Antimicrobial-resistant Gram-negative bacteria in febrile neutropenic patients with cancer: current epidemiology and clinical impactTrecarichi, Enrico M.; Tumbarello, MarioCurrent Opinion in Infectious Diseases: April 2014 - Volume 27 - Issue 2 - p 200–210 doi: 10.1097/QCO.0000000000000038 Special Commentary Abstract Author Information Purpose of review In the recent years, several studies involving cancer patients have demonstrated a clear trend in the epidemiology of bacterial infections showing a shift in the prevalence from Gram-positive to Gram-negative bacteria and the extensive emergence of antimicrobial-resistant strains among Gram-negatives isolated from the blood. The aim of this systematic review was to examine the recent trends in epidemiology and antimicrobial resistance in Gram-negatives recovered from neutropenic cancer patients, with particular emphasis on the impact of antimicrobial resistance on the clinical outcome of severe infections caused by such microorganisms. Recent findings Overall, from 2007 to date, the rate of Gram-negative bacteria recovery ranged from 24.7 to 75.8% (mean 51.3%) in cancer patient cohorts. Escherichia coli represented the most common species (mean frequency of isolation 32.1%) among the Gram-negatives, followed by Pseudomonas aeruginosa (mean frequency of isolation 20.1%). An increasing frequency of Acinetobacter spp. and Stenotrophomonas maltophilia was also reported. Increased rates of multidrug-resistant Gram-negative strains have been highlighted among Enterobacteriaceae and nonfermenting Gram-negative rods, despite discontinuation of fluoroquinolone-based antibacterial prophylaxis for neutropenic patients. In addition, antimicrobial resistance and/or the inadequacy of empirical antibiotic treatment have been frequently linked to a worse outcome in cancer patients with bloodstream infections caused by Gram-negative isolates. Summary Sound knowledge of the local distribution of pathogens and their susceptibility patterns and prompt initiation of effective antimicrobial treatment for severe infections caused by Gram-negative bacteria are essential in cancer patients. Institute of Infectious Diseases, Catholic University of the Sacred Heart, A. Gemelli Hospital, Rome, Italy Correspondence to Mario Tumbarello, MD, Istituto Malattie Infettive, Università Cattolica del Sacro Cuore, Largo A. Gemelli 8, 00168 Roma, Italy. Tel: +39 0630155373; fax: +39063054519; e-mail: firstname.lastname@example.org © 2014 Lippincott Williams & Wilkins, Inc.