Streptococcus suis serotyping by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Chadaporn Chaiden; Janthima Jaresitthikunchai; Anusak Kerdsin; Nattakan Meekhanon; Sittiruk Roytrakul; Suphachai Nuanualsuwan

doi:10.1371/journal.pone.0249682

Peer Review History

Original SubmissionJanuary 24, 2021
25 Feb 2021 Decision Letter - Joseph Banoub, Editor PONE-D-21-02524 Streptococcus suis serotyp ing by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry PLOS ONE Dear Dr. Nuanualsuwan, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please submit your revised manuscript by Apr 11 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. Please include the following items when submitting your revised manuscript: A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter. If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols We look forward to receiving your revised manuscript. Kind regards, Joseph Banoub, Ph,D., D. Sc., FRSC Academic Editor PLOS ONE Journal Requirements: When submitting your revision, we need you to address these additional requirements. 1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf 2. Thank you for stating the following in the Acknowledgments Section of your manuscript: "We also thank the Agricultural Research Development Agency (Public organization), Bangkok, Thailand, for the financial support." We note that you have provided funding information that is not currently declared in your Funding Statement. However, funding information should not appear in the Acknowledgments section or other areas of your manuscript. We will only publish funding information present in the Funding Statement section of the online submission form. Please remove any funding-related text from the manuscript and let us know how you would like to update your Funding Statement. Currently, your Funding Statement reads as follows: "Chadaporn Chaiden The 100th Anniversary Chulalongkorn University Fund for Doctoral Scholarship. The 90th Anniversary of Chulalongkorn University Fund (Ratchadaphiseksomphot Endowment Fund); The Scholarship from the Graduate School, Chulalongkorn University to commemorate the 72nd anniversary of his Majesty King Bhumibol Adulyadej." Please include your amended statements within your cover letter; we will change the online submission form on your behalf. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes Reviewer #2: Yes ******** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #2: Yes ****** 3. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: No Reviewer #2: Yes ****** 4. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes Reviewer #2: Yes ****** 5. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: In the manuscript titled “Streptococcus suis serotyping by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry”, Chaiden et al. used MALDI-TOF mass spectrometry to serotype Streptococcus suis from reference samples and compare against the use of multiplex-PCR, then validate the mass spectrometry method using clinical isolates. Specific comments are as follows: 1. On line 83, it is a bit misleading to state that “the classification of SSs has never been reported”. In reading through reference #8, it seems the authors of that paper have been able to examine serotypes 2, 7, and 9, as well as what they referred to as “less prevalent” serotypes. Though not a complete listing of serotypes (as it seems the authors assessed at least eight serotypes), the authors of the current manuscript cannot state that any classification/serotype attempts have not been reported previously. This needs to be corrected through the manuscript, where appropriate. 2. Is multiplex-PCR really considered a “gold standard”, when it has a reasonably poor rate of identifying serotypes? Sequencing, and likely of just the 16S RNA, would really provide near 100% serotype identity. (After all, the authors in the current manuscript indicate that the 32 reference strains were determined by sequencing of the 16S rRNA). It is strongly recommended to remove reference to “gold standard” throughout the manuscript regarding multiplex-PCR. 3. Under “Validation”, provide the source/location of the clinical isolates used (i.e., which hospital or clinic, and what parts of the country the subjects came from). 4. Figure 2 is not clear at all at the resolution provided. 5. In the Discussion, the authors state that “other peptide masses were found to be different from those in previous studies, which can be explained by the different preparation protocols…”. This is of concern if the purpose of the study is to develop a new, reproducible method for serotype detection. Some different preparation protocols should be considered and examined with the current study, to attempt to provide common spectra that could be used by other groups and their own protocols. 6. The authors state in the Discussion that “the obtained PMFs dendrogram in this study (Fig 2) clustered both SS32 and SS34 together but separate from the other S. suis isolates, indicating that these two serotypes possibly possessed a high genetic dissimilarity from the other examined SSs”. Provide a dendrogram based on 16S RNA to show this, and any dissimilarity of other serotypes. Make a comparison between this and the dendrogram for the mass spectrometry data. 7. Within the Discussion, the authors state that “In order to improve the correct serotype classification rate, we suggested that the repeatability test of the serotype classification, including unknown serotyping, should require at least two times more than 8 MS spectra (spots)”. This reviewer recommends that the authors carry this out. 8. The complete list of m/z identified and used should be provided as a data supplement. Reviewer #2: This manuscript describes a novel matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis of the extracted peptides obtained from Streptococcus suis, and in particularly S. suis serotype (SS2). In this method, cellular proteins (and peptides) of S. suis are extracted and then used for species identification via peptide mass fingerprints (PMFs) formed using MALDI-TOF-MS. The authors showed that this MALDI-TOF-MS analysis permitted to improve the classification of 32 serotypes of S. suis. Indeed, each individual MALDI-TOF-MS exhibited an individual PMFs patterns, which allowed to differentiate each serotype. This was followed by developing an exclusive peptide mass fingerprint (PMFs) database of S. suis, which was generated from the whole-cell peptides of 32 reference strains of S. suis. This PMFs database was generated by inserting 20 qualified MS spectra from each of the 32 individual reference serotypes into the MALDI Biotyper database system according to Bruker’s recommendation. It should be noted that although, it was suggested that multiplex (m)PCR analysis could be used to serotype S. suis isolates. However, it was shown that it did not allow the differentiation of SS2 from SS1/2, or SS14 from SS1 due to the high capsular gene cluster similarity. The authors showed that this discrepancy could be resolved by using the PMFs blueprints to discriminate the previously indistinguishable highly pathogenic SS2 and SS14 from SS1/2 and SS1. Indeed, serotyping using MALDI-TOF-MS correctly classified SS2 from SS1/2, or SS14 from SS1serotypes in 68.8% (22/32); while the validity for the clinical human isolates was 62.5% (20/32). The agreement between the MALDI-TOF MS and mPCR serotyping was moderate with a Kappa score of 0.522, considering that mPCR could correctly serotype up to 75%. In conclusion, the authors have demonstrated that PMFs from the developed MALDI-TOF-MS based method can successfully discriminate the previously indistinguishable highly pathogenic SS2 and SS14 from SS1/2 and SS1, respectively. Moreover, this serotyping method distinguished pathogenic SS6, and so is an alternative approach of choice to rapidly and reliably serotype clinically pathogenic S. suis isolates. This manuscript is generally well written and the authors have shown that by using MALDI-TOF-MS serotyping using PMFs it was possible to classify the correct serotypes of S. suis isolates. Nevertheless, few changes are requested to improve the scientific flow of this manuscript. 1. To be compliant with the IUPAC MS nomenclature, please change all your MALDI-TOF MS into MALDI-TOF-MS. 2. Your Figure 2 is illegible, change for a better and crisper one. 3. I am confused and cannot understand the following argument of page 14: Cohen’s unweighted Kappa statistic was used to elucidate the agreement between the mPCR, as the gold standard method, and this developed MALDI-TOF MS serotyping method, and gave a Kappa score of approximately 0.522. While the true serotype classifications of the mPCR and MALDI-TOF MS, based on the results from Table 4, were approximately 76% (78/103) and 60% (62/103), respectively Query: Is the serotyping using mPCR (76 %) better than the MALDI-TOF-MS (60%)? Then I suggest that for the validation of your manuscript, you make it clearer. You must stress the benefit of your PMFs method allows better discrimination between the serotypes especially for the previously indistinguishable highly pathogenic SS2 and SS14 from SS1/2 and SS1, respectively ****** 6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review?** For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: No Reviewer #2: No [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. https://doi.org/10.1371/journal.pone.0249682.r001
Revision 1
7 Mar 2021 Author Response Response to reviewers of PLOS ONE We would like to thank the editor and the reviewers for their thoughtful comments. We have carefully addressed all the comments. The corresponding changes and refinements made in the revised paper are summarized in our response below. Reviewer#1: In the manuscript titled “Streptococcus suis serotyping by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry”, Chaiden et al. used MALDI-TOF mass spectrometry to serotype Streptococcus suis from reference samples and compare against the use of multiplex-PCR, then validate the mass spectrometry method using clinical isolates. Specific comments are as follows: 1. On line 83, it is a bit misleading to state that “the classification of SSs has never been reported”. In reading through reference #8, it seems the authors of that paper have been able to examine serotypes 2, 7, and 9, as well as what they referred to as “less prevalent” serotypes. Though not a complete listing of serotypes (as it seems the authors assessed at least eight serotypes), the authors of the current manuscript cannot state that any classification/serotype attempts have not been reported previously. This needs to be corrected through the manuscript, where appropriate. RESPONSE : We thank the reviewer for pointing this out. After considering, we decided to remove the phrase “never been reported” to “Nevertheless, one previous study successfully examined few serotypes of SS using MALDI-TOF-MS still most of the serotypes were not classified especially undistinguishable serotypes by current serotyping methods [8].” 2. Is multiplex-PCR really considered a “gold standard”, when it has a reasonably poor rate of identifying serotypes? Sequencing, and likely of just the 16S RNA, would really provide near 100% serotype identity. (After all, the authors in the current manuscript indicate that the 32 reference strains were determined by sequencing of the 16S rRNA). It is strongly recommended to remove reference to “gold standard” throughout the manuscript regarding multiplex-PCR. RESPONSE : The reviewer has made some excellent points and we sincerely appreciated these well-thought comments. However, sequencing of the 16S rRNA gene was performed only to confirm the reference strains used in this study. As our objective was to determine the ability of serotyping methods commonly used by the laboratories, thus mPCR detecting cps gene was chosen for agreement testing between two serotyping methods. Nevertheless, we recognized this insightful suggestion from reviewer, so reference to “gold standard” throughout the manuscript regarding mPCR was removed. Moreover, to make it clearer, the mPCR results in Table 2-3 were also removed. 3. Under “Validation”, provide the source/location of the clinical isolates used (i.e., which hospital or clinic, and what parts of the country the subjects came from). RESPONSE : We agreed and have updated the source/location of the clinical isolates used in materials and methods section line 101, “local S. suis SS2 (n = 23) and SS14 (n = 9) isolates from humans were used, the strains were originally collected from hospital, distributed in 5 regions (north, northeast, central, east, and south) of Thailand.” 4. Figure 2 is not clear at all at the resolution provided. RESPONSE : We apologized for our original Figure 2. We have modified the figure and hope that it is now clear. 5. In the Discussion, the authors state that “other peptide masses were found to be different from those in previous studies, which can be explained by the different preparation protocols…”. This is of concern if the purpose of the study is to develop a new, reproducible method for serotype detection. Some different preparation protocols should be considered and examined with the current study, to attempt to provide common spectra that could be used by other groups and their own protocols. RESPONSE : We agreed with the reviewer that further elaborating on this point would be helpful. However, the peptide extraction method was only modified from Bruker’s recommendation, since it could not provide satisfying signals for serotyping. We also pointed out some different preparation protocols to Paragraph 2 in Discussion “In the present study, the principal difference in the preparation protocol was the modified peptides extraction method, that formic acid was not included, gentle dissolve pellet by vortex and vigorously mix peptides with sinapinic matrix, which likely accounted for some of the dissimilar PMFs. Moreover, dissimilar PMFs could be inherent in the intraspecies discrepancy as well. 6. The authors state in the Discussion that “the obtained PMFs dendrogram in this study (Fig 2) clustered both SS32 and SS34 together but separate from the other S. suis isolates, indicating that these two serotypes possibly possessed a high genetic dissimilarity from the other examined SSs”. Provide a dendrogram based on 16S RNA to show this, and any dissimilarity of other serotypes. Make a comparison between this and the dendrogram for the mass spectrometry data. RESPONSE : We agreed and have updated a phylogenetic tree base on 16s rRNA gene as Figure 4. We also made a comparison to Paragraph 3 in Discussion “The phylogenetic tree based on 16s rRNA gene (Fig 4) also supported this finding as SS32 and SS34 were also clustered separately from the main group of S. suis”, to Paragraph 3 in Discussion “However, these divergent characters were not displayed in phylogenetic tree (Fig 4)” and to Paragraph 4 in Discussion “Notably that, these two pairs of serotypes closely clustered together in phylogenetic tree (Fig 4) but separately in peptide dendrogram (Fig 2). This finding could be used to explain why our modified method could differentiate these two pairs of high similarity serotypes” 7. Within the Discussion, the authors state that “In order to improve the correct serotype classification rate, we suggested that the repeatability test of the serotype classification, including unknown serotyping, should require at least two times more than 8 MS spectra (spots)”. This reviewer recommends that the authors carry this out. RESPONSE : We have fixed the error by changing the word “more than” to “at least” to Paragraph 5 in Discussion. 8. The complete list of m/z identified and used should be provided as a data supplement. RESPONSE : We agreed and have submitted the complete list of m/z identified as a supplement data. Reviewer#2: This manuscript describes a novel matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis of the extracted peptides obtained from Streptococcus suis, and in particularly S. suis serotype (SS2). In this method, cellular proteins (and peptides) of S. suis are extracted and then used for species identification via peptide mass fingerprints (PMFs) formed using MALDI-TOF-MS. The authors showed that this MALDI-TOF-MS analysis permitted to improve the classification of 32 serotypes of S. suis. Indeed, each individual MALDI-TOF-MS exhibited an individual PMFs patterns, which allowed to differentiate each serotype. This was followed by developing an exclusive peptide mass fingerprint (PMFs) database of S. suis, which was generated from the whole-cell peptides of 32 reference strains of S. suis. This PMFs database was generated by inserting 20 qualified MS spectra from each of the 32 individual reference serotypes into the MALDI Biotyper database system according to Bruker’s recommendation. It should be noted that although, it was suggested that multiplex (m)PCR analysis could be used to serotype S. suis isolates. However, it was shown that it did not allow the differentiation of SS2 from SS1/2, or SS14 from SS1 due to the high capsular gene cluster similarity. The authors showed that this discrepancy could be resolved by using the PMFs blueprints to discriminate the previously indistinguishable highly pathogenic SS2 and SS14 from SS1/2 and SS1. Indeed, serotyping using MALDI-TOF-MS correctly classified SS2 from SS1/2, or SS14 from SS1serotypes in 68.8% (22/32); while the validity for the clinical human isolates was 62.5% (20/32). The agreement between the MALDI-TOF MS and mPCR serotyping was moderate with a Kappa score of 0.522, considering that mPCR could correctly serotype up to 75%. In conclusion, the authors have demonstrated that PMFs from the developed MALDI-TOF-MS based method can successfully discriminate the previously indistinguishable highly pathogenic SS2 and SS14 from SS1/2 and SS1, respectively. Moreover, this serotyping method distinguished pathogenic SS6, and so is an alternative approach of choice to rapidly and reliably serotype clinically pathogenic S. suis isolates. This manuscript is generally well written and the authors have shown that by using MALDI-TOF-MS serotyping using PMFs it was possible to classify the correct serotypes of S. suis isolates. Nevertheless, few changes are requested to improve the scientific flow of this manuscript. 1. To be compliant with the IUPAC MS nomenclature, please change all your MALDI-TOF MS into MALDI-TOF-MS. RESPONSE : We have fixed the error by changing the words from MALDI-TOF MS into MALDI-TOF-MS 2. Your Figure 2 is illegible, change for a better and crisper one. RESPONSE : We apologize for our original Fig 2. We have modified the figure and hope that it is now clear. 3. I am confused and cannot understand the following argument of page 14: Cohen’s unweighted Kappa statistic was used to elucidate the agreement between the mPCR, as the gold standard method, and this developed MALDI-TOF MS serotyping method, and gave a Kappa score of approximately 0.522. While the true serotype classifications of the mPCR and MALDI-TOF MS, based on the results from Table 4, were approximately 76% (78/103) and 60% (62/103), respectively Query: Is the serotyping using mPCR (76 %) better than the MALDI-TOF-MS (60%)? Then I suggest that for the validation of your manuscript, you make it clearer. You must stress the benefit of your PMFs method allows better discrimination between the serotypes especially for the previously indistinguishable highly pathogenic SS2 and SS14 from SS1/2 and SS1, respectively RESPONSE : We recognized this insightful suggestion from reviewer, thus to Paragraph 8 in Discussion these following sentences were added “this MALDI-TOF-MS serotyping method allows better discrimination between the serotypes especially for the previously indistinguishable highly pathogenic SS2 and SS14 from SS1/2 and SS1, respectively.” To make it clear, we also decided to remove the word “gold standard” and mPCR results in Table 2. Moreover, we also add 95% CI value of both methods in line 258 “While the true serotype classifications of the MALDI-TOF-MS and mPCR were not statistically significant (p > 0.05) approximately 60% (95% CI: 51%-70%) and 76% (95% CI: 67%-84%), respectively.” We also discussed more in line 364 “Nevertheless, 95% CI of both methods indicated that the true serotype classification rate of both methods was not statistically different”. Attachments Attachment Submitted filename: Response to reviewers.docx https://doi.org/10.1371/journal.pone.0249682.r002
23 Mar 2021 Decision Letter - Joseph Banoub, Editor Streptococcus suis serotyp ing by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry PONE-D-21-02524R1 Dear Dr. Nuanualsuwan, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Joseph Banoub, Ph,D., D. Sc. Academic Editor PLOS ONE Additional Editor Comments (optional): The authors have answered all the demanded queries of both referees. This manuscript is now acceptable. Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation. Reviewer #2: All comments have been addressed ******** 2. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #2: Yes ****** 3. Has the statistical analysis been performed appropriately and rigorously? Reviewer #2: Yes ****** 4. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #2: Yes ****** 5. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #2: Yes ****** 6. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #2: This is my second review . I noticed that answers from authors to my previous comments bring the required elemnts. I have not more comments. ****** 7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review?** For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #2: No https://doi.org/10.1371/journal.pone.0249682.r003
Formally Accepted
23 Apr 2021 Acceptance Letter - Joseph Banoub, Editor PONE-D-21-02524R1 Streptococcus suis serotyping by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry Dear Dr. Nuanualsuwan: I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department. If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org. If we can help with anything else, please email us at plosone@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Joseph Banoub Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0249682.r004

Open letter on the publication of peer review reports

PLOS recognizes the benefits of transparency in the peer review process. Therefore, we enable the publication of all of the content of peer review and author responses alongside final, published articles. Reviewers remain anonymous, unless they choose to reveal their names.

We encourage other journals to join us in this initiative. We hope that our action inspires the community, including researchers, research funders, and research institutions, to recognize the benefits of published peer review reports for all parts of the research system.

Learn more at ASAPbio .