A closed genome of Streptococcus agalactiae ST347/II reveals a composite integrative element coupling nisin P biosynthesis to erm(B) and tet(O) in Dominican group B Streptococcus
Clindamycin is the alternative for intrapartum prophylaxis against group B Streptococcus in penicillin-allergic women, and whether it works depends on which lineages carry the resistance and on the mobile element that moves it. No Dominican group B Streptococcus genome has been closed. A Streptococcus agalactiae isolate from residual diagnostic material was sequenced twice on Oxford Nanopore,…
A comprehensive genome analysis of Streptococcus agalactiae ST347/II uncovers a unique combination of antibiotic resistance genes coupled with a nisin P biosynthesis element. This Dominican strain, serotype II, carries the erm(B) and tet(O) genes, which confer resistance to clindamycin, along with the mef(J) and msr(I) genes. The sequencing of this bacterium's circular chromosome, totaling 2,066,859 base pairs, revealed two integrative conjugative elements.
One element, approximately 34 kilobases in length, is related to Tn5252 and carries the erm(B) and tet(O) genes. The other element, roughly 35 kilobases long, sits near a tRNA-Lys gene and encompasses the mef(J) and msr(I) genes. A fascinating eleven-gene class I lanthipeptide cluster was found adjacent to the first conjugative element, with both components located on the same strand and without any distinguishing features between them.
The nisin P precursor gene is encoded within this cluster, spanning 96 base pairs. Intriguingly, this operon was detected in 12 out of the 83 analyzed genomes, while the resistance genes were present in 12 of 12 and 3 of 71 samples, respectively. Notably, the ST1 and ST1010/IV genotypes do not possess either the operon or the nisin P resistance protein.
This research highlights the distinct association between clindamycin resistance and a lantibiotic-encoding element in the ST347/II strain, offering valuable insights into the potential susceptibility of the Dominican lineage and the possibility of further investigation through deferred antagonism.
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