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Identification of two major direct repeat unit clusters, 8i and 11ce, among methicillin resistant Staphylococcus aureus strains: the emergence of novel dru types and repeats

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Abstract

Background

The changing epidemiology and decreasing susceptibility to first-line antibiotics, such as vancomycin and linezolid, leave clinicians with few therapeutic options for MRSA infections. This study aimed to conduct an epidemiology study and characterize MRSA isolates.

Methods

A total of 150 MRSA isolates were collected from clinical specimens. Antimicrobial susceptibility was determined using the disk diffusion method. Resistance and major virulence genes were screened using the polymerase chain reaction. The SCCmec and dru typing were used to conduct molecular epidemiology. The BioNumerics tandem-repeat sequence typing plug-in tool was utilized for dru type cluster analysis. We constructed a minimum spanning tree using the similarity matrix of the DSI model.

Results

We discovered 24 dru types among the 55 dru sequenced MRSA isolates. Additionally, eight new dru types were discovered and added to the dru typing database. Two dru clusters (8i, 11ce) and nine single dru types were identified in 55 dru sequenced MRSA isolates. The two dru clusters, 8i and 11ce, accounted for 46 MRSA isolates (83.63%). The most common one of the nine singles dru types in this study was dt9bd, which belonged to the SCCmec types of IX.

Conclusions

Given that two clusters account for the majority of strains in our study, we can conclude that the genetic origin of these strains is the same. Therefore, the spread of these strains can be prevented with effective MRSA monitoring in hospitals and communities.

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Data availability

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Abbreviations

Dru :

Direct repeat unit

S. aureus :

Staphylococcus aureus

MRSA:

Methicillin-resistant S. aureus

MSSA :

Methicillin-sensitive S. aureus

SCCmec :

Staphylococcal chromosome cassette mec

CA-MRSA:

Community-acquired MRSA

nuc :

Thermostable nuclease

CLSI:

Clinical and laboratory standards institute

BHI:

Brain heart infusion broth

MDR:

Multidrug-resistance

MST:

Minimum spanning tree

MAR:

Multiple antibiotic-resistant

ERY:

Erythromycin

CD:

Clindamycin

SXT:

Trimethoprim/sulfamethoxazole

GM:

Gentamicin

TE:

Tetracycline

RA:

Rifampin

hla :

Hemolysin A

tst :

Toxic shock syndrome toxin

pvl :

Panton–Valentine leucocidin

sea, seb, and sec :

Staphylococcal enterotoxin a, b, and c

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Acknowledgements

The authors would like to express their gratitude to the Department of Microbiology and the Al-Zahra Laboratory at Isfahan University of Medical Sciences.

Funding

This study was funded by Shahed University of Medical Science’s Vice Chancellor for Research.

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Authors and Affiliations

  1. Department of Medical Microbiology, Faculty of Medicine, Shahed University of Medical Sciences, Tehran, Iran

    Mohammad Latifpour & Mohammad Niakan

  2. Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, NE, USA

    Richard V. Goering

  3. Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran

    Seyed Asghar Havaei, Tahmineh Narimani, Mohammad Sadegh Damavandi & Amin Sadeghi

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  1. Mohammad Latifpour
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  2. Richard V. Goering
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  4. Tahmineh Narimani
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  5. Mohammad Sadegh Damavandi
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Contributions

ML designed and performed the experiments with support from TN, AS, RVG, analyzed the results of dru sequencing and added new dru types to database. MSD, analyzed the results and wrote the manuscript with support from SAH, RVG, MN, supervised the project. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Mohammad Niakan.

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Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

This study has the formal approval of the Research Ethics Committee of Shahed University of Medical Sciences, Tehran, Iran (Approval No: IR.SHAHED.REC.1398.089).

Consent to participate

All experiments and methods were performed in accordance with relevant guidelines and regulations. All phases of the study have received ethics approval from the Shahed University of Medical Sciences, Tehran, Iran (Approval No: IR.SHAHED.REC.1398.089), and the informed consent was obtained from each participant included in the study. Also, informed consent was obtained from the parents or legal guardians of participants under 18 years of age.

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Latifpour, M., Goering, R.V., Havaei, S.A. et al. Identification of two major direct repeat unit clusters, 8i and 11ce, among methicillin resistant Staphylococcus aureus strains: the emergence of novel dru types and repeats. Mol Biol Rep 49, 8229–8239 (2022). https://doi.org/10.1007/s11033-022-07484-0

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  • DOI: https://doi.org/10.1007/s11033-022-07484-0

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