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[Pseudomonas aeruginosa]
Abstract:
We investigated the causes of nosocomial infection of P. aeruginosa in a recent outbreak of P. aeruginosa in our hospital. Multi-drug-resistant-P. aeruginosa(MDRPS) that did not produce class B beta-lactamase was isolated from 20(40.0%) patients, occurring in 50 patients hospitalized in the Internal Medicine Ward E in our hospital in 1999 was investigated. All of the patients had brain-vesicular damage as the underlying disease, and 12 patients had been fed by nasal feeding or through a gastric stoma. MDRPS was isolated from sputum(7), urine samples(8), wound discharge(4) and 1 catheter. The bacteria were resistant to piperacillin, ceftazidime, sulbactam/cefoperazone, minocycline and ofloxacin, and in 40% the MIC of the imipenem was more than 8 micrograms/ml. We did not detect MDRPS in any equipment parts or waste water, including the sink in Ward E, but it was detected in the nutrient fluid for nasal feeding and in the line of one patient. The DNA homology of MDRPS isolated from the patient and the nutritive liquid was the same as that of some strains isolated in Ward E, as shown by random amplified DNA polymorphism PCR. In conclusion, we speculated that some nosocomial infections due to MDRPS resistant to imipenem were caused by contaminated nasal feeding.
Insights
Contaminated nasal feeding solutions likely caused a multi-drug resistant Pseudomonas aeruginosa outbreak in a hospital's internal medicine ward. This resistant bacteria strain led to infections in 40% of patients, primarily those with brain-vesicular damage.
Area of Science:
- Infectious Diseases
- Microbiology
- Hospital Epidemiology
Background:
- Nosocomial infections caused by multi-drug resistant Pseudomonas aeruginosa (MDRPS) pose a significant threat in healthcare settings.
- An outbreak of MDRPS occurred in the Internal Medicine Ward E of a hospital in 1999, affecting 50 patients.
Purpose of the Study:
- To investigate the source and transmission routes of the MDRPS outbreak.
- To identify risk factors associated with MDRPS infection in the affected patient population.
Main Methods:
- Isolation and identification of MDRPS from patient samples (sputum, urine, wound discharge, catheter).
- Antimicrobial susceptibility testing, including minimum inhibitory concentration (MIC) for imipenem.
- Environmental sampling of equipment, wastewater, and nutrient feeding solutions.
- Molecular typing using random amplified polymorphic DNA (RAPD) PCR to assess DNA homology.
Main Results:
- MDRPS was isolated from 20 (40.0%) patients, with resistance to multiple antibiotics including piperacillin, ceftazidime, sulbactam/cefoperazone, minocycline, and ofloxacin.
- 40% of isolates showed an imipenem MIC of >8 µg/ml.
- MDRPS was detected in nutrient fluid for nasal feeding and in the feeding line of one patient, but not in general equipment or wastewater.
- RAPD PCR confirmed DNA homology between MDRPS strains from patients and the contaminated nutrient fluid.
Conclusions:
- Contaminated nutrient fluid used for nasal feeding is a likely source of the MDRPS outbreak.
- This highlights the critical importance of strict hygiene protocols in managing medical feeding supplies to prevent nosocomial infections.