Temporal Trends in Antimicrobial Resistance of Klebsiella pneumoniae in Clinically Affected Canine and Feline Populations in Germany: A 2019–2021 Analysis

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Comments for author File: Comments.pdf

Author Response

Response to the reviewer 1

This manuscript describes the prevalence of antimicrobial resistance among Klebsiella pneumoniae isolated from dogs and cats in Germany. The authors analysed the prevalence of resistant K. pneumoniae in many samples collected between 2019 and 2021, which enabled the determination of antimicrobial resistance using MIC values. Although these studies belong to the passive surveillance of AMR, they are valuable because they provide essential data. The advantage of passive monitoring is the low cost; although the disadvantages of such data are worth mentioning, the information gained is likely to need to be completed. As the authors noted in the manuscript, they did not have access to data on the previous use of antibiotics in patients, which could have influenced the obtained results.

Thank you very much for taking the time reviewing our manuscript!

Comment: The authors used simple research methods without molecular biology elements, although a valuable aspect of the manuscript is the large number of samples examined. However, I have a few comments about the manuscript. The authors use imprecise terms or "colloquial" language, e.g.: in line 18 "cats exhibited ... resistance...". Instead, Kp isolates obtained from cats exhibited resistance or analogously. Thus, I suggest a major revision before acceptance for publication. The manuscript requires extensive corrections on the issues mentioned in the review.

Response: Thank you for your advice! We have reviewed the manuscript and made the necessary changes. We hope this is to your satisfaction.

 

General comments

Comment: First of all, I am confident about the title. It is worth mentioning in the title whether the isolates tested were obtained from sick or healthy animals.

Response: Thank you for your valuable comment. We changed the title and abstract accordingly to your suggestion.

Comment: Please add a short introduction about the pathogenicity of Kp for dogs and cats.

Response: Thank you for your advice. We have added two new paragraphs to the introduction. One on pathogenicity in companion animals and one on pathogenicity in humans.

Comment: What methods of Kp isolation from humans were used in the results presented in the manuscript? Were they the same as animals?

Response: Thank you. The resistance data from the ARS database come from many different participating laboratories. We have included a paragraph on the comparability of the data sets in the discussion. 

Comment: Please unify the research aims presented in the abstract and the introduction because they differ slightly.

Response: Thank you very much! We took a close look at the objectives in the abstract and in the introduction and harmonized them as suggested.

Comment: The Kp isolation procedure described in the materials and methods also raises some doubts. Specifically, I am referring to the enrichment procedure. The presented results need to provide clear information on whether the results of direct culture on solid media and the enrichment procedure were the same. It can be assumed that these results were different. When using the enrichment procedure, there is a high probability of isolating single Kp cells with asymptomatic colonization. No information is provided on whether Kp was isolated in pure culture or whether these were mixed infections. Therefore, such results distort the picture of Kp prevalence in dogs and cats. This is an essential element of the study since the aim was to assess the prevalence of Kp.

Response: We have included in the materials and methods section how many K. pneumoniae required enrichment culture before they could be isolated. We also added how many K. pneumoniae were pure cultures and how many were from mixed cultures. We hope this clears up the questions.

Comment: The results presented in the manuscript's text and Table 1 need to be more accurate. The text gives results (and %) for all samples tested. The results presented in Table 1 refer only to Kp. I understand the authors' intention, but it may be worth noting this in the text and changing the Table 1 title because the current title, "frequency and percentages..." is misleading. In addition, please include a comment regarding the enrichment procedure for Kp isolation, which may affect the results.

Response: Thank you for pointing this out. We have added a note in the text that Table 1 is about K. pneumoniae isolates with evaluable MIC. We also changed the title of the table. See comment above regarding enrichment procedure.

Comment: Please include the number of isolates obtained from cats and dogs each year in Figure 1. Similarly in Figure 2.

Response: Thank you for your comment. We changed both figures accordingly.

Detailed comments:

Comment: Lines 25, 132, 138, 140, 142-148, 172, 184, 186, 194, 217: "colloquial" language, see above comment. Cats, dogs and samples cannot be resistant to antibiotics. Please check the entire manuscript carefully, especially the results and discussion sections; I may need to include some lines.

Response: We reviewed the manuscript and made the corresponding changes. See comment above.

Comment: Lines 184-193: The explanation for this may be more complex, e.g. why the authors do not take into account the specificity of the Covid-19 pandemic period when isolation limited access to tests and visits to veterinary clinics.

Response: Many thanks for the hint. We have tried to incorporate the influence of the Covid pandemic. In our opinion, there are factors during the pandemic that favor a reduction in resistance rates, but also others that could possibly increase resistance rates in K. pneumoniae isolates.

Comment: Lines 216-221: Duplication of the results described earlier in the text.

Response: Thank you! We have tried to change the paragraph and connect it better with the cited literature. We hope this meets your expectations.

Comment: Lines 282-288: The conclusion described here is too general; instead, it justifies the research undertaken. Please correct this fragment.

Response: We have adapted the Conclusions to incorporate the research aims once again. On the one hand, to document the prevalence of resistance rates in K. pneumoniae, but also to examine the usability of passive monitoring as a supplement to active monitoring. These points have been included in the conclusion.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Comparison of the author's findings with third-generation cephalosporin resistant humans-Isolation strains in the Antimicrobial Resistance Surveillance Database (ARS), the resistance rate is relatively low (7.7%). This study presents the most comprehensive three-year comprehensive dataset of Klebsiella pneumoniae drug resistance in companion animals in Germany. The research results can strengthen the national drug resistance monitoring work and benefit the health management of all mankind.

(1) I think some of the latest references should be cited.

(2) Frequency and percentage of Klebsiella pneumoniae isolates in dogs and cats (2019-2021), including organ specific isolates. Why only choose dogs and cats to study this data?

(3) Antimicrobial susceptibility patterns of 1185 isolates of Klebsiella pneumoniae in dogs and cats. Is there the most obvious discovery? Select a strain of bacteria with the strongest drug resistance for detailed analysis, which is particularly significant

Author Response

Response to the reviewer 2

Comparison of the author's findings with third-generation cephalosporin resistant humans-Isolation strains in the Antimicrobial Resistance Surveillance Database (ARS), the resistance rate is relatively low (7.7%). This study presents the most comprehensive three-year comprehensive dataset of Klebsiella pneumoniae drug resistance in companion animals in Germany. The research results can strengthen the national drug resistance monitoring work and benefit the health management of all mankind.

Thank you very much for taking the time and reviewing our paper!

Comment:  I think some of the latest references should be cited.

Response: Thank you very much for your comment! We have included 3 rather new publications in our manuscript. Two of them on the pathogenicity of K. pneumoniae in companion animals [1] and humans [2] and one on the influence of the Covid-19 pandemic on the development of resistance in our data [3].

Comment:  Frequency and percentage of Klebsiella pneumoniae isolates in dogs and cats (2019-2021), including organ specific isolates. Why only choose dogs and cats to study this data?

Response: Thanks for the advice. Since we obtained the retrospective data from our study in the sense of passive monitoring from a commercial veterinary diagnostic laboratory, we were limited in that we could not obtain resistance data from several species. This manuscript can be seen as the second part of our work on third generation cephalosporin resistant (3GCR) Enterobacterales in companion animals. The first part focuses on 3GCR E.coli and is accepted but not yet published.

Comment: Antimicrobial susceptibility patterns of 1185 isolates of Klebsiella pneumoniae in dogs and cats. Is there the most obvious discovery? Select a strain of bacteria with the strongest drug resistance for detailed analysis, which is particularly significant

Response: Unfortunately, we were also limited in this respect, as the data were retrospective and we had no opportunity to carry out a detailed genotypic analysis subsequently. We are aware of this constraint and have formulated this in our limitations.

References

1. Ribeiro, M.G.; Morais, A.B.C. de; Alves, A.C.; Bolaños, C.A.D.; Paula, C.L. de; Portilho, F.V.R.; Nardi Júnior, G. de; Lara, G.H.B.; Souza Araújo Martins, L. de; Moraes, L.S.; et al. Klebsiella-induced infections in domestic species: a case-series study in 697 animals (1997-2019). Braz. J. Microbiol. 2022, 53, 455–464, doi:10.1007/s42770-021-00667-0.
2. Choby, J.E.; Howard-Anderson, J.; Weiss, D.S. Hypervirulent Klebsiella pneumoniae - clinical and molecular perspectives. J. Intern. Med. 2020, 287, 283–300, doi:10.1111/joim.13007.
3. Schlemmer, A. All Creatures Great and Small: The Impact of the Covid-19 Pandemic on Veterinary Medicine. Available online: https://cedar.wwu.edu/wwu_honors/580.

 

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have satisfactorily addressed all my concerns except the comment concerning the isolation procedure and the reporting of the results.
This issue applies to the presentation of results considering Kp isolation in pure culture compared with mixed  cultures, also providing details of other isolated bacteria species. In  addition, please provide the results of Kp isolation using the  enrichment procedure and whether, in these cases, other bacteria were  isolated in direct culture on agar media. As I mentioned in the previous review, it is possible that the authors isolated single Kp cells  responsible only for the carrier state during infection with other  bacteria using the enrichment procedure. Therefore, they cannot be  recognized as an etiological factor of infections.

Author Response

Comment: The authors have satisfactorily addressed all my concerns except the comment concerning the isolation procedure and the reporting of the results.
This issue applies to the presentation of results considering Kp isolation in pure culture compared with mixed  cultures, also providing details of other isolated bacteria species. In  addition, please provide the results of Kp isolation using the  enrichment procedure and whether, in these cases, other bacteria were  isolated in direct culture on agar media. As I mentioned in the previous review, it is possible that the authors isolated single Kp cells  responsible only for the carrier state during infection with other  bacteria using the enrichment procedure. Therefore, they cannot be  recognized as an etiological factor of infections.

Response: Thank you very much for your valuable comment! We have added the bacterial pathogens found in addition to K. pneumoniae to the results. We have reported this once for the mixed cultures and once for the samples from which K. pneumoniae could be isolated after enrichment. We have also added to the limitations that it remains unclear which pathogen in a sample is ultimately the cause of the disease. We hope this meets your expectations and that the paper has been revised to your satisfaction.