No abstract

Seftenberg and Virchow were also isolated although less than three times each. Antimicrobial susceptibility analysis showed that the highest level of resistance was against tetracycline (68.8 %). Sulphonamides and their combination with trimethoprim were only active against 67.7 % and 53.1 % of the strains, respectively. Regarding b-lactams, 41.6 % of the strains were resistant to ampicillin and 18.7 % were resistant to the combination of amoxycillin and clavulanic acid. Finally, 17.7 % of strains were resistant to cloramphenicol. Sixty-two percent of the strains showed resistance to three or more antimicrobial agents and 46 % were resistant to five or more drugs. The maximum number of compounds to which one strain was resistant was 10 (corresponding to a 4,5,12:i:-strain. In addition 3 strains were resistant to eight or nine compounds. None of the strains was resistant to colistin or ceftriaxone and 12 strains were susceptible to all antimicrobial agents tested (serotypes Anatum, Goldcoast, Kapemba and Ohio). These results indicate that sub-clinical infection with Salmonella can be produced by multi-drug resistant strains. In addition, with very few exceptions, most of the detected serotypes were able to be resistant to more than three drugs. This fact suggests that antimicrobial resistance in Salmonella isolates from pigs is not an exclusive property of a given serotype, for instance Typhimurium, but a widespread characteristic. However, the wider spectrum of resistance is usually found in the 4,5,12:i:-variants of Typhimurium (De la Torre et al., 2002). Taking together, these results show that antimicrobial resistance is a real problem in swine isolates of Salmonella and reinforce the notion than an improved knowledge of the impact of antimicrobial agents used in swine is required.

Summary Nystatin (100 000 units/day for 14 days) and clotrimazole (100 mg/day for 6 days) were equivalent to miconazole (100 mg/day for 14 days or 100 mg twice daily for 7 days) in curing vaginal candidiasis. However significantly more patients relapsed in the nystatin and clotrimazole groups than in either of the miconazole groups.

The objective of this study was to evaluate the effect of stringent cleaning and subtherapeutic chlortetracycline (CTC) on Salmonella enterica (SE) prevalence in market age swine. Twenty-four finisher barns from one farm were enrolled in a 2X2 factorial study design. Treatments included 1) assignment to a "stringent" or standard cleaning protocol and 2) inclusion of 50g of CTC/ton of feed or no feed antimicrobials. Barn swab samples were obtained pre-and post-cleaning for SE detection. Post-cleaning aerobic plate counts (APC) were collected. Feces were collected to determine SE prevalence pre-market. The stringent cleaning protocol resulted in decreased mean APC post-cleaning, but there was no difference in isolation of SE from the barn environment between cleaning protocols. Pigs housed in barns that received CTC had decreased odds of being SE positive, but there was no difference in the odds of a pig being SE positive between cleaning protocols.

The objective of this study was to evaluate the effect of stocking density and subtherapeutic chlortetracycline on Salmonella prevalence in swine. From one farm, four finisher barns with eight pens per barn were selected for entry into the study. Two barns received subtherapeutic chlortetracycline in the diet, and 2 rooms received the same diet without antimicrobials. Within each barn, alternate pens were assigned to high or low stocking density. Overall 6% of all fecal samples were positive. Salmonella was cultured from all barns. Of the 30 pens included in the study, 21 (70%) were positive at least once. Preliminary data suggests that there was no difference in the proportion of pen samples positive or the odds of a pen to be positive associated with stocking density. There were increased overall proportion of positive samples and increased odds of a pen to be Salmonella positive if it was in a barn that received chlortetracycline.Introduction Animal stocking density has been proposed as a potential risk factor for Salmonella shedding in swine. Stocking density has known impacts on growth performance in swine (Hyun and Ellis, 2001;Hyun et al., 1998), but data regarding animal density and marketing group as risk factors for shedding of salmonellae are sparse. In a study of US swine, groups of finisher pigs categorized as having high Salmonella prevalence were more likely to be stocked at higher pig densities (ie, less space allowance per pig) at the time of sampling, compared to low prevalence groups. (Funk et al., 2001) The association with stocking density itself was unclear, as the variation at the time of finisher sampling was accounted for by the number of pigs that had been marketed prior to sampling. Linton et al. (1970) identified higher prevalence of infection in pens with higher pig density, but this result was not confirmed on subsequent sampling in the same herd.Subtherapeutic antimicrobial use, in particular for the purpose of growth promotion, is under increasing scrutiny regarding its contribution to antimicrobial resistance in human pathogens. It is currently unclear what the effect of subtherapeutic antimicrobial use has on the prevalence of Salmonella. Few on-farm clinical trials evaluating the effect of subtherapeutic antimicrobials on Salmonella prevalence have been conducted.The objective of this study was to evaluate the effect of group size/stocking density and subtherapeutic chlortetracycline on Salmonella prevalence in swine.