[Anomalous origin of the left coronary artery from the right sinus of Valsalva with retro-aortic path]

We present the case of a patient with a dilated cardiomyopathy in which an anomaly in the origin of the left coronary artery, that arose from the right sinus of Valsalva through an own ostium and followed a retro aortic course, was recognized as an angiographic finding. The possible pathways the anomalous artery may follow, and their different clinical significances are reviewed. The angiographic sign of the aortic root, described for the identification of the anomalous origin of circumflex artery, is reviewed and its utility in the case of anomalous left coronary artery is demonstrated. In our case, Thallium-201 didn't show myocardial ischemia with the exercise and that justified, beside the doubtful efficacy of surgery as prophylaxis of sudden death when the anomalous course is retro-aortic, to maintain a conservative attitude.

Bleomycin-kanamycin resistance as a marker of the presence of transposon Tn5 in clinical strains of Escherichia coli

The aminoglycoside modifying enzyme aminoglycoside 3'-phosphotransferase II (APH(3')II) is encoded for on transposon Tn5 by the aphA gene, in the same operon as the ble gene determining bleomycin resistance. To document this linkage 82 kanamycin-resistant Escherichia coli strains of clinical origin were studied; all 18 isolates presenting bleomycin-kanamycin resistance were shown by an enzymatic assay to produce APH(3')II, and the presence of Tn5 was demonstrated by gene hybridization. Similarly, bleomycin-kanamycin resistance was shown to be linked to APH(3')II production in Salmonella spp. The epidemiology of strains with Tn5-encoded APH(3')II may thus be studied, at least in Escherichia coli, by a simple diffusion test using bleomycin and kanamycin discs.