Since around 2000 - earlier in Poland and Spain and later in France and the UK - dramatic shifts have occurred in the prevalence and types of extended-spectrum b-lactamases (ESBLs) in Europe. Before this watershed, most producers were nosocomial isolates, often Klebsiella spp. or Enterobacter spp. from specialist care units, and had mutant TEM or SHV ESBLs. Subsequently, CTX-M ESBLs have become dominant, with much greater penetration into Escherichia coli, and with many infections in 'complicated community' patients, usually with underlying disease, recent antibiotic usage, or healthcare contact. The degree of clonality among producers varies with the country, as does the enzyme type produced, with group 9 (CTX-M-9 and -14) enzymes dominant in Spain and group 1 enzymes particularly CTX-M-3 and -15) dominant elsewhere. Irrespective of the particular enzyme, most producers are multiresistant. These changing patterns present major therapeutic and infection control challenges, with the public health intervention points unclear.
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Conflicts of interest: D. M. L., grants from AstraZeneca, Merck and Wyeth; speakers’ bureaux for AstraZeneca, Johnson & Johnson, Merck and Wyeth; shareholdings in AstraZeneca GlaxoSmithkline, Pfizer and Schering Plough. G. M. R., grants from Wyeth; consultancies from Wyeth, Janssen-Cilag and Nabi Pharmaceuticals; speakers’ bureaux for Wyeth and Merck; R. C., grants from Sanofi-Aventis and Wyeth. Other authors: no conflicts to declare.
- Antibiotic resistance
- CTX-M β-lactamases
- Extended-spectrum b-lactamases