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Patient factors contributing to the emergence of gentamicin-resistant Serratia marcescens
Abstract:
One hundred forty nosocomial Serratia marcescens infections (including 76 cases of bacteremia) were identified by prospective surveillance from 1975 through 1977 and retrospective chart review from 1968 through 1974. Thirty-four cases (24 per cent) involved gentamicin-resistant strains. All gentamicin-resistant strains appeared after 1974. Ninety per cent of the patients had undergone surgery, and 88 per cent had received prior antimicrobial therapy. The emergence of gentamicin-resistant S. marcescens paralleled the increase in usage of gentamicin. Prior use of gentamicin for more than two days in an individual patient was a significant risk factor (P = 0.0002) for being infected with a Serratia that was gentamicin-resistant. Other factors which separated gentamicin-resistant Serratia infections from gentamicin-sensitive Serratia infections were (1) urinary site of infection (P = 0.0005), (2) urinary catheter (P = 0.002), (3) endotracheal tube or tracheotomy (P = 0.03) and (4) increasing duration of hospitalization (P less than 0.05). Thirty-three of 34 (97 per cent) patients with gentamicin-resistant strains had urinary catheters. Specific measures to control infection were effective in decreasing the incidence of infections caused by gentamicin-resistant Serratia.
Insights
Gentamicin-resistant Serratia marcescens infections emerged after 1974, linked to increased gentamicin use. Urinary catheters and prolonged hospitalization were significant risk factors for these resistant strains.
Area of Science:
- Infectious Diseases
- Microbiology
- Hospital Epidemiology
Background:
- Nosocomial infections caused by Serratia marcescens are a significant concern in healthcare settings.
- The emergence of antibiotic resistance, particularly to gentamicin, poses a challenge in treating these infections.
- Understanding risk factors associated with gentamicin-resistant S. marcescens is crucial for effective infection control.
Purpose of the Study:
- To investigate the incidence and characteristics of nosocomial Serratia marcescens infections.
- To identify risk factors associated with gentamicin-resistant S. marcescens strains.
- To evaluate the impact of infection control measures on gentamicin-resistant S. marcescens.
Main Methods:
- Prospective surveillance and retrospective chart review were conducted to identify cases of S. marcescens infections.
- Statistical analysis was used to compare characteristics of gentamicin-resistant and gentamicin-sensitive S. marcescens infections.
- Patient data, including prior antimicrobial therapy, surgical history, and device usage, were analyzed.
Main Results:
- A total of 140 nosocomial S. marcescens infections were identified between 1968 and 1977.
- Gentamicin-resistant strains accounted for 24% of infections and emerged after 1974, paralleling increased gentamicin usage.
- Prior gentamicin use (>2 days), urinary site of infection, urinary catheter, endotracheal tube/tracheotomy, and longer hospitalization were significant risk factors for gentamicin-resistant infections.
Conclusions:
- The rise in gentamicin-resistant S. marcescens is strongly associated with increased gentamicin use.
- Urinary catheterization is a critical risk factor for gentamicin-resistant S. marcescens infections, with 97% of resistant cases involving urinary catheters.
- Implementation of specific infection control measures was effective in reducing the incidence of gentamicin-resistant S. marcescens infections.