Pseudo-Outbreak of an Unusual Gram-negative Bacillus Associated with VATS Procedures

Background: Video-Assisted Thoracoscopic Surgery (VATS) is a procedure that utilizes a thoracoscope, inserted into a small chest incision and two other small incisions into the chest cavity allow the surgeon to perform procedures ranging from biopsy to tumor removal or lobectomy. Twenty-four new operating rooms (ORs) were opened in a new Surgery and Emergency Service Pavillion of a 613-bed university teaching hospital.  We describe a pseudo-outbreak in 6 patients that underwent VATS procedures in a 3-week period immediately following the opening of the new ORs.  A single surgeon performed all VATS procedures from mid-September through early October 2010.  All had lung tissue specimens that grew an oxidase-positive, glucose non-fermenting Gram-negative rod (not P. aeruginosa or B. cepacia).

Objective: Define the source of the organism responsible for the outbreak.

Methods: An epidemiological investigation was conducted which included chart review, direct observation of subsequent procedures in the OR, central processing department, and the microbiology laboratory.  Environmental sampling was done.

Results: From Sept. 16 through Oct. 7, 2010 6 patients had lung tissue specimens that grew an unusual, slow-growing Gram-negative rod.  All of these tissue specimens had been obtained during VATS procedures performed by a single surgeon. Four of the 6 were lung biopsies performed for diagnosis in patients with interstitial lung disease.  Two were pleural tissues obtained during decortication of known empyemas. No patients had evidence of infection.  The organism had pink colonies, favored slightly lower temperatures for optimal growth and could not be identified to species level.  They have been sent to a reference laboratory for further identification.  Subsequently 2 more patients were identified, one undergoing VATS and the other with an X-ray guided needle biopsy. Environmental samples were collected in the OR during a VATS procedure, in the newly opened Central Processing Department, as well as the Microbiology Laboratory where the specimens are processed.  All environmental samples were negative for this organism except for the sterile deionized water that is used in the laboratory to process these tissue specimens (to promote growth of Legionella if present).  The Microbiology Lab prepared its own supply of sterile water.  It was identified that the steps used for this process had not been followed, which resulted in contamination.  Because this water was not frequently used, this contaminated water was allowed to remain in use for several months.

Conclusions: Preparation of sterile solutions requires careful adherence to protocol.  Thorough understanding of sterile technique is necessary when educating staff responsible for the preparation of these solutions.  Establishing a shorter shelf-life for this sterile water as well as routine monitoring of practice and periodic staff re-education are important to assure quality.