Screening for vancomycin-resistant enterococci: results of a survey in Stockholm

Vancomycin-resistant enterococci (VRE) are emerging in Stockholm hospitals. To rapidly screen for VRE from stool and rectal swab samples, a detection assay combining broth enrichment and real-time PCR was set up. From September to December 2008, 6914 samples were screened for VRE using the broth-PCR combined assay. Of them, 5463 samples were reported as negative the day after sampling. Among the 6914 samples, 47 was screened as vanA probable and 44 of them were confirmed as VRE; 1314 samples was screened as vanB probable and 93 of them were confirmed as VRE. The 44 vanA-type VRE isolates, detected from 31 patients, were clustered into four genetic types by pulsed-field gel electrophoresis (PFGE). The same PFGE type was observed in multiple isolates recovered from the same patient with vanA VRE. The 93 vanB-type VRE isolates were detected from 60 patients, 59 of them harboring VRE with PFGE type 1. One patient with vanB VRE had two isolates of distinct PFGE types (types 1 and 5). PFGE type 1 and PFGE type 2 were predominant clones in vanB and vanA strains, respectively, represented by 98.3% (59/60) of patients with vanB VRE and 77.4% (24/31) of patients with vanA VRE.