BACKGROUND: The aim of this study was to characterize resistance of @entity526 in our environment to four associations of @entity7660 and beta-lactamase inhibitors (beta Lac) studying the influence of the type and level of beta Lac production. METHODS: The minimum inhibitory concentration (MIC) to @entity869 / @entity5899 (A/S), @entity115 / @entity798 (A/C), @entity4967 / @entity798 ( @entity14552 ) and @entity3400 / @entity7120 (P/T) assessed was in 245 strains of @entity526 resistant to @entity869 , consecutively isolated in our laboratory from September 1995 to March 1996. The beta Lac produced by these isolates were identified by isoelectrofocusing and spectrophotometrically quantified. RESULTS: The sensitivity to A/S, A/C, T/C and P/T was of 9.4, 86.9, 64.5 and 89.4%, respectively. The strains with only one beta Lac which cofocused with @entity18585 were the most frequent (215/245), followed by those producing a cofocusing enzyme with SHV-1 (7/245). A significant correlation was observed between beta Lact activity of the 215 @entity18585 strains and their MIC at A/S (r = 0.53; p < 0.001), @entity6407 (r = 0.46; p < 0.001), T/TC (r = 0.58; p < 0.001), and P/T (r = 0.42; p < 0.001). The comparison between enzyme activity of the isolates of the different categories of susceptibility showed significant differences (p < 0.05) for the four associations studied. CONCLUSION: @entity18585 production is the main cause of resistance to @entity7660 in @entity526 in our environment. The inhibitory efficacy of @entity5899 , @entity798 and @entity7120 over @entity18585 is inversely proportional to the amounts of enzyme produced. The high rate of resistance to A/S and T/C @entity526 presents in our environment is mainly due to a hyperproduction of @entity18585 .

[Characterization of the resistance to combinations of XXXX and inhibitors of beta-lactamases in @entity526 . Effect of the type and amount of beta-lactamase production].

@entity18585 :: ('2716540(Tax:562)', 'Gene') :: ['TEM-1'] @entity115 :: ('MESH:D000658', 'Chemical') :: ['amoxycillin'] @entity7660 :: ('MESH:D047090', 'Chemical') :: ['beta-lactams'] @entity798 :: ('MESH:D019818', 'Chemical') :: ['clavulanic acid'] @entity7120 :: ('MESH:C043265', 'Chemical') :: ['tazobactam'] @entity14552 :: ('c|SUB|T||C', 'DNAMutation') :: ['T/C'] @entity4967 :: ('MESH:D013982', 'Chemical') :: ['ticarcillin'] @entity6407 :: ('c|SUB|A||C', 'DNAMutation') :: ['A/C'] @entity3400 :: ('MESH:D010878', 'Chemical') :: ['piperacillin'] @entity869 :: ('MESH:D000667', 'Chemical') :: ['ampicillin'] @entity5899 :: ('MESH:D013407', 'Chemical') :: ['sulbactam'] @entity526 :: ('562', 'Species') :: ['Escherichia coli', 'E. coli']
@entity7660 :: (MESH:D047090,Chemical) :: ['beta lactams']
