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Updated: Sep 7, 2025
Genotyping of Staphylococcus aureus by Ribosomal Spacer PCR RS-PCR
Published on: November 4, 2016
Tracking Infection and Genetic Divergence of Methicillin-Resistant Staphylococcus aureus at Pets, Pet Owners, and
Muhammad Shoaib1,2, Amjad Islam Aqib3, Muhammad Muddassir Ali4
1Key Laboratory of New Animal Drug Project, Gansu Province, Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture and Rural Affairs, Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS, Lanzhou, China.
Abstract:
Staphylococcus aureus (S. aureus) has become a leading animal and public health pathogen that keeps on transferring from one host to other, giving rise to newer strains by genetic shifts. The current study was designed to investigate the epidemiology and genetic relatedness of mecA gene in S. aureus isolated from pets, immediate individuals in contact with pets, and veterinary clinic environments. A total of n = 300 samples were collected from different veterinary hospitals in Pakistan using convenience sampling. The collected samples were subjected to microbiological and biochemical examination for the isolation of S. aureus. Methicillin resistance was investigated by both phenotypically using oxacillin disk diffusion assay and by genotypically targeting mecA gene by PCR. PCR amplicons were subjected for sequencing by Sanger method of sequencing, which were subsequently submitted to NCBI GenBank under the accession numbers MT874770, MT874771, and MT874772. Sequence evolutionary analysis and mecA gene characterization was done using various bioinformatics tools. Overall, 33.66% mecA genes harboring S. aureus strains were isolated from all sources (33.33% from pets, 46.0% from surrounding, and 28.0% from immediate contact individuals). The bioinformatics analysis noted that one SNP was identified at position c.253C>A (Transvertion). The phylogenetic tree (two clades) of S. aureus mecA revealed a possibility of inter-transmission of disease between the environment and pets. Frequency of adenine and thymine nucleotide in motifs were found to be the same (0.334). Cytosine and guanine frequency were also the same (0.166). Threonine was replaced by asparagine (p.T84D) in each sample of cat, environment, and human. On the other hand, protein structures ofcat-1 and cat-2 proteins were found identical while cat-3, environmental, and human proteins shared identical structures. The study thus concludes rising circulation of methicillin-resistant S. aureus (MRSA) strains in animal-human-environment interfaces, forecasting the development of novel strains withmodified range of resistance.
Insights
Methicillin-resistant Staphylococcus aureus (MRSA) is spreading among pets, people, and environments. Genetic analysis reveals potential transmission between pets and their surroundings, indicating evolving resistance patterns.
Area of Science:
- Microbiology and Molecular Epidemiology
- One Health Pathogen Surveillance
Background:
- Staphylococcus aureus (S. aureus) is a significant pathogen in both animals and humans, with increasing host-to-host transmission.
- Genetic shifts in S. aureus contribute to the emergence of novel strains with potentially altered resistance profiles.
Purpose of the Study:
- To investigate the epidemiology and genetic relatedness of the mecA gene in S. aureus.
- To analyze S. aureus isolates from pets, their close human contacts, and veterinary clinic environments.
Main Methods:
- Collection of 300 samples from veterinary hospitals in Pakistan.
- Isolation and identification of S. aureus using microbiological and biochemical methods.
- Detection of methicillin resistance phenotypically (oxacillin disk diffusion) and genotypically (mecA gene PCR).
- Sanger sequencing of PCR amplicons, submission to GenBank (Accession numbers: MT874770, MT874771, MT874772).
- Bioinformatic analysis including sequence evolution and mecA gene characterization.
Main Results:
- Overall isolation rate of mecA-positive S. aureus was 33.66% across all sample sources.
- Specific isolation rates: 33.33% from pets, 46.0% from environments, and 28.0% from immediate contacts.
- Bioinformatics identified one single nucleotide polymorphism (SNP) at c.253C>A (Transversion) in the mecA gene.
- Phylogenetic analysis suggested potential inter-transmission of S. aureus between environments and pets.
- Identified amino acid substitution p.T84D (Threonine to Asparagine) in protein structures across cat, environmental, and human isolates.
- Identical protein structures were observed between cat-1 and cat-2, and separately among cat-3, environmental, and human isolates.
Conclusions:
- The study highlights the increasing circulation of methicillin-resistant Staphylococcus aureus (MRSA) at the animal-human-environment interface.
- Findings suggest a significant risk of inter-species transmission and the potential for developing novel MRSA strains with expanded resistance.
