Abstract:
OBJECTIVE: To describe an outbreak of multi-resistant Pseudomonas aeruginosa bloodstream infections (MRPA-BSI) that
occurred in the haematology ward of a tertiary academic hospital in Cape Town, South Africa, and determine risk factors for
acquisition of MRPA-BSI.
METHODS: The outbreak investigation included a search for additional cases, review of patient records, environmental and
staff screening, molecular typing using pulsed-field gel electrophoresis (PFGE) and Multi-locus sequencing (MLST) and a
retrospective case-control study.
RESULTS: Ten MRPA-BSI cases occurred in the haematology ward between January 2010 and January 2011. The case fatality
rate was 80%. Staff screening specimens were negative for MRPA and an environmental source was not identified. PFGE
showed that 9/10 isolates were related. MLST showed that 3 of these 9 isolates belonged to Sequence type (ST) 233 while
the unrelated isolate belonged to ST260.
CONCLUSION: We have described an outbreak of MRPA-BSI occurring over an extended period of time among neutropenic
haematology patients. Molecular typing confirms that the outbreak was predominantly due to a single strain. The source of
the outbreak was not identified, but the outbreak appears to have been controlled following intensive infection control
measures.
