Biology subjects

Gawor, J.

Publications and source records attributed to Gawor, J..

4 recordsLinked to original sources

bioRxiv2025

Genome-Wide Identification of Essential Genes in the Invasive Streptococcus anginosus Strain

BackgroundStreptococcus anginosus, part of the Streptococcus anginosus group (SAG), is a human commensal increasingly recognized as an opportunistic pathogen responsible for abscesses formation and infections, also invasive ones. Despite its growing clinical importance, the genetic determinants of its pathogenicity remain poorly understood. ObjectivesThis study aimed to identify essential genes in S. anginosus 980/01, a bloodstream isolate, under optimal laboratory conditions using a transposon mutagenesis combined with Transposon-Directed Insertion Site Sequencing (TraDIS). MethodsA mutant library was generated using the ISS1 transposon delivered via the thermosensitive plasmid pGh9:ISS1. Following transposition, insertions were mapped using Illumina sequencing and analyzed. Essential genes were identified based on the absence of insertions and statistical filtering. ResultsThe library exhibited 98% genome saturation with over 130,000 unique insertion sites. Among 1,825 genes, 348 (19.1%) were essential, 1,446 non-essential, and 30 non-conclusive. Comparative analyses were performed with S. pyogenes MGAS5005 and S. agalactiae A909. Similarly to the latter, essential genes were enriched in functions related to translation, transcription, and cell wall biosynthesis. However, 40 genes uniquely essential to S. anginosus 980/01 were identified, suggesting unique survival strategies in S. anginosus. ConclusionsThis study presents the first genome-wide identification of essential genes for S. anginosus 980/01, highlighting conserved and unique essential genes. These findings provide a basis for understanding its pathogenic potential and for identifying novel antimicrobial targets.

microbiology↗

bioRxiv2024

A newly-identified IncY plasmid from multi-drug resistant Escherichia coli isolated from dairy cattle feces in Poland

Comprehensive whole-genome sequencing was performed on two multi-drug resistant Escherichia coli strains isolated from cattle manure from a typical dairy farm in Poland in 2020. The identified strains are resistant to beta-lactams, aminoglycosides, tetracyclines, trimethoprim/sulfamethoxazole, and fluoroquinolones. The complete sequences of the harbored plasmids revealed antibiotic-resistance genes (ARGs) located within many mobile genetic elements (e.g., insertional sequences or transposons), and genes facilitating conjugal transfer or promoting horizontal gene transfer. These plasmids are hitherto undescribed. Similar plasmids have been identified, but not in Poland. The identified plasmids carried resistance genes, including the tetracycline resistance gene tet(A), aph family aminoglycoside resistance genes aph(3")-lb and aph(6)-ld, {beta}-lactam resistance genes blaTEM-1, blaCTX-M-15, sulfonamide resistance gene sul2, fluoroquinolone resistance gene qnrS1, and the trimethoprim resistance gene dfrA14. The characterized resistance plasmids were categorized into the IncY incompatibility group, indicating a high possibility for dissemination among the Enterobacteriaceae. While similar plasmids (99% identity) have been found in environmental and clinical samples, none have been identified in farm animals. This findings are significant within the One Health framework, as they underline the potential for antimicrobial-resistant E. coli from livestock and food sources to be transmitted to humans and vice versa. It highlights the need for careful monitoring and strategies to limit the spread of antibiotic resistance in the One Health approach.

microbiology↗

bioRxiv2024

The IncC and IncX1 resistance plasmids present in multi-drug resistant Escherichia coli strains isolated from poultry manure in Poland

The study describes the whole-genome sequencing of two antibiotic-resistant representative Escherichia coli strains, isolated from poultry manure in 2020. The samples were obtained from a commercial chicken meat production facility in Poland. The antibiotic resistance profile was characterized by co-resistance to {beta}-lactam antibiotics, aminoglycosides, and fluoroquinolones. The three identified resistance plasmids (R-plasmids), pECmdr13.2, pECmdr13.3 and pECmdr14.1, harbored various genes conferring resistance to tetracyclines (tetR[A]) for, aminoglycoside (aph, aac and aad families), {beta}-lactam (blaCMY-2, blaTEM-176), sulfonamide (sul1, sul2), fluoroquinolone (qnrS1), and phenicol (floR). These plasmids, which have not been previously reported in Poland, were found to carry IS26 insertion elements, the intI1-integrase gene, as well as conjugal transfer genes, facilitating horizontal gene transfer. Plasmids pECmdr13.2 and pECmdr14.1 also possessed a mercury resistance gene operon related to transposon Tn1696; this promotes plasmid persistence even without antibiotic selection pressure due to co-selection mechanisms such as co-resistance. The chicken manure-derived plasmids belonged to the IncX1 (narrow host range) and IncC (broad host range) incompatibility groups. Similar plasmids have been identified in various environments, clinical isolates, and farm animals, including cattle, swine, and poultry. This study holds significant importance for the One Health approach, as it highlights the potential for antimicrobial-resistant bacteria from livestock and food sources, particularly E. coli, to transfer through the food chain to humans and vice versa. This underscores the need for vigilant monitoring of R-plasmids prevalence in the human, animal and natural environments, and to implement strategies to mitigate the spread of antibiotic resistance.

microbiology↗

bioRxiv2024

Insights from comparative plastid genomics of colorless facultative pathogens Prototheca (Chlorophyta): Unveiling membrane transport and organelle division as key functions

Plastids are usually involved in photosynthesis, but the secondary loss of this function is a widespread phenomenon in various lineages of algae and plants. In addition to the loss of genes associated with photosynthesis, the plastid genomes of colorless algae are frequently reduced further. To understand the pathways of reductive evolution associated with the loss of photosynthesis, it is necessary to study a number of closely related strains. Prototheca, a chlorophytean genus of facultative pathogens, provides an excellent opportunity to study this process with its well-sampled array of diverse colorless strains. We have sequenced the plastid genomes of 13 Prototheca strains and reconstructed a comprehensive phylogeny that reveals evolutionary patterns within the genus and among its closest relatives. Our robust phylogenomic analysis revealed three independent losses of photosynthesis among the Prototheca strains and considerable coding content variability in their ptDNA. Despite this diversity, all Prototheca strains retain the same key plastid functions. These include processes related to gene expression, as well as crucial roles in fatty acid and cysteine biosynthesis, membrane transport, and organelle division. While the retention of vestigial genomes in colorless plastids is typically associated with the biosynthesis of secondary metabolites, the remarkable conservation of plastid membrane transport and organellar division systems in the nonphotosynthetic genera Prototheca and Helicosporidium provides an additional constraint against the loss of ptDNA in this lineage. Furthermore, these genes can potentially serve as targets for therapeutic intervention, indicating their importance beyond the evolutionary context.

evolutionary biology↗