Strategy of antibiotic rotation: long-term effect on incidence and susceptibilities of Gram-negative bacilli responsible for ventilator-associated pneumonia.
OBJECTIVE
To evaluate the long-term effect of a program of rotating antibiotics on the incidence of ventilator-associated pneumonia and the susceptibilities of Gram-negative bacilli responsible for ventilator-associated pneumonia.


METHODS
Prospective program for the surveillance of antibiotic susceptibilities of microorganisms responsible for ventilator-associated pneumonia.


METHODS
Academic, university-based, medical intensive care unit (16 beds).


METHODS
2,856 mechanically ventilated patients.


METHODS
A new program of antibiotic use was introduced at the end of 1996 that involved the rotation of antibiotics in empirical and therapeutic use of the treatment of ventilator-associated pneumonia. The rotation concerned the beta-lactam and aminoglycoside classes, with a rotation interval of 1 month. The use of antibiotics was monitored monthly. No preference was given to any particular antibiotic. In a previous study, the period before the introduction of this protocol (1995-1996) was compared with the period 2 yrs after (1997-1998): The results indicated a decreased incidence of ventilator-associated pneumonia, a lower incidence of potentially resistant Gram-negative bacilli, and increased sensitivities of Gram-negative bacilli, especially Pseudomonas aeruginosa and Burkholderia cepacia. After 1998, we decided to continue a routine for this rotation. The long-term effect of this program was studied by comparing the incidence of Gram-negative bacilli responsible for ventilator-associated pneumonia and their susceptibilities obtained in a third period: 1999-2001. The long-term effect (5 yrs) of such a strategy-2-yr protocol period (1997-1998) and 3-yr routine period (1999-2001)-could be evaluated.


RESULTS
During the 7-yr study period, 2,856 patients were mechanically ventilated for >48 hrs. The incidence of ventilator-associated pneumonia remained significantly lower in period 3 (1999-2001): 23% (period 1, 1995-1996) vs. 15.7% (period 2, 1997-1998) vs. 16.3% (period 3, 1999-2001; p =.002). Late-onset ventilator-associated pneumonia occurred in 86.6% and 94% of cases, respectively, in periods 1 and 3 (p =.02). The decrease of the incidence of early-onset ventilator-associated pneumonia was statistically significant during the 7-yr study period: 13% vs. 9% vs. 5.9% (p =.02). Combined with a higher incidence of late-onset ventilator-associated pneumonia, the incidence of potentially resistant Gram-negative bacilli increased in period 3: 42.2% vs. 34.5% vs. 41.7% (nonsignificant), except for B. cepacia: 11.7% vs. 7.4% vs. 3.7% (p =.005). Nevertheless, the potential antibiotic-resistant Gram-negative bacilli were more sensitive to most of the beta-lactams, especially piperacillin-tazobactam and cefepime.


CONCLUSIONS
Rotation of antibiotics could help to avoid ventilator-associated pneumonia. It could greatly improve the susceptibilities of the potentially antibiotic-resistant Gram-negative bacilli responsible for late-onset ventilator-associated pneumonia. This program could be applied in routine with good results 5 yrs after its introduction. Further studies, especially multiple-center trials, are necessary to confirm this result and better define the rotation type and intervals.
Gruson
Didier
D
Intensive Care Unit 2, Department of Pulmonary and Critical Care Medicine, Bordeaux, France.
Hilbert
Gilles
G
Vargas
Frederic
F
Valentino
Ruddy
R
Bui
Nam
N
Pereyre
Sabine
S
Bebear
Christianne
C
Bebear
Cecile-Marie
CM
Gbikpi-Benissan
Georges
G
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000009:adverse effects; D019072:Antibiotic Prophylaxis / Q000379:methods*; D003422:Critical Care; D003428:Cross Infection / Q000382:microbiology / Q000401:mortality / Q000517:prevention & control*; D004334:Drug Administration Schedule; D018432:Drug Resistance, Multiple; D004359:Drug Therapy, Combination / Q000008:administration & dosage* / Q000009:adverse effects; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology / Q000401:mortality / Q000517:prevention & control*; D017052:Hospital Mortality; D006785:Hospitals, University; D006801:Humans; D007769:Lactams; D008134:Long-Term Care; D008826:Microbial Sensitivity Tests; D018410:Pneumonia, Bacterial / Q000382:microbiology / Q000401:mortality / Q000517:prevention & control*; D011446:Prospective Studies; D015996:Survival Rate; D012122:Ventilators, Mechanical / Q000009:adverse effects*
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D007769:Lactams