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Pseudomonas maltophilia bacteremia in children undergoing open heart surgery
Abstract:
Pseudomonas maltophilia was isolated from intraoperative blood cultures in eight of 13 children undergoing open heart surgery during a five-week period. Antibiograms were identical and included resistance to prophylactic antibiotics. The source of the outbreak was traced to contamination of both the calibration device used on the pressure monitoring system and the sensor surface of transducers used in this system. In a mock system, calibration with a contaminated device resulted in recovery of the organism from transducer dome fluid. Dye studies confirmed the integrity of the transducer membrane but demonstrated reflux of dome fluid into the monitoring line fluid. A case-control study revealed no patient- or surgery-related factors predisposing to P maltophilia bacteremia and no excess of morbidity or mortality in patients as a result of bacteremia. The outbreak was confined to patients undergoing open heart surgery and was terminated abruptly by sterilization of transducers and revision of the calibration device.
Insights
A Pseudomonas maltophilia outbreak occurred in pediatric open heart surgery patients due to contaminated monitoring equipment. Prompt sterilization and device revision successfully ended the nosocomial infection.
Area of Science:
- Infectious Diseases
- Hospital Epidemiology
- Medical Device Contamination
Background:
- Nosocomial bloodstream infections pose significant risks in healthcare settings, particularly during invasive procedures.
- Pseudomonas maltophilia (now known as Stenotrophomonas maltophilia) can cause opportunistic infections in vulnerable patient populations.
- Intraoperative contamination of medical devices can lead to outbreaks of multidrug-resistant organisms.
Purpose of the Study:
- To identify the source and characteristics of a Pseudomonas maltophilia outbreak in pediatric open heart surgery patients.
- To determine the transmission route of the organism within the surgical environment.
- To implement and evaluate control measures to terminate the outbreak.
Main Methods:
- Isolation and identification of Pseudomonas maltophilia from intraoperative blood cultures.
- Antibiogram analysis to assess resistance patterns.
- Investigation of the pressure monitoring system, including calibration devices and transducers.
- Mock system experiments and dye studies to elucidate the contamination pathway.
- Case-control study to identify patient-specific risk factors.
Main Results:
- Eight of 13 pediatric patients developed Pseudomonas maltophilia bacteremia during a five-week period.
- Identical antibiograms indicated a common source, with resistance to prophylactic antibiotics.
- The outbreak was traced to contamination of the calibration device and transducer sensors.
- Fluid reflux from the transducer dome into the monitoring line was confirmed.
- No patient- or surgery-related predisposing factors or increased morbidity/mortality were identified.
Conclusions:
- Contaminated medical devices, specifically pressure monitoring equipment, were the source of the Pseudomonas maltophilia outbreak.
- The outbreak was successfully controlled by sterilizing transducers and revising the calibration device.
- This highlights the critical importance of rigorous disinfection and sterilization protocols for medical equipment in preventing healthcare-associated infections.