Contamination of pulse oximeter probes before and after decontamination in two intensive care units.

Background: The internal surfaces of pulse oximeter probes may be overlooked as hot spots for pathogenic microorganisms in an intensive care unit (ICU), thereby contributing to the high incidence of hospital-acquired infections.

Objectives: To determine the growth and identification of microorganisms on pulse oximeter probes in the multidisciplinary ICU (MICU) at Charlotte Maxeke Johannesburg Academic Hospital and the burns ICU (BICU) at Chris Hani Baragwanath Academic Hospital, before and after decontamination.

Methods: This was a cross-sectional, comparative and contextual study, using purposive sampling. Data were collected from the internal surfaces of 34 pulse oximeter probes in a MICU and BICU. Each pulse oximeter probe was swabbed before and after decontamination. The endemic microorganism profile for the two ICUs was obtained from a laboratory database.

Results: Internal surfaces of 31 (91%; 95% confidence interval (CI) 0.76 - 0.98) pulse oximeter probes were contaminated with 9 different pathogenic microorganisms pre decontamination. Acinetobacter baumannii, Klebsiella pneumoniaei and Pseudomonas aeruginosa were endemic to both ICUs, and were the most-frequently isolated microorganisms. Staphylococcus aureus was the most common microorganism endemic to both ICUs, isolated on the internal surfaces of only 2 pulse oximeter probes. Of the internal surfaces of pulse oximeter probes, 6 (18%; 95% CI 0.07 - 0.35) remained contaminated post decontamination, with a microorganism growth reduction of 80% (p=0.0001).

Conclusion: The internal surfaces of pulse oximeter probes may serve as hot spots for an array of pathogens with the potential to cause infection and outbreaks in ICUs. Decontamination of the internal surfaces of pulse oximeter probes should be emphasised.

Contributions of the study: This study identifies internal surfaces of pulse oximeter probes as reservoirs for infection in intensive care units (ICUs), particularly in a burns ICU setting, pinpointing one of many sources of hospital-acquired infections within ICU cubicles.The study emphasises the need to clean the internal surfaces of pulse oximeter probes (whether visibly soiled or not) prior to disinfection.