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Gentamicin use and Pseudomonas and Serratia resistance: effect of a surgical prophylaxis regimen
Abstract:
An outbreak of prosthetic valve endocarditis due to methicillin-resistant Staphylococcus epidermidis prompted a change in antimicrobial prophylaxis for open heart surgery in a general hospital from a regimen of aqueous penicillin G, methicillin, and kanamycin to a 5-day regimen of cefazolin and gentamicin. As a result, total gentamicin use in the hospital more than doubled. Increased resistance of pseudomonas and serratia isolates paralleled the increased total use of gentamicin. For pseudomonas species, the incidence of gentamicin resistance increased from 3 to 15%; for serratia species, from 8 to 88%; and for the total of both organisms, from 4 to 28%. Resistance decreased rapidly after removal of gentamicin from the prophylaxis regimen. Review of serratia isolates from the urinary tract showed that gentamicin resistance was associated with prior antibiotic therapy, especially with gentamicin, care on the surgical services, especially the surgical intensive care unit, and presence of indwelling bladder catheters. Gentamicin use in a 5-day antimicrobial prophylaxis regimen for open heart surgery can represent a large proportion of the total hospital use of that antibiotic, with potential adverse effects on hospital flora.
Insights
Increased gentamicin use for surgical prophylaxis led to higher antibiotic resistance in hospital bacteria, particularly Pseudomonas and Serratia. Resistance declined after gentamicin was removed from the regimen, highlighting the impact of antibiotic stewardship.
Area of Science:
- Infectious Diseases
- Hospital Epidemiology
- Antimicrobial Resistance
Background:
- Prosthetic valve endocarditis outbreak caused by methicillin-resistant Staphylococcus epidermidis.
- Shift in antimicrobial prophylaxis for open heart surgery from penicillin G, methicillin, and kanamycin to cefazolin and gentamicin.
Purpose of the Study:
- To evaluate the impact of a new antimicrobial prophylaxis regimen on gentamicin use and resistance patterns in a hospital setting.
Main Methods:
- Retrospective analysis of antibiotic use and microbial resistance data.
- Comparison of resistance rates for Pseudomonas and Serratia species before and after the change in prophylaxis.
Main Results:
- Total hospital gentamicin use more than doubled.
- Gentamicin resistance increased significantly: Pseudomonas (3% to 15%), Serratia (8% to 88%), combined (4% to 28%).
- Resistance decreased rapidly upon gentamicin removal from prophylaxis.
Conclusions:
- Extended gentamicin use in prophylaxis regimens can substantially increase overall hospital consumption.
- This increased use is linked to significant rises in gentamicin resistance among key hospital pathogens.
- Antibiotic stewardship is crucial to mitigate adverse effects on hospital flora.