The techniques used to clean and sterilise flexible ureteroscopes leave behind contamination including debris, residue, and bacteria, according to a small study.
The US researchers concluded that such failures may result in the use of dirty scopes. Most flexible ureteroscopes – used to look for and remove kidney stones – are reused following cleaning and high-level disinfection or sterilisation.
“Sterilisation failures were unexpected and are deeply concerning”
Researchers sampled 16 ureteroscopes at two institutions after they were cleaned and sterilised with hydrogen peroxide gas.
They detected contamination on 100% of the scopes. Every scope exceeded the benchmark for protein, haemoglobin was found on 63%, and 44% had higher adenosine triphosphate (ATP) levels than anticipated.
Visual inspections identified debris protruding into channels, oily deposits, and white foamy residue, an abnormality researchers had never seen before.
Sterilisation is supposed to eradicate all viable microbes, and as such, microbial cultures should always be negative for sterilised instruments, noted the researchers.
They also tested two new ureteroscopes and found haemoglobin and protein levels increased after initial reprocessing – before they had ever been used.
“We are concerned that the techniques used in the field are insufficient”
While no patients were involved in the study, Ofstead said it was evidence that contaminated scopes were being used, with unknown implications for patients.
The study also uncovered a lack of bedside cleaning in operating rooms, and long delays in processing of scopes after use, fundamental flaws that may have contributed to reprocessing failures.
Meanwhile, the researchers highlighted a previous study conducted by researchers at Duke University in North Carolina found that 15% of patients suffer complications such as sepsis, urinary tract infections, and hospitalisation following ureteroscopy.
The study, conducted by research firm Ofstead and Associates, is the latest to raise concerns about infections associated with endoscopic procedures.
Previous outbreaks have been linked to contaminated duodenoscopes, gastroscopes, bronchoscopes, and cystoscopes.
Lead study author Cori Ofstead said: “Sterilisation failures were unexpected and are deeply concerning.”
“This study underscores the importance of consistently monitoring reprocessing outcomes to ensure ureteroscopes are sterile and safe for patient use,” she said.
The study is being presented at the 44th annual conference of the Association for Professionals in Infection Control and Epidemiology in Portland, Oregon.
A forthcoming article in the American Journal of Infection Control is set to contain more detail on the study, said the researchers.
Concerns raised over infection risk from endoscopes
Nurse and APIC president Linda Greene said: “APIC is concerned that the techniques used in the field are insufficient, and that current methods in place are introducing more contamination with the reprocessing of each scope.
“The results of this study are concerning and should prompt hospitals to ensure that proper cleaning verification and visual inspections are being performed,” she added.
Meanwhile, another study presented at the conference found 37% of heater-cooler devices used in open heart surgery may be contaminated with deadly bacteria.
It found 33 of 89 heater-cooler units assessed between July 2015 and December 2016 tested positive for Mycobacterium chimaera, a bacterium associated with fatal infections in open-heart surgery patients.
A further study presented at the conference indicated significant gaps in infection prevention in US care homes.
Researchers warned that such facilities continued to lack the resources, including qualified personnel, necessary to implement adequate infection control programmes.