Zoonotic Foodborne Infections in a Tertiary Healthcare Setting: Clinical and Epidemiological Aspects of Campylobacter and Salmonella Infection in Northern Portugal in 2010–2020

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

General comments:

The work presented in the paper sounds relevant to the field and brings important insights into the bacterial and foodborne pathogen prevalence in public health. The manuscript presents very interesting data mapping the prevalence of Salmonella and Campylobacter in the Oporto metropolitan area. It brings insight into the multi-drug resistance of these pathogens that can help the treatment of new patients.

 

All figures have poor-quality images and need to be re-inserted with higher resolution. It is suggested to increase the font size to all figures inside texts.

 

Specific comments:

Materials and methods section:

Lines 150-152: Localized is when it is restricted to only part/tissue. This concept should be revised throughout the manuscript.

Line 173: It is suggested to change to "... 95% confidence interval (CI)." since it is the first time it appears in the manuscript text.

Figure 1: Graphs texts are too small to read. Please, increase font size and figure quality.

Figure 2 (legend): The data for Campylobacter is only from 2015-2020, please adjust the figure legend to reflect that.

Figure 3 (legend): Please, adjust the legend to better represent the data presented. What year does figure 3 represent? Is it the average of cases per month for all the years present in the study?

Figure 4: Please, adjust the "y" axis to show the case number of all ages. It can be done by splitting the axis into 2 segments or transforming the case numbers into percentages.

Table 1: The table is very large and has several types of data together making it very confusing. Please, further explain why the table has 3 p-values. It should be broken by type of data, it is suggested to separate the table creating a separate table for each subsection of the results section (3.1 to 3.5).

 

Line 248 and Figure legend 5: Localized disease means that is retrained or affects a single area of an organ, like an abscess. Invasive means it is spreading through the body. Authors must revise the term.

Author Response

All changes mentioned below have been introduced in the revised version of the manuscript with track changes.

General comment: The work presented in the paper sounds relevant to the field and brings important insights into the bacterial and foodborne pathogen prevalence in public health. The manuscript presents very interesting data mapping the prevalence of Salmonella and Campylobacter in the Oporto metropolitan area. It brings insight into the multi-drug resistance of these pathogens that can help the treatment of new patients. All figures have poor-quality images and need to be re-inserted with higher resolution. It is suggested to increase the font size to all figures inside texts.

General response: The authors would like to thank the positive feedback on the manuscript and the recognition of the relevance of this work in mapping the prevalence of Salmonella and Campylobacter in the Oporto metropolitan area, as well as its contributions to understanding multidrug resistance. The authors appreciate the suggestions regarding the figures and have taken the following actions to address the concerns: all figures have been re-inserted with higher resolution to enhance their clarity and readability; the font size in all figures has been increased to ensure legibility and consistency with the text.

Comment 1: Materials and methods section: Lines 150-152: Localized is when it is restricted to only part/tissue. This concept should be revised throughout the manuscript.

Response 1: The authors have replaced the term "localized" with "extraintestinal focal" throughout the manuscript, as this better reflects infections beyond the intestinal tract. Additionally, the authors recognize that "invasive" encompasses both extraintestinal focal infections and bacteremia, ensuring consistency and precision in the descriptions.

Comment 2: Line 173: It is suggested to change to "... 95% confidence interval (CI)." since it is the first time it appears in the manuscript text.

Response 2: The authors have updated the text on Line 173 to read "... 95% confidence interval (CI)" to ensure proper introduction and clarity, as this is the first mention of the abbreviation in the manuscript.

Comment 3: Figure 1: Graphs texts are too small to read. Please, increase font size and figure quality.

Response 3: The authors have increased the font size of all text within the graphs in Figure 1 to ensure readability. Additionally, the figure quality has been enhanced by re-inserting it with higher resolution.

Comment 4: Figure 2 (legend): The data for Campylobacter is only from 2015-2020, please adjust the figure legend to reflect that.

Response 4: The authors have updated the legend for Figure 2 to clearly indicate that the data for Campylobacter covers the period from 2015 to 2020.

Comment 5: Figure 3 (legend): Please, adjust the legend to better represent the data presented. What year does figure 3 represent? Is it the average of cases per month for all the years present in the study?

Response 5: The legend for Figure 3 has been revised to clarify that the numbers represented are the total cases diagnosed per month between 2010 and 2020 for Salmonella and between 2015 and 2020 for Campylobacter. It does not represent the average number of cases per month for the study period.

Comment 6: Figure 4: Please, adjust the "y" axis to show the case number of all ages. It can be done by splitting the axis into 2 segments or transforming the case numbers into percentages.

Response 6: In response, the authors have split the "y" axis into two segments to better display the case numbers for all ages. This adjustment allows for clearer visualization of the data across different age groups.

Comment 7: Table 1: The table is very large and has several types of data together making it very confusing. Please, further explain why the table has 3 p-values. It should be broken by type of data, it is suggested to separate the table creating a separate table for each subsection of the results section (3.1 to 3.5).

Response 7: In response to the reviewer’s suggestion, the authors have split Table 1 into multiple tables (one for each subsection of the results section) to improve clarity and organization. The p-values in the table represent comparisons between the following groups: Campylobacter coli and C. jejuni; Salmonella Typhimurium and S. Enteritidis; and Campylobacter and Salmonella. The authors have added this explanation as footnotes in each respective table to ensure clarity.

Comment 8: Line 248 and Figure legend 5: Localized disease means that is retrained or affects a single area of an organ, like an abscess. Invasive means it is spreading through the body. Authors must revise the term.

Response 8: The authors have reviewed and revised the terminology throughout the manuscript to ensure consistency and accuracy. Specifically, the term "localized" has been replaced with "extraintestinal focal" in Line 248, the legend of Figure 5, and all relevant sections of the manuscript. This adjustment better reflects infections occurring outside the intestinal tract. Additionally, the authors acknowledge that "invasive" is used to describe infections spreading through the body, encompassing both extraintestinal focal and bacteremia cases.

Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript presents a decade-long analysis of Salmonella infection data and a five-year overview of Campylobacter infection cases, both sourced from a tertiary hospital in Northern Portugal. It further investigates the risk factors linked to invasive disease outcomes and the necessity for hospitalization. To enhance clarity and understanding for readers, the figures and tables have been meticulously optimized, and efforts have been made to refine the manuscript's logical progression throughout. Here are the specific suggestions for revision:

1.     Line 36, Please reconsider these two keywords “zoonoses” and “One Health” to better align them with the content of the manuscript.

2.     Section 2. Materials and Methods, reorganize this section by listing subheadings based on specific experiments and supplementing with the specific methods used, such as antimicrobial susceptibility testing.

3.     Line 171, why p<0.20?

4.     Figure 1, Please adjust the colors and font sizes of the images to enhance clarity.

5.     Lines 213, 246, 247 and others, the letter “S” in S. Typhimurium and S. Enteritidis should be italicized.

6.     Line 227, What does "group" stand for?

7.     Table 1, please add the information of other species/serovars in the table.

8.     There are too many figures; it is suggested to merge similar ones, such as Figures 3, 4, and 6.

9.     Table 2, What does "yo" stand for?

10.   Line 358, “S. enterica subsp. enterica serovar Typhimurium” should be changed into “S. Typhimurium”.

Comments on the Quality of English Language

The English could be improved to more clearly express the research.

Author Response

All changes mentioned below have been introduced in the revised version of the manuscript with track changes.

General comment: This manuscript presents a decade-long analysis of Salmonella infection data and a five-year overview of Campylobacter infection cases, both sourced from a tertiary hospital in Northern Portugal. It further investigates the risk factors linked to invasive disease outcomes and the necessity for hospitalization. To enhance clarity and understanding for readers, the figures and tables have been meticulously optimized, and efforts have been made to refine the manuscript's logical progression throughout.

General response:The authors would like to thank the valuable feedback. The authors appreciate the reviewer’s recognition of the analysis of Salmonella and Campylobacter infection data, as well as the investigation of associated risk factors. In response to the reviewer’s suggestion, the authors have carefully optimized the figures and tables to improve clarity and readability. Additionally, the authors have made efforts to further refine the manuscript's logical flow to ensure a more cohesive and accessible presentation of the data. The authors believe these revisions have significantly enhanced the manuscript and appreciate the reviewer’s constructive input in guiding these improvements.

Comment 1: Line 36, Please reconsider these two keywords “zoonoses” and “One Health” to better align them with the content of the manuscript.

Response 1: The authors have removed the keywords "zoonoses" and "One Health" to better align with the manuscript's focus. Instead, the authors have added the keywords "invasive disease," "immunosuppression," and "reporting," as these more accurately reflect the main topics covered in the study.

Comment 2: Section 2. Materials and Methods, reorganize this section by listing subheadings based on specific experiments and supplementing with the specific methods used, such as antimicrobial susceptibility testing.

Response 2: The authors have reorganized Section 2 (Materials and Methods) by listing subheadings based on specific experiments. Additionally, the authors have supplemented the section with more detailed descriptions of the methods used, including antimicrobial susceptibility testing.

Comment 3: Line 171, why p<0.20?

Response 3: The p<0.20 threshold was chosen based on the purposeful variable selection method, as proposed by Hosmer, Lemeshow, and Sturdivant (2013). In this approach, variables that achieve statistical significance at a p-value of 0.20 in univariate analysis or are known to be clinically important are selected for further analysis. This threshold allows us to identify potential predictor variables for inclusion in the next steps of the analysis, even if they do not meet the stricter p<0.05 criterion typically used for hypothesis testing. The purpose of this approach is to explore potential associations and select variables that may warrant further investigation, rather than to test a specific hypothesis. This more liberal threshold helps avoid missing potentially meaningful variables that could be relevant to the model, while also considering their scientific plausibility and clinical significance.

Comment 4: Figure 1, Please adjust the colors and font sizes of the images to enhance clarity.

Response 4: The authors have adjusted the colors and increased the font sizes in Figure 1 to enhance clarity and readability.

Comment 5: Lines 213, 246, 247 and others, the letter “S” in S. Typhimurium and S. Enteritidis should be italicized.

Response 5: The authors have corrected the formatting in the manuscript by italicizing the letter "S" in S. Typhimurium and S. Enteritidis in lines 213, 246, 247, and any other relevant instances.

Comment 6: Line 227, What does "group" stand for?

Response 6: In Line 227, by "group," the authors are referring to the three groups of infections: Campylobacter, non-typhoidal Salmonella (NTS), and typhoidal Salmonella (TS). The authors have also clarified this in the text to ensure better understanding.

Comment 7: Table 1, please add the information of other species/serovars in the table.

Response 7: The authors decided not to include other species/serovars in the table because there were only 7 cases of C. fetus, 1 case of C. ureolyticus, and 1 case of S. Montevideo during the study period, as shown in Figure 1. The remaining isolates were either of the species/serovars already represented in the table or were not identified at the species/serovar level. Additionally, the authors considered that including these species/serovars would make the table denser, adding more columns without providing significant additional information. As a result, the authors have decided to include this information in the text instead. Isolates that were not identified to the species/serovar level were not included in a separate column, as the authors believe this would not contribute meaningful insights to the work. The authors appreciate your understanding and hope this clarification addresses your concern.

Comment 8: There are too many figures; it is suggested to merge similar ones, such as Figures 3, 4, and 6.

Response 8: The authors have merged Figures 3, 4, and 6 to reduce the number of figures and improve the overall flow of the manuscript.

Comment 9: Table 2, What does "yo" stand for?

Response 9: "Yo" stands for "years old." To ensure clarity, the authors have written "years old" in full in every case throughout the manuscript.

Comment 10: Line 358, “S. enterica subsp. enterica serovar Typhimurium” should be changed into “S. Typhimurium”.

Response 10: The authors have updated Line 358 to replace “S. enterica subsp. enterica serovar Typhimurium” with “S. Typhimurium,” as suggested, to simplify the terminology and ensure consistency throughout the manuscript.