Risk of nosocomial bacteria transmissions: evaluation of cleaning methods of probes used for routine ultrasonagraphy

Abstract

Background: There exists a small but definite risk of nosocomial infection transmission attributable to ultrasonography probes and coupling gels.

Objective: Our objective was to ascertain whether the current method of probe disinfection in between patients is adequate to prevent cross infection, and to determine the best and safest method of probe disinfection applicable during routine ultrasonography in our institution.

Materials and method: Forty consecutive patients sent for routine ultrasonography at the Radiology Department of our institution in the month of January 2004 were studied. Each patient had a standardized ultrasound scan of the abdomen, after which swabs were taken from the surface of the unclean probe and after probe disinfection by single and double paper wipe cleaning method. The swabs were cultured on Blood agar to determine the characteristics of the colony forming units (CFU).

Result: Forty four bacterial isolates were recovered from 37 patients who cultured positive, with MRSA constituting 36.4%, MRCONS 22.7%, MSSA 13.6%, MSCONS 13.6%, Klebsiella spp 9.1% and Proteus mirabilis 4.6%. The average CFU transmitted by the unclean probe was significantly higher (P<0.05) than that transmitted by the probe after single or double paper wipe. Also, the average CFU transmitted following single and double paper wipe, in the inpatients was significantly higher (P<0.05) than in the outpatients.

Conclusion: Single paper wipe is adequate for outpatients, but for inpatients, especially those with high risk of cross infection, double paper wipe is preferred with probe thoroughly wiped until visibly clean

Keywords: nosocomial infection, US probes

West African Journal of Medicine Vol. 24(2) 2005: 167-170