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Updated: Jul 19, 2026
Genotyping of Staphylococcus aureus by Ribosomal Spacer PCR (RS-PCR)
Published on: November 4, 2016
The smr gene resides on a novel plasmid pSP187 identified in a Staphylococcus pasteuri isolate recovered from
Jostein Bjorland1, Marit S Bratlie, Terje Steinum
1Department of Production Animal Clinical Sciences, Norwegian School of Veterinary Science, P.O. Box 8146 Dep, N-0033 Oslo, Norway. jostein.bjorland@veths.no
Unlabelled:
This work describes a novel plasmid pSP187 (5550 bp) carrying the small multidrug resistance determinant smr encoding resistance to quaternary ammonium compounds (QACs). pSP187 was identified in a Staphylococcus pasteuri isolate recovered from bulk milk in a dairy cattle herd in Norway. Sequence analysis revealed 6 putative ORFs in addition to the smr gene within a cassette with identical genetic organization to that found in the pSK41-like Staphylococcus aureus plasmid pTZ22. A protein homology search suggested the gene product of ORF7 to be a putative replication initiation protein, while ORF2 was predicted to encode a protein homologous to members of FtsK/SpoIIIE cell division-DNA segregation protein families. Sequence similarities to some initiator proteins of rolling circle replicons (RCR) indicated that pSP187 uses a RCR mode of replication, supported by the detection of intermediate ssDNA using S1 nuclease treatment and hybridization analysis. Interestingly, a 30-bp sequence found upstream from ORF7 showed high similarity to other dyad symmetry motifs proposed as putative double-strand origins of replication in the plasmids pGI3 (Bacillus thuringiensis), pSTK1 (Bacillus stearothermophilus), and pER1-2 (Streptococcus thermophilus).
In Conclusion:
The novel smr-containing plasmid pSP187 is the first member of RCR group VI to be identified in a Staphylococcus sp.
Insights
A novel plasmid, pSP187, carrying the small multidrug resistance (smr) gene was discovered in Staphylococcus pasteuri. This plasmid confers resistance to quaternary ammonium compounds (QACs) and utilizes rolling circle replication.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Quaternary ammonium compounds (QACs) are widely used disinfectants.
- Multidrug resistance in bacteria poses a significant public health threat.
- Plasmids are key vectors for the dissemination of antibiotic resistance genes.
Purpose of the Study:
- To characterize a novel plasmid, pSP187, identified in Staphylococcus pasteuri.
- To investigate the genetic organization and replication mechanism of pSP187.
- To determine the role of pSP187 in conferring resistance to QACs.
Main Methods:
- Plasmid DNA isolation and sequencing.
- Bioinformatic analysis of open reading frames (ORFs) and genetic elements.
- Replication mode determination using S1 nuclease treatment and hybridization analysis.
Main Results:
- A novel 5550 bp plasmid, pSP187, was identified in Staphylococcus pasteuri from dairy cattle.
- pSP187 carries the small multidrug resistance (smr) gene, conferring resistance to QACs.
- Sequence analysis revealed homology to pSK41-like plasmids and suggested a rolling circle replication (RCR) mechanism.
Conclusions:
- pSP187 represents the first identified member of RCR group VI in Staphylococcus species.
- The discovery of pSP187 provides insights into the evolution and spread of QAC resistance in staphylococci.
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