Epidemiological studies have demonstrated high rates of bacterial colonisation of hand-held mobile devices in hospital settings, but have not established a molecular epidemiological link between organisms colonising mobile devices and those causing disease in patients.
Over a 12-week period in a quaternary intensive care unit (n = 45 beds) all routine clinical isolates defined as multi-drug resistant (MDR) (MRSA, VRE and MDR Gram-negative bacteria) were prospectively collected and stored. During the same time period, the mobile devices of all medical staff were swabbed. Swabs were cultured for resistant organisms, with identification by matrix –assisted laser desorption ionisation. Illumina whole genome sequencing was performed to assess the genetic relatedness of MDR organisms found on phones and in clinical isolates.
During the 12-week study period, 67 MDR clinical isolates were collected from patients including 11 MRSA, 2 VRE, and 58 MDR Gram-negative bacteria. A total of 45 mobile devices used by medical staff were swabbed. Of these, two phones cultured MRSA, one phone cultured A. baumannii and another phone cultured A. calcoaceticus. WGS was performed on the 17 MRSA and Acinetobacter isolates from phones and patient isolates. The two MRSA isolates from the phones were highly similar genetically (103 SNP difference), but were different to all the clinical isolates (> 10,000 SNP difference). These two phones were spatio-temporally linked and came from the same 14-bed area of the ICU. All four MDR Acinetobacter isolates were genetically different.
We found that despite MDR organisms being able to colonise physician mobile devices, these organisms were genetically different to those seen in patient isolates during the same time period. We focused on clinically relevant MDR organisms rather than any bacterial growth, which is often reported by other studies. Future studies should avoid solely reporting on bacterial colonisation of inanimate surfaces, and focus on the most clinically relevant hospital pathogens and make molecular links with those infecting patients.
E. Woolnough, None
T. Seemann, None
G. Carter, None
D. Spelman, None
A. Peleg, None