Browsing by Subject "bacteria"
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Item Detection of Pathogenic Bacteria During Rhinovirus Infection is Associated with Increased Respiratory Symptoms and Exacerbations of Asthma(Elsevier, 2014-05) Kloepfer, Kirsten M.; Lee, Wai Ming; Pappas, Tressa E.; Kang, Teresa; Vrtis, Rose F.; Evans, Michael D.; Gangnon, Ronald E.; Bochkov, Yury A.; Jackson, Daniel J.; Lemanske, Robert F.; Gern, James E.; Department of Pediatrics, IU School of MedicineBackground Detection of either viral or bacterial pathogens is associated with wheezing in children, however the influence of both bacteria and virus on illness symptoms has not been described. Objective We evaluated bacterial detection during peak RV season in children with and without asthma to determine if an association exists between bacterial infection and the severity of RV illnesses. Methods 308 children (166 with asthma, 142 without asthma) ages 4–12 years provided five consecutive weekly nasal samples during September, and scored cold and asthma symptoms daily. Viral diagnostics and quantitative PCR for Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis were performed on all nasal samples. Results Detection rates were 53%, 17% and 11% for H. influenzae, S. pneumoniae and M. catarrhalis, respectively, with detection of RV increasing the risk of detecting bacteria within the same sample (OR 2.0, 95% CI 1.4–2.7, p<0.0001) or the following week (OR 1.6 (1.1–2.4), p=0.02). In the absence of RV, S. pneumoniae was associated with increased cold symptoms (mean 2.7 (95% CI 2.0–3.5) vs. 1.8 (1.5–2.2), p=0.006) and moderate asthma exacerbations (18% (12%–27%) vs. 9.2% (6.7%–12%), p=0.006). In the presence of RV, S. pneumoniae was associated with increased moderate asthma exacerbations (22% (16%–29%) vs. 15% (11%–20%), p=0.01). Furthermore, M. catarrhalis detected alongside RV increased the likelihood of experiencing cold and/or asthma symptoms compared to isolated detection of RV (OR 2.0 (1.0–4.1), p=0.04). Regardless of RV status, H. influenzae was not associated with respiratory symptoms. Conclusion RV infection enhances detection of specific bacterial pathogens in children with and without asthma. Furthermore, these findings suggest that M. catarrhalis and S. pneumoniae contribute to the severity of respiratory illnesses, including exacerbations of asthma.Item DOES LOW MAGNESIUM IN CYSTIC FIBROSIS CONTRIBUTE TO BACTERIAL PATHOGENICITY?(2012-04-13) Coffey, Barbara M.; Anderson, Gregory G.Cystic fibrosis (CF) is a genetic disease for which there is currently no cure. Individuals with CF are plagued by myriad symptoms, including chronic pneumonia, which diminishes quality of life and reduces life expectancy to 40 years. The most common bacterium in CF patients’ lungs is Pseudomonas aeruginosa, a highly adaptable organism capable of surviving robust antibi-otic treatment. At the heart of developing improved treatments for CF pa-tients is the need to better understand P. aeruginosa pathogenicity. To this end, we have been studying the role of magnesium, which is often found at below normal levels in CF patients. Magnesium is an essential element in numerous cellular functions in both bacteria and humans. In previous re-search, we developed a P. aeruginosa strain with a deletion of the magnesi-um transport protein MgtE, as well as 16 plasmids carrying different muta-tions of the mgtE gene. Experiments with these constructs demonstrated a relationship between magnesium transport and bacterial toxin production. In the research presented here, we hypothesize that lower levels of magnesium may trigger a bacterial response, causing a change in P. aeruginosa patho-genicity. Changes may include differential growth, toxin release, and for-mation of biofilms, which are surface-adhered, antibiotic tolerant bacterial communities in a protective polysaccharide matrix. Using various magnesi-um levels, we have measured P. aeruginosa growth rates, motility, biofilm formation, and cytotoxicity toward cultured cells derived from the CF bron-chial epithelium. Preliminary results suggest that lower magnesium contrib-utes to changes in the bacterium that favor persistence in the CF lung. On-going studies include the effect of long-term growth of P. aeruginosa in low magnesium and how this impacts a number of virulence factors. We antici-pate that our research will elucidate the relationship between magnesium and P. aeruginosa pathogenicity and potentially lead to improved treatments for CF patients.Item Effect of Caffeine on the Growth of Streptococcus mutans(Office of the Vice Chancellor for Research, 2015-04-17) DuBois, Aubrey E.; Gregory, Richard L.Caffeine consumption is a staple of the typical adult diet. Previous research has demonstrated many possible health benefits of regular consumption of caffeine-containing beverages such as coffee and tea. Coffee may contain up 200 mg caffeine/cup (84 μg/ml). This study investigated the correlation between oral health and caffeine consumption by observing the effects of the compound on the growth of a leading contributor to tooth decay, Streptococcus mutans. Assays were performed to examine the effect of different concentrations of caffeine on both the planktonic and biofilm growth of the bacteria. Caffeine concentrations of 200 and 400 μg/ml demonstrated significant biofilm formation enhancement (p<0.05). Contrastingly, concentrations from 31.25 through 100 μg/ml caused a slight, significant inhibition in biofilm formation. Planktonic growth of S. mutans was marginally inhibited in concentrations of 31.25 through 200 μg/ml. The results of this study indicate a potential for adverse side effects to oral health when caffeine is consumed in high concentrations. Lower concentrations such as those naturally found in coffee and tea may inhibit formation of biofilm and dental plaque, thereby promoting good oral health.Item Enteric viruses exploit the microbiota to promote infection(Elsevier, 2019-08-01) Robinson, Christopher M; Microbiology and Immunology, School of MedicineEnteric viruses infect the mammalian gastrointestinal tract which is home to a diverse community of intestinal bacteria. Accumulating evidence suggests that certain enteric viruses utilize these bacteria to promote infection. While this is not surprising considering their proximity, multiple viruses from different viral families have been shown to bind directly to bacteria or bacterial components to aid in viral replication, pathogenesis, and transmission. These data suggest that the concept of a single virus infecting a single cell, independent of the environment, needs to be reevaluated. In this review, I will discuss the current knowledge of enteric virus-bacterial interactions and discuss the implications for viral pathogenesis and transmission.Item Fecal Microbiota Transplant Decreases Mortality in Patients with Refractory Severe or Fulminant Clostridioides difficile Infection(Elsevier, 2020) Cheng, Yao-Wen; Phelps, Emmalee; Nemes, Sara; Rogers, Nicholas; Sagi, Sashidhar; Bohm, Matthew; El-Halabi, Mustapha; Allegretti, Jessica R.; Kassam, Zain; Xu, Huiping; Fischer, Monika; Medicine, School of MedicineBackground & Aims Fecal microbiota transplantation (FMT) is recommended for recurrent Clostridioides difficile infection (CDI). FMT cures nearly 80% of patients with severe or fulminant CDI (SFCDI) when utilized in a sequential manner. We compared outcomes of hospitalized patients before and after implementation of an FMT program for SFCDI and investigated whether the changes could be directly attributed to the FMT program. Methods We performed a retrospective analysis of characteristics and outcomes of patients hospitalized for SFCDI (430 hospitalizations) at a single center, from January 2009 through December 2016. We performed subgroup analyses of 199 patients with fulminant CDI and 110 patients with refractory SFCDI (no improvement after 5 or more days of maximal anti-CDI antibiotic therapy). We compared CDI-related mortality within 30 days of hospitalization, CDI-related colectomy, length of hospital stay, and readmission to the hospital within 30 days before (2009–2012) vs after (2013–2016) implementation of the inpatient FMT program. Results CDI-related mortality and colectomy were lower after implementation of the FMT program. Overall, CDI-related mortality was 10.2% before the FMT program was implemented vs 4.4% after (P = .02). For patients with fulminant CDI, CDI-related mortality was 21.3% before the FMT program was implemented vs 9.1% after (P = .015). For patients with refractory SFCDI, CDI-related mortality was 43.2% before the FMT program vs 12.1% after (P < .001). The FMT program significantly reduced CDI-related colectomy in patients with SFCDI (6.8% before vs 2.7% after; P = .041), in patients with fulminant CDI (15.7% before vs 5.5% after; P = .017), and patients with refractory SFCDI (31.8% vs 7.6%; P = .001). The effect of FMT program implementation on CDI-related mortality remained significant for patients with refractory SFCDI after we accounted for the underlying secular trend (odds ratio, 0.09 for level change; P = .023). Conclusions An FMT program significantly decreased CDI-related mortality among patients hospitalized with refractory SFCDI.Item L-Asparaginase delivered by Salmonella typhimurium suppresses solid tumors(Nature Publishing Group, 2015) Kim, Kwangsoo; Jeong, Jae Ho; Lim, Daejin; Hong, Yeongjin; Lim, Hyung-Ju; Kim, Geun-Joong; Shin, So-ra; Lee, Je-Jung; Yun, Misun; Harris, Robert A.; Min, Jung-Joon; Choy, Hyon E.; Department of Biochemistry & Molecular Biology, IU School of MedicineBacteria can be engineered to deliver anticancer proteins to tumors via a controlled expression system that maximizes the concentration of the therapeutic agent in the tumor. L-asparaginase (L-ASNase), which primarily converts asparagine to aspartate, is an anticancer protein used to treat acute lymphoblastic leukemia. In this study, Salmonellae were engineered to express L-ASNase selectively within tumor tissues using the inducible araBAD promoter system of Escherichia coli. Antitumor efficacy of the engineered bacteria was demonstrated in vivo in solid malignancies. This result demonstrates the merit of bacteria as cancer drug delivery vehicles to administer cancer-starving proteins such as L-ASNase to be effective selectively within the microenvironment of cancer tissue.Item Plasmodium Impairs Antibacterial Innate Immunity to Systemic Infections in Part Through Hemozoin-Bound Bioactive Molecules(Frontiers, 2020-06-30) Harding, Christopher L.; Villarino, Nicolas F.; Valente, Elena; Schwarzer, Evelin; Schmidt, Nathan W.; Pediatrics, School of MedicineOne complication of malaria is increased susceptibility to invasive bacterial infections. Plasmodium infections impair host immunity to non-Typhoid Salmonella (NTS) through heme-oxygenase I (HO-I)-induced release of immature granulocytes and myeloid cell-derived IL-10. Yet, it is not known if these mechanisms are specific to NTS. We show here, that Plasmodium yoelii 17XNL (Py) infected mice had impaired clearance of systemic Listeria monocytogenes (Lm) during both acute parasitemia and up to 2 months after clearance of Py infected red blood cells that was independent of HO-I and IL-10. Py-infected mice were also susceptible to Streptococcus pneumoniae (Sp) bacteremia, a common malaria-bacteria co-infection, with higher blood and spleen bacterial burdens and decreased survival compared to naïve mice. Mechanistically, impaired immunity to Sp was independent of HO-I, but was dependent on Py-induced IL-10. Splenic phagocytes from Py infected mice exhibit an impaired ability to restrict growth of intracellular Lm, and neutrophils from Py-infected mice produce less reactive oxygen species (ROS) in response to Lm or Sp. Analysis also identified a defect in a serum component in Py-infected mice that contributes to reduced production of ROS in response to Sp. Finally, treating naïve mice with Plasmodium-derived hemozoin containing naturally bound bioactive molecules, excluding DNA, impaired clearance of Lm. Collectively, we have demonstrated that Plasmodium infection impairs host immunity to diverse bacteria, including S. pneumoniae, through multiple effects on innate immunity, and that a parasite-specific factor (Hz+bound bioactive molecules) directly contributes to Plasmodium-induced suppression of antibacterial innate immunity.Item Protecting enzymatic function through directed packaging into bacterial outer membrane vesicles(Nature, 2016-04) Alves, Nathan J.; Turner, Kendrick B.; Medintz, Igor L.; Walper, Scott A.; Emergency Medicine, School of MedicineBacteria possess innate machinery to transport extracellular cargo between cells as well as package virulence factors to infect host cells by secreting outer membrane vesicles (OMVs) that contain small molecules, proteins, and genetic material. These robust proteoliposomes have evolved naturally to be resistant to degradation and provide a supportive environment to extend the activity of encapsulated cargo. In this study, we sought to exploit bacterial OMV formation to package and maintain the activity of an enzyme, phosphotriesterase (PTE), under challenging storage conditions encountered for real world applications. Here we show that OMV packaged PTE maintains activity over free PTE when subjected to elevated temperatures (>100-fold more activity after 14 days at 37 °C), iterative freeze-thaw cycles (3.4-fold post four-cycles), and lyophilization (43-fold). We also demonstrate how lyophilized OMV packaged PTE can be utilized as a cell free reagent for long term environmental remediation of pesticide/chemical warfare contaminated areas.Item SOLUTION STRUCTURE OF THE TOXIC E. COLI PEPTIDE, TISB(Office of the Vice Chancellor for Research, 2012-04-13) Li, Beilin; Wassall, Stephen R.; Ray, Bruce D.; Gurnev, Philip A.; Petrache, Horia I.Antibiotics act by interfering in bacterial metabolism. Thus, antibiotics are only effective against metabolically active bacteria while dormant cells are highly tolerant to antibiotics. Such persistent bacterial cells may be the main culprits in chronic infectious diseases resistance to antimicrobial thera-py. In Escherichia coli, expression of a toxic peptide, TisB, sends cells into dormancy by decreasing the proton motive force thus decreasing ATP levels. TisB is a 29 amino acid residue peptide with 70% hydrophobic residues. It has a predicted alpha helical transmembrane domain spanning residues 6 - 28. In membrane channel studies, ion transport is observed with TisB and with some TisB mutants. As a preliminary to combining multi-dimensional NMR spectroscopy with circular dichroism to determine the structure of the TisB membrane ion transport complex in lipid micelles, NMR spectroscopy is used to determine the structure of TisB in ethanol.Item Statistical signatures of a targeted search by bacteria(IOP, 2017) Jashnsaz, Hossein; Anderson, Gregory G.; Pressé, Steve; Microbiology and Immunology, School of MedicineChemoattractant gradients are rarely well-controlled in nature and recent attention has turned to bacterial chemotaxis toward typical bacterial food sources such as food patches or even bacterial prey. In environments with localized food sources reminiscent of a bacterium's natural habitat, striking phenomena—such as the volcano effect or banding—have been predicted or expected to emerge from chemotactic models. However, in practice, from limited bacterial trajectory data it is difficult to distinguish targeted searches from an untargeted search strategy for food sources. Here we use a theoretical model to identify statistical signatures of a targeted search toward point food sources, such as prey. Our model is constructed on the basis that bacteria use temporal comparisons to bias their random walk, exhibit finite memory and are subject to random (Brownian) motion as well as signaling noise. The advantage with using a stochastic model-based approach is that a stochastic model may be parametrized from individual stochastic bacterial trajectories but may then be used to generate a very large number of simulated trajectories to explore average behaviors obtained from stochastic search strategies. For example, our model predicts that a bacterium's diffusion coefficient increases as it approaches the point source and that, in the presence of multiple sources, bacteria may take substantially longer to locate their first source giving the impression of an untargeted search strategy.