BackgroundThe use of antibiotics in food animal production has been associated with antibiotic-resistant infections in humans. In 2005, the Food and Drug Administration (FDA) banned fluoroquinolone use in U.S. poultry production in order to reduce the prevalence of fluoroquinolone-resistant Campylobacter. Little is known about the potential efficacy of this policy.ObjectivesOur primary objective was to follow temporal changes in the prevalence of fluoroquinolone-resistant Campylobacter among poultry products from two conventional producers who announced their cessation of fluoroquinolone use in 2002 (3 years before the FDA’s ban). Our secondary objective was to compare, over time, the prevalence of fluoroquinolone-resistant Campylobacter in conventional poultry products to those from producers who claim to use no antibiotics.MethodsWe collected poultry samples from two conventional producers and three antibiotic-free producers over the course of 20 weeks in 2004 (n = 198) and 15 weeks in 2006 (n = 210). We compared the rates of fluoroquinolone resistance among Campylobacter isolates from the different producers.ResultsWe found no significant change in the proportion of fluoroquinolone-resistant Campylobacter isolates from the two conventional producers over the study period. In addition, Campylobacter strains from the two conventional producers were significantly more likely to be fluoroquinolone resistant than those from the antibiotic-free producers.ConclusionsThe results from this study indicate that fluoroquinolone-resistant Campylobacter may be persistent contaminants of poultry products even after on-farm fluoroquinolone use has ceased. The FDA’s ban on fluoroquinolones in poultry production may be insufficient to reduce resistant Campylobacter in poultry products.

BackgroundAntimicrobial use in food-animal production is an issue of growing concern. The application of antimicrobials for therapy, prophylaxis, and growth promotion in broiler chicken production has been associated with the emergence and dissemination of antimicrobial-resistant enteric bacteria. Although human exposure to antimicrobial-resistant bacteria through food has been examined extensively, little attention has been paid to occupational and environmental pathways of exposure.ObjectiveOur objective was to measure the relative risk for colonization with antimicrobial-resistant Escherichia coli among poultry workers compared with community referents.MethodsWe collected stool samples and health surveys from 16 poultry workers and 33 community referents in the Delmarva region of Maryland and Virginia. E. coli was cultured from stool samples, and susceptibility to ampicillin, ciprofloxacin, ceftriaxone, gentamicin, nitrofurantoin, and tetracycline was determined for each E. coli isolate. We estimated the relative risk for carrying antimicrobial-resistant E. coli among poultry workers compared with community referents.ResultsPoultry workers had 32 times the odds of carrying gentamicin-resistant E. coli compared with community referents. The poultry workers were also at significantly increased risk of carrying multidrug-resistant E. coli.ConclusionsOccupational exposure to antimicrobial-resistant E. coli from live-animal contact in the broiler chicken industry may be an important route of entry for antimicrobial-resistant E. coli into the community.

Global use of biodiesel is increasing rapidly. Combustion of biodiesel changes the emissions profile of diesel engines, altering their impact on both urban air pollution and climate. Here, we characterize exhaust emissions from conventional petroleum diesel and three neat biodiesels manufactured from soybean, canola, and yellow grease feedstocks. Exhaust was sampled from a fixed-speed 4.8 kW diesel generator at idle and full loads, and mass emission rates were determined for nitrogen oxides (NO, NO2, and NO x ), particulate matter (PM), and elemental, organic, and black carbon (EC, OC, and BC). Additionally, particle size distributions were characterized. Largely consistent with a growing body of data on emissions from biodiesel, biodiesel emissions were cleaner by most metrics than those for conventional diesel. Emissions from the two primary-oil fuels, synthesized from soy and canola feedstocks, were cleaner by most metrics than emissions from diesel, producing approximately 55, 65, and 60% less PM, EC, and OC at engine idle and 40, 20, and 15% less at engine load. In addition, while primary-oil NO x emissions were 5% higher than diesel emissions at engine idle, they were more than 30% lower at engine load. Yellow grease emissions of PM, EC, and OC were reduced in comparison to diesel at engine idle by 60, 30, and 20%. However, at engine load, most yellow grease emissions were increased in comparison to diesel, resulting in approximately 5, 60, and 70% more PM, EC, and OC. Organic vapor emissions from primary-oil biodiesels were also lower, and aromatic emissions were much lower compared to diesel. Yellow grease NO x emissions were increased in comparison to diesel by approximately 5% at engine idle and 10% at engine load. Notably, NO2 accounted for a smaller fraction of NO x for all three biodiesels compared to diesel, a difference that may be more important than the somewhat higher NO x emissions in determining the impact of biodiesel on urban ozone formation. Taken together, our results suggest that widespread implementation of primary-oil biodiesels could result in improvements in urban ozone and PM pollution. In addition, by reducing both the mass and the EC content of those particles, primary-oil biodiesels may reduce anthropogenic climate forcing.

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