Molecular epidemiology of the plasmid-encoded TEM-1 β-lactamase in Scotland

Abstract

SUMMARY: A survey of the β-lactamases responsible for ampicillin resistance in urinaryEscherichia coliisolated in central Scotland has been performed. The TEM-1 β-lactamase was found to be most prevalent occurring in 88.2% of ampicillin-resistant isolates tested. Forty-six percent of the TEM-1 producing strains were able to transfer this resistance toE. coliJ62–2 at 37 ° C. Analysis of the resulting transconjugants revealed that the degree of resistance to amoxycillin and amoxycillin in combination with clavulanic acid was related to the specific activity of the TEM-1 β-lactamase. The variation in specific activity was shown to be related to plasmid type as determined by restriction analysis. No obvious relationship between β-lactamase specific activity and resistance to amoxycillin and amoxycillin plus clavulanic acid could be demonstrated in the original plasmid donor strains.