[Fecal carriage of third-generation cephalosporins-resistant Enterobacteriaceae in asymptomatic young adults:...

The aim of this work was to evaluate the fecal carriage of third generation cephalosporins resistant Enterobacteriaceae in nonhospitalized asymptomatic young adults.

A total of 517 normal fecal samples were spread onto plates agar containing cefotaxime. Isolated strains were identified and studied with agar disk diffusion antibiogram, minimal inhibition concentration in liquid medium and phenotypic and molecular study. Data were compared with a previous study realised in the same conditions in 1999.

In 2009, the prevalence of cefotaxime resistant enterobacteria was 4.2%. Of these 22 Enterobacteriaceae, 11 harboured overexpressed cephalosporinase and 11 produced extended-spectrum-betalactamase (ESBL). Among ESBL, six E. coli produced CTX-M from group 1 (n=6), group 2 (n=1), group 9 (n=2), one E. coli produced SHV-12 and one Klebsiella pneumoniae produced CTX-M from group 1. All ESBL were multiresistant. In 1999, all the CTX resistant isolates recovered produced a cephalosporinase and no ESBL was found.

This study highlights the increasing prevalence of fecal carriage of ESBL-producing enterobacteria in asymptomatic young patients in the community (0% in 1999 versus 2.1% in 2009; P<0.001). E. Coli with CTX-M from group 1 was the most frequent ESBL identified, while fecal carriage of Enterobacteteriaceae overproducing cephalosporinase was similar (2.1%).