Culture-Independent Quantification of Legionella pneumophila in Evaporative Cooling Systems Using Immunomagnetic Separation Coupled with Flow Cytometry

Round 1

Reviewer 1 Report

The study is interesting and important as far as human health is concerned, and the obtained results are reasonable. However, a few minor issues should be addressed. Hence, I recommend this work for publication after minor revision as noted.

1) The introduction section should also include a few other important techniques for the detection or counting of various pathogens such as optical and magnetic separation techniques: https://iopscience.iop.org/article/10.1088/2043-6262/aceda9/meta; https://iopscience.iop.org/article/10.1088/1361-6528/ac137a/meta

2) Purity of the materials and chemicals used should be given.

3) The efficiency and reliability of the process should also be discussed.

4) What about the interference of the other pathogens in the samples?

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

The authors employed the IMS-FCM method as a quantitative rapid test by general analytical procedures. This method is an innovative, antibody-based method for culture-independent quantification of L. pneumophila. The calibration experiments were performed to determine concentration-dependent results of viable L. pneumophila. the cryopreserved L. pneumophila standards were established. This is very important study, I recommend it is publishable after minor revision.

The authors should revise the figures to uniform the font, font size to make the figures clearly.

Author Response

Dear Referee 2,

we want to thank you for your thoughtful and constructive comments and evaluating our manuscript. We revised our manuscript respective to your comments. All changes in the manuscript are highlighted and lines/chapters/figures mentioned in the text refer to the revised version.

Comments:

- The authors should revise the figures to uniform the font, font size to make the figures clearly.

Thank you for these helpful and constructive comment. We adjusted the font style and size of figures 1, 2 and 3 to match the running text in the manuscript. Figure 4 are downloaded PNG files from the device, which are normally illustrated on the display during and after the measurements. We added those PNG files to the manuscript to represent data examples from the device and therefore no changes have been made to figure 4.

With kind regards,

Philipp Streich and Michael Seidel on behalf of all authors

Reviewer 3 Report

The manuscript presents a combination of  methods for quantification of Legionella without need of cultivation. The manuscript structure is logical, the presentation is clear and easy to follow. However, the presentation of equations is really poor.

Comments:

1. Equations. The equations should be revised completely. They should not contain text, symbols should be used for each physical quantity. Also, the equations should be independent of the units of measure. The character "*" is only allowed in computer programming to represent multiplication.

2. Figures. Figures 2-3: unit of 100^-1 ml^-1 is awkward, use (100 ml)^-1 instead. Figure 4: units of measure are missing, should be provided.   

Author Response

Please see the attachment

Author Response File: Author Response.pdf