Antimicrobial resistance patterns of Campylobacter from feedlot cattle

Aims: This study examined 448 Campylobacter strains isolated in 1999 and 2000 from US feedlot cattle for resistance to 12 antimicrobials. Methods and Results: Isolates were tested for antimicrobial susceptibility using the E-test method. Approximately 60% (n = 267) were resistant to one or more antimicrobials, and 19·6% (n = 88) were resistant to two or more antimicrobials. Of the Campylobacter jejuni isolates, 49·1% (n = 187) were resistant to tetracycline, 10·2% (n = 39) were resistant to nalidixic acid, 8·4% were resistant to trimethoprim/sulfamethoxazole, and 1·8% (n = 7) were resistant to ciprofloxacin. Resistance to any of the other eight antimicrobials was 1·3% or less, but 14·4% (n = 55) were resistant to two or more antimicrobials. In the Campylobacter coli group, 65·7% (n = 44) were resistant to tetracycline, 52·2% (n = 35) were resistant to trimethoprim/sulfamethoxazole, 22·4% (n = 15) were resistant to nalidixic acid, and 9·0% (n = 6) were resistant to ciprofloxacin. Resistance to any of the remaining eight antimicrobials was 3·0% or less, although 49·3% (n = 33) were resistant to two or more antimicrobials. Conclusions: Although antimicrobials are widely used in US feedlot cattle production, our results demonstrate generally low levels of resistance to a broad range of commonly used antimicrobials relative to other recent studies. Significance and Impact of the Study: Resistance data on Campylobacter isolated from this major US livestock commodity is lacking. This overview enhances current knowledge and provides a basis for further studies

Antimicrobial resistance patterns of Campylobacter from feedlot cattle

Aims: This study examined 448 Campylobacter strains isolated in 1999 and 2000 from US feedlot cattle for resistance to 12 antimicrobials. Methods and Results: Isolates were tested for antimicrobial susceptibility using the E-test method. Approximately 60% (n = 267) were resistant to one or more antimicrobials, and 19·6% (n = 88) were resistant to two or more antimicrobials. Of the Campylobacter jejuni isolates, 49·1% (n = 187) were resistant to tetracycline, 10·2% (n = 39) were resistant to nalidixic acid, 8·4% were resistant to trimethoprim/sulfamethoxazole, and 1·8% (n = 7) were resistant to ciprofloxacin. Resistance to any of the other eight antimicrobials was 1·3% or less, but 14·4% (n = 55) were resistant to two or more antimicrobials. In the Campylobacter coli group, 65·7% (n = 44) were resistant to tetracycline, 52·2% (n = 35) were resistant to trimethoprim/sulfamethoxazole, 22·4% (n = 15) were resistant to nalidixic acid, and 9·0% (n = 6) were resistant to ciprofloxacin. Resistance to any of the remaining eight antimicrobials was 3·0% or less, although 49·3% (n = 33) were resistant to two or more antimicrobials. Conclusions: Although antimicrobials are widely used in US feedlot cattle production, our results demonstrate generally low levels of resistance to a broad range of commonly used antimicrobials relative to other recent studies. Significance and Impact of the Study: Resistance data on Campylobacter isolated from this major US livestock commodity is lacking. This overview enhances current knowledge and provides a basis for further studies

Salmonella serotypes from 1997-2003 NARMS swine diagnostic, on-farm, and slaughter samples

The veterinary component of the National Antimicorbial Resistance Monitoring System (NARMS) identified 8527 Salmonella isolates from swine samples in the years 1997-2003. Fifty-one Salmonella serotypes were identified from 3147 diagnostic, 2138 on-farm, and 3246 slaughter samples

Antimicrobial resistance in Salmonella from 1997-2003 NARMS swine samples

A total of 3246 swine slaughter and 3147 swine diagnostic Salmonella isolates from the National Antimicrobial Resistance Monitoring System (NARMS) for the years 1997-2003 were tested for antimicrobial resistance. No resistance was detected in any Salmonella isolates for ciprofloxacin or amikacin. For all other antimicrobics tested, more resistance was observed in diagnostic isolates compared to slaughter isolates

Pulmonary arterial pressures, arterial blood-gas tensions, and serum biochemistry of beef calves born and raised at high altitude

Includes bibliographical references (page 8).High-altitude exposure is physiologically challenging. This is particularly true for animals native to low-altitude environments, such as British breeds of cattle. The objective of this study was to document the effect of high altitude on select physiological parameters of healthy beef calves (Bos taurus) born and raised on a high-altitude ranch typical of the Rocky Mountain region. Pulmonary arterial pressures, arterial blood-gas tensions, serum biochemistry, and hematocrit were evaluated. The calves studied were a composite of British (50%-75%) and Continental (25-50%) breeds born on one ranch at an altitude of 2410 m. Calves were sampled at an altitude of 2410 m when 1 month old and again at an altitude of 2730 m when 3 and 6 months old. Between 3 and 6 months of age, calves had access to grazing from 2730 m to approximately 3500 m above sea level. On each occasion, 16 to 50 calves were sampled. Only calves that remained healthy throughout all three testing periods were included in the dataset. Calves with the highest pulmonary arterial pressures at 1 month of age tended to have the highest pressures at 6 months of age (r = 0.43, P = 0.16, n = 12). Respiratory alkalosis was greatest at 6 months of age (pH 7.48 ± 0.06). Mean alveolar-arterial oxygen pressure gradients were 11.7and 11.6 mmHg at 3 and 6 months of age, indicating poor transfer of oxygen from the alveoli into the pulmonary blood. Median values for blood lactate ranged from 1.4 to 3.4 mmol/L indicating substantial anaerobic respiration at all ages. Mean hematocrits were ≤ 35.7%, only slightly higher than values obtained from age-matched calves at sea level. These results suggest that the provision of oxygen to the peripheral tissues of beef calves may be compromised at altitudes over 2410 m. This may have implications for diseases of the cardiopulmonary system.Published with support from the Colorado State University Libraries Open Access Research and Scholarship Fund

Prevalence of internal parasites in beef cows in the United States: Results of the National Animal Health Monitoring System’s (NAHMS) beef study, 2007–2008

During the United States Department of Agriculture (USDA) National Animal Health Monitoring System’s (NAHMS) 2007–2008 beef study, 567 producers from 24 US States were offered the opportunity to collect fecal samples from weaned beef calves and have them evaluated for the presence of parasite eggs (Phase 1). Participating producers were provided with instructions and materials for sample collection. Up to 20 fresh fecal samples were collected from each of the 99 participating operations. Fresh fecal samples were submitted to one of 3 randomly assigned laboratories for evaluation. Upon arrival at the laboratories, all samples were processed for the enumeration of strongyle, Nematodirus, and Trichuris eggs using the modified Wisconsin technique. The presence or absence of coccidian oocysts and tapeworm eggs was also noted. In submissions where the strongyle eggs per gram exceeded 30, aliquots from 2 to 6 animals were pooled for DNA extraction. Extracted DNA was subjected to genus level polymerase chain reaction (PCR) identification for the presence of Ostertagia, Cooperia, Haemonchus, Oesophagostomum, and Trichostrongylus. In this study, 85.6% of the samples had strongyle type, Nematodirus, and Trichuris eggs. Among the samples evaluated, 91% had Cooperia, 79% Ostertagia, 53% Haemonchus, 38% Oesophagostomum, 18% Nematodirus, 7% Trichuris, and 3% Trichostrongylus. The prevalence of coccidia and tapeworm eggs was 59.9% and 13.7%, respectively

Effectiveness of current anthelmintic treatment programs on reducing fecal egg counts in United States cow-calf operations

During the United States Department of Agriculture (USDA) National Animal Health Monitoring System’s (NAHMS) 2007–2008 beef study, producers from 24 states were offered the opportunity to evaluate their animals for internal parasites and for overall responses to treatment with anthelmintics. A lapse of 45 d was required between initial sampling and any previous treatments. Choice of anthelmintic (oral benzimidazoles, and both injectable and pour-on endectocides) was at the discretion of the producer so as not to alter the local control programs. Fresh fecal samples were collected from 20 animals, or from the entire group if less than 20, then randomly assigned to 1 of 3 participating laboratories for examination. Analyses consisted of double centrifugation flotation followed by enumeration of strongyle, Nematodirus, and Trichuris eggs (the presence of coccidian oocysts and tapeworm eggs was also noted). Where strongyle eggs per gram (epg) exceeded 30, aliquots from 2 to 6 animals were pooled for egg isolation and polymerase chain reaction (PCR) analysis for the presence of Ostertagia, Cooperia, Haemonchus, Oesophagostomum, and Trichostrongylus. Results from 72 producers (19 States) indicated that fecal egg count reductions were , 90% in 1/3 of the operations. All operations exhibiting less than a 90% reduction had used pour-on macrocyclic lactones as the anthelmintic treatment. While some of these less than expected reductions could have been the result of improper drug application, PCR analyses of the parasite populations surviving treatment, coupled with follow-up studies at a limited number of sites, indicated that less than expected reductions were most likely due to anthelmintic resistance in Cooperia spp. and possibly Haemonchus spp

Serotypes and Antimicrobial Resistance in Salmonella Isolates from Swine, NARMS-EB 1997-2000

The National Antimicrobial Resistance Monitoring System (NARMS) was developed in 1996 as a collaborative effort between the FDA, USDA, and CDC to monitor antimicrobial resistance development in enteric organisms in humans and animals. Salmonella was selected as the sentinel organism

National antimicrobial resistance monitoring system: Results for swine

Use of antimicrobics has increased in both human and veterinary medicine. This is due in part to the availability of the antimicrobics and the efficacy they impart in control of certain infectious diseases. However, use of antimicrobics can lead to the development of resistance to the antirnicrobics. Antimicrobial resistance can diminish effectiveness and may even render an antimicrobic ineffective as a therapeutic. Although use may result in a portion of bacteria that are resistant, the exact fate of this population in terms of persistence and transmission has been difficult to determine. Use panerns in veterinary medicine (therapeutic versus preventive versus growth promotion use) also complicates the picture. Additionally, while transmission of resistant bacteria from animals to humans occurs, it has been difficult to assess the extent to which this occurs and the impact transmission has on actual dissemination of resistant populations