Gram-Negative, Hospital-Acquired Infections: A Growing Problem

Abstract

This issue of Infection Control and Hospital Epidemiology contains multiple articles focusing on the clinical and public health implications of infections by extended-spectrum beta-lactamase (ESBL)–producing Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii and their resistance profiles to commonly prescribed antimicrobials. The first five articles in this issue1-5 add to a growing body of literature that substantiates the following: (1) as in North America, gramnegative pathogens are important causes of hospitalacquired infections in Europe and Asia; (2) antimicrobial resistance among gram-negative pathogens is a global problem; (3) the pathogens encountered in healthcare institutions in North America, Europe, and Asia are, for the most part, similar; (4) the risk factors (eg, device use or antimicrobial overprescribing) associated with hospitalacquired infections and antimicrobial resistance are universal; (5) surveillance activities are important for the characterization and control of gram-negative, healthcareassociated infections in Europe and Asia and require appropriate integration of epidemiologic, microbiologic, and clinical data; and (6) the microbiology laboratory is important in the characterization and control of healthcare-associated infections and antimicrobial resistance. In the first article in this issue of Infection Control and Hospital Epidemiology, Yu et al. used a combination of phenotypic and molecular typing methods to demonstrate clonal dissemination of ESBL-producing Klebsiella pneumoniae in 24 hospitals located in several regions of Taiwan.1 Using a combination of ribotyping and pulsed-field gel electrophoresis (PFGE), they identified two epidemic clones in hospitals located in the northern and central regions of the country. Within each clone, however, there were variations in the antibiogram and isoelectric focusing profiles of isolates. Their findings suggest significant intrahospital and interhospital clonal transmission of ESBL-producing K. pneumoniae and confirm the ubiquity of this resistant pathogen in major teaching hospitals in all regions of Taiwan. They provide evidence that interinstitutional transmission of ESBL-producing K. pneumoniae parallels the movement of mobile patient populations. Previously, Monnet et al. used molecular typing to demonstrate interhospital transmission of ESBL-producing Klebsiella species in one region of the United States, and concluded that physical proximity of hospitals might facilitate interhospital transmission of ESBL-producing K. pneumoniae.6 More recently, the results of a case–control study at a district teaching hospital in Taiwan identified ceftazidime use as an independent risk factor associated with acquisition of ESBL-producing K. pneumoniae.7 The findings of Yu et al. are consistent with those of a 2004 report of nationwide surveillance data on antimicrobial resistance among gram-negative pathogens in 21 Taiwanese medical centers—gramnegative bacterial resistance is prevalent in medical centers and regional hospitals throughout Taiwan.8 In the second article in this issue of Infection Control and Hospital Epidemiology, Rodriguez-Bano et al. report the results of a multicenter study conducted to characterize the clinical features and molecular epidemiology of A. baumannii infections in 28 hospitals in Spain that together served a catchment area containing approximately 25% of the Spanish population.2 During November 2000, every new patient with A. baumannii infection or colonization was included in the study: all isolates were typed first using phenotypic methods and then using genotyping with PFGE. Twenty-five (89%) of the 28 participating hospitals