title: Blood stream infections in allogeneic hematopoietic stem cell transplant recipients: reemergence of Gram-negative rods and increasing antibiotic resistance.
abstract: Blood stream infections (BSI) are a well-known cause of morbidity and mortality in hematopoietic stem cell transplant (HSCT) patients. The aim of this study was to analyze etiology and microbial resistance of BSI in patients undergoing allogeneic HSCT in a single center over a 4-year period (2004-2007). There were 168 episodes of BSI in 132 patients (median 10 days after HSCT) and 182 pathogens were isolated. Gram-positive bacteria (GPB) accounted for 57% of 182 isolates. Gram-negative rods (GNR) for 37% and fungi for 6%. All patients received routine fluoroquinolone prophylaxis. There was a significant decrease in GPB/GNR ratio over time, from 2.4 in 2004 to 1 in 2007 (P = .043). Among GPB, staphylococci decreased from 37 of 68 (64%) in 2004-2005 to 8 of 35 (23%) in 2006-2007 (P < .002). The Enterococcus faecalis/E. faecium ratio decreased from 4.5 in 2004 to 0.33 in 2007 (P = .006), whereas the total number of enterococcal strains per year did not change. The incidence of Escherichia coli among GNR increased from 3 of 15 (20%) in 2004 to 13 of 21 (62%) in 2007 (P = .003). Fluoroquinolone-resistance was common, both among GPB and GNR (81% and 74%, respectively). Mortality rate at 7 days after BSI was 11% (19 of 168), reaching 39% for Pseudomonas aeruginosa BSI (7 of 18). BSI remains a frequent and potentially life-threatening complication of allogeneic HSCT, the causative organism influencing 7- and 30-day mortality rate. BSI etiology may change rapidly, requiring implementation of new empirical-therapy schemes.
authors.affiliation: University of Genoa, Division of Infectious Diseases, San Martino Hospital Genoa, Italy.
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Mikulska
authors.forename: Valerio
authors.initials: V
authors.lastname: Del Bono
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Raiola
authors.forename: Barbara
authors.initials: B
authors.lastname: Bruno
authors.forename: Francesca
authors.initials: F
authors.lastname: Gualandi
authors.forename: Domenico
authors.initials: D
authors.lastname: Occhini
authors.forename: Carmen
authors.initials: C
authors.lastname: di Grazia
authors.forename: Francesco
authors.initials: F
authors.lastname: Frassoni
authors.forename: Andrea
authors.initials: A
authors.lastname: Bacigalupo
authors.forename: Claudio
authors.initials: C
authors.lastname: Viscoli
mesh_terms: D000293:Adolescent; D000328:Adult; D019072:Antibiotic Prophylaxis; D016470:Bacteremia / Q000209:etiology* / Q000382:microbiology; D004352:Drug Resistance, Microbial; D005260:Female; D024841:Fluoroquinolones / Q000627:therapeutic use; D016469:Fungemia; D006090:Gram-Negative Bacteria / Q000302:isolation & purification*; D006094:Gram-Positive Bacteria / Q000302:isolation & purification; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects* / Q000401:mortality / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014184:Transplantation, Homologous; D055815:Young Adult
chemical_list: D024841:Fluoroquinolones