1 The potential role of copper (Cu 2+ ) in modulating the activity of nitric oxide synthase (NOS) and guanylyl cyclase (GC) was investigated by use of diethyldithiocarbamic acid (DEDCA), a high a nity Cu 2+ chelator. 2 DEDCA 100 mM inhibited sodium nitroprusside (SNP; 0.005 ± 10 mM)-evoked relaxation of rat isolated aortic rings precontracted with 3 mM phenylephrine (PE). A lower concentration of DEDCA (10 mM) did not signi®cantly attenuate SNP-evoked responses but did inhibit relaxation to the endothelium-dependent dilator, A23187 (0.01 ± 10 mM). 3 The presence of 100 mM Cu 2+ , but not 100 mM Fe 2+ , alone enhanced A23187-and SNP-evoked relaxation of aortae precontracted with PE. 4 The inhibitory e ect of DEDCA on SNP-and A23187-induced relaxation was reversed by equimolar concentrations of Cu 2+ but not Fe 2+ , indicating that DEDCA does not act via removal of haem-iron from the NOS and GC complexes. 5 Superoxide dismutase (30 m ml 71 ) was without e ect on the inhibition of DEDCA relaxation induced by either SNP or A23187 in aortae precontracted with PE. 6 When assessed by radioimmunoassay, DEDCA inhibited SNP-and A23187-stimulated cyclic GMP formation with IC 50 values of 0.5 mM and 50 mM, respectively. 7 These data demonstrate that Cu 2+ plays a role in controlling NOS and GC activity in the rat aorta.

With the exception of penicillin, doxycycline and tetracycline, the level of resistance to the antimicrobial agents tested was minimal. Prudent antibiotic use in treating companion animals with skin infections will reduce the selection of MRSP and other multidrug-resistant bacteria.

Introduction: Significant effort has been invested in looking at the antimicrobial activity of plant extracts from tropical regions of Australia, with less interest in those from more temperate environments. We sought to redress this imbalance by examining antimicrobial activities of extracts from native plants of Victoria. Methods: Sixteen plant samples were obtained around the Ballarat region of Victoria. Plant material was desiccated, ground and extracted with methanol at room temperature. Methanol extracts were subsequently dissolved in water, filtered and freeze dried. Extracts were dissolved in water and their activity determined against eight bacterial species. Plant extracts that showed appreciable antibacterial activity in the initial antimicrobial screen were examined further with both their MICs and MBCs determined. Results: Ten of the sixteen plant extracts showed antimicrobial activity. Extracts of Eucalyptus, Melaleuca, Prostanthera and Westringia were particularly active with MICs as low as 0.25 mg/ml against organisms including P. aeruginosa and S. aureus. Conclusion: The current study demonstrates the antimicrobial activity of plant extracts from temperate Australia. These may serve as precursors for future chemotherapy agents.

Resistance to last-resort antibiotics is significant public health issue. Antibiotic use in animal husbandry may be a driver of resistance that can subsequently be disseminated via the food chain. This study sought to determine the level of polymyxin resistance in Gram-negative pathogens present in Australian poultry, particularly the presence of mobilizable mechanisms of polymyxin resistance. Cloacal swabs from 213 birds were taken in a point prevalence survey from six different farms at a Victorian chicken processing facility. Colistin resistant organisms were recovered by direct plating on CHROMagar COL-APSE media. Bacterial isolates were identified and analyzed by MALDI-TOF, biochemical and genotypic assays. The 213 specimens yielded 57 (26.8%) colistin-resistant Gram-negative organisms, all of which have been previously described as exhibiting intrinsic resistance to polymyxin antibiotics. The most frequent organism was identified as Hafnia paralvei (40/57; 70%). Other colistin-resistant organisms included Aeromonas hydrophila (16%), Myroides odoratus (7%), Alcaligenes faecalis (5%), and Pseudochrobactrum spp. (2%). No mobile colistin resistance (mcr) genes were detected, although the arnA gene was identified in two A. hydrophila isolates and may mediate colistin resistance in these isolates. Intrinsic polymyxin-resistant organisms are widely distributed in the food chain, with over a quarter of the birds tested yielding a polymyxin-resistant organism. However, strains containing mcr genes remain rare in Australian poultry.

Staphylococcus cohnii subsp. urealyticus strain SW120 was isolated from the ear swab of a healthy dog. The isolate is resistant to methicillin and fusidic acid. The SW120 draft genome is 2,805,064 bp and contains 2,667 coding sequences, including 58 tRNAs and nine complete rRNA coding regions.