Isolation and characterization of a new plasmid pSpnP1 from a multidrug-resistant clone of Streptococcus pneumoniae

Patricia Romero, Daniel Llull, Ernesto García, Tim J Mitchell, Rubens López, Miriam Moscoso

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


A novel Streptococcus pneumoniae plasmid (pSpnP1; 5413bp) has been isolated from the multidrug-resistant clone Poland(23F)-16, and its complete nucleotide sequence has been determined. Sequence analysis predicted seven co-directional open reading frames and comparative analyses revealed that plasmid pSpnP1 is different to pDP1, the only previously described pneumococcal plasmid, whereas it is highly similar to pSt08, a plasmid from Streptococcus thermophilus. A double-stranded origin for replication similar to the replication origin of the pC194/pUB110 family was located upstream of the putative rep gene (orf2). It also contained a 144-bp region with over 60% identity to the single-stranded origin type A of the Streptococcus agalactiae plasmid pMV158/pLS1. Detection of single-stranded DNA by Southern blot analysis indicated that pSpnP1 replicates via a rolling circle mechanism. Interestingly, the product of orf1 has a putative Zonular occludens toxin conserved domain present in toxigenic strains of Vibrio cholerae. Real-time PCR assays revealed that this ORF was expressed. Hybridization experiments showed that the pSpnP1 replicon was unusual among other examined antibiotic-resistant pneumococcal clones, although the recombinant plasmids based on pSpnP1 were able to replicate in Bacillus subtilis and Lactococcus lactis.
Original languageEnglish
Pages (from-to)51-60
Number of pages10
Issue number1
Publication statusPublished - Jul 2007


  • Amino Acid Sequence
  • Base Sequence
  • Clone Cells
  • Drug Resistance, Multiple, Bacterial
  • Molecular Sequence Data
  • Plasmids
  • Streptococcus pneumoniae


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