Improving the aseptic transfer procedures in hospital pharmacies. Part B: evaluation of disinfection methods for materials with a non-sterile surface

Abstract

ObjectivesTo improve the disinfection methods for materials with a non-sterile surface to be used in aseptic handling.MethodsThe surface bioburden on ampoules (A) and injection vials (IV) is determined by contact plates and total immersion. The occurrence of spore-forming bacteria is determined by strain colouring and matrix-assisted laser desorption ionisation-time of flight mass spectrometry. The disinfection procedures of non-sterile materials in 10 hospital pharmacies are judged by observing.ResultsAfter wiping according to local disinfection methods, the mean surface bioburden determined by contact plates in 10 hospital pharmacies is 0.36 (plastic A), 0.50 (glass A) and 0.29 colony-forming unit (cfu) (IV). The observers found great differences in accuracy of wiping and degree of wetting the sterile gauzes.After improved wiping with commercially available alcohol impregnated sterile wipes and a two-towel technique (one-step TT disinfection), the mean surface bioburden determined by contact plates is 0.03 (plastic A), 0.2 (glass A) and 0.13 cfu (IV). Further improvement can be reached by submerging A and IV in ethanol 70% followed by improved wiping (two-step TT disinfection), but still micro-organisms will remain (mean surface bioburden determined by total immersion is 0 (plastic A) and 0.3 cfu (IV); glass A not determined). Two-step TT disinfection is more labour intensive. Spilling of alcohol is another disadvantage. However, we presume one-step TT disinfection is effective enough in daily practice. Routine surface bioburden determinations have to prove this.The effectiveness of the combination of spray and wipe is not examined because we observed a quick disappearance of alcohols from vertical as well as horizontal surfaces, which shortens the contact time to far below the advised 2 min.Spore-forming bacteria disappear as quickly as other micro-organisms during disinfection by alcohols.ConclusionLocal disinfection procedures can be improved. Complete removal of micro-organisms from materials with a non-sterile surface, even after two-step TT disinfection, is impossible. Routine surface bioburden determinations have to prove if one-step TT disinfection is effective enough.

Reducing the risk of non-sterility of aseptic handling in hospital pharmacies, part B: risk control

“…► A systematic survey to reduce the risks of non-sterility of aseptic handling ► The results can be used in prioritising risk reducing measures ► The risk of non-sterility caused by needle or spike contact with critical spots of vials and ampoules (stopper or ampoule neck), blocking first air under downflow and touch of critical spots cannot be eliminated completely in an SOP. 4 The team considered these measures important and reduced the value of occurrence by 2 points. Regular surface monitoring after disinfection is strongly advised.…”

Improving the aseptic transfer procedures in hospital pharmacies part C: evaluation and redesign of the transfer process

“…The mean number of particles from each kind of cardboard box after five-times rubbing are expressed in table 3 as particle per m 3 . The maximum limits for airborne particles in Grade C in operation are also presented in table 3.…”

“…As mentioned previously, it is important to have materials with a low-surface bioburden before disinfection. 3 In Hospital pharmacies 3, 4 and 5 ampoules and injection vials are stored in their original white boxes up to use. The surface bioburdens are low and are comparable with the bioburdens in materials stored under the same conditions, as described earlier.…”

“…Vertical axis: mean cfu/sample. Note: For infusion bottles only about 15% of the vial surface was examined 3.…”

“…Particle emission after rubbing white cardboard boxes expressed as mean particles ≥0.5 and ≥5 µm per m3 …”