RESUMEN
Enterococcus species are a normal flora of animals and humans. However, life-threatening opportunistic infections can be caused by antimicrobial resistant strains. Fecal (n = 42) and feed (n = 8) samples were obtained from a mink farm and cultured for the enumeration and detection of erythromycin-resistant (a macrolide; ERYr)- and tetracycline-resistant (TETr) enterococci. ERYr and TETr enterococci were detected from all fecal (mean concentrations = 6 and 7 logs, respectively) and feed (mean concentrations = 5 and 4 logs, respectively) samples. While Enterococcus faecalis and Enterococcus faecium were detected at equal proportions among the fecal TETr isolates, E. faecium predominated among ERYr fecal isolates. All ERYr and 90% of the TETr isolates (n = 50) were multidrug resistant (resistant to three or more antimicrobial classes). Among ERYr isolates, while 83% of E. faecalis (n = 12) were positive for erm(B), 58% of E. faecium (n = 38) isolates were positive for msr(C). Among ERYr isolates, tet(M) was detected from 92% of E. faecalis (n = 12) and 97% of E. faecium (n = 38) isolates. Conversely, however, erm(B) was detected in 18% of E. faecalis (n = 22) and 33% of E. faecium (n = 27) TETr isolates. Our study provides a baseline for future efforts to reduce antimicrobial resistance and improve antimicrobial stewardship in commercial mink production facilities.
Asunto(s)
Enterococcus faecium , Enterococcus , Animales , Antibacterianos/farmacología , Farmacorresistencia Bacteriana , Enterococcus faecalis , Granjas , Macrólidos/farmacología , Pruebas de Sensibilidad Microbiana , Visón , Tetraciclina/farmacología , Estados UnidosRESUMEN
Nontyphoidal Salmonella is a leading cause of foodborne illnesses, and concentrated animal production such as commercial mink farming can be a reservoir. The objective of this study was to determine the prevalence, serotypes, antimicrobial resistance, virulence genes and mobile genetic elements, and phylogenetic characterization of Salmonella from mink fecal (n = 42) and feed (n = 8) samples at a commercial mink farm in the United States. Salmonella was detected from 11 (26.2%) fecal and 1 (12.5%) feed samples. Twelve fecal isolates obtained from the positive samples were identified into four serotypes: Salmonella Uganda (eight isolates; two isolates were obtained from one sample), Salmonella Reading (two isolates), Salmonella Heidelberg (one isolate), and Salmonella Orion (one isolate). Two isolates from the positive feed sample were identified as Salmonella Cerro. Twelve isolates, one isolate per positive sample, were whole genome sequenced for further characterization. The two Salmonella Reading isolates were multidrug resistant (MDR) with the classical ASSuT (ampicillin, streptomycin, sulfisoxazole, and tetracycline) phenotype. Genotypically, the isolates were correspondingly positive, both by polymerase chain reaction and by whole-genome sequencing (WGS), for blaTEM-1, aph(3â³)-Ib and aph(6)-Id, sul2, and tet(A). WGS additionally identified trimethoprim resistance gene dfrA8 in Salmonella Reading, and fosfomycin resistance gene fosA7 in Salmonella Heidelberg. All isolates carried Salmonella-specific multidrug resistance (mdsA/B), gold resistance, and intimin-like virulence genes. In addition, Salmonella Orion carried copper and silver resistance gene clusters. The two Salmonella Reading isolates also carried a cytolethal distension toxin (cdtB) gene. Salmonella Reading isolates belonged to ST412, a predominant sequence type among turkey and human isolates obtained in relation to recent salmonellosis outbreaks in North America. Phylogenetically, Salmonella Uganda, Salmonella Heidelberg, and Salmonella Reading were mostly associated with historic human/clinical, and poultry and swine source isolates. This study indicates that mink production can be a reservoir for foodborne pathogens such as Salmonella with MDR serovars commonly associated with human illnesses.
Asunto(s)
Antibacterianos , Salmonella enterica , Animales , Antibacterianos/farmacología , Farmacorresistencia Bacteriana , Farmacorresistencia Bacteriana Múltiple/genética , Heces , Pruebas de Sensibilidad Microbiana , Visón , Filogenia , Prevalencia , Salmonella enterica/genética , Serogrupo , Porcinos , Estados Unidos/epidemiologíaRESUMEN
Antibiotic-resistant infections caused by extended-spectrum ß-lactamases (ESBLs) and carbapenemases are increasing worldwide. Bacteria resistant to extended-spectrum cephalosporins and last resort carbapenems have been reported from food animals and their environments. Other concentrated nonfood-producing animals such as mink farming can be a reservoir of bacteria resistant to these critically important antibiotics. The objective of this study was to determine the prevalence of ESBL-producing bacteria and carbapenem-resistant (CR) bacteria from mink fecal (n = 42) and feed (n = 8) samples obtained from a commercial mink farm in the United States. The most prevalent ESBL-producing bacteria identified from the fecal samples were Escherichia coli (93%), Klebsiella pneumoniae (76%), and Proteus species (88%). E. coli (100%) and K. pneumoniae (75%) were also the most prevalent ESBL-producing bacteria identified from feed samples. All ESBL E. coli isolates were resistant to penicillin and most cephem beta-lactam antibiotics. Among the ESBL E. coli isolates, co-resistance was observed to ciprofloxacin (33%) and gentamicin (28%) indicating multidrug resistance. ESBL E. coli isolates predominantly carried blaCTX-M-14 and blaCTX-M-15 genes. Although all feed K. pneumoniae isolates carried blaCTX-M-9, all fecal K. pneumoniae isolates carried blaSHV. CR Pseudomonas species (7%), Hafnia alvei (24%), and Myroides odoratimimus (9.5%) were detected from fecal samples. H. alvei (37.5%) was the only CR bacteria detected from the feed samples. All CR isolates were polymerase chain reaction negative for the tested carbapenemases that are commonly reported, which may indicate intrinsic rather than acquired resistance. This study indicates that mink production can be a reservoir for bacteria resistant to the highest priority critically important antibiotics for human health.
Asunto(s)
Proteínas Bacterianas/genética , Infecciones por Escherichia coli/veterinaria , Escherichia coli/genética , Resistencia betalactámica/genética , beta-Lactamasas/genética , Animales , Antibacterianos/farmacología , Proteínas Bacterianas/metabolismo , Carbapenémicos/farmacología , Escherichia coli/efectos de los fármacos , Escherichia coli/aislamiento & purificación , Infecciones por Escherichia coli/microbiología , Heces/microbiología , Klebsiella pneumoniae/genética , Pruebas de Sensibilidad Microbiana , Visón/microbiología , Estados Unidos , beta-Lactamasas/metabolismoRESUMEN
American mink (Neovison vison) is a significant source of global fur production. Except for a few studies from Denmark and Canada reporting antimicrobial resistance in bacteria isolated from clinical cases, studies from the general mink population are scarce and absent in the United States. Mink feces (n = 42) and feed (n = 8) samples obtained from a mink farm were cultured for the enumeration and detection of tetracycline-resistant (TETr)- and third-generation cephalosporin-resistant (TGCr)-Escherichia coli. Isolates were characterized phenotypically for their resistance to other antibiotics and genotypically for resistance genes. TETrE. coli were detected from 98% of feces samples (mean concentration = 6 log10) and from 100% of feed samples (mean concentration = 3.2 logs). Among TETrE. coli isolates, 44% (n = 41) of fecal- and 50% (n = 8) of feed isolates were multidrug resistant (MDR; resistance to ≥3 antimicrobial classes), and 96% (n = 49) of TETr isolates were positive for tet(A) and/or tet(B). TGCrE. coli were detected from 95% of feces and 75% of feed samples with 78% (n = 40) of fecal isolates, and all six of the feed isolates were MDR. Nearly two-thirds (65%) of the TGCrE. coli isolates (n = 46) were positive for blaCMY-2; the remaining 35% were positive for blaCTX-M, with the blaCTX-M-14 being the predominant (75%, n = 16) variant detected. Metagenomic DNA was extracted directly from feces and feed samples, and it was tested for 84 antimicrobial resistance genes by using quantitative polymerase chain reaction (PCR) array; selected genes were also quantified by droplet digital PCR. The genes detected from the fecal samples belonged mainly to five antimicrobial classes: macrolide-lincosamide-streptogramin B (MLSB; 100% prevalence), TETs (88.1%), ß-lactams (71.4%), aminoglycosides (66.7%), and fluoroquinolones (47.6%). ß-Lactam, MLSB, and TET resistance genes were also detected from feed samples. Our study serves as a baseline for further studies and to streamline antimicrobial use in mink production in accordance with current regulations as in food animals.
Asunto(s)
Alimentación Animal/microbiología , Farmacorresistencia Bacteriana Múltiple/genética , Escherichia coli/genética , Heces/microbiología , Visón/genética , Animales , Antibacterianos , Cefalosporinas , Escherichia coli/efectos de los fármacos , Metagenoma , Visón/microbiología , TetraciclinaRESUMEN
On-road vehicles have become a dominant source of air pollution and energy consumption in many parts of the world. As a result, estimating the amount of pollution from these vehicles and analyzing the factors affecting their emission is necessary to understand and manage ambient air quality. Traditionally, automobile emissions have been measured with dynamometer tests using representative driving cycles. A review of the related literature shows that there is a lack of real life, on-the-road testing of automobile emissions. Moreover, a few previous studies have directly discussed the impact of driver variability on emissions from the vehicles. This research analyzes the impacts of driver experience, gender, speed, and road grade on vehicle emissions through on-the-road testing experiment in Logan, Utah, USA during summer of 2016. The methodology of the research starts by selecting a representative car to perform the tests on. The next step was to choose test drivers representing four groups: young males, young females, experienced males, and experienced females. After that, the drivers were assigned a specified route that has different speed limits and grades. Emissions from the car exhaust (specifically carbon monoxide-CO, hydrocarbons-HC, and nitrogen oxides-NOx) in addition to the engines rotational speed (rpm), car speed, and exhaust temperature, were measured every second while driving on the specified route. Statistical analysis of the results shows that contrary to the common stereotypes, experienced drivers emitted 52% more HC and 49% more NOx than young drivers and female drivers, and male drivers emitted 14% more HC and 44% more NOx than female drivers. It also shows that CO emission is not significantly dependent on age, gender, nor driving conditions. Finally, driving through low-speed segments emits significantly higher HC (79%), while driving through uphill segments emits significantly higher (98%) NOx than driving through downhill segment. Implications: This study showed that there are significant differences in vehicular emissions among drivers from different genders and age. These differences should be taking into consideration in future emission modeling studies and regulatory scenarios.
Asunto(s)
Contaminantes Atmosféricos/análisis , Conducción de Automóvil/estadística & datos numéricos , Monóxido de Carbono/análisis , Hidrocarburos/análisis , Óxidos de Nitrógeno/análisis , Emisiones de Vehículos/análisis , Adulto , Automóviles , Monitoreo del Ambiente , Femenino , Humanos , Masculino , Persona de Mediana Edad , Utah , Adulto JovenRESUMEN
Soil preparation for agricultural crops produces aerosols that may significantly contribute to seasonal atmospheric particulate matter (PM). Efforts to reduce PM emissions from tillage through a variety of conservation management practices (CMPs) have been made, but the reductions from many of these practices have not been measured in the field. A study was conducted in California's San Joaquin Valley to quantify emissions reductions from fall tillage CMP. Emissions were measured from conventional tillage methods and from a "combined operations" CMP, which combines several implements to reduce tractor passes. Measurements were made of soil moisture, bulk density, meteorological profiles, filter-based total suspended PM (TSP), concentrations of PM with an equivalent aerodynamic diameter ≤10 µm (PM) and PM with an equivalent aerodynamic diameter ≤2.5 µm (PM), and aerosol size distribution. A mass-calibrated, scanning, three-wavelength light detection and ranging (LIDAR) procedure estimated PM through a series of algorithms. Emissions were calculated via inverse modeling with mass concentration measurements and applying a mass balance to LIDAR data. Inverse modeling emission estimates were higher, often with statistically significant differences. Derived PM emissions for conventional operations generally agree with literature values. Sampling irregularities with a few filter-based samples prevented calculation of a complete set of emissions through inverse modeling; however, the LIDAR-based emissions dataset was complete. The CMP control effectiveness was calculated based on LIDAR-derived emissions to be 29 ± 2%, 60 ± 1%, and 25 ± 1% for PM, PM, and TSP size fractions, respectively. Implementation of this CMP provides an effective method for the reduction of PM emissions.