Assessment of Bacterial Cross-Transmission as a Cause of Infections in Patients in Intensive Care Units

Abstract

The prevalence of possible cross-transmission of selected bacteria (Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Pseudomonas aeruginosa, Staphylococcus aureus, and enterococci) among infected patients was evaluated in five intensive care units (ICUs) over 6 months. A total of 284 isolates from clinical specimens were typed by plasmid profile analysis (E. coli, K. pneumoniae, and E. cloacae), restriction endonuclease analysis of plasmid DNA (S. aureus), and/or pulse-field gel electrophoresis of chromosomal DNA (P. aeruginosa, enterococci, S. aureus, and other bacteria without plasmid DNA). By typing criteria, only 13% of the 177 isolates obtained after > 2 days in an ICU were classified as possibly cross-transmitted. Many patients whose cultures yielded bacteria of an identical type may have been the sources rather than the recipients of these organisms. Episodes of possible cross-transmission were scattered among all ICUs, usually affected only two patients, and were associated with most bacterial species. These data suggest that endemic bacterial cross-transmission in ICUs is relatively infrequent and that cross-transmitted bacteria are not common causes of endemic ICU-related nosocomial infections.

Carbapenems and subsequent multiresistant bloodstream infection: does treatment duration matter?

“…For example, the approach of Denmark and The Netherlands to MRSA suggests that infection control may have a greater impact than antimicrobial restriction in controlling MRSA [28], and in an ICU setting the reported contribution of crosstransmission to the development of nosocomial infection has varied widely between studies, with between 10% and 54% of nosocomial infections explained by transmission between patients [29][30][31][32]. Our ICU consisted predominantly of open rooms during the study period.…”

Epidemiology and Infection Control Implications of Acinetobacter spp. in Hong Kong

“…Other clusters (six) contained possibly related isolates from different patients, indicating cross-transmission among patients. Transmission of gram-negative rods among ICU patients in a setting where these rods are endemic was regarded as low, accounting for only 6 to 10% of clinical isolates (6,11). Yet we identified eight clusters (including two with isolates from 2 patients and one location) of possible cross-transmission among 68 clinical isolates from 29 patients over a period of 6 weeks (Tables 2 and 3).…”

Can Escherichia coli be used as an indicator organism for transmission events in hospitals?

“…Our results also questions studies that tried to determine the proportion of exogenous versus endogenous nosocomial infections in intensive care patients by identifying transmission events by the typing of clinical isolates [7,8]. In this way 13-35% of nosocomial infections are marked as exogenous.…”