The impact of hospital-acquired infections with multidrug-resistant bacteria in an oncology intensive care unit

Abstract

To describe overall site-specific hospital-acquired infection (HAI) rates and to describe the microbiological and antibiotic resistance profiles of infecting pathogens, together with their impact on multidrug-resistant (MDR) bacteria-associated mortality. We conducted a 5-year retrospective descriptive study of HAI in patients in the intensive care unit (ICU) of a cancer center in Mexico from January 2007 to December 2011. The following information was collected: patient characteristics and comorbidities, data related to the neoplasm and its treatment, microbiology, and the resistance pattern of all isolates. During the study period, 1418 patients were admitted to the ICU; 134 of them developed 159 infections, with an incidence of 11.2/100 hospitalized patients and 32.2/per 1000 patient-days. Two hundred sixty-six microorganisms were isolated. The overall prevalence of MDR-HAI was 39.5%. The most frequent organisms were as follows: 54 (20%) Escherichia coli (94.4% of these were extended-spectrum beta-lactamase producers), 32 (12%) Staphylococcus aureus (90.6% of these were methicillin-resistant), 32 (12%) Enterococcus faecium (18.7% of these were vancomycin-resistant), and 20 (6%) Acinetobacter baumannii (all were MDR). Among patients admitted to the ICU, 252 (17.8%) died. Death was related to the HAI in 58 (23%) of these patients (p<0.001) and 51 (88%) had a MDR organism isolated (p=0.05). The emergence of MDR bacteria poses a difficult task for physicians, who have limited therapeutic options. Critically ill cancer patients admitted to the ICU are at major risk of a bacterial MDR-HAI that will impact adversely on mortality.