Molecular Characterization Of Pathogenic Salmonella Spp From Raw Beef In Karachi, Pakistan

Round 1

Reviewer 1 Report

In the present study, Hussain et al. performed a study to examine the incidence of Salmonella in raw beef meat samples collected from butcher shops and supermarkets of Karachi. They demonstrated that, beef samples from butcher shops of Karachi city are heavily contaminated with S. Enteritidis (37.5%) and S. Typhimurium (31.25%). They showed that, the raw beet was determined with higher S. Enteritidis contamination, followed by S. Typhimurium, S. Choleraesuis, S. Pullorum; while S. Enterica prevalence was least. The manuscript is well written and references are cited properly. However, there are some concerns that need to be addressed.

 

Comments:

Authors have performed PCR screening of virulence and resistance genes in Salmonella isolates, what is the house keeping gene they have used normalized the value? Need to provide statistical analysis. Are there any reasons to choose these specific Salmonella isolates in their study? There are some typo and spacing error throughout the manuscript.

Author Response

Reviewer#1:

Thank you very much for the thorough and critical review of our manuscript. We cordially appreciate your suggestions. We believed that the prescribed changes will definitely improve the quality of our manuscript. The data which is considered as unnecessary in our work has been removed and the manuscript has been revised accordingly (please see the comments). We are confident that the amended version of the manuscript will match the quality standard of the journal Antibiotics.

Replies to reviewer comments:

Reviewer comment: Authors have performed PCR screening of virulence and resistance genes in Salmonella isolates, what is the house keeping gene they have used normalized the value?

Our response: We really appreciate your critical review. We have used conventional PCR for screening of virulence and resistance genes in Salmonella isolates. The housekeeping genes were therefore not necessary. We used positive and negative controls every time we did a PCR reaction. We have now revised the manuscript and clearly mentioned in the materials and methods section about the conventional PCR used in our research study. Conventional PCR has been used by several researchers for screening of resistance and virulence genes [1] [2].

Reviewer comment: Need to provide statistical analysis

Our response: Thank you very much for the valuable suggestion. We really agreed with the reviewer and applied the statistical analysis where applicable. For the statistical analysis the following para under the heading “statistical analysis” has been added please “The data are presented as mean ± SEM. Computer software SPSS 20.0 was used for statistical analysis and variation between the groups was determined through the Student’s t-test. Variations were considered statistically significant at _*p < 0.05.

Reviewer comment: Are there any reasons to choose these specific Salmonella isolates in their study  

Our response: Thank you very much for your response. We didn’t choose them rather they are the result of proper identification of the strains.

Reviewer comment: There are some typo and spacing error throughout the manuscript

Our response: Thank you for your kind response. Our manuscript has been reviewed and revised by our colleague Professor. Professor Nasir Abbas Ph.D. English Language and Literary from University Of ESSEX UK. for English language.

References

Lozano-Leon, A., Garcia-Omil, C., Dalama, J., Rodriguez-Souto, R., Martinez-Urtaza, J., & Gonzalez-Escalona, N. (2019). Detection of colistin resistance mcr-1 gene in Salmonella enterica serovar Rissen isolated from mussels, Spain, 2012 to 2016. Eurosurveillance, 24(16), 1900200. Shah, A. H., & Korejo, N. A. (2012). Antimicrobial resistance profile of Salmonella serovars isolated from chicken meat. J Vet Anim Sci, 2, 40-46.

Author Response File: Author Response.docx

Reviewer 2 Report

Many thanks for the opportunity to comment on this article, which I read with great interest. The authors sought to determine the prevalence of Salmonella in raw beef sold at butcher shops and at supermarkets of Karachi city, Pakistan. Methodology has been clearly described. The manuscript gives an insight into the situation regarding an important food-borne pathogen in developing countries and the risk it pose to public health. However, I do have some general comments and a few questions that would help potential readers understand the Pakistan situation regarding Salmonella.

General comments:

While I commend the authors for their ability to present their work in a language (English) that is other than their first language, I respectfully suggest that they might ask to review the manuscript. Authors use the word "incidence" instead of "prevalence" several times, when they are describing the prevalence or percentage of Salmonella and its antimicrobial resistance. Use of same terms/concepts help makes easier to catch the idea, for example: prevalence or percentage instead of percentage incidence, raw beef instead of cattle meat, and so on. Data in tables do not demonstrate anything, but show information or describe the situation. Sections 2.2 and 2.5 are missed. And because I am not a lab person, I do not understand the relevance of section 2.6, is there any difference from standard Salmonella spp cultures? Sections 4.4. and 4.7 are exactly the same, they are repeated.

Questions:

Introduction: Is this the first study of this type carried out in Pakistan?. Authors mention the general prevalence of Salmonella at public level. Is there any information about the source, i.e. which percentage is due to consumption of raw beef, other meats, milk, etc. ? Is there any data about prevalence of Salmonella in beef cattle in Pakistan? Results: Figure 1 and Table 1 show the same data, I would suggest to remove Figure 1. Also L 101-104: Table 1 does not show the percentage of different Salmonella serovars. Besides, the total percentage counts 93.75%, how these percentages were calculated?. L 100 reads that "statistically, the variation (..)" Which statistics? There is not description in methods. L 113-118 report same data than figure 3. Which was the selection criteria to show the genes in Figure 4 L 136-141: Table 1 show that not isolates were found in supermarkets, however in these lines it is mentioned the contrary, and gives a P-value. Please revise this section L 144-147: These two sentences are quite confused, please revise. Discussion Discussion starts with general information about foodborne pathogens, but which is the relevance for this study? There are also several sentences that seem to be introduction or results instead of discussion, could the authors please revise?. Authors several times mentioned that results were similar to other studies: studies carried out to describe prevalence of E.coli or Salmonella in vegetables. I cannot see the relationship between studies. Some more discussion about this type of studies in Pakistan or the regions would highlight the importance of this work. There is not discussion at all about AMR or genes.

Author Response

Reviewer#2:

We are very thankful to you for your comprehension of our work and for your suggestions to improve the quality of our manuscript. We cordially appreciate your nice suggestion. We revised the M&M discussion section. We also revised the results and followed proper format for reference citation in the text. We are confident that the amended version of the manuscript will match the quality standard of the journal Antibiotics.

Reviewer comment: While I commend the authors for their ability to present their work in a language (English) that is other than their first language, I respectfully suggest that they might ask to review the manuscript

Our response: We really appreciate your kind suggestion. Our manuscript has been reviewed and revised by our colleague Professor Nasir Abbas Ph.D. English Language and Literary from University Of ESSEX UK for English language.

Reviewer comment: Authors use the word "incidence" instead of "prevalence" several times, when they are describing the prevalence or percentage of Salmonella and its antimicrobial resistance.

Our response: Thank you for suggestion. We have replaced the word incidence with prevalence in the revised version of the manuscript.

Reviewer comment: Use of same terms/concepts help makes easier to catch the idea, for example: prevalence or percentage instead of percentage incidence, raw beef instead of cattle meat, and so on.

Our response: We really appreciate the suggestion and revised the manuscript for such type of errors.

Reviewer comment: Data in tables do not demonstrate anything, but show information or describe the situation.

Our response: We respect your comment. We have made changes to improve the quality of tabulated data. We also have added extra tables for better comprehension of the virulence gene profiles in each serovars.

Reviewer comment: Sections 2.2 and 2.5 are missed.

Our response: We have checked and rectified the error.

Reviewer comment: And because I am not a lab person, I do not understand the relevance of section 2.6, is there any difference from standard Salmonella spp cultures?

Our response: We respect your remarks. The section 2.6 provides general information regarding the growth of Salmonella on two different biochemical media i.e. Salmonella Shigella agar and XLD agar. As far as the differentiation of Salmonella serovars on these media is concerned, serovars don’t display vast difference in growth characteristic on SS and XLD agar. However, genus Salmonella can be easily identified on SS and XLD agar.   

Reviewer comment: Sections 4.4 and 4.7 are exactly the same, they are repeated.

Our response: Thanks for your kind response. We have immediately rectified the error in the revised version of manuscript.

Reviewer comment: Is this the first study of this type carried out in Pakistan?

Our response: To the best of our knowledge, this is the first report on contamination and characterization of Salmonella serovars isolated from raw beef in Pakistan (especially Karachi city of Pakistan).

Reviewer comment: Authors mention the general prevalence of Salmonella at public level. Is there any information about the source, i.e. which percentage is due to consumption of raw beef, other meats, milk, etc.?

Our response: Thanks for your response. Due to absence of proper surveillance system for monitoring potential food-borne bacterial pathogens, data regarding Salmonella prevalence in meats (beef, chicken, mutton etc.) is very rare. However, few research studies have reported 20-50% prevalence of Salmonella in chicken meat [3], [4], [5] and [6].   

Reviewer comment: Is there any data about prevalence of Salmonella in beef cattle in Pakistan?

Our response: We found only one research study conducted in slaughterhouse of Peshawar city back in 2012 [5]. They have collected samples from hide of animals, freshly open carcasses and meat from butcher shops after display. They reported 100% prevalence of Salmonella in slaughterhouse which could be due to unhygienic practices over there. Although they have not clearly described the prevalence of Salmonella after skinning or after display in butcher shops, however, they reported that prevalence increases by 52% from slaughterhouse to retail shops in Peshawar. We were unable to retrieve any other data regarding prevalence and virulence characterization of Salmonella isolates from butcher shops and supermarkets. 

Reviewer comment: Figure 1 and Table 1 show the same data, I would suggest to remove Figure 1. Also L 101-104

Our response:  We agreed with the reviewer and removed Figure 1 and L 101-104

Reviewer comment: Table 1 does not show the percentage of different Salmonella serovars

Our response: We have added a new Table which clearly describes the prevalence of individual serovars in different raw beef samples from butcher shops.

Reviewer comment: The total percentage counts 93.75%, how these percentages were calculated?

Our response: We appreciate your review. We have once again retrieved raw data from excel sheet and rectified the error. The percentage now counts 100%.

Reviewer comment: L 100 reads that "statistically, the variation (..)" Which statistics? There is not description in methods.

Our response: We have used student T-test for derivation of p-value

Reviewer comment: L 113-118 report same data than figure 3.

Our response: Thanks for your comment. We have removed the sentences and replaced them with meaningful ones.

Reviewer comment: Which was the selection criterion to show the genes in Figure 4?

Our response: Thanks. We randomly selected a single picture from the various gel electrophoresis pictures. Due to current trends of not including gel pictures in research article we avoided the addition of multiple gel pictures. If you want us to add more gel picture please let us know.

Reviewer comment: L 136-141: Table 1 shows that not isolates were found in supermarkets, however in these lines it is mentioned the contrary, and gives a P-value.

Our response: Thanks for the kind response. We have revised the manuscript accordingly.

Reviewer comment: Please revise this section L 144-147: These two sentences are quite confused, please revise.

Our response: We are pleased to hear from you. We have revised the sentences and tried our best to improve the quality by adding some more information extracted from raw data in excel sheets collected during our research study.

Reviewer comment: Discussion starts with general information about foodborne pathogens, but which is the relevance for this study?

Our response: We have revised the introductory sentences of the discussion section and provided information regarding Salmonella prevalence in cattle in Pakistan and other countries of the world.

Reviewer comment: There are also several sentences that seem to be introduction or results instead of discussion could the authors please revise?

Our response: We have positively revised the discussion section and did provide relevant information regarding the prevalence, resistance and virulence characterization of Salmonella serovars isolated from retail beef shops and supermarkets from different location all over the globe. Special preference was given to research data originated in our neighboring countries.   

Reviewer comment: Authors several times mentioned that results were similar to other studies: studies carried out to describe prevalence of E.coli or Salmonella in vegetables. I cannot see the relationship between studies

Our response: As mentioned above, we have added most relevant data.

Reviewer comment: Some more discussion about this type of studies in Pakistan or the regions would highlight the importance of this work.

Our response: We highly appreciate your suggestion. We have provided information regarding Salmonella prevalence in the region.

Reviewer comment: There is not discussion at all about AMR or genes

Our response: Thanks for kind response. We have added paragraph in discussion section to highlight and relate the importance of AMR genes.

Once again we would like to highly appreciate your keen review and critics. Thank you very much for the suggestions that improved our manuscript.

 

 

References

Soomro, A. H., Khaskheli, M., Bhutto, M. B., Shah, G., Memon, A., & Dewani, P. (2011). Prevalence and antimicrobial resistance of Salmonella serovars isolated from poultry meat in Hyderabad, Pakistan. Turkish Journal of Veterinary and Animal Sciences, 34(5), 455-460. Samad, A., Abbas, F., Tanveer, Z., Ahmad, Z., Asmat, T. A. U. S. E. E. F., Raziq, A. B. D. U. L., & Zahid, M. (2018). Prevalence of Salmonella in chicken meat from Quetta retail outlets and typing through multiplex PCR. Khan, S. B., Khan, M. A., Ahmad, I., ur Rehman, T., Ullah, S., Dad, R & Memon, A. M. (2019). Phentotypic, gentotypic antimicrobial resistance and pathogenicity of Salmonella enterica serovars Typimurium and Enteriditis in poultry and poultry products. Microbial pathogenesis, 129, 118-124. Aftab, M., Rahman, A., Qureshi, M. S., Akhter, S., Sadique, U., Sajid, A., & Zaman, S. (2012). Level of Salmonella in beef of slaughtered cattle at Peshawar. J Animal Plant Sci, 22, 24-27.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

I am happy for the opportunity to re-review this article, which has already improved. Main results are nicely presented in conclusion, and discussion presents now a clear discussion. I have still some few question:

General:

1. Could the authors please correct the total percentage counts of Salmonella in the following sections, and use the same number of decimals? I guess that the correct values are the ones presented in Table 2 (sum up 100%)

L 104-105: S. Enteritidis (37.5%) - S. Cholerasuis (31.25) - S. Pullorum (19.6%) - S. Typhimurium (12.5%)

Table 2: S. Enteritidis (37.5%) - S. Cholerasuis (30.4) - S. Pullorum (19.6%) -  S. Typhimurium (12.5%).

L 21-23: S. Enteritidis (37.50 %), S. Typhimurium (31.25 %), S. Choleraesuis (12.50%) and S. 23 Pullorum (12.50%)

2. Authors have added a section (4.7) abut statistical analysis. However, results of prevalence variations and their p-values are not shown in the results sections (as they were in the previous version). Could author please revise?

3. Use the same term along the text, but only one: "minced meat (e.g. L 102)" or "minced beef" (e.g. Table 1).

Introduction

Authors have highlighted the importance of beef meat and the importance of Salmonella in cattle and in human population. It would improve this section to explicitly mention which is the gap of knowledge (e.g. no previous information about this food-borne pathogen in raw beef) they are trying to discover, and /or the principal hypothesis they want to test (e.g. if the isolates of Salmonella were resistant to common antimicrobials).

Also, in my opinion, mentioning that this is the first report on contamination and characterization of Salmonella serovars isolated from raw beef in Pakistan (especially Karachi city of Pakistan) should be one important point, as it can justify the study (already mentioned in discussion). Add some notes of their responses to the reviewer's questions related to the general prevalence of Salmonella at public level and in cattle in Pakistan will also add value to the introduction section.

L 76-77: Does the authors have any reference for this sentence? If yes, please provide it.

L 88: change "has" to "have"

L 94: "Salmonella in raw beef samples" as in title. Please update the manuscript accordingly, by using always the same. By the way, are lymph node considered edible meat co-products in Pakistan? If yes, it should be mention somewhere.

L 95: "testing was also performed"

Material and methods

L 239-241: Change "The study was based on 150 samples of raw beef sold at butcher shops and at supermarkets of Karachi city, Pakistan. The meat samples separately comprised of muscles, lymph nodes and minced meat. Meat samples from … " for "The study was carried out on samples of raw beef sold at butcher shops and at supermarkets of Karachi city, Pakistan. Raw beef from muscles…"

L 274-276: Authors mention that the above antimicrobials are commonly used for treatment people. I think it would be worthy to mention where these are used.

L 294: "three times to lyse"

Results:

Table 1: What do asterisks (*) mean?

There is not Figure 1.

Figure 2 is not mentioned in the text.

L 118: "The data showed in Figure"

L 123: The number of the Table is missed.

L 145: "Salmonella isolates exhibited a higher level.." Higher than what? Please complete the sentence.

There are two Table 2 (L 111 and L 163)

L 147: "of Clinical"

L 167-169: Please check the English language

Discussion

Is there any other hypothesis than refrigeration that could explain why there were not Salmonella in supermarkets? Was the origin of meat (slaughterhouse or farm) different? Could the authors add some more information, if available?

L 180- 182: Remove the sentences about the complications.

L 182 – 184: "Food of animal origin such as beef meat is deemed to be the a vehicle of transmission of Salmonella to humans [3], [43]" instead of "Food of animal origin such as meat (beef, poultry, pork etc.), milk, eggs and vegetables is deemed to be the main vehicle of transmission of Salmonella to humans [3], [43]".

L 185: What does it meat "wet"? Please clarify

L 185-186: Also add this to introduction that sentence (see my comment above)

L 187: "other research"

L 189: "indicated"

L 215-223: Move the discussion about the prevalence to paragraph before resistance (L 209).

Author Response

Reviewer#2:

Once again thank you critical review of our manuscript. We deeply appreciate your nice suggestions. We believe that the prescribed changes will further polish the quality of the revised manuscript. The data which is considered as unnecessary in our work has been removed and the manuscript has been revised accordingly (please see the comments). We are confident that the amended version of the manuscript will match the quality standard of the journal Antibiotics.

Replies to reviewer comments:

Reviewer comment: Could the authors please correct the total percentage counts of Salmonella in the following sections, and use the same number of decimals? I guess that the correct values are the ones presented in Table 2 (sum up 100%)

L 104-105: S. Enteritidis (37.5%) - S. Cholerasuis (31.25) - S. Pullorum (19.6%) - S. Typhimurium (12.5%)

Table 2: S. Enteritidis (37.5%) - S. Cholerasuis (30.4) - S. Pullorum (19.6%) -  S. Typhimurium (12.5%).

L 21-23: S. Enteritidis (37.50 %), S. Typhimurium (31.25 %), S. Choleraesuis (12.50%) and S. 23 Pullorum (12.50%)   

Our response: Thank you for nice comments and critical review. We immediately corrected the error and checked the whole manuscript for correction of Salmonella prevalence data in raw beef parts according to your suggestion, which is actually the correct data, the rest was typing mistake.

Reviewer comment: Authors have added a section (4.7) abut statistical analysis. However, results of prevalence variations and their p-values are not shown in the results sections (as they were in the previous version). Could author please revise?

Our response: Cordially appreciated. We have now clearly mentioned the statistical analysis in results as mentioned in section 4.7. 

Reviewer comment: Use the same term along with the text, but only one: "minced meat (e.g. L 102)" or "minced beef" (e.g. Table 1).

Our response: Thank you very much for your nice suggestion. We replaced the term mention in L 102 from minced meat to minced beef. We also looked the whole manuscript for such changes.

Reviewer comment: Authors have highlighted the importance of beef meat and the importance of Salmonella in cattle and in the human population. It would improve this section to explicitly mention which is the gap of knowledge (e.g. no previous information about this food-borne pathogen in raw beef) they are trying to discover, and /or the principal hypothesis they want to test (e.g. if the isolates of Salmonella were resistant to common antimicrobials).

Our response: We are very thankful for your helpful suggestion. We have revised the introduction in a way that now clearly describes the importance of Salmonella in food especially beef and other meats and the association of virulence and resistance genes (found in Salmonella isolates of food origin i.e. beef) to severity of the complications that can arise from consumptions of virulent and resistant Salmonella in food.

Reviewer comment: Also, in my opinion, mentioning that this is the first report on contamination and characterization of Salmonella serovars isolated from raw beef in Pakistan (especially Karachi city of Pakistan) should be one important point, as it can justify the study (already mentioned in the discussion). Add some notes of their responses to the reviewer's questions related to the general prevalence of Salmonella at public level and in cattle in Pakistan will also add value to the introduction section.

Our response: We much admire your excellent and useful suggestion. As we have already mentioned in our previous response to the question over Salmonella prevalence in general public in Pakistan, there is very limited data available about prevalence of Salmonella in beef however, there are reports over the prevalence of Salmonella in poultry sector. Few articles also described prevalence of Salmonella in milk. We tried our best to retrieve all data regarding Non-typhoidal Salmonella prevalence in Pakistan and especially Karachi (Sindh region).

Reviewer comment: L 76-77: Do the authors have any reference for this sentence? If yes, please provide it.

Our response: Thanks for the comment. The sentence can be justified by the second line of Introduction section of [1], and serovars diversity section of [2]. S. Dublin was the most prevalent serovar in Europe while S. Enteritidis was one of most prevalent serovars in Africa. Surprisingly, [1] has reported that S. Enteritidis was rarely isolated in that region (Alberta). As a matter of fact, serotype diversity of Salmonella varies considerably with geographical boundaries, species they infect, seasonal variations and many more. With aim in mind to further improve our introduction section (as recommended); we have added recent data regarding Salmonella serovars diversity in cattle in major parts of the world with special reference to our region.     

Reviewer comment: L 88: change "has" to "have"

Our response: Thanks for the comment. That correction has been made according to your nice suggestion.

Reviewer comment: Salmonella in raw beef samples" as in the title. Please update the manuscript accordingly, by using always the same. By the way, are lymph nodes considered edible meat co-products in Pakistan? If yes, it should be mention somewhere.

Our response: Thanks for your nice suggestion. We have revised the manuscript once again to eliminate the use of the different terms for same concept. The lymph nodes especially the sub-mandibular ones are consumed by public in Pakistan.

Reviewer comment: L 95: "testing was also performed"

Our response: Thanks. We have made the changes accordingly.

Reviewer comment: L 239-241: Change "The study was based on 150 samples of raw beef sold at butcher shops and at supermarkets of Karachi city, Pakistan. The meat samples separately comprised of muscles, lymph nodes, and minced meat. Meat samples from … “for "The study was carried out on samples of raw beef sold at butcher shops and at supermarkets of Karachi city, Pakistan. Raw beef from muscles…"

Our response: Thanks for the useful suggestion. The replacement has been made accordingly.

Reviewer comment: L 274-276: Authors mention that the above antimicrobials are commonly used for treatment people. I think it would be worthy to mention where these are used.

Our response: Thanks for the precious suggestion. The paragraph regarding the use of antimicrobials mentioned in the M&M section has been added to Introduction section to signify the relevance.

Reviewer comment: L 294: "three times to lyse"

Our response: Thanks. The change has been accordingly.

Reviewer comment: Table 1: What do asterisks (*) mean?

Our response: We have removed the asterisks

Reviewer comment: There is not Figure 1.

Our response: Thanks for the comment. We have made all corrections regarding figure numbering in the revised version of the manuscript.

Reviewer comment: L 118: "The data showed in Figure."

Our response: Thank you for the nice comment. The correction has been made to the sentence.

Reviewer comment: L 123: The number of the Table is missed

Our response: Thanks. We have removed the sentence.

Reviewer comment: Salmonella isolates exhibited a higher level." Higher than what? Please complete the sentence.

Our response:  Thanks for the comment. We removed the sentence. 

Reviewer comment: There are two Table 2 (L 111 and L 163)

Our response: Thanks for the critical review. We have corrected all errors regarding table numbers through the manuscript.

Reviewer comment: L 147: "of Clinical"       

Our response: Thanks. The error has been rectified immediately.

Reviewer comment: L 167-169: Please check the English language

Our response: Thank you for  nice suggestion. We have excluded grammatical errors and repetitions in the two sentences and added few extra lines about differences in morphological and cultural characteristics of Salmonella serovars

Reviewer comment: Is there any other hypothesis than refrigeration that could explain why there were not Salmonella in supermarkets? Was the origin of meat (slaughterhouse or farm) different? Could the authors add some more information, if available?

Our response: Thanks for the really nice comment and suggestion. Because there is lack of proper inspection and monitoring systems for the elimination of foodborne pathogens like Salmonella in our province, we assume that zero prevalence of Salmonella in supermarket’s beef could be due to the hygienic practices they have adopted. The salesmen wear clean disposable gloves every time they cut beef. Moreover, the transport vehicles are usually observed to be very clean as compared to the one used in slaughterhouses for transportation of beef and other meats to retail butcher shops. Majority supermarkets have the washing facilities which might have significantly reduced/eliminated the bacterial load including Salmonella.

Reviewer comment:L 180- 182: Remove the sentences about the complications.

Our response: Thanks. We have removed the sentences.

Reviewer comment: L 182 – 184: "Food of animal origin such as beef meat is deemed to be the a vehicle of transmission of Salmonella to humans [3], [43]" instead of "Food of animal origin such as meat (beef, poultry, pork etc.), milk, eggs, and vegetables is deemed to be the main vehicle of transmission of Salmonella to humans [3], [43]".

Our response: Thank you for helpful suggestion. The correction has been made accordingly

Reviewer comment: L 185: What does it mean "wet"? Please clarify

Our response: The research papers (we have cited in that part of the discussion section) have used the term “wet” to describe retail meats markets. 

Reviewer comment:L 185-186: Also add this to the introduction that sentence (see my comment above)

Our response: We are really pleased. It has been added to the introduction section.  

Reviewer comment: L 187: "other research"

 

Our response:  Thanks. We separated the words.

Reviewer comment: L 189: "indicated"

Our response: Thanks. Corrected

Reviewer comment: L 215-223: Move the discussion about the prevalence to the paragraph before resistance (L 209).

Our response: Thanks for the nice suggestion. Changes have been made accordingly

References

Guerin, M. T., Martin, S. W., Darlington, G. A., & Rajic, A. (2005). A temporal study of Salmonella serovars in animals in Alberta between 1990 and 2001. Canadian Journal of Veterinary Research, 69(2), 88. Gutema, F. D., Agga, G. E., Abdi, R. D., Duchateau, L., DeZutter, L., & Gabriël, S. (2019). Prevalence and Serotype Diversity of Salmonella in apparently healthy Cattle: Systematic Review and Meta-Analysis of Published Studies, 2000-2017. Frontiers in veterinary science, 6, 102.

Author Response File: Author Response.docx