[Pseudomonas aeruginosa outbreak, in the area of surgical wound ambulatory care, in postmastectomy patients].

Objective: To describe an outbreak due to Pseudomonas aeruginosa in postmastectomy wounds.
Material and Methods: Cases were patients with a surgical infection caused by P. aeruginosa resistant to ciprofloxacin and gentamycin seen between March 13, 2000 and May 18, 2000, at Instituto Nacional de Cancerologia in Mexico City. Specimens for culturing were taken from faucets, antiseptics, and tap water, as well as from healthcare workers. A case-control analysis was conducted.
Results: Thirteen late surgical infections were caused by a ciprofloxacin and gentamycin-resistant P. aeruginosa. The causative Pseudomonas was isolated from a nurse's nostrils and non-sterile gauzes left by her on the Mayo table at the Breast Tumor ambulatory clinic. None of the closed packages was positive to Pseudomonas. On April 14, 2000, the nurse was transferred to another ward and strict infection control practices were established. After this date, 4 additional cases were diagnosed. Radiation therapy was the only risk factor for infection (Or = 5.1, 95% cI 1.1-28.4).
Conclusions: This outbreak was probably caused by a common source initially, and later disseminated by cross-infection among patients. The poor compliance with infection control practices during wound cleaning and drainage led to implementing a series of specific preventive interventions.