TITLE:
Other Possible Causes of a Well-Publicized Outbreak of Pseudomonas aeruginosa Following Arthroscopy in Texas
AUTHORS:
Lawrence F. Muscarella
KEYWORDS:
Pseudomonas aeruginosa; Arthroscopy; Disease Transmission; Healthcare-Associated Infection; Root Cause Analysis; Instrument Reprocessing; Bacterial Outbreak; Sterilization; Sterile Technique
JOURNAL NAME:
Advances in Infectious Diseases,
Vol.3 No.2,
June
11,
2013
ABSTRACT:
Background: Seven
patients at a hospital in Houston, TX, were diagnosed during a two-week period in 2009 with joint space
infection of pansusceptible P. aeruginosa following arthroscopic procedures of the knee or shoulder. Tosh et al. (2011), who investigated and
published the principal report discussing this bacterial outbreak, conclude
that its most likely cause was the improper reprocessing of certain reusable,
physically-complex, heat-stable arthroscopic instruments used during these arthroscopic
procedures. These reusable instruments reportedly remained contaminated with
remnant tissue, despite
diligent efforts by the hospital to clean their internal structures. This retained bioburden presumably
shielded the outbreak’s strain of embedded P.
aeruginosa from contact with the pressurized steam, reportedly resulting in
ineffective sterilization of these arthroscopic instruments and bacterial
transmission. Objectives: First, to clarify which specific
sterilization methods, in addition to steam sterilization, Methodist Hospital
employed to process its reusable arthroscopic instrumentation at the time of
its outbreak, in 2009; second, to evaluate Tosh et al.’s (2011) conclusion that ineffective steam sterilization due
to inadequate cleaning was the most likely cause of this hospital’s outbreak;
third, to consider whether any other hitherto unrecognized factors could have
plausibly contributed to this outbreak; and, fourth, to assess whether any
additional recommendations might be warranted to prevent disease transmission
following arthroscopic procedures. Methods: The medical literature was reviewed; some of the principles of quality
assurance, engineering and a root-cause analysis were employed; and Tosh et al.’s (2011) findings and conclusions
were reviewed and compared with those of other published reports that evaluated
the risk of disease transmission associated with the steam sterilization of
physically-complex, heat-stable, soiled surgical instruments. Results and Conclusion: Reports
documenting outbreaks of P. aeruginosa or
another vegetative bacterium associated with the steam sterilization
of inadequately cleaned
surgical or arthroscopic instruments are scant. This finding—coupled with a number of
published studies demonstrating the effective steam sterilization of complex
instruments contaminated with vegetative bacteria mixed with organic debris,
or, in one published series of tests, with resistant bacterial endospores
coated with hydraulic fluid—raises
for discussion whether Methodist Hospital’s outbreak might have been due to one or more factors
other than, or in addition to, that which Tosh et al. (2011) conclude was its most likely cause. An example of such a factor not ruled out by
Tosh et al. (2011) findings would be the re-contamination of the implicated arthroscopic
instruments after sterilization. The specific methods that Methodist Hospital
employed at the time of its outbreak to sterilize some of its arthroscopic
instrumentation remain unclear. A number of additional recommendations are provided
to prevent disease transmission following arthroscopic procedures.