The spectrum of Gram-positive bloodstream infections in patients with hematologic malignancies, and the in vitro activity of various quinolones against Gram-positive bacteria isolated from cancer patients.
OBJECTIVE
To determine the current spectrum of Gram-positive bloodstream infections (BSI) in patients with hematologic malignancies at our institution, and to determine the in vitro activity of various fluoroquinolones against clinical Gram-positive isolates collected from such patients.


METHODS
Institutional microbiology records from 493 consecutive episodes of Gram-positive BSI were reviewed. The in vitro activity of six fluoroquinolones against 477 clinical isolates was determined using an NCCLS approved, broth-dilution method.


RESULTS
The most common Gram-positive organisms isolated from the bloodstream of patients with hematological malignancies were coagulase-negative staphylococci (33%), Staphylococcus aureus (15%), viridans group streptococci (10%), and the enterococci (8%). Acute leukemias were the most common underlying malignancies, and 73% of patients were neutropenic when they developed their BSI. The newer generation quinolones--moxifloxacin and gatifloxacin--had the best overall in vitro activity against the Gram-positive isolates tested, and were at least 2 to 8-fold more potent than the early generation quinolones (ofloxacin and ciprofloxacin). Of the 477 isolates tested, 405 (85%) were from patients receiving quinolone (ciprofloxacin or levofloxacin) prophylaxis.


CONCLUSIONS
In patients with hematologic malignancies, Gram-positive BSI are caused by a large number of bacterial species and many occur despite antimicrobial prophylaxis. The newer generation quinolones--moxifloxacin and gatifloxacin--have better in vitro activity against these organisms than early generation agents (ciprofloxacin and ofloxacin).
Rolston
Kenneth V I
KV
Section of Infectious Diseases, Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas, M.D. Anderson Cancer Center, 1515 Holcombe Blvd, Box 402, Houston, TX 77030, USA. krolston@mail.mdanderson.org
Yadegarynia
Davood
D
Kontoyiannis
Dimitrios P
DP
Raad
Issam I
II
Ho
Dah H
DH
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000890:Anti-Infective Agents / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology*; D019337:Hematologic Neoplasms / Q000150:complications / Q000382:microbiology*; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D015363:Quinolones / Q000494:pharmacology*; D012189:Retrospective Studies
D000890:Anti-Infective Agents; D015363:Quinolones