Molecular epidemiology of multidrug-resistant organisms on mobile phones: an observational study conducted at a German university hospital.

BACKGROUND

Mobile phones are integral to modern clinical workflows and increasingly bridge clinical and private environments. Yet, their role as portable high-touch surfaces in infection prevention remains insufficiently characterized. We hence assessed prevalence and molecular epidemiology of multidrug-resistant organisms (MDRO) on mobile phones used by healthcare workers (HCWs) at a German university hospital and compared them with devices used by non-HCWs.

METHODS

In this 30-month cross-sectional study, 232 HCW and 241 non-HCW mobile phones were analyzed to determine MDRO prevalence and overall bacterial count. A subset of devices was examined before and after disinfection with alcohol-based wipes. Whole genome sequencing with subsequent core genome multilocus sequence typing (cgMLST) was applied to identify clonal clusters.

RESULTS

MDRO prevalence was significantly higher on HCW phones compared to non-HCW phones (15.1% vs. 0.4%, p < 0.001), with particularly high rates on intensive care unit devices and shared phones (23.4% and 23.0%, respectively). Vancomycin-resistant Enterococcus faecium, predominantly the endemic ST117/CT71 clone, and methicillin-resistant Staphylococcus aureus were detected on 11.2% and 4.7% of devices, respectively. In contrast, no multidrug-resistant Gram-negatives (MDRGN) were identified, despite contamination with susceptible Enterobacterales or nonfermenters. cgMLST analyses revealed clonal MDRO strains mainly within wards and only rarely across wards, consistent with both local clustering and possible cross-ward dissemination. Total bacterial count did not predict MDRO detection. Alcohol-based wipes reliably eliminated MDRO from all tested devices.

CONCLUSIONS

Given the high MDRO burden on HCW mobile phones and genomic clustering across wards, mobile phones may represent a relevant reservoir with potential to facilitate in-hospital MDRO dissemination. Standardized mobile phone disinfection routines - particularly for shared and ICU devices - should be considered in infection prevention strategies to reduce potential phone-associated MDRO transmission risk and may represent a conceptual "Sixth Moment" complementing the WHO "Five Moments for Hand Hygiene".