Virulence gene profiles: alpha-hemolysin and clonal diversity in  Staphylococcus aureus  isolates from bovine clinical mastitis in China

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

Abstract

Background

Staphylococcus aureus, a common cause of bovine mastitis, is known for its ability to acquire to antimicrobial resistance and to secrete numerous virulence factors that can exacerbate inflammation. In addition, alpha-hemolysin has an important role in S. aureus infections, diversity of the hla gene (that produces alpha-hmolysin) in S. aureus isolated from bovine mastitis has not been well characterized. The objective was, therefore, to determine diversity of virulence genes, hla gene sequences, and clonal profiles of S. aureus from bovine mastitis in Chinese dairy herds, and to evaluate inter-relationships.

Results

The antimicrobials resistance varies from as low as 1.9% (2/103) for CTX to as high as 76.7% (79/103) for penicilin in the 103 isolates and 46 (44.7%) S. aureus were determined as multi-resistant isolates with diverse resistance patterns. Thirty-eight virulence gene patterns (with variable frequencies) were identified in the 103 isolates and correlated with MLST types, indicating a great diversity. Although the hla gene also had great diversity (14 genotypes), Hla peptides were relatively more conserved. With 7 clonal complexes identified from 24 spa types and 7 MLST types. Regarding the letter, ST 97 was the dominant type in S. aureus from bovine mastitis in China. Furthermore, based on phylogenetic analysis, there was a distinct evolutionary relationship between the hla gene and MLST.

Conclusion

Multi-resistant S. aureus occurred in bovine mastitis with diverse resistance patterns. The diversity of virulence gene profiles, especially the hla gene and, their relationship with molecular types were reported for the first time in S. aureus from bovine mastitis, which will be useful for future studies on immunogenicity and vaccine development. In addition, based on the distinct evolutionary relationship between the hla gene and MLST types, we inferred that the hla gene has potential role for molecular typing of S. aureus.

Electronic supplementary material

The online version of this article (10.1186/s12917-018-1374-7) contains supplementary material, which is available to authorized users.

Related collections

Most cited references 36

Record: found
Abstract: found
Article: not found

Targeting virulence: can we make evolution-proof drugs?

Richard Allen, Roman Popat, Stephen P. Diggle … (2014)

Antivirulence drugs are a new type of therapeutic drug that target virulence factors, potentially revitalising the drug-development pipeline with new targets. As antivirulence drugs disarm the pathogen, rather than kill or halt pathogen growth, it has been hypothesized that they will generate much weaker selection for resistance than traditional antibiotics. However, recent studies have shown that mechanisms of resistance to antivirulence drugs exist, seemingly damaging the 'evolution-proof' claim. In this Opinion article, we highlight a crucial distinction between whether resistance can emerge and whether it will spread to a high frequency under drug selection. We argue that selection for resistance can be reduced, or even reversed, using appropriate combinations of target and treatment environment, opening a path towards the development of evolutionarily robust novel therapeutics.

0 comments Cited 193 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Incidence of clinical mastitis and distribution of pathogens on large Chinese dairy farms.

Jian Gao, Herman Barkema, Limei Zhang … (2017)

Knowledge of the incidence of clinical mastitis (CM) and the distribution of pathogens involved is essential for development of prevention and control programs as well as treatment protocols. No country-wide study on the incidence of CM and the distribution of pathogens involved has been conducted in China. Core objectives of this study were, therefore, to determine the cumulative incidence of CM and the distribution of pathogens causing CM on large Chinese (>500 cows) dairy farms. In addition, associations between the distribution of CM pathogens and bedding materials and seasonal factors were also investigated. Bacterial culture was done on a total of 3,288 CM quarter milk samples from 161 dairy herds (located in 21 provinces) between March 2014 and September 2016. Additional data, including geographical region of herds, herd size, bedding types, and number of CM cases during the last month, were also recorded. Mean cumulative incidence of CM was 3.3 cases per 100 cows per month (range = 1.7 to 8.1). The most frequently isolated pathogens were Escherichia coli (14.4%), Klebsiella spp. (13.0%), coagulase-negative staphylococci (11.3%), Streptococcus dysgalactiae (10.5%), and Staphylococcus aureus (10.2%). Streptococcus agalactiae was isolated from 2.8% of CM samples, whereas Streptococcus uberis were isolated from 2.1% of samples, and 15.8% of 3,288 samples were culture-negative. Coagulase-negative staphylococci, E. coli, and other Enterobacter spp. were more frequently isolated in the northwest than the northeast or south of China. Streptococcus dysgalactiae, other streptococci, and Strep. agalactiae were more frequently isolated in winter (October-March), whereas E. coli and Klebsiella spp. were mostly isolated in summer (April-September). Streptococcus dysgalactiae was more often isolated from CM cases of herds using sand bedding, whereas Klebsiella spp. and other streptococci were more common in herds using organic bedding. The incidence of CM and distribution of pathogens differed among herds and better mastitis management is needed. Furthermore, geography, bedding materials, and season should be included when designing mastitis control and prevention schemes for Chinese dairies.

0 comments Cited 77 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Autophagy mediates tolerance to Staphylococcus aureus alpha-toxin.

Katie Maurer, Tamara Reyes-Robles, Francis Alonzo … (2015)

Resistance and tolerance are two defense strategies employed by the host against microbial threats. Autophagy-mediated degradation of bacteria has been extensively described as a major resistance mechanism. Here we find that the dominant function of autophagy proteins during infections with the epidemic community-associated methicillin-resistant Staphylococcus aureus USA300 is to mediate tolerance rather than resistance. Atg16L1 hypomorphic mice (Atg16L1(HM)), which have reduced autophagy, were highly susceptible to lethality in both sepsis and pneumonia models of USA300 infection. Autophagy confers protection by limiting the damage caused by α-toxin, particularly to endothelial cells. Remarkably, Atg16L1(HM) mice display enhanced survival rather than susceptibility upon infection with α-toxin-deficient S. aureus. These results identify an essential role for autophagy in tolerance to Staphylococcal disease and highlight how a single virulence factor encoded by a pathogen can determine whether a given host factor promotes tolerance or resistance.

0 comments Cited 69 times – based on 0 reviews      Review now

Bookmark

All references

Author and article information

Contributors

Limei Zhang: 20073175@163.com

Jian Gao: gaojian2016@cau.edu.cn

Herman W. Barkema: barkema@ucalgary.ca

Tariq Ali: tariq_ali@cau.edu.cn

Gang Liu: liugang_0402@126.com

Youtian Deng: idyt@outlook.com

Sohail Naushad: sohail.naushad@ucalgary.ca

John P. Kastelic: j.kastelic@ucalgary.ca

Bo Han:

ORCID: http://orcid.org/0000-0002-4798-7725

86-10-62733801 , hanbo@cau.edu.cn

Journal

Journal ID (nlm-ta): BMC Vet Res

Journal ID (iso-abbrev): BMC Vet. Res

Title: BMC Veterinary Research

Publisher: BioMed Central (London )

ISSN (Electronic): 1746-6148

Publication date (Electronic): 2 March 2018

Publication date PMC-release: 2 March 2018

Publication date Collection: 2018

Volume: 14

Electronic Location Identifier: 63

Affiliations

[1 ]ISNI 0000 0004 0530 8290, GRID grid.22935.3f, College of Veterinary Medicine, , China Agricultural University, ; Yuan Ming Yuan West Road No. 2, Haidian District, Beijing, 100193 People’s Republic of China

[2 ]ISNI 0000 0004 1936 7697, GRID grid.22072.35, Department of Production Animal Health, Faculty of Veterinary Medicine, , University of Calgary, ; Calgary, AB T2N 4N1 Canada

Author information

Bo Han http://orcid.org/0000-0002-4798-7725

Article

Publisher ID: 1374

DOI: 10.1186/s12917-018-1374-7

PMC ID: 5834907

PubMed ID: 29499697

SO-VID: 519b71c4-5b55-4e1d-9b40-7ffcf4f3c907

License:

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License ( http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

History

Date received : 18 November 2017

Date accepted : 14 February 2018

Funding

Funded by: FundRef http://dx.doi.org/10.13039/501100001809, National Natural Science Foundation of China;

Award ID: 31572587

Award ID: 31550110200

Award ID: 31772813

Award Recipient : Bo Han

Funded by: High-end Foreign Experts Recruitment Program

Award ID: GDT20171100013

Award Recipient : Bo Han

Funded by: Chinese thirteen “Five-year” National Key R&D Project

Award ID: 2016YFD0501203

Award Recipient : Bo Han

Custom metadata

ScienceOpen disciplines: Veterinary medicine

Keywords: staphylococcus aureus,virulence gene,hla,mlst,spa, bovine mastitis

Data availability:

ScienceOpen disciplines: Veterinary medicine

Keywords: staphylococcus aureus, virulence gene, hla, mlst, spa, bovine mastitis

Virulence gene profiles: alpha-hemolysin and clonal diversity in Staphylococcus aureus isolates from bovine clinical mastitis in China

Read this article at

Abstract

Background

Results

Conclusion

Electronic supplementary material

Related collections

Horses and Humans Research Foundation

Most cited references 36

Targeting virulence: can we make evolution-proof drugs?

Incidence of clinical mastitis and distribution of pathogens on large Chinese dairy farms.

Autophagy mediates tolerance to Staphylococcus aureus alpha-toxin.

Author and article information

Contributors

Journal

Affiliations

Author information

Article

History

Funding

Categories

Custom metadata

Comments

Comment on this article

Similar content 176

Cited by 19

Most referenced authors 537