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

Investigations into the infection-contamination-infection cycle of zoonotic Salmonella on swine farms: Serovar and sensitivity patterns of Salmonella isolates from animals and environments from selected Minnesota swine farms

Approximately 12000 samples (5400 ileocecal lymph nodes from slaughter pigs and 6600 diverse environmental material such as feces. feed, dust, soil and water from swine farms) have been cultured for Salmonella since 1997 in the framework of the long-term research project Salmonella Abatement in the Pork Chain at the University of Minnesota

USDA Multi-Agency Project: Collaboration in Animal Health, Food Safety & Epidemiology (CAHFSE)

Despite producer interventions, on-going research and continued surveillance, food borne outbreaks continue and multiple antimicrobial resistant bacteria have emerged. A multi-agency APublic Health Action Plan to Combat Antimicrobial Resistance@ was developed to address these concerns and one USDA response was the development of the Collaboration in Animal Health, Food Safety and Epidemiology (CAHFSE), a partnership among the Agriculture Research Service (ARS), Animal and Plant Health Inspection Service (APHIS), and Food Safety Inspection Service (FSIS. The objective of CAHFSE is to implement and expand a surveillance system patterned after the APHIS National Animal Health Monitoring System (NAHMS) which focuses on animal health and food safety. Swine is the first commodity in CAHFSE. To date, fecal samples from 8 farms have been collected and processed for culture of Salmonella, Campylobacter, Enterococci and E. coli. Preliminary results indicate that all four bacteria have been recovered from a number of operations and are currently being characterized

Antimicrobial resistance patterns of Salmonella isolates collected from slaughter age pigs

Salmonellae are ubiquitous in nature and are recovered from many animal species including swine. However, prevalence of specific serotypes can vary. Although carriage is often observed, fecal shedding can be sporadic (2). Salmonella, as well as other food borne pathogens, can be transferred from animals to the human population. However, since the federally mandated HACCP program has been implemented, a reduction in Salmonella among the major food animals has been observed

Repeated observations on the Salmonella culture status of midwest U.S. herds

Mesenteric lymph nodes were collected from pigs from 115 Midwest U.S. swine herds at slaughter on two occasions separated by 6-9 months. These herds were sampled up to three additional times during a three-year period, with 30 herds sampled five times. Thirty pigs were sampled at each collection. Herds were categorized positive if one or more samples revealed Salmonella spp. While culture status at collection one was associated with the second sampling collection (p \u3c 0.01), the association was only moderate in strength (OR = 2.6). Herds with three consecutive positive tests (9 of 38) were all positive on sample four. Prevalence estimates were weakly or not correlated between samplings. In conclusion, Salmonella culture status of these swine herds was weakly predictive of future culture results. Accurate description of Salmonella status based on bacterial culture appears to require repeated or ongoing testing

Use of Defined Competitive Exclusion Cultures to Enhance Colonization Resistance to Enteric Pathogens

During the past several years our laboratory has conducted research towards developing defined competitive exclusion cultures that enhance colonization resistance against salmonellae in baby chicks. Previously in our laboratory it was shown that 10-day-old broiler and layer chicks that were fed diets containing 5-10% lactose provided either in the feed or in water from day-of-hatch were significantly more resistant to Salmonella typhimurium, and S. enteritidis cecal colonization than control chicks not provided a diet supplemented with lactose. Additionally, resistance against salmonellae cecal colonization was further enhanced in treatment groups provided dietary lactose in combination with an undefined mixture of anaerobic bacteria (i.e. undefined competitive exclusion culture or Nurmi culture) originally obtained from the ceca of adult broiler chickens maintained on a diet containing lactose. In order to make a defined competitive exclusion culture that was efficacious in enhancing colonization resistance against salmonellae, we cultured cecal contents obtained from adult broilers maintained on a unmedicated diet containing 5% lactose in a continuous-flow (CF) culture apparatus (i.e. chemostat), that was maintained at parameters that would best represent the cecal environment

Effect of competitive exclusion on salmonella shedding in swine

Despite the efforts of researchers and public health agencies, the incidence of human salmonellosis has continued to increase over the past 20 years. Salmonellosis is now the most common cause of food-borne gastroenteritis. The number of reported cases of human Salmonella infection exceeds 40,000 per year. The Communicable Disease Center estimates that the true annual incidence of human salmonellosis in the United States may be as high as 4 million cases

Effects of some methodologic factors on detection of Salmonella in swine feces

Bacteriologic culture of feces for Salmonella continues to be a central component of epidemiologic studies. We conducted a series of experiments on fecal samples collected from commercial swine farms to evaluate the effects of several methodologic factors on detection of Salmonella. Factors examined included fecal sample storage (no storage, 4C, -15C) and fecal sample weight. In addition we compared the standard method (Method I) used in our laboratory [JOg feces/buffered peptone water pre-enrichment/selective enrichment in Rappaport Vassiliadis (RV) broth] with another method (Method 2) used by ourselves and others in the USA (=I g sample/primary enrichments in tetrathionate and Hajna GN broths/secondary enrichment in RV broth). Inunediate processing of samples yielded the best recovery of Salmonella, although storage at 4C for 6 days did not significantly reduce detection. Freezing of fecal samples resulted in significant reduction of detection. The weight of feces sampled had a marked linear effect on the detection of Salmonella using method I. Direct comparison of Method I and Method 2 indicated comparable results, with Method I tending to yield higher detection of Salmonella. However, when conducted on samples of equal weight, Method 2 had significantly better detection than Method I. The choice of methods can markedly affect the results of fecal sample culture. The preferred methodology for epidemiologic studies will be determined by many factors including logistics and cost. Our data highlight the imperfect sensitivity of culture methods, and the need for researchers to consider the sensitivity of their bacteriologic methods in the design and interpretation of field studies based on fecal culture