This is the first study among a large collection of Dutch companion animals and horses characterizing ESBL/AmpC-producing isolates. A similarity in resistance genes and E. coli STs among these isolates and isolates from Dutch poultry and humans may suggest exchange of resistance between different reservoirs.

Extended-spectrum-β-lactamase (ESBL)/AmpC producing Enterobacteriaceae have been reported worldwide amongst isolates obtained from humans, food-producing animals, companion animals, and environmental sources. However, data on prevalence of fecal carriage of ESBL/AmpC producing Enterobacteriaceae in healthy companion animals is limited. This pilot study describes the prevalence of ESBL/AmpC encoding genes in healthy cats and dogs, and cats and dogs with diarrhea. Twenty fecal samples of each group were cultured on MacConkey agar supplemented with 1 mg/L cefotaxime and in LB-enrichment broth supplemented with 1 mg/L cefotaxime, which was subsequently inoculated on MacConkey agar supplemented with 1 mg/L cefotaxime. ESBL/AmpC genes were identified using the Check-Points CT103 micro array kit and subsequently by sequencing analysis. Chromosomal ampC promoter mutations were detected by PCR and sequencing analysis. From the healthy and diarrheic dogs, respectively 45 and 55% were positive for Escherichia coli with reduced susceptibility for cefotaxime. From the healthy and diarrheic cats, the estimated prevalence was respectively 0 and 25%. One diarrheic cat was positive for both reduced susceptible E. coli and Proteus mirabilis. The ESBL/AmpC genes found in this study were mainly blaCTX-M-1, but also blaCTX-M-14, blaCTX-M-15, blaTEM-52-StPaul, blaSHV-12, and blaCMY-2 were detected. This pilot study showed that the prevalence of ESBL/AmpC producing Enterobacteriaceae in healthy and diarrheic dogs, and diarrheic cats was relatively high. Furthermore, the genes found were similar to those found in isolates of both human and food-producing animal origin. However, since the size of this study was relatively small, extrapolation of the data to the general population of cats and dogs should be done with great care.

Despite a strict control program for methicillin-resistant Staphylococcus aureus (MRSA) in human medicine in the Netherlands, MRSA was cultured from exudative epidermitis lesions of 4 piglets on a breeding farm, 20 pigs on a supplier farm, and 2 workers on these farms. The MRSA strains were indistinguishable, suggesting direct transmission.

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31Since the emergence of MRSA in livestock, screening of animals for the detection of MRSA is widely 36Hinton broth with 6.5% NaCl followed by selective enrichment with 4 µg/ml oxacillin + 75 µg/ml 37 aztreonam (Procedure 1) and 5 µg/ml ceftizoxime + 75 µg/ml aztreonam (Procedure 2) respectively. 38Procedure 3 used a selective enrichment broth only, containing 4% NaCl, 5 µg/ml ceftizoxime + 50 39 µg/ml aztreonam. After selective enrichment, media were streaked on to three different chromogenic 45In conclusion, the results of this study show that procedures 1 and 2, both using additional high salt

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