Two episodes of vancomycin-resistant Enterococcus faecium outbreaks caused by two genetically different clones in a newborn intensive care unit.
In 2001 two outbreak episodes (January-March and June-July) caused by vancomycin-resistant E. faecium (VRE) of the VanA-type were observed at a neonatal intensive care unit (NICU) of a university hospital in south-west Germany. To identify the initial source and the route of transmission environmental samples were examined as well as stool samples from patients and the staff. VRE was not found in environmental samples. However, stool samples from 24 hospitalised children tested positive and bacterial clonality was assessed by Sma1-based macro restriction analysis. Furthermore, esp gene and vancomycin resistance gene carriage were examined as well as bacteriocin production. PCR analysis showed that all 24 isolates carried vanA gene cluster, encoding resistance to vancomycin and teicoplanin. However, five of the vanA-positive isolates were resistant to vancomycin but not to teicoplanin. Only these five isolates produced bacteriocin, but in none of the isolates esp gene was detected. PFGE revealed that both outbreaks were caused by two different clones. The patient initiating the first episode, was identified whereas the origin of the second episode remained unknown. From one of the 40 staff stool samples VRE was isolated. This strain was related to the clone of the summer outbreak. In conclusion there were two independent episodes of self limiting VRE outbreaks and transmission on the ward is highly probable.
Department of Medical Microbiology and Hygiene, University of Tübingen, Germany.
Stefan
S
Borgmann
Doris Maria
DM
Niklas
Ingo
I
Klare
Lutz T
LT
Zabel
Peter
P
Buchenau
Ingo B
IB
Autenrieth
Peter
P
Heeg
D001426:Bacterial Proteins / Q000235:genetics; D019729:Carbon-Oxygen Ligases / Q000235:genetics; D003428:Cross Infection / Q000453:epidemiology* / Q000235:genetics* / Q000635:transmission; D004196:Disease Outbreaks; D016984:Enterococcus faecium / Q000235:genetics; D005260:Female; D005858:Germany / Q000453:epidemiology; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology* / Q000235:genetics* / Q000635:transmission; D006801:Humans; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D008565:Membrane Proteins / Q000235:genetics; D020713:Vancomycin Resistance
D001426:Bacterial Proteins; D008565:Membrane Proteins; C071437:VanA ligase, Bacteria; C116707:enterococcal surface protein, esp; D019729:Carbon-Oxygen Ligases