Risk factors for colonization with third-generation cephalosporin-resistant enterobacteriaceae

Colonization and infections caused by Enterobacteriaceae resistant to third-generation cephalosporins (CRE) have been observed with increasing frequency in intensive care unit (ICU) patients. In contrast to outbreak investigations, information about risk factors for colonization in an endemic situation are rare. We studied risk factors for colonization with CRE in a case control study including 1,706 patients, admitted to any of the 15 ICUs of Heidelberg University Hospitals.

163 patients carried CRE with Enterobacter spp. representing the predominant species. Independent risk factors for CRE carriage in the multivariate logistic regression analysis were an age of under 2.5 years (OR 4.034), an indwelling central venous catheter (CVC) for more than 3 days (OR 2.640), treatment with second- or third generation cephalosporin for longer than 3 days (OR 2.260) and any antibiotic therapy before admission to the ICU.

Apart from the well-recognized risk factor previous antibiotic treatment, the risk factors age and presence of a CVC might suggest that bacterial overgrowth of the gut either due to an increased susceptibility in younger age or as a consequence of parenteral nutrition is a relevant mechanism for acquiring carriage of CRE in a non-outbreak situation.