plants (BProcessing, = 4), municipal sewage (MSewage; = 98) and human clinical specimens (CHumans, = 25). Generic isolates (663) included: CFeces ( = 142), CBasins ( = 185), SStreams ( = 81), BProcessing ( = 159) and MSewage ( = 96). All isolates were screened for antimicrobial susceptibility to 9 antimicrobials and two clavulanic acid combinations. In ESC oxytetracycline (87.7%), ampicillin (84.4%) and streptomycin (73.8%) resistance phenotypes were the most common, with source influencing AMR prevalence ( < 0.001). In generic oxytetracycline (51.1%), streptomycin (22.6%), ampicillin (22.5%) and sulfisoxazole (14.3%) resistance were most common. Overall, 88.8% of ESC, and 26.7% of generic isolates exhibited multi-drug resistance (MDR). MDR in ESC was high from all sources: CFeces (97.1%), MSewage (96.9%), CHumans (96%), BProcessing (100%), CBasins (70.5%) and SStreams (61.4%). MDR in generic was lower with CFeces (45.1%), CBasins (34.6%), SStreams (23.5%), MSewage (13.6%) and BProcessing (10.7%). ESBL phenotypes were confirmed in 24.7% ( = 174) ESC and 0.6% of generic . Prevalence of genes in ESC were (30.1%), (21.6%), (20%), (7.9%), (3.0%), (6.4%), (1.4%) and AmpC β-lactamase (81.3%). The lower AMR in ESC from SStreams and BProcessing and higher AMR in CHumans and CFeces likely reflects antimicrobial use in these environments. Although MDR levels were higher in ESC as compared to generic , AMR to the same antimicrobials ranked high in both ESC and generic sub-populations. This suggests that both sub-populations reflect similar AMR trends and are equally useful for AMR surveillance. Considering that MDR ESC MSewage isolates were obtained without enrichment, while those from CFeces were obtained with enrichment, MSewage may serve as a hot spot for MDR emergence and dissemination.
PubMed: 32545206
DOI: 10.3390/microorganisms8060885 -
Antimicrobial Agents and Chemotherapy Apr 1978The susceptibility of 19 isolates of Haemophilus ducreyi from a recent chancroid outbreak and four reference strains was determined in vitro to 13 antimicrobial agents....
The susceptibility of 19 isolates of Haemophilus ducreyi from a recent chancroid outbreak and four reference strains was determined in vitro to 13 antimicrobial agents. The rabbit intradermal test for virulence was positive for all of the local isolates, but not for the reference strains. The "nonvirulent" reference strains were inhibited by lower minimum inhibitory concentrations (MICs) of most agents tested. For the virulent isolates, the range of MICs (in micrograms per milliliter) of the following were: of vancomycin, 8 to 128; of polymyxin, 32 to 128; of cloxacillin, 32 to 64; of tetracycline, 0.5 to 32; of cephalothin, 4 to 8; of doxycycline, 0.25 to 8; and of kanamycin, 1 to 8. Three strains were resistant to penicillin and ampicillin (MIC >/= 128 mug/ml), and these three strains produced beta-lactamase. The remainder were susceptible to 4 mug/ml. All strains were susceptible to rifampin (MIC = 1 mug/ml), chloramphenicol (MIC = 4 mug/ml), sulfisoxazole (MIC = 8 mug/ml), and nalidixic acid (MIC = 8 mug/ml). These susceptibilities of H. ducreyi indicate several antimicrobial agents that may be effective for chancroid treatment and support the use of vancomycin in a selective medium for the culture of chancroid genital ulcers.
Topics: Animals; Anti-Bacterial Agents; Drug Resistance, Microbial; Haemophilus ducreyi; Humans; Microbial Sensitivity Tests; Penicillinase; Rabbits
PubMed: 307364
DOI: 10.1128/AAC.13.4.608 -
BMC Microbiology Sep 2019This study is based on data collected to investigate the relation of peri-parturient events (colostrum quality, passive transfer of immunity, calving difficulty) on calf...
Antimicrobial use policy change in pre-weaned dairy calves and its impact on antimicrobial resistance in commensal Escherichia coli: a cross sectional and ecological study.
BACKGROUND
This study is based on data collected to investigate the relation of peri-parturient events (colostrum quality, passive transfer of immunity, calving difficulty) on calf health and antimicrobial use. A component of the study was to provide feedback to farm management to identify calves at risk for disease and promote antimicrobial stewardship. At the start of the study (May 2016), a combination of enrofloxacin, penicillin, and sulfamethoxazole was the first treatment given to clinically abnormal calves. Based on feedback and interaction between study investigators, farm management and consulting veterinarians, a new policy was implemented to reduce antimicrobial use in calves. In August, the first treatment was changed to a combination of ampicillin and sulfamethoxazole. In September, the first treatment was reduced to only sulfamethoxazole. We investigated the effects of these policy changes in antimicrobial use on resistance in commensal Escherichia coli.
RESULTS
We enrolled 4301 calves at birth and documented antimicrobial use until weaning. Most calves (99.4%) received antimicrobials and 70.4% received a total of 2-4 treatments. Antimicrobial use was more intense in younger calves (≤ 28 days) relative to older calves. We isolated 544 E. coli from fecal samples obtained from 132 calves. We determined resistance to 12 antimicrobials and 85% of the isolates were resistant to at least 3 antimicrobial classes. We performed latent class analysis to identify underlying unique classes where isolates shared resistance patterns and selected a solution with 4 classes. The least resistant class had isolates that were mainly resistant to only tetracycline and sulfisoxazole. The other 3 classes comprised isolates with resistance to ampicillin, chloramphenicol, aminoglycosides, sulfonamides, tetracycline, in addition to either ceftiofur; or nalidixic acid; or ciprofloxacin plus nalidixic acid and ceftiofur. Overall, E coli from younger calves and calves that received multiple treatments were more likely to have extensive resistance including resistance to fluoroquinolones and ceftiofur. In general, there was a declining trend in resistance to most antimicrobials during and after policy changes were implemented, except for ampicillin, ciprofloxacin, ceftiofur and gentamicin.
CONCLUSIONS
Information feedback to farms can influence farm managers to reduce antimicrobial use and this can change endemic farm resistance patterns.
Topics: Animals; Animals, Newborn; Anti-Bacterial Agents; Antimicrobial Stewardship; Cattle; Cattle Diseases; Cross-Sectional Studies; Dairying; Drug Resistance, Bacterial; Escherichia coli; Feces; Feedback; Microbial Sensitivity Tests; Weaning
PubMed: 31514734
DOI: 10.1186/s12866-019-1576-6 -
Frontiers in Microbiology 2019Using multiple antimicrobials in food animals may incubate genetically-linked multidrug-resistance (MDR) in enteric bacteria, which can contaminate meat at slaughter....
Using multiple antimicrobials in food animals may incubate genetically-linked multidrug-resistance (MDR) in enteric bacteria, which can contaminate meat at slaughter. The U.S. National Antimicrobial Resistance Monitoring System tested 21,243 chicken-associated between 2004 and 2012 for resistance to 15 antimicrobials, resulting in >32,000 possible MDR patterns. We analyzed MDR patterns in this dataset with association rule mining, also called market-basket analysis. The association rules were pruned with four quality measures resulting in a <1% false-discovery rate. MDR rules were more stable across consecutive years than between slaughter and retail. Rules were decomposed into networks with antimicrobials as nodes and rules as edges. A strong subnetwork of beta-lactam resistance existed in each year and the beta-lactam resistances also had strong associations with sulfisoxazole, gentamicin, streptomycin and tetracycline resistances. The association rules concur with previously identified resistance patterns but provide significant flexibility for studying MDR in large datasets.
PubMed: 31031716
DOI: 10.3389/fmicb.2019.00687