Project description:The increasing rate of penicillin resistance in S. pneumoniae in the early 1970s has resulted in therapeutic challenges and has prompted the need for alternative therapy in the management of pneumococcal infections. The development of penicillin resistance has been documented to be as a result of altered penicillin binding protein which alters the binding capacity of the drug to the organism. We used microarrays to investigate other genes which may be involved in the development of penicillin resistance in S. pneumoniae and identified classes of genes on the surface of the organism which may contribute to resistance. Strains of S. pneumoniae with varying initial susceptibility to penicillin were selected. These strains were grown to the logarithmic phase before being exposed to subinhibitory concentration of penicillin. RNA was extracted before and after penicillin stress and hybridized on Affymetrix microarrays and represented as either Untreated (before penicillin stress) or treated (after penicillin stress). This was carried out for 3 representative strains; S676, I81, and R98. S, I, and R abbreviates Sensitive, Intermediate and resistant to Penicillin.
Project description:The increasing rate of penicillin resistance in S. pneumoniae in the early 1970s has resulted in therapeutic challenges and has prompted the need for alternative therapy in the management of pneumococcal infections. The development of penicillin resistance has been documented to be as a result of altered penicillin binding protein which alters the binding capacity of the drug to the organism. We used microarrays to investigate other genes which may be involved in the development of penicillin resistance in S. pneumoniae and identified classes of genes on the surface of the organism which may contribute to resistance.
Project description:The anti-bacterial mechanism of the leaves of Strobilanthes cusia Kuntze against the Penicillin-resistant Streptococcus pneumoniae were analyzed by the comparative proteomics
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:To gain deeper insights into antibacterial mechanisms of NAD+ and bacterial adaptation, we generated and sequenced NAD+ resistant clones of Spn. For this purpose, Spn was cultivated in liquid medium with increasing concentrations (50 µM to 5 mM) of NAD+. After six passages, bacteria were plated on blood agar supplemented with 500 µM NAD+ and three clones were picked
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.
