title: Epidemiology and emerging resistance in bacterial bloodstream infections in patients with hematologic malignancies.
abstract: BACKGROUND
  The objective of this study was determine the frequency of bloodstream infections (BSIs) and the causative bacteria and their resistance patterns in patients with hematological malignancies (HMs) in a large tertiary care university hospital in Turkey over a 5-year period.
  
  
  METHODS
  A total of 2098 patients with HMs with 3703 neutropenic episodes were included. Patients were classified as high-risk (n = 843) and low-risk (n = 1255) groups and evaluated for frequency of BSIs, causative bacteria, and their resistance patterns.
  
  
  RESULTS
  The frequency of BSIs was 14.5%. The frequency of gram-negative BSIs in high-risk and low-risk groups was 10.7% and 5.4% (p < 0.001), respectively. The frequency of gram-positive BSIs in high-risk and low-risk groups was 7.0% and 3.9% (p < 0.001), respectively. Gram-negative bacteria predominated (52.6%), with Escherichia coli (17.3%) and Klebsiella spp. (11.0%) as the most frequent organisms. Coagulase-negative staphylococci (10.4%) and Corynebacterium spp. (6.3%) were the most common gram-positive bacteria (35.8%). The rate of extended-spectrum beta-lactamase (ESBL) production was 45% for E. coli and 58% for Klebsiella spp. Quinolone resistance was 58% for E. coli and 11% for Klebsiella spp.. The overall frequency of ceftazidime resistance in Pseudomonas aeruginosa was 28%, and 87% of Acinetobacter spp. were multidrug-resistant. Of Staphylococcus aureus isolates, 24.8% were resistant to methicillin.
  
  
  CONCLUSIONS
  The dominating causes of BSIs in patients with HMs in our hospital are resistant gram-negative bacteria, which has made empirical antimicrobial choice a highly challenging issue in this patient population.
authors.affiliation: Sections of Infectious Diseases, Department of Internal Medicine, Hacettepe University School of Medicine , Ankara , Turkey.
authors.forename: Özgür
authors.initials: Ö
authors.lastname: Kara
authors.forename: Pinar
authors.initials: P
authors.lastname: Zarakolu
authors.forename: Sibel
authors.initials: S
authors.lastname: Aşçioğlu
authors.forename: Sezgin
authors.initials: S
authors.lastname: Etgül
authors.forename: Burak
authors.initials: B
authors.lastname: Uz
authors.forename: Yahya
authors.initials: Y
authors.lastname: Büyükaşik
authors.forename: Murat
authors.initials: M
authors.lastname: Akova
mesh_terms: D000150:Acinetobacter / Q000187:drug effects / Q000302:isolation & purification; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D016470:Bacteremia / Q000150:complications / Q000453:epidemiology* / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000302:isolation & purification; D005260:Female; D006090:Gram-Negative Bacteria / Q000145:classification / Q000187:drug effects* / Q000302:isolation & purification; D006094:Gram-Positive Bacteria / Q000145:classification / Q000187:drug effects* / Q000302:isolation & purification; D019337:Hematologic Neoplasms / Q000150:complications*; D006801:Humans; D007709:Klebsiella / Q000302:isolation & purification / Q000472:pathogenicity; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009503:Neutropenia / Q000150:complications; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000302:isolation & purification; D013211:Staphylococcus aureus / Q000302:isolation & purification; D062606:Tertiary Care Centers; D013997:Time Factors; D014421:Turkey / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents
keywords: Bloodstream infection; antimicrobial resistance; bacteremia; hematologic malignancy; neutropenia