Multidrug-resistant bacteria isolated from cell phones in five intensive care units: Exploratory dispersion analysis

Cell phones are susceptible to bacterial contamination. The aim of this study was to characterize the bacterial isolates and to explore their dispersion in five Intensive Care Units (ICUs) over the time.

We performed a secondary analysis of non-fermenting Gram-negative bacteria and Gram-positive cocci isolated from a 5-month observational cohort study developed among health care workers' cell phones in five ICUs. Cell phones were sampled using a swab every 15 days. Antimicrobial resistance was determined by the minimum inhibitory concentration method. We constructed resistance phenotypes to group the isolates according to species and antimicrobial resistance pattern to explore dispersion through time.

A total of 35 P. aeruginosa, 16 Acinetobacter spp., 30 S. aureus and 26 Enterococcus spp. were isolated from 491 phone samples. Multidrug resistance was 2.9% for P. aeruginosa, 31.3% for Acinetobacter spp., 46.7% for S. aureus and 80.8% for Enterococcus spp. The resistance to methicillin in S. aureus and to vancomycin in Enterococcus spp. was 26.7% and 42.3%, respectively. We did not observe distribution patterns or clusters over the time for P. aeruginosa, Acinetobacter spp. and Enterococcus spp. isolates. All the S. aureus isolates grouped into eight phenotypes. Interestingly, we observed S. aureus isolates with the same phenotype in consecutive and separate sampling dates in the same cell phone.

Cell phones are contaminated with highly harmful bacteria and potentially can maintain them for prolonged periods of time. These devices could be considered as a potential source of nosocomial infections in ICUs.