Project description:Alterations in genes for penicillin-binding proteins (pbp) are well-known determinants for the resistance of Streptococcus pneumoniae to B-lactam antibiotics. Surprisingly, some mutations in non-pbp genes were also found to contribute to B-lactam resistance. Two of them discovered in the piperacillin resistant mutants P106 and P104, affect the expression of cpoA (encoding a glycosyltransferase) and of the rgtABCDHR cluster (encoding two small membrane proteins, an ABC transporter and a regulatory two-component system), respectively. cpoA and rgtABCDHR are involved in maintaining the synthesis and the proper ratio of the two major membrane glycolipids, and deletions in these genes led to complex phenotypes. In attempts to identify genetic determinants for these phenotypes, the global trancription patterns of the deletion mutants R6 delta cpoA, R6 delta rgtA and R6 delta rgtD were compared to that of the parent strain R6.
Project description:<p><em>Streptococcus pneumoniae</em> is the primary cause of community-acquired bacterial pneumonia with rates of penicillin and multi-drug resistance exceeding 80% and 40%, respectively. The innate immune response generates a variety of antimicrobial agents to control infection including zinc stress. Here, we characterized the impact of zinc intoxication on <em>S. pneumoniae</em>, revealing disruptions in central carbon metabolism, lipid biogenesis and peptidoglycan biosynthesis. Characterization of the pivotal peptidoglycan biosynthetic enzyme GlmU revealed an exquisite sensitivity to zinc inhibition. Disruption of the sole zinc efflux pathway, czcD, rendered <em>S. pneumonia</em>e highly susceptible to β-lactam antibiotics. To dysregulate zinc homeostasis in the wild-type strain, we investigated the safe-for-human use ionophore PBT2. PBT2 rendered wild-type <em>S. pneumoniae</em> strains sensitive to a range of antibiotics. Using an invasive ampicillin-resistant strain, we demonstrate in a murine pneumonia infection model the efficacy of PBT2+ampicillin treatment. These findings present a therapeutic modality to break resistance of drug-resistant <em>S. pneumoniae</em>.</p>
Project description:Extracellular vesicles (EVs) have recently garnered attention for their participation in host-microbe interactions in Streptococcus pneumoniae infections. However, the effect of pEVs on the disruption of alveolar epithelial barrier remain poorly understood. Our studies focus on EVs produced by Streptococcus pneumoniae (pEVs), and reveal that pEVs are internalized by alveolar epithelial cells. In vitro, pEVs induce autophagy activation in a dosage-dependent manner and decrease the alveolar epithelial barrier’s trans-epithelium electrical resistance (TEER). In addition, pEV-containing bacterial peotein serine/threonine-protein kinase StkP may act as an activator for Streptococcus pneumoniae-induced autophagy activation. When administered systemically in mice, Streptococcus pneumoniae wild type strain induced acute lung injury, the deletion of stkP deletion strain attenuated this injury. Taken together, pEVs cargos emerge as critical contributors to tissue damage in mammalian hosts.
Project description:This SuperSeries is composed of the following subset Series: GSE31815: ccpA mutant compared to D39 wild-type in Streptococcus pneumoniae in CDM + Glucose at MID-log growth phase GSE31816: ccpA mutant compared to D39 wild-type in Streptococcus pneumoniae in CDM + GLucose at transition-phase of growth (TS) GSE31817: ccpA mutant compared to D39 wild-type in Streptococcus pneumoniae in CDM + Galactose at MID-log growth phase GSE31818: ccpA mutant compared to D39 wild-type in Streptococcus pneumoniae in CDM + galactose at transition-phase of growth (TS) Refer to individual Series
Project description:Zn and Mn are essential micronutrients for many bacteria including Streptococcus pneumoniae. While Zn performs vital structural or catalytic roles in certain proteins, in excess, Zn can inhibit Mn uptake by S. pneumoniae and displace, but not functionally replace Mn from key enzymes including superoxide dismutase A (SodA). Here, we show that the Ccn small regulatory RNAs promote S. pneumoniae Mn uptake and resistance to the oxidative stress. Furthermore, we demonstrate that these small regulatory RNAs modulate the ability of S. pneumoniae to cause invasive pneumonia. Altogether, these findings reveal a new layer of regulation of S. pneumoniae Zn and Mn homeostasis and suggest that there are factors in addition to known transporters that modulate intracellular Mn levels.
Project description:Treatment of pneumococcal infections is limited by antibiotic resistance and exacerbation of disease by bacterial lysis releasing pneumolysin toxin and other inflammatory factors. We identified a novel peptide in the Klebsiella pneumoniae secretome, which enters Streptococcus pneumoniae via its AmiA-AliA/AliB permease. Subsequent downregulation of genes for amino acid biosynthesis and peptide uptake was associated with reduction of pneumococcal growth in defined medium and human cerebrospinal fluid, irregular cell shape, decreased chain length and decreased genetic transformation. The bacteriostatic effect was specific to S. pneumoniae and Streptococcus pseudopneumoniae with no effect on Streptococcus mitis, Haemophilus influenzae, Staphylococcus aureus or K. pneumoniae. Peptide sequence and length were crucial to growth suppression. The peptide reduced pneumococcal adherence to primary human airway epithelial cell cultures and colonization of rat nasopharynx, without toxicity. We also analysed the effect of peptide on the proteome of S. pneumoniae. We found alteration of the proteome by the peptide with some proteins turned on or off in line with the transcriptomic changes. We therefore identified a peptide with potential as a therapeutic for pneumococcal diseases suppressing growth of multiple clinical isolates, including antibiotic resistant strains, while avoiding bacterial lysis and dysbiosis.
2024-04-08 | PXD050408 | Pride
Project description:Beta-lactam resistance acquisition in Streptococcus pneumoniae
Project description:The maltose regulon (mal regulon) has previously been shown to consist of the mal gene cluster (malQP, malXCD and malAR operons) in Streptococcus pneumoniae. In this study, we have further elucidated the complete mal regulon in S. pneumoniae D39 using microarray analyses and β-galactosidase assays. In addition to the mal gene cluster, the complete mal regulon of S. pneumoniae D39 consists of a pullulanase (PulA), a glucosidase (DexB), a glucokinase (RokB), a PTS component (PtsG) and an amylase (AmyA2). Our microarray studies and β-galactosidase assays further showed that the LacI-family transcriptional regulator MalR represses the expression of the mal regulon in the absence of maltose. Furthermore, the role of the pleiotropic transcriptional regulator CcpA in the regulation of the mal regulon in the presence of maltose was also explored. Our microarray analysis with a ΔccpA strain showed that CcpA only represses the expression of the malXCD operon and the pulA gene in the presence of maltose. Comparison of the Streptococcus pneumoniae D39 ccpA mutant compared to D39 wild type in MM17 (0.5 % (w/v) Maltose + M17) medium One condition design comparision of two strains including a dye swap
Project description:The maltose regulon (mal regulon) has previously been shown to consist of the mal gene cluster (malQP, malXCD and malAR operons) in Streptococcus pneumoniae. In this study, we have further elucidated the complete mal regulon in S. pneumoniae D39 using microarray analyses and β-galactosidase assays. In addition to the mal gene cluster, the complete mal regulon of S. pneumoniae D39 consists of a pullulanase (PulA), a glucosidase (DexB), a glucokinase (RokB), a PTS component (PtsG) and an amylase (AmyA2). Our microarray studies and β-galactosidase assays further showed that the LacI-family transcriptional regulator MalR represses the expression of the mal regulon in the absence of maltose. Furthermore, the role of the pleiotropic transcriptional regulator CcpA in the regulation of the mal regulon in the presence of maltose was also explored. Our microarray analysis with a ΔccpA strain showed that CcpA only represses the expression of the malXCD operon and the pulA gene in the presence of maltose. Comparison of the Streptococcus pneumoniae D39 malR mutant compared to D39 wild type in GM17 (0.5 % (w/v) Glucose + M17) medium One condition design comparision of two strains including a dye swap