Isolation and characterization of a new plasmid pSpnP1 from a multidrug-resistant clone of Streptococcus pneumoniae.
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.
Romero
Patricia
P
Departamento de Microbiología Molecular, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain.
Llull
Daniel
D
García
Ernesto
E
Mitchell
Tim J
TJ
López
Rubens
R
Moscoso
Miriam
M
D000595:Amino Acid Sequence; D001483:Base Sequence; D002999:Clone Cells; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D008969:Molecular Sequence Data; D010957:Plasmids / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D013296:Streptococcus pneumoniae / Q000166:cytology / Q000235:genetics*