Outbreak of Pseudomonas aeruginosa Surgical Site Infections Following Arthroscopy — Texas, 2009

Background: Arthroscopy is a minimally invasive method of surgery with low rates (0.01%-0.48%) of surgical site infection (SSI).  Seven post-arthroscopy organ/space SSIs caused by  Pseudomonas aeruginosa of indistinguishable pulsed field gel electrophoresis (PFGE) patterns were identified at Hospital X in Texas between April 22, 2009 and May 7, 2009. Objective: To determine the source of the infections and prevent future infections.
Methods: A case-control study was conducted. A case was defined as a patient undergoing knee or shoulder arthroscopy at Hospital X during the outbreak period and subsequently developing an organ/space SSI with P. aeruginosa. Laboratory records from January to May 2009 were reviewed for additional case finding.  Results of environmental and surgical equipment cultures performed by Hospital X in May 2009 were reviewed.  Selected P. aeruginosa isolates underwent PFGE testing at the Texas Department of State Health Services.  Surgical and instrument reprocessing practices were reviewed and observed.  Surgical instrument lumens were inspected using a 3 mm video scope.

Results: No association was found between infection and any of the variables examined, including patient characteristics, hospital personnel, operating rooms, or the type of surgical instruments used.  P.  aeruginosa grew from 62 (16%) of 388 environmental samples; PFGE patterns for 3 of the isolates (samples from the gross decontamination sink and 2 suction canisters) were indistinguishable from case-patient isolates.  All surgical instrument cultures were negative for P.  aeruginosa.  Review of instrument reprocessing practices revealed that reprocessing of some arthroscopic equipment was not being performed according to the manufacturer’s recommendations.  Endoscopic evaluation of reprocessed arthroscopic inflow/outflow cannulae, which were rinsed but not brushed during gross decontamination, revealed retained tissue in the lumen.  Although the shaver handpieces were processed according to the manufacturer’s recommendations, endoscopic evaluation revealed retained tissue in the shaver handpiece suction cannulae.  No further cases occurred after changes in instrument reprocessing protocols were implemented.

Conclusions: Isolation of indistinguishable P. aeruginosa isolates from case-patients and the gross decontamination sink suggests that the post-arthroscopic SSIs were most likely related to surgical instrument contamination with P. aeruginosa during instrument reprocessing.  The bacteria could have survived sterilization due to the presence of retained tissue in the arthroscopic inflow/outflow cannulae and/or the shaver handpiece suction cannulae.  Tissue remained in the shaver handpiece despite cleaning according to the manufacturer’s recommendations.  The FDA and manufacturers are currently developing validated reprocessing protocols for arthroscopic shaver handpieces.