The impact of beta-lactamases on the management of community-acquired infections

Abstract number: 1133_55

Cantón R.

During the last decade extended spectrum beta-lactamase (ESBL) producing isolates were epidemiologically linked to nosocomial outbreaks whereas few isolates were encountered in the community setting. These isolates were recognized to produce ESBLs belonging to TEM or SHV families and they were mainly identified in Klebsiella pneumoniae and to a lesser extent in Escherichia coli isolates. Risk factors for the acquisition of infections due to these isolates included admission to intensive care units, recent surgery, urinary catheterization, prolonged hospitalization and previous beta-lactam and/or aminoglycoside exposure. Nowadays, an outburst of ESBL producing isolates, mainly E. coli with different CTX-M variants, has been recognized in the community. Complex population structures have been identified in different countries with high clonal variability and coexistence with the spread of specific clones. In these isolates, co-resistance with fluoroquinolones is a general feature rather than exception. This fact has been suggested to play an important role in the dispersion of these isolates in the community. On the other hand the insertion of blaCTX-M genes in different genetic environments (ISEcp1, In60 like structures) participating in horizontal gene transfer processes may has also facilitated the spread of these genes and these enzymes producing isolates. Recent recognition of frequent fecal carriage of healthy volunteers and out-patients with ESBL producing isolates depicts future increase of these isolates in the community. Moreover the accumulation of different blaESBL-genes in bacterial populations, co-existence with other beta-lactamases, including cephamycinases, the recognition of extended-spectrum beta-lactamase variants with carbapenemase activity, and the association of certain blaESBL genes with new recognized resistance genes like qnr represents new threats in the antimicrobial resistance scenario. Intervention strategies to control the spread of these isolates in the community are limited for the frequent exhibited multirresistance phenotype and the absence of efficient oral alternatives for the management of infections due to ESBL producing isolates.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Location: Oxford, UK
Presentation type:
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