Meropenem use and colonization by antibiotic-resistant Gram-negative bacilli in a pediatric intensive care unit.

OBJECTIVE: The carbapenems are broad-spectrum beta-lactam antibiotics with activity against most organisms encountered in the pediatric intensive care unit (PICU). In anticipation of their increased use in critically ill children, we measured the effect of sustained meropenem use on the pattern of Gram-negative bacillus colonization in patients admitted to a tertiary care PICU.

DESIGN: : Prospective preintervention/postintervention comparison.

SETTING: Medical/surgical PICU.

PATIENTS: Consecutive PICU admissions over 2.5 yrs.

INTERVENTIONS: After a 6-mo baseline period, all children with serious infections admitted to the PICU during the subsequent 2 yrs were administered meropenem. The incidence of colonization by Gram-negative bacilli resistant to one of a battery of broad-spectrum parenteral agents, and by organisms resistant specifically to meropenem, during the baseline period was compared with the period of preferred meropenem use.

RESULTS: During the period of preferred meropenem use, the amount of meropenem used increased >seven-fold, whereas the use of other advanced generation beta-lactams was reduced by nearly 80%. The mean prevalence of colonization by antibiotic-resistant bacilli in general was not statistically altered during the period of meropenem preference (7.3 organisms/100 patient-days, vs. 9.4 organisms/100 patient-days at baseline, p < 0.09). The prevalence of colonization by Gram-negative organisms resistant specifically to meropenem was 0.61 organisms/100 patient-days during the baseline period vs. 1.04 organisms/100 patient-days during the period of meropenem preference (p < 0.30). The incidence of nosocomial infections did not change, and the prevalence of nosocomial infections caused by meropenem-resistant organisms was always <1% of all admissions during the period of meropenem preference.

CONCLUSION: There was no statistically detectable effect on the prevalence of colonization by Gram-negative organisms resistant to one or more classes of broad-spectrum parenteral antibiotics, or to colonization by organisms resistant specifically to meropenem, when meropenem was the preferred antibiotic in a PICU.