Brevundimonas diminuta infections and its resistance to fluoroquinolones.
OBJECTIVE
To report infections caused by Brevundimonas diminuta and antibiotic studies of this Gram-negative bacterium.


METHODS
Seven patients with infection and eight bacterial strains were studied. Tests included antibiotic susceptibility and analysis of the DNA gyrase and topoisomerase genes and the effect of efflux pump inhibitor Phe-Arg-beta-naphthylamide (PANA).


RESULTS
The patients all had underlying disease of cancer. The infections involved bloodstream (one case), intravascular catheter (four cases), urinary tract (one case) and pleural space (one case of empyema). Fever up to 39.2 degrees C characterized these infections, which resolved upon treatment by combination antibiotics. Microbiologically, all organisms were resistant to multiple fluoroquinolones and cefepime, but were susceptible to amikacin, imipenem and ticarcillin/clavulanate. These quinolone-resistant B. diminuta strains were probably selected out by the prophylactic use of a quinolone in six of these patients. Additionally, the B. diminuta type strain ATCC 11568(T) that was isolated before the quinolone era from water was also resistant to ciprofloxacin and intermediate to levofloxacin, suggesting intrinsic quinolone resistance. The DNA gyrase and topoisomerase of six analysed strains all contained GyrA Ala-83 and Met-87, GyrB Leu-466 or Thr-466, and ParC Gln-57, Val-66 and Ala-80 that were probably the cause of fluoroquinolone resistance. PANA had nearly negligible effect.


CONCLUSIONS
B. diminuta is intrinsically resistant to fluoroquinolones and can be selected out to cause infections.
Han
Xiang Y
XY
Section of Clinical Microbiology, The University of Texas M.D. Anderson Cancer Center, Unit 84, 1515 Holcombe Boulevard, Houston, TX 77030, USA. xhan@mdanderson.org
Andrade
Roberto A
RA
D000328:Adult; D000368:Aged; D001483:Base Sequence; D027081:DNA Gyrase / Q000235:genetics; D027101:DNA Topoisomerase IV / Q000235:genetics; D004151:Dipeptides / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D005260:Female; D024841:Fluoroquinolones / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D008969:Molecular Sequence Data; D011549:Pseudomonas / Q000187:drug effects*; D011552:Pseudomonas Infections / Q000188:drug therapy*
D004151:Dipeptides; D024841:Fluoroquinolones; C474925:phenylalanylarginine-naphthylamide; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase