Efficacy of 75% alcohol in pretreatment of the Andersen sampler in trapping maximum airborne microbes

The present study was conducted to evaluate the effects of the pretreatment methods and sampling time on the sampling of airborne bacteria in hospitals. Methods for the pretreatment of Andersen samplers, namely, non-sterilized, 75% ethanol and autoclaving sampled for 5 min, 10 min and 15 min in the general ward and class 1000 clean operating department, respectively, were studied. Statistical analysis was used to compare the differences in sampling results of airborne bacteria under different pretreatment methods, sampling time and environmental conditions. In the first test, the sampling results of the airborne bacteria obtained by pretreatment of the sampler with 75% ethanol and without pre-treatment were not very different, and the sampling results showed a certain declining trend with the extension of the sampling time. In the second test, the pretreatment effect of autoclaving was significantly better than that of 75% ethanol, and the sampling time had no effect on the sampling results. After removing the influencing factors of the environment, the results were consistent with the results of the second test. It was observed that the Andersen samplers should not be pretreated with 75% ethanol before airborne microbes sampling. The pretreatment should be carried out by autoclaving, and the sampling time has little effect on the sampling results. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s10453-020-09668-2) contains supplementary material, which is available to authorized users.