REDUCING INFECTION IN US PROBES

“Reducing Infection in US Probes”

Table of Contents

INTRODUCTION3

Subject3

Purpose3

METHOLDOGY4

DISCUSSION AND ANALYSIS5

Undetected Pathogens6

Decolonizing Patients7

Infection prevention is everyone's business8

Ultrasound Probes and Coupling Gel Be a Source of Nosocomial Infection in Patients Undergoing Sonography?9

CONCLUSION12

REFERENCES13

“Reducing Infection in US Probes”

INTRODUCTION

Subject

After their use at ultrasonography (US) in the intensive therapy unit, probes were used to directly inoculate blood agar plates before and after various cleaning procedures. The uncleaned probes transmitted large numbers of clinically important microbes. Simple cleaning methods were effective in reducing transmission among certain patients: fit patients, double paper wipe; patients at risk of contracting infection, single paper wipe followed by alcohol wipe; patients with a potential source of infection, single paper wipe followed by alcohol wipe. The problem of multiresistant organisms in hospitals is increasing (Livornese, 1992).

Purpose

Of particular concern is methicillin-resistant Staphylococcus aureus (MRSA). It is essential that vulnerable patients (i.e., neonates or patients in the intensive therapy unit, with hematologic or renal disease, or with unhealed wounds) are not exposed to multiresistant organisms. This can be ensured if such patients are isolated from those who are a potential source of infection by means of an effective infection control policy.

Ultrasonographic (US) machines are ideal vectors for cross infection. A busy machine may be used to scan 30 patients a day including both patients who may act as a source of infection and those who are vulnerable. The probe of the US machine could act as a vector between these groups unless there is effective cleaning. To our knowledge, the best practice has yet to be established.

The limited literature is divided regarding the propensity of US probes to act as a source for cross infection and the way this may be prevented (1-3) (Muradali, 1995). The manufacturer's recommendation, to soak the probe for 20 minutes in weak sodium hypochlorite solution, is generally impractical due to time constraints. The lack of an effective and easy cleaning method for US probes may place patients at risk. Our aim was to assess the potential for US probes to act as vectors for cross infection and to compare cleaning methods that can be used to prevent this.

METHOLDOGY

A prospective study was carried out to assess the ability of US probes to transfer colony-forming units (CFU) from patients to blood agar plates after various cleaning procedures. Forty specimens were obtained from patients in the intensive therapy unit after abdominal US performed to exclude an abdominal source of sepsis. Thirty-four of these specimens were taken from patients who were known to have been infected with MRSA. The specimens were divided randomly into two equally sized study groups: the double paper wipe group (n = 20) and the alcohol wipe group (n = 20).

The samples were collected by one operator (C.F.), who performed standardized abdominal US (Toshiba, Tokyo, Japan) with 10 sweeps across the lower abdomen of each patient with use of a sector probe and sterile gel (Livornese, 1992). For each sample, the uncleaned probe was used to directly inoculate the first ...