Publications (2)7.93 Total impact
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ABSTRACT: Multidrug-resistant (MDR) Acinetobacter baumannii is a growing concern in many countries. This report describes patient demographics, antimicrobial susceptibilities and molecular characteristics of A. baumannii cases identified through the Canadian Ward Surveillance Study (CANWARD). In addition, clinical cases involving MDR carbapenem-resistant A. baumannii are also detailed in this report. From January to December 2007, 12 hospital centres across Canada submitted pathogens from clinics, emergency rooms, intensive care units and medical/surgical wards as part of the CANWARD study. MICs were determined using microbroth dilution (CLSI). PCR and sequence analysis identified OXA genes among carbapenem-resistant isolates. PFGE was used to determine genetic relatedness and compare representatives of the Midlands 2 strain, OXA-23 clone 1 or 2, T strains and isolates collected from military sources. This study identified A. baumannii in 0.33% (n = 26) of infections. The majority of isolates remained susceptible to the antimicrobials tested, however, 7.7% (n = 2) displayed an MDR phenotype, including resistance to carbapenems. In one isolate bla(OXA-58) was found to be the likely cause of carbapenem resistance while the other isolate had an insertion sequence element upstream of its intrinsic bla(OXA-51). The clinical data of these two isolates suggest that one is travel-related while the source of the other remains unknown. A. baumannii infections from Canadian hospitals were relatively low. Carbapenem-resistant MDR A. baumannii were also rare and unrelated to previously observed isolates from military sources. Continued surveillance in Canada is suggested in order to determine if such organisms will become a problem.
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ABSTRACT: Military members, injured in Afghanistan or Iraq, have returned home with multi-drug resistant Acinetobacter baumannii infections. The source of these infections is unknown. Retrospective study of all Canadian soldiers who were injured in Afghanistan and who required mechanical ventilation from January 1 2006 to September 1 2006. Patients who developed A. baumannii ventilator associated pneumonia (VAP) were identified. All A. baumannii isolates were retrieved for study patients and compared with A. baumannii isolates from environmental sources from the Kandahar military hospital using pulsed-field gel electrophoresis (PFGE). During the study period, six Canadian Forces (CF) soldiers were injured in Afghanistan, required mechanical ventilation and were repatriated to Canadian hospitals. Four of these patients developed A. baumannii VAP. A. baumannii was also isolated from one environmental source in Kandahar - a ventilator air intake filter. Patient isolates were genetically indistinguishable from each other and from the isolates cultured from the ventilator filter. These isolates were resistant to numerous classes of antimicrobials including the carbapenems. These results suggest that the source of A. baumannii infection for these four patients was an environmental source in the military field hospital in Kandahar. A causal linkage, however, was not established with the ventilator. This study suggests that infection control efforts and further research should be focused on the military field hospital environment to prevent further multi-drug resistant A. baumannii infections in injured soldiers.
University of Alberta
Edmonton, Alberta, Canada
- Department of Laboratory Medicine and Pathology