BIOINFORMATIC SEARCH OF NOVEL BACTERIOPHAGE LYSINS: POTENTIAL TREATMENT TO FIGHT ANTIMICROBIAL RESISTANCE IN Streptococcus agalactiae

KOVACEC V; DI GREGORIO S; POKLEPOVICH T; CAMPOS J; MOLLERACH M; BONOFIGLIO L

Buenos Aires

Congreso; V International Congress on Translational Medicine; 2021

Universidad de Buenos Aires

Streptococcus agalactiae (GBS) causes severe infections in neonates, pregnant women and adults with comorbidities. The increase in antimicrobial resistance (AMR) is a concern. The absence of a vaccine leads efforts towards the development of new alternatives, such as the employment of phage lysins for the control of these infections. We aimed to detect prophages in the genomes of 10 representative Argentinean GBS strains recovered from a National Multicentre Study, characterize their lysins and select the novel lysins for future cloning, purification and testing of their activity against GBS.Total genomic DNA was extracted using a commercial kit and whole genome sequencing was performed using Illumina MiSeq v2 platform. The quality of the reads was controlled with FastQC and Kraken. De novo assemblies were obtained with SPAdes and quality checked with Quast. Genomes were annotated with RAST. The detection of prophages was performed with PhiSpy and manual inspection. Lysin sequences were analyzed with ExPASy and NCBI tools. The lysins amino acid sequences, including those from 50 publicly available GBS prophages, were aligned with MAFFT and a Maximum Likelihood phylogenetic tree was constructed using IQTree and 100 bootstrap replicates. Thirteen prophages were found in 9/10 GBS genomes. Putative lysins were found in all prophages (n=15), ranging from 16-53kDa. They were classified, according to their cleavage site, into three of the four major endolysin classes. Bifunctional lysins were found. Our lysins were present in the five phylogenetic clusters identified, 9/15 having 90-100% identity with already characterized GBS lysins, 6/15 being novel GBS endolysins. Three of these novel lysins were classified as N-acetylmuramoil-L-alanine-amidases, two as N-acetyl-ß-D-glucosaminidases and one as both N-acetylmuramoil-L-alanine-amidase and N-acetyl-ß-D-glucosaminidase, as two catalytic domains with different cleavage sites were found.The novel lysins will be cloned, purified and their lytic activity will be studied against our GBS collection. The variety of endolysin classes found in our prophages is encouraging as these lysins could potentially be used against the diverse GBS strains circulating not only in Argentina but in other regions, regardless of their antimicrobial resistance profile.