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Antibacterial activity and lantibiotic post-translational modification genes in Streptococcus spp. isolated from ruminal fluid

Sabino, Yasmin Neves Vieira, Fochat, Romário Costa, Lima, Junior Cesar Fernandes, Ribeiro, Marlice Teixeira, Arcuri, Pedro Braga, da Costa Carneiro, Jailton, Machado, Marco Antônio, de Lima Reis, Daniele Ribeiro, Ferreira Machado, Alessandra Barbosa, Húngaro, Humberto Moreira, Ribeiro, João Batista, Paiva, Aline Dias
Annals of microbiology 2019 v.69 no.2 pp. 131-138
Streptococcus equinus, Streptococcus gallolyticus, Streptococcus lutetiensis, antibacterial properties, antibiotics, antimicrobial peptides, bacteriocins, ecosystems, genes, peptidase K, polymerase chain reaction, post-translational modification, pulsed-field gel electrophoresis, ribosomal RNA, rumen bacteria, rumen fluids
The production of bacteriocins is frequently described in high microbial diversity environments. The aims of this study were to screen Streptococcus spp. isolated from rumen for their antibacterial potential and to determine the presence of post-translational modification genes for lantibiotic class of bacteriocins. The isolates were tested for production of antibacterial compounds by the spot-on-lawn assay. Presence of interfering factors and the sensitivity to proteinase K were evaluated. The ruminal bacteria were identified by 16S rRNA gene sequencing and the subspecific discrimination of the isolates belonging to the same specie was performed by PFGE. The presence of lantibiotic post-translational modification genes (lanB, lanC, and lanM) into bacterial genomes was performed by PCR. The bacteriocin-like inhibitory substances showed broad inhibitory activity and the producer cells were identified as S. equinus, S. lutetiensis, and S. gallolyticus. According to PFGE, the isolates identified as S. equinus belong to different strains. Three ruminal isolates showed at least one of the lantibiotic post-translational modification genes, and lanC was more frequently detected (75%). The production of broad-spectrum bacteriocin-like inhibitory substances by rumen strains suggests that antimicrobial peptides may play an important role in competition in the complex ruminal ecosystem.