Author's response to reviews Title: Air sampling procedures to evaluate microbial contamination: a comparison between active and passive methods in operating theatres Authors:

on behalf of all authors of the manuscript " Air sampling procedures to evaluate microbial contamination: comparison between active and a passive method in operating theatres " (Ms. for publication in BMC Public Health after major revisions. Moreover, I thank your qualified Referees for their comments that permitted us to greatly improve the paper. Please find in attachment the revised paper and the cover letters addressed to the Referees. The manuscript was rewritten following-point by point-all the reviewers' comments (all changes are written in red in the text) and the additional editorial requirements that you kindly requested in your last e-mail. Moreover, some comments of Referees concern the English language. For this reason, the manuscript underwent to a professional English editing, held by: We hope that all our efforts will allow you to accept the article. Please do not hesitate to contact me at anytime for further information. Thank you for your time and best regard. thank you for your evaluation and for your important suggestions. We apologize for the confusion in the previous version of the manuscript and we really appreciate your efforts for reviewing it. We are now re-submitting the correct manuscript. A point-by-point description of the changes follows (in black small letters your comments, in red capital letters our reply): 1. This study devoted to research on the relationship between active and passive sampling for bioaerosol in operating theaters. The results obtained from this study may clarify the relationship between active and passive sampling for bioaerosol. However, less constructive conclusions can be made since their results are very limited. Some related results have already been published as reference 18 to 22; however, there is no consistent conclusion among these studies. I suggest the authors to make more discussions, why readers have to believe there is a significant correlation between active and passive sampling results since there are already some opposite findings have been published? What's the same or different among their findings and previous reports? In methods, some descriptions are too rough, the readers may get confused. Detailed comments and questions are given page by page in the section that follows. 3 2. Background: Since the major focus is related to active and passive sampling, some issues have to be addressed in this paragraph. What's the possible reason could explain the inconsistent findings from previous studies? What kind of factor may affect the active and passive sampling …