Cross-Transmission of Multidrug-ResistantAcinetobacter baumanniiClonal Strains Causing Episodes of Sepsis in a Trauma Intensive Care Unit

Abstract

Objective.To investigate the mode of transmission of imipenem-resistantAcinetobacter baumanniistrains causing episodes of sepsis.Setting.A 7-bed trauma intensive care unit (ICU) in an orthopedic hospital in Greece.Design.During a 14-week period (from January 10 to April 16, 2006), clinical specimens, along with samples taken on a weekly basis from the ICU environment and from the hands of health care workers (HCWs), were prospectively tested for imipenem-resistantA. baumannii.Pulsed-field gel electrophoresis was used to study the genetic relatedness of the isolates recovered from these specimens and samples.Results.During the survey, imipenem-resistantA. baumanniiwas identified in 14 hospitalized patients, from whom 40 multidrug-resistant and imipenem-resistantA. baumaniiisolates were recovered. These pathogens caused episodes of bacteremia and sepsis in all but one of the patients and contributed to the death of 3 patients. Samples for culture were obtained from the environment and from the hands of HCWs; 29 imipenem-resistantA. baumanniiisolates were recovered from the environment, and 12 from HCWs. One predominant genotype and 2 less predominant genotypes were detected among the 81 imipenem-resistantA. baumanniiisolates. All 3 of these genotypes were found among patients and HCWs and were recovered from environmental samples.Interventions.Control measures consisted of the closure of the ICU and the transfer of the patients to other units. The ICU was disinfected, and adherence to proper hand hygiene protocol was reinforced. These same clonal isolates were not recovered from clinical or environmental samples during the month after the reopening of the ICU.Conclusions.The extensive dissemination of imipenem-resistantA. baumanniiclonal strains causing episodes of bacteremia and/or sepsis resulted from modes of transmission via multiple contaminated surfaces and objects and transiently colonized HCWs' hands. Closure of the ICU and its meticulous environmental decontamination led to the successful control of the outbreak.