Emergence and dissemination of quinolone-resistant Escherichia coli in thecommunity

We studied the evolution of resistance to quinolones in Escherichia coli fr om 1992 to 1997 in Barcelona, Spain. An increasing proportion of quinolone- resistant E, coli (QREC) infections was observed. QREC strains were more co mmon in patients with nosocomial infections but also increased in patients with community-acquired infections (9% in 1992 to 17% in 1996), Seventy (12 %) of 572 episodes of E, coli bacteremia were due to QREC, Factors signific antly associated with QREC bacteremia were the presence of underlying disea se, recent exposure to antibiotics, and bacteremia of unknown origin. In th e multivariate analysis, only prior exposure to antimicrobial agents (P < 0 .001; odds ratio [OR] = 2), specifically, to quinolones (P < 0.001; OR = 14 ), and the presence of a urinary catheter (P < 0.001; OR = 2) were signific antly associated with QREC bacteremia, Among 16 QREC isolates from cultures of blood of community origin selected at random, 13 different pulsed-field gel electrophoresis patterns were recognized, showing the genetic diversit y of these isolates and in turn indicating the independent emergence of QRE C in the community. The prevalence of QREC in the feces of healthy people w as unexpectedly high (24% in adults and 26% in children), A survey of the p revalence of QREC of avian and porcine origin revealed a very high proporti on of QREC in animal feces (up to 90% of chickens harbored QREC), The high prevalence of QREC in the stools of healthy humans in our area could be lin ked to the high prevalence of resistant isolates in poultry and pork.