An evaluation of Cidex OPA (0.55% ortho-phthalaldehyde) as an alternative to 2% glutaraldehyde for high-level disinfection of endoscopes.

Cidex OPA (0.55% ortho-phthalaldehyde) is marketed as a safer alternative to 2% glutaraldehyde for endoscope decontamination. As clinical experience is limited, an evaluation was undertaken in a busy endoscopy unit. Cidex OPA cycle dilution was monitored by manufacturer's test strips and high-pressure liquid chromatography (HPLC). Eight endoscopy staff completed daily occupational health questionnaires before and after its introduction. Patient throughput times were assessed in view of Cidex OPAs reduced disinfection time. HPLC confirmed that Cidex OPA levels are maintained above 0.3% for at least 50 cycles. Indicator strips proved generally reliable when tested by pharmacy staff. However, busy endoscopy staff found the indicator strips difficult to interpret, with 28 out of 223 (12.5%) test results being inappropriately recorded as 'fails'. Two hundred and two questionnaires were completed and no short-term health problems were noted. Apart from bronchoscopy lists, patient turnaround times were not improved. The increased cost of changing to Cidex OPA was estimated as pound 7691 per annum. Staining of washer-disinfectors was of concern as it proved very difficult to remove.

Bacteria-free water for automatic washer-disinfectors: an impossible dream?

The ability of a new automatic washer-disinfector system (AWDS), fitted with a water filtration system to provide bacteria-free water and so avoid the risk of mycobacterial contamination of fibreoptic bronchoscopes, was examined. Four new Astec 'MP' Safescope washer-disinfectors, with coarse and fine (0.2 micron) filters attached close to the outlet taps, were supplied with non-softened mains water. Water samples from the tank supply and outlet taps were regularly assessed for bacterial quality over a six-month period. Outlet samples were also analysed after fine filter change and purgation with peracetic acid. All bronchoalveolar lavage specimens (BALS) were stained and cultured for mycobacteria. Only 13 out of 53 outlet samples (24%) were culture-negative. There was no improvement after filter change. Residual anti-bacterial effect of peracetic acid lasted up to 48 h following AWDS purgation. No tank samples were bacteria-free. Sixty BALS were processed, two samples were culture-positive and grew M. tuberculosis and one was also smear-positive. Though mycobacterial contamination of bronchoscopes was not evident, the water filtration system was unable to reliably provide sterile rinse water.