[Impact of initial antibiotic therapy on the course of resistance to fluoroquinolones and aminoglycosides in Gram-negative bacilli isolated from intensive care patients].
OBJECTIVE
To evaluate the effect of the initial antibiotic therapy associating a betalactam antibiotic (BLA) with either an aminoglycoside (AG) or a fluoroquinolone (FQ) on the development of resistance of gram-negative bacilli in an intensive care unit.


METHODS
Prospective bacteriological surveillance study.


METHODS
The study included 51 patients experiencing a second infection with gram-negative organisms, eight days or more after a first infection.


METHODS
The incidences of bacterial infection and the antimicrobial susceptibility have been assessed.


RESULTS
The first-choice therapy was based either on BLA + AG (51%), or on BLA + FQ in the others (46%). The causative organisms were Enterobacteriaceae (57%) and Pseudomonas aeruginosa (31%). The second infection occurred 23 +/- 11 days after the first. The main organisms involved were Pseudomonas aeruginosa (51%) and Enterobacteriaceae (41%). In the group treated initially with an AG, only the antibiotic susceptibility for amikacin decreased significantly (72 vs 36%, p < 0.05). The latter was the most prescribed antibiotic (56%). In the FQ group, there was a significant decrease of susceptibility for ciprofloxacin, pefloxacin, netilmicin and tobramycin. The decrease was not significant for gentamicin and amikacin.


CONCLUSIONS
In intensive care patients, the use of FQ in association with a BLA increases the resistance to AG and FQ. Therefore it seems preferable to administer an AG in association with a BLA. Amikacine should only be prescribed when justified for a given case.
Mathon
L
L
Service d'anesthésie et réanimation chirurgicale, hôpital de l'Hôtel-Dieu, Lyon, France.
Decaillot
F
F
Allaouchiche
B
B
D000617:Aminoglycosides / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000890:Anti-Infective Agents / Q000494:pharmacology*; D003422:Critical Care; D005260:Female; D024841:Fluoroquinolones; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008875:Middle Aged
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D024841:Fluoroquinolones