Biomedical subjects

David A Dargatz

Publications and source records attributed to David A Dargatz.

22 records · Page 2Linked to original sources

PubMed2002

Antimicrobial susceptibility patterns of Salmonella isolates from cattle in feedlots.

OBJECTIVE: To evaluate the antimicrobial susceptibility patterns of Salmonella isolates from feedlot cattle. DESIGN: Cross-sectional study. SAMPLE POPULATION: 263 Salmonella isolates. PROCEDURES: Fecal samples were collected from the floor of 2 pens in each of 100 feedlots. Two hundred eighty Salmonella isolates were recovered after bacteriologic culture from 38 pens. Of these, 263 isolates were available for antimicrobial susceptibility testing to 16 antimicrobials, using microbroth dilution breakpoint plates. RESULTS: Less than 5% of isolates were resistant to any of the antimicrobials tested, with the exception of sulfamethoxazole (15; 5.7%) and tetracycline (61; 23.2%). Most isolates (197; 74.9%) were susceptible to all antimicrobials tested, whereas 18 (6.8%) were resistant to 2 or more antimicrobials. The percentage of isolates with resistance to any antimicrobial varied by serotype. The percentage of isolates resistant to various antimicrobials was not related to concurrent use of antimicrobials in the feed. CONCLUSIONS AND CLINICAL RELEVANCE: With the exception of tetracycline and sulfamethoxazole, resistance of Salmonella isolates to any of the antimicrobials was uncommon. Most isolates were susceptible to all antimicrobials tested. Antimicrobial resistance was not related to the presence of antimicrobials in the ration being fed at the time of sample collection.

Animals↗

PubMed2002

Survey of complications and antimicrobial use in equine patients at veterinary teaching hospitals that underwent surgery because of colic.

OBJECTIVE: To determine current practices regarding use of antimicrobials in equine patients undergoing surgery because of colic at veterinary teaching hospitals. DESIGN: Survey. SAMPLE POPULATION: Diplomates of the American College of Veterinary Surgeons performing equine surgery at veterinary teaching hospitals in the United States. PROCEDURE: A Web-based questionnaire was developed, and 85 surgeons were asked to participate. The first part of the survey requested demographic information and information about total number of colic surgeries performed at the hospital, number of colic surgeries performed by the respondent, and whether the hospital had written guidelines for antimicrobial drug use. The second part pertained to nosocomial infections. The third part provided several case scenarios and asked respondents whether they would use antimicrobial drugs in these instances. RESULTS: Thirty-four (40%) surgeons responded to the questionnaire. Respondents indicated that most equine patients undergoing surgery because of colic at veterinary teaching hospitals in the United States received antimicrobial drugs. Drugs that were used were similar for the various hospitals that were represented, and for the most part, the drugs that were used were fairly uniform irrespective of the type of colic, whereas the duration of treatment varied with the type of colic and the surgical findings. The combination of potassium penicillin and gentamicin was the most commonly used treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Results of this study document the implementation of recommendations by several authors in veterinary texts that antimicrobial drugs be administered perioperatively in equine patients with colic that are undergoing surgery. However, the need for long-term antimicrobial drug treatment in equine patients with colic is unknown.

Animals↗

PubMed2002

An introduction to biosecurity of cattle operations.

Recent world events have heightened awareness for the need to safeguard our livestock industries from disease agents. Biosecurity is the outcome of all activities undertaken to preclude introduction of disease agents into an animal population. The concepts of biosecurity are not new. Activities directed at ensuring biosecurity include controlling exposure and optimizing resistance. Programs for biosecurity must be individually tailored to specific situations to account for varying risks and perceptions of risk by decision makers. It is important for practitioners to take a holistic approach to disease control, considering the epidemiology of the disease in addition to the available vaccines and therapeutics.

Animal Diseases↗

PubMed2002

Comparison of sampling techniques for measuring the antimicrobial susceptibility of enteric Escherichia coli recovered from feedlot cattle.

OBJECTIVE: To evaluate the effectiveness of various sampling techniques for determining antimicrobial resistance patterns in Escherichia coli isolated from feces of feedlot cattle. SAMPLE POPULATION: Fecal samples obtained from 328 beef steers and 6 feedlot pens in which the cattle resided. PROCEDURE: Single fecal samples were collected from the rectum of each steer and from floors of pens in which the cattle resided. Fecal material from each single sample was combined into pools containing 5 and 10 samples. Five isolates of Escherichia coli from each single sample and each pooled sample were tested for susceptibility to 17 antimicrobials. RESULTS: Patterns of antimicrobial resistance for fecal samples obtained from the rectum of cattle did not differ from fecal samples obtained from pen floors. Resistance patterns from pooled samples differed from patterns observed for single fecal samples. Little pen-to-pen variation in resistance prevalence was observed. Clustering of resistance phenotypes within samples was detected. CONCLUSIONS AND CLINICAL RELEVANCE: Studies of antimicrobial resistance in feedlot cattle can rely on fecal samples obtained from pen floors, thus avoiding the cost and effort of obtaining fecal samples from the rectum of cattle. Pooled fecal samples yielded resistance patterns that were consistent with those of single fecal samples when the prevalence of resistance to an antimicrobial was > 2%. Pooling may be a practical altemative when investigating patterns of resistance that are not rare. Apparent clustering of resistance phenotypes within samples argues for examining fewer isolates per fecal sample and more fecal samples per pen.

Animals↗