Volume 26-21
1 November 2000

[Table of Contents]

PSEUDO-OUTBREAK OF PSEUDOMONAS PUTIDA IN A HOSPITAL OUTPATIENT CLINIC ORIGINATING FROM A CONTAMINATED COMMERCIAL ANTI-FOG SOLUTION - VANCOUVER, BRITISH COLUMBIA

Introduction

In July and August 2000, Pseudomonas putida was recovered from 10 specimens originating from a tertiary-care hospital's ear, nose, and throat (ENT) outpatient clinic. The specimens, consisting of sinus aspirations and biopsies, were taken from 10 patients with refractory, chronic sinusitis. Physicians in the hospital's medical microbiology laboratory first became aware of a potential infection control problem on 6 July 2000, when four specimens from the ENT clinic grew P. putida. Within a week, the same organism was recovered from two more specimens originating from the same outpatient clinic. An infection control investigation was promptly launched to determine a potential environmental reservoir, as well as to limit subsequent contamination of patients' sinuses and their specimens.

Microbiology

P. putida is a gram-negative, aerobic, fluorescent pseudomonad, which grows optimally at room temperature. Like other pseudomonads, P. putida thrives in moist environments. Its isolation from clinical specimens, especially non-sterile sites, is a unusual event and is considered to have uncertain pathogenic significance⁽¹⁾. In immunocompromised patients, P. putida has been found to cause septicemia and septic arthritis^(2,3). Nosocomial transmission of P. putida has only been reported twice^(4,5).

Investigation

A review of the patients implicated in the P. putida cluster revealed a common examination room in the outpatient clinic. A preliminary investigation by the hospital's infection control nurse identified multiple potential reservoirs including the clinic's endoscopes, enzymatic cleaning and glutaraldehyde solutions, suction apparatus, and tap water. Initial environmental cultures failed to grow P. putida. Nevertheless, a number of recommendations were made to staff in the ENT clinic in order to improve infection control practices and minimize the possibility of nosocomial transmission of the organism. Sporadic cases of P. putida colonization/infection continued to be identified in the microbiology laboratory, however, and a more thorough secondary environmental investigation was launched. High colony counts (> 10⁸ CFU/L) of P. putida were recovered from the examination room's solution of StaKleer, a commercial anti-fog product used to prevent condensation from forming on mirrors and endoscopes. Unopened stock solutions of StaKleer were also found to be contaminated with the same organism. Molecular epidemiologic testing of the clinical and environmental isolates is ongoing.

Discussion

Commercial anti-fog solutions, which are marketed primarily for use in dental offices, may be used in the hospital setting, especially in endoscopy suites where condensation on endoscope tips and mirrors may prevent adequate visualization of tissues. These products are not usually sterilized by the manufacturer. Moreover, the bottles containing anti-fog solution are not sealed by the manufacturer and bottle caps are not shrink-wrapped in order to prevent contamination or tampering. Contamination of large bottles of anti-fog solution may not be detected in the dental setting where clinical specimens are not routinely sent for microbiologic culture. Contaminated commercial anti-fog solutions or instruments that have come into contact with contaminated solutions pose an infection control hazard when introduced into normally sterile sites, such as sinuses.

References

1. Kiska D, Gilligan P. Pseudomonas. In: Murray PR, Baron EJ, Pfaller MA et al., eds. Manual of clinical microbiology. Washington DC: ASM Press 1999:517-25.

2. Anaissie E, Fainstein V, Miller E et al. Pseudomonas putida: newly recognized pathogen in patients with cancer. Amer J Med 1987;82:1191-94.

3. Macfarlane L, Oppenhein BA, Lorrigan P. Septicaemia and septic arthritis due to Pseudomonas putida in a neutropenic patient. J Infect 1991;23:346-47.

4. Taylor M, Keane CT, Falkiner FR. Pseudomonas putida in transfused blood. Lancet 1984;2:107.

5. CDC. Reported contamination of heparin soduim with Pseudomonas putida. MMWR 1986;35:123-24.

Source: M Romney, MD, Medical Microbiology Resident, C Sherlock, MB, BS, Infection Control Officer, G Stephens, MD, Medical Microbiologist, A Clarke, MB, ChB, Director, Division of Medical Microbiology, Providence Health Care, University of British Columbia, Vancouver, British Columbia.

[Previous] [Table of Contents] [Next]