Our experience with cryopreserved arterial allograft in the management of abdominal aortic infection suggests that this technique seems to be a useful option for treating one of the most dreaded vascular complications.

These preliminary results show that total laparoscopic AAA repair is feasible and worthwhile for patients once the learning curve is overcome. However, prior training and experience in laparoscopic aortic surgery are needed to perform total laparoscopic AAA repair. Despite these encouraging results, a greater experience and further evaluation are required to ensure the real benefit of this technique compared with open AAA repair.

The novel ,B-lactamase CTX-1 (pl 6.3) encoded on a transferable 84-kilobase plasmid was found in six different bacterial species. It was responsible for a significant decrease in susceptibility towards most penicillins and cephalosporins, except imipenem, temocillin, and' cephalosporins which have a 7-a-methoxy substituent.Synergy between either ampicillin, piperacillin, cefotaxime, ceftazidime, or aztreonam and three D-lactamase inhibitors (clavulanic acid, sulbactam, and YTR 830) was generally found for different strains harboring CTX-1. This enzyme may be related to or derived from the TEM enzyme, since an intragenic probe of the TEM-1 gene hybridized with a fragment of the plasmid carrying CTX-1.Only few plasmid-mediated 1-lactamases able to hydrolyze novel broad-spectrum cephalosporins have been described in Klebsiella pneumoniae, Serratia marcescens, and Klebsiella ozaenae (5, 6). The plasmid-mediated enzyme found in K. ozaenae has been designated SHV-2 by Kliebe et al. (5) and is probably a natural derivative of SHV-1. In this study, we report some characteristics of a novel plasmidmediated P-lactamase, its spectrum of activity, and its inhibition by different ,B-lactamase inhibitors. The enzyme is referred to as CTX-1, the name of an enzyme recently found by Sirot et al. (13) in France in K. pneumoniae. MATERIALS AND METHODSBacterial strains and plasmids. Twenty-three distinct clinical isolates belonging to six bacterial species and harboring the novel plasmid-mediated ,-lactamase CTX-1 were isolated from five patients during a 3-month period in 1986 in the intensive care unit (four patients) and vascular surgery unit (one patient) at Hopital Saint-Joseph in Paris. The detection of CTX-1 was facilitated by the observation of synergy between ceftazidime and clavulanic acid (contained in Augmentin disk) on standard antibiograms. Escherichia coli BM694 (7) was used as recipient for plasmids encoding the different P-lactamases studied.' These included R6K (TEM-1), RP1 (TEM-2), and p453 (SHV-1). SHV-2 was transferred to E. coli BM694 from K. pneumoniae 2144 kindly given by H. Knothe. CTX-1 was transferred after selection on either cefotaxime (2 ,ug/ml) or amikacin (5 ,ug/ml) plus nalidixic acid (20 ,g/ml).Media and antibiotics. Cultures were grown in standard Mueller-Hinton medium broth or on Mueller-Hinton agar. Antimicrobial agents were kindly provided as follows:

YTR 830, a new ,-lactamase inhibitor, combined with amoxicillin or carbenicillin, showed a synergistic effect similar to that observed with clavulanic acid, and generally better than that with sulbactam, against strains harboring chromosome-encoded penicillinases and broad-spectrum ,-lactamases or plasmiddetermined 13-lactamases. With ampicillin, YTR 830 showed the best synergistic activity of the inhibitors against Proteus morganii, Citrobacterfreundii, and Enterobacter cloacae and their mutants with a derepressed chromosome-encoded cephalosporinase.YTR 830 is a new derivative of penicillinate sulfone, which was previously shown to have a spectrum of activity similar to that of clavulanic acid when combined with amoxicillin against clinical isolates of Staphylococcus aureus, Haemophilus influenzae, and different Enterobacteriaceae (1). In this study we have compared YTR 830 with clavulanic acid and sulbactam, in combination with different 3-lactam antibiotics, against a range of bacteria harboring known Plactamases.YTR 830 was obtained from Taiho Pharmaceuticals; ampicillin was from Bristol Laboratories; amoxicillin, carbenicillin, and sodium clavulanate were from Beecham Laboratories; cefotaxime was from Roussel-Uclaf; cefoperazone and sulbactam were from Pfizer Inc. We studied strains harboring known chromosome-or plasmid-mediated ,Blactamases (2, 4). MICs (18 h) were determined by using the agar dilution method. Increasing concentrations of P-lactam antibiotics were added to Mueller-Hinton agar containing 8 ,ug of the inhibitor per ml, and about 104 CFU were deposited onto the surface of the agar plate with a Steers-type replicator device. The MICs of the different inhibitors were .32 ,ugIml. Synergy or antagonism was defined as a fourfold or greater decrease or increase, respectively, in the MIC of the

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