Cranberry Research Today is a free monthly online journal that collates and summarizes the latest research about Cranberry, including details on benefits, antioxidants, utis, cystitis. | ||||||||
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Virulence genotype and nematode-killing properties of extra-intestinal Escherichia coli producing CTX-M beta-lactamases.Lavigne JP, Blanc-Potard AB, Bourg G, Moreau J, Chanal C, Bouziges N, O'callaghan D, Sotto A Laboratoire Universitaire d'Antibiologie, UFR de Médecine, Nîmes, France. This study evaluated the virulence potential of Escherichia coli isolates producing CTX-M beta-lactamases. During a 24-month period, 33 extended-spectrum beta-lactamase (ESBL)-producing E. coli, including 14 CTX-M-producers, were isolated from urinary tract infections at Nîmes University Hospital, France. The prevalence of 14 major virulence factors (VFs) was investigated by PCR and compared with the prevalence in a group of 99 susceptible E. coli isolates. Ten VFs were less prevalent (p <0.05) in the ESBL isolates than the susceptible E. coli, while iutA and traT were more prevalent in ESBL isolates (p <0.05). Moreover, the CTX-M-producing isolates had significantly fewer VFs than TEM-producing isolates. A novel infection model using the nematode Caenorhabditis elegans was developed to assess the virulence properties of extra-intestinal pathogenic E. coli (ExPEC) strains in vivo. C. elegans infection assays, using 14 ESBL-producing E. coli and ten susceptible E. coli isolates, indicated that the ability to kill nematodes correlated with the presence of VFs, and that CTX-M-producing isolates had relatively low virulence in vivo. Overall, the results suggested that hospital-acquired CTX-M-producing E. coli, although adapted for survival in an antibiotic-rich environment such as the hospital milieu, have a relatively low intrinsic virulence potential. Published 23 November 2006 in Clin Microbiol Infect, 12(12): 1199-206.
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