Diagnosis of MRSA and VRE possible in one to two hours compared to two to five days with conventional testing
The recent acquisition of a GeneXpert device for polymerase chain reaction (PCR) testing is speeding up the diagnosis of MRSA and VRE infections, and reducing the number of patients required to be placed in isolation at Thunder Bay Regional Health Sciences Centre.
The hospital acquired the device in October 2015 and began using it in April 2016.
“In the past, we had to culture a specimen in a Petri dish and wait two to five days for a result,” said Hilary McIver, the hospital’s manager of infection control and risk management. “With the GeneXpert and PCR, we can get a result within one or two hours, shortening the amount of time a patient has to remain in isolation.”
The PCR test is administered on high-risk patients, who are swabbed on admission and placed in isolation until the result is available. If the result is negative, “the nurses are ecstatic because they don’t have to use their personal protective equipment to go into the room,” said McvIver.
“If they are positive, we have to put them in isolation for the duration of their admission to hospital.”
The requirement for isolation continues for at least three months, so if they are discharged and return to hospital as an outpatient during that period of time, the necessary precautions still have to be taken.
Hospitals are high-risk locations housing patients who are susceptible to infection because of compromised immune systems, explained McIver. The risk is much less of an issue when patients with MRSA and VRE are in the community.
Thunder Bay Regional uses PCR testing on patients coming from other high-risk locations, including hospitals where testing for antibiotic-resistant infections has not been performed. It also performs the test on patients who have previously been tested as positive to determine if the infection has cleared up and if they can be removed from isolation.
If a hospital transfers a patient who has been tested as positive, the patient would be placed in isolation on admission to Thunder Bay Regional and only tested following the expiry of the three-month period.
“Usually, the infection control department at the transferring hospital would give us a call and tell us the patient is positive,” said McIver. “We will then flag these patients in our system and a screen would pop up telling the nurses to isolate them in a private room.”
On average, approximately 700 patients per year are placed in isolation for MRSA and VRE infections at Thunder Bay Regional.
Reducing the number and length of time patients are in isolation results in substantial cost savings for gowns, gloves and laundering. It also improves efficiency for hospital staff who would otherwise spend more time gowning up every time they enter the room of a patient in isolation.
Each PCR test costs approximately $70, and the hospital has budgeted to do 750 of them this fiscal year.
“We’re on track with that number and looking at expanding the criteria for administering PCR testing,” said McIver.
If a patient doesn’t meet the current criteria, is swabbed and found to be positive after two to five days as a result of Petri dish testing, the infection control department has to trace the movements of the patient through the hospital, requiring staff and patients who have been in contact with the patient to be placed in isolation and tested.
“If people who have been in contact with the patient have gone home, we have to notify them and tell them to go see their family doctor for testing, so it’s a big process,” said McIver. “We also have to do a thorough cleaning of the room because VRE will stay in the environment for up to 18 months.
“We’re collecting data to see how often this happens. If we used PCR on these patients, we would know within two hours if they were positive and we’d only have to isolate them – not all of their contacts.”
The acquisition of the GeneXpert was made possible by a grant of close to $80,000 from the Thunder Bay Regional Health Sciences Foundation.