Pseudomonas aeruginosa

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.