Pulling the plug on a pseudomonas outbreak: ancillary equipment as vectors of infection

Abstract

Objectives: Outbreaks of infection related to flexible endoscopes are well described. However, flexible endoscopy also requires the use of ancillary equipment such as irrigation plugs. These are potential vectors of infection but are infrequently highlighted in the literature. We report a cystoscopy associated outbreak of Pseudomonas aeruginosa from contaminated irrigation plugs, in a UK tertiary care centre. Methods: Laboratory, clinical, and decontamination unit records were reviewed, and audits of the decontamination unit were performed. The flexible cystoscopes and irrigation plugs were assessed for contamination. Retrospective and prospective case finding was performed utilising the microbiology laboratory information management system. Available P.aeruginosa isolates underwent Variable Nucleotide Tandem Repeat (VNTR) typing. Confirmed cases were defined as P.aeruginosa infection with an identical VNTR profile to an outbreak strain. Results: Three strains of P.aeruginosa were isolated from five irrigation plugs, but none of the flexible cystoscopes. No acquired resistance mechanisms were detected. Fifteen confirmed infections occurred, including bacteraemia, septic arthritis and urinary tract infection. While failure of decontamination likely occurred because the plugs were not dismantled prior to reprocessing, the manufacturer's reprocessing instructions were also incompatible with standard UK practice. The Medicines and Healthcare products Regulatory Agency (MHRA) were informed. A field safety notice was issued, and the manufacturer issued updated reprocessing instructions. Conclusions: Ancillary equipment are important vectors for infection, and should be considered during outbreakinvestigations. Users should review the manufacturer's instructions for reprocessing ancillary equipment to ensure they are compatible with available procedures.