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Paper text:
uhb is an acute - care hospital with 735 beds , of which 8.7% are in rooms with 4 beds and the remaining are in rooms with 12 beds .
fph is a university - affiliated geriatric and rehabilitation center with 320 beds , of which 47.5% are in rooms with 4 beds and 52.5% are in rooms with 12 beds . in both facilities ,
the average distance between beds is 2 m. the 2 institutions share an infection - control team and microbiology laboratory .
the study was approved by the local ethics committee as part of the quality assurance program ; informed consent was waived .
fph and uhb abandoned routine contact precautions for patients infected or colonized with esbl - producing e. coli beginning january and june 2012 , respectively ; patients were included in this study through december 2013 .
we defined index patients as patients colonized or infected with an esbl - producing e. coli in any specimen from any body site and contact patients as patients hospitalized for at least 24 hours in the same room as an index patient .
contact time was defined as the time index and contact patients shared a room before the contact patient was screened .
contact patients were prospectively screened once before discharge by swab sampling of the rectum and any open wounds or drainage sites ; if foley catheters were used , urine was also sampled and cultured .
transmission was considered to have occurred if esbl screening results for the contact patient were positive and molecular typing by pulsed - field gel electrophoresis ( pfge ) showed that the strain shared identity with the strain of the index patient .
we used standard culture methods with chromogenic medium ( chromid esbl ; biomrieux , marcy letoile , france ) to detect esbl - producing e. coli .
we performed routine identification and susceptibility testing using the vitek 2 system ( biomrieux , durham , nc , usa ) with cefpodoxime , ceftriaxone , and ceftazidime .
we confirmed positive results by using etest strips ( biomrieux , marcy letoile ) containing cefotaxime or ceftazidime , with and without clavulanic acid .
we used the fisher exact test and the mann - whitney u test for univariable comparisons .
, 231 contact patients ( 151 from uhb , and 80 from fph ) were exposed to 211 index patients ( 178 from uhb , 33 from fph ) .
contact patients were screened for esbl - producing e. coli after a median contact time of 4 ( interquartile range 36 ) days at uhb and 15 ( interquartile range 923 ) days at fph .
we recovered esbl - producing e. coli from 24 contact patients ( 12 from each institution ) and confirmed strain identity for 11 , accounting for an overall transmission rate of 4.8% ( 11/231 ) ( figure 1 ) .
transmission occurred in 2.6% ( 4/151 ) of contacts at uhb and 8.8% ( 7/80 ) at fph ( p = 0.052 ) .
we found no differences between contact patients with and without transmission of esbl - producing e. coli in regard to baseline characteristics ; use of antimicrobial drugs ; or exposure to index patients , except for contact time , which was longer for patients with transmission ( table ) .
exposure to an index patient for > 5 days was associated with increased odds for transmission ( odds ratio 10.18 , 95% ci 1.2880.91 ; p = 0.028 ) ( figure 2 ) .
pulsed - field gel electrophoresis results for escherichia coli samples from a ) index and b ) contact patients who shared rooms for at least 24 hours in an acute - care hospital or a geriatric / rehabilitation center , basel , switzerland .
thick black outlining indicates results for patient pairs with extended - spectrum -lactamase  producing e. coli transmission .
fph , felix platter hospital ; uhb , university hospital basel . * bold indicates significance .
contact patient exposures occurred through the sharing of a room for at least 24 hours with an esbl - producing e. coli  infected or colonized index patient in an acute - care hospital or a geriatric / rehabilitation center .
transmission of extended - spectrum -lactamase  producing escherichia coli over contact time among index and contact patients who shared rooms for at least 24 hours in an acute - care hospital or a geriatric / rehabilitation center , basel , switzerland .
after contact precautions for esbl - producing e. coli were discontinued at the 2 hospitals in this study , transmissions occurred in 2.6% of contact patients at uhb and in 8.8% of contact patients at fph .
transmissions were associated with duration of hospitalization in the same room as an index patient . at uhb ,
the rate of transmissions was similar to that reported during the period before discontinuation of contact precaution measures ( 1.5% ) ( 2 ) . at other swiss acute - care hospitals ,
esbl - producing e. coli transmission has affected 4.5% of all contact patients ( 3 ) , and transmission of all esbl - producing enterobacteriaceae has affected 2.8% , despite implementation of contact precautions ( 4 ) .
the proportion of contact patients with transmission at fph ( 8.8% ) compares well with the proportion reported from similar settings ( 6.5% ) ( 5 ) .
our finding that the transmission rate at the acute - care hospital was similar before and after discontinuation of contact precaution measures may be explained by high adherence to standard precautions ( 6 ) , especially hand hygiene , for which compliance exceeded 90% ( 7 ) , and the mainly short - term hospitalizations ( < 5 days ) .
thus , these findings may not be generalizable to other settings , especially when longer hospitalization is required , as is the case in geriatric / rehabilitation centers .
other factors may also have influenced transmission rates in our study , impeding generalizability of the findings to other countries .
for example , the european surveillance of antimicrobial consumption network ( http://ecdc.europa.eu/en/healthtopics/antimicrobial_resistance/esac-net-database/pages/database.aspx ) reports that antimicrobial drug use in hospitals in switzerland ( 1.9 defined daily doses/1,000 inhabitants / day ) is lower than that in hospitals in other european countries ( mean of 2.0 defined daily doses/1,000 inhabitants / day ) .
furthermore , the incidence of esbl - producing e. coli may be lower in switzerland than in other european countries ( 8) , as suggested by a lower proportion ( 8.2% ) of third - generation cephalosporin - resistant e. coli among invasive isolates in switzerland as compared with those in other european countries ( http://www.anresis.ch/index.php/anresisch-data-de.html ) .
person - to - person transmission may play a substantial role in sustaining the global esbl epidemic . in nursing homes , esbl - producing e. coli isolates from residents living in adjacent rooms were found to be closely genetically related ( 9 ) , and high esbl - producing e. coli transmission rates ( 23% ) have been reported in households ( 3 ) , supporting our results that sustained contact over longer periods may facilitate transmission .
furthermore , patients hospitalized in the fph may require more care , resulting in increased contact between healthcare workers and patients , possibly facilitating transmission ( 5 ) . in our study , contacts were screened only once before discharge , long - term surveillance for acquisition was not performed , and preenrichment of rectal swab samples was not conducted , all of which may have led to an underestimation of esbl - producing e. coli cases . however , the circulation of esbl - producing clones in the community may have resulted in an overestimation of transmission ; before hospitalization , contact patients may have been colonized with strains in the community identical to those of index patients with whom they eventually shared a room .
we acknowledge that our study lacks the robustness of a cluster - randomized trial to evaluate the effect of contact precautions on esbl - producing e. coli transmission .
however , we found that , when exposure times are short and adherence to standard precautions is high , the discontinuance of contact precautions for esbl - producing e. coli in healthcare settings results in transmission rates similar to those observed when contact precautions are used .
after contact precautions were discontinued , we determined nosocomial transmission of extended - spectrum -lactamase ( esbl)producing escherichia coli by screening hospital patients who shared rooms with esbl - producing e. coli  infected or colonized patients . 
 transmission rates were 2.6% and 8.8% at an acute - care and a geriatric / rehabilitation hospital , respectively . 
 prolonged contact was associated with increased transmission .