Results
In the first part of the study, 93 diamorphine and seven fentanyl ampoules were studied. Nine (18%; 95% CI: 10– 31%) of the unwiped ampoules grew organisms compared with none (95% CI: 0–9%) of the ampoules wiped with alcohol (p = 0.004); median (IQR [range]) score for growth in the non-wiped group 1 (1–1 [0–2]; p = 0.002). Organisms grown were micrococcus in five samples, a coagulase-negative staphylococcus in three samples, and both organisms in one sample. Results from the second part of the study are shown in Fig. 1. Most contamination occurred in the unwiped ampoules, and this appeared to be reduced by the use of a filter straw, although the numbers were small. Only the wiped ⁄ filtered plates yielded no significant growth.