scholarly journals Activity of Tedizolid Phosphate (TR-701) in Murine Models of Infection with Penicillin-Resistant and Penicillin-Sensitive Streptococcus pneumoniae

2012 ◽  
Vol 56 (9) ◽  
pp. 4713-4717 ◽  
Author(s):  
Sunghak Choi ◽  
Weonbin Im ◽  
Ken Bartizal
Keyword(s):  
Streptococcus Pneumoniae ◽  
Inflammatory Cell ◽  
Systemic Infection ◽  
Murine Models ◽  
Once Daily ◽  
Content Type ◽  
Lung Histopathology ◽  
Phosphate Treatment

ABSTRACTThein vitroactivity of tedizolid (previously known as torezolid, TR-700) against penicillin-resistantStreptococcus pneumoniae(PRSP) clinical isolates and thein vivoefficacy of tedizolid phosphate (torezolid phosphate, TR-701) in murine models of PRSP systemic infection and penicillin-susceptibleS. pneumoniae(PSSP) pneumonia were examined using linezolid as a comparator. The MIC90against 28 PRSP isolates was 0.25 μg/ml for tedizolid, whereas it was 1 μg/ml for linezolid. In mice infected systemically with a lethal inoculum of PRSP 1 h prior to a single administration of either antimicrobial, oral tedizolid phosphate was equipotent to linezolid (1 isolate) to 2-fold more potent than linezolid (3 isolates) for survival at day 7, with tedizolid phosphate 50% effective dose (ED50) values ranging from 3.19 to 11.53 mg/kg of body weight/day. In the PSSP pneumonia model, the ED50for survival at day 15 was 2.80 mg/kg/day for oral tedizolid phosphate, whereas it was 8.09 mg/kg/day for oral linezolid following 48 h of treatment with either agent. At equivalent doses (10 mg/kg once daily tedizolid phosphate or 5 mg/kg twice daily linezolid), pneumococcal titers in the lungs at 52 h postinfection were approximately 3 orders of magnitude lower with tedizolid phosphate treatment than with linezolid treatment or no treatment. Lung histopathology showed less inflammatory cell invasion into alveolar spaces in mice treated with tedizolid phosphate than in untreated or linezolid-treated mice. These results demonstrate that tedizolid phosphate is effective in murine models of PRSP systemic infection and PSSP pneumonia.

scholarly journals A Novel Ketolide, RBx 14255, with Activity against Multidrug-Resistant Streptococcus pneumoniae

2014 ◽  
Vol 58 (8) ◽  
pp. 4283-4289 ◽  
Author(s):  
V. Samuel Raj ◽  
Tarani Kanta Barman ◽  
Vandana Kalia ◽  
Kedar Purnapatre ◽  
Smita Dube ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Pulmonary Infection ◽  
Systemic Infection ◽  
Multidrug Resistant ◽  
Infection Model ◽  
The Novel ◽  
Content Type ◽  
Pharmacokinetic Properties

ABSTRACTWe present here the novel ketolide RBx 14255, a semisynthetic macrolide derivative obtained by the derivatization of clarithromycin, for itsin vitroandin vivoactivities against sensitive and macrolide-resistantStreptococcus pneumoniae. RBx 14255 showed excellentin vitroactivity against macrolide-resistantS. pneumoniae, including an in-house-generated telithromycin-resistant strain (S. pneumoniae3390 NDDR). RBx 14255 also showed potent protein synthesis inhibition against telithromycin-resistantS. pneumoniae3390 NDDR. The binding affinity of RBx 14255 toward ribosomes was found to be more than that for other tested drugs. Thein vivoefficacy of RBx 14255 was determined in murine pulmonary infection induced by intranasal inoculation ofS. pneumoniaeATCC 6303 and systemic infection withS. pneumoniae3390 NDDR strains. The 50% effective dose (ED50) of RBx 14255 againstS. pneumoniaeATCC 6303 in a murine pulmonary infection model was 3.12 mg/kg of body weight. In addition, RBx 14255 resulted in 100% survival of mice with systemic infection caused by macrolide-resistantS. pneumoniae3390 NDDR at 100 mg/kg four times daily (QID) and at 50 mg/kg QID. RBx 14255 showed favorable pharmacokinetic properties that were comparable to those of telithromycin.

scholarly journals Antimicrobial Photodynamic Inactivation Inhibits Candida albicans Virulence Factors and ReducesIn VivoPathogenicity

2012 ◽  
Vol 57 (1) ◽  
pp. 445-451 ◽  
Author(s):  
Ilka Tiemy Kato ◽  
Renato Araujo Prates ◽  
Caetano Padial Sabino ◽  
Beth Burgwyn Fuchs ◽  
George P. Tegos ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Virulence Factors ◽  
Sodium Dodecyl ◽  
Systemic Infection ◽  
Tube Formation ◽  
Photodynamic Inactivation ◽  
Content Type ◽  
Daughter Cells

ABSTRACTThe objective of this study was to evaluate whetherCandida albicansexhibits altered pathogenicity characteristics following sublethal antimicrobial photodynamic inactivation (APDI) and if such alterations are maintained in the daughter cells.C. albicanswas exposed to sublethal APDI by using methylene blue (MB) as a photosensitizer (0.05 mM) combined with a GaAlAs diode laser (λ 660 nm, 75 mW/cm2, 9 to 27 J/cm2).In vitro, we evaluated APDI effects onC. albicansgrowth, germ tube formation, sensitivity to oxidative and osmotic stress, cell wall integrity, and fluconazole susceptibility.In vivo, we evaluatedC. albicanspathogenicity with a mouse model of systemic infection. Animal survival was evaluated daily. Sublethal MB-mediated APDI reduced the growth rate and the ability ofC. albicansto form germ tubes compared to untreated cells (P< 0.05). Survival of mice systemically infected withC. albicanspretreated with APDI was significantly increased compared to mice infected with untreated yeast (P< 0.05). APDI increasedC. albicanssensitivity to sodium dodecyl sulfate, caffeine, and hydrogen peroxide. The MIC for fluconazole forC. albicanswas also reduced following sublethal MB-mediated APDI. However, none of those pathogenic parameters was altered in daughter cells ofC. albicanssubmitted to APDI. These data suggest that APDI may inhibit virulence factors and reducein vivopathogenicity ofC. albicans. The absence of alterations in daughter cells indicates that APDI effects are transitory. The MIC reduction for fluconazole following APDI suggests that this antifungal could be combined with APDI to treatC. albicansinfections.

scholarly journals The Fungal Cyp51-Specific Inhibitor VT-1598 DemonstratesIn VitroandIn VivoActivity againstCandida auris

2018 ◽  
Vol 63 (3) ◽  
Author(s):  
Nathan P. Wiederhold ◽  
Shawn R. Lockhart ◽  
Laura K. Najvar ◽  
Elizabeth L. Berkow ◽  
Rosie Jaramillo ◽  
...  
Keyword(s):  
Specific Inhibitor ◽  
Candida Auris ◽  
Once Daily ◽  
Content Type ◽  
Fungal Burden ◽  
Invasive Infections ◽  
Trough Concentrations ◽  
Dose Dependent

ABSTRACTCandida aurisis an emerging pathogen associated with significant mortality and often multidrug resistance. VT-1598, a tetrazole-based fungal CYP51-specific inhibitor, was evaluatedin vitroandin vivoagainstC. auris. Susceptibility testing was performed against 100 clinical isolates ofC. aurisby broth microdilution. Neutropenic mice were infected intravenously withC. auris, and treatment began 24 h postinoculation with a vehicle control, oral VT-1598 (5, 15, and 50 mg/kg of body weight once daily), oral fluconazole (20 mg/kg once daily), or intraperitoneal caspofungin (10 mg/kg once daily), which continued for 7 days. Fungal burden was assessed in the kidneys and brains on day 8 in the fungal burden arm and on the days the mice succumbed to infection or on day 21 in the survival arm. VT-1598 plasma trough concentrations were also assessed on day 8. VT-1598 demonstratedin vitroactivity againstC. auris, with a mode MIC of 0.25 μg/ml and MICs ranging from 0.03 to 8 μg/ml. Treatment with VT-1598 resulted in significant and dose-dependent improvements in survival (median survival, 15 and >21 days for VT-1598 at 15 and 50 mg/kg, respectively) and reductions in kidney and brain fungal burden (reductions of 1.88 to 3.61 log10CFU/g) compared to the control (5 days). The reductions in fungal burden correlated with plasma trough concentrations. Treatment with caspofungin, but not fluconazole, also resulted in significant improvements in survival and reductions in fungal burden compared to those with the control. These results suggest that VT-1598 may be a future option for the treatment of invasive infections caused byC. auris.

scholarly journals Characterization of the Anti-Inflammatory Capacity of IL-10-Producing Neutrophils in Response to Streptococcus pneumoniae Infection

2021 ◽  
Vol 12 ◽  
Author(s):  
Liliana A. González ◽  
Felipe Melo-González ◽  
Valentina P. Sebastián ◽  
Omar P. Vallejos ◽  
Loreani P. Noguera ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Lung Injury ◽  
Interleukin 10 ◽  
Effector Cells ◽  
Cellular Source ◽  
Lung Histopathology ◽  
Morphological Differences ◽  
Direct Recognition

Neutrophils are immune cells classically defined as pro-inflammatory effector cells. However, current accumulated evidence indicates that neutrophils have more versatile immune-modulating properties. During acute lung infection with Streptococcus pneumoniae in mice, interleukin-10 (IL-10) production is required to temper an excessive lung injury and to improve survival, yet the cellular source of IL-10 and the immunomodulatory role of neutrophils during S. pneumoniae infection remain unknown. Here we show that neutrophils are the main myeloid cells that produce IL-10 in the lungs during the first 48 h of infection. Importantly, in vitro assays with bone-marrow derived neutrophils confirmed that IL-10 can be induced by these cells by the direct recognition of pneumococcal antigens. In vivo, we identified the recruitment of two neutrophil subpopulations in the lungs following infection, which exhibited clear morphological differences and a distinctive profile of IL-10 production at 48 h post-infection. Furthermore, adoptive transfer of neutrophils from WT mice into IL-10 knockout mice (Il10-/-) fully restored IL-10 production in the lungs and reduced lung histopathology. These results suggest that IL-10 production by neutrophils induced by S. pneumoniae limits lung injury and is important to mediate an effective immune response required for host survival.

scholarly journals Draft Genome Sequence of Pediatric Otitis Media Isolate Streptococcus pneumoniae Strain EF3030, Which Forms In Vitro Biofilms That Closely Mimic In Vivo Biofilms

2019 ◽  
Vol 8 (2) ◽  
Author(s):  
Edgar J. Scott ◽  
Nicole R. Luke-Marshall ◽  
Anthony A. Campagnari ◽  
David W. Dyer
Keyword(s):  
Streptococcus Pneumoniae ◽  
Otitis Media ◽  
Genome Sequence ◽  
Dna Sequences ◽  
Draft Genome ◽  
Draft Genome Sequence ◽  
Draft Assembly ◽  
Content Type

Here, we report the draft genome sequence of Streptococcus pneumoniae EF3030, a pediatric otitis media isolate active in biofilm assays of epithelial colonization. The final draft assembly included 2,209,198 bp; the annotation predicted 2,120 coding DNA sequences (CDSs), 4 complete rRNA operons, 58 tRNAs, 3 noncoding RNAs (ncRNAs), and 199 pseudogenes.

scholarly journals The Novel Arylamidine T-2307 Demonstrates In Vitro and In Vivo Activity against Candida auris

2019 ◽  
Vol 64 (3) ◽  
Author(s):  
Nathan P. Wiederhold ◽  
Laura K. Najvar ◽  
Rosie Jaramillo ◽  
Marcos Olivo ◽  
Hoja Patterson ◽  
...  
Keyword(s):  
The Novel ◽  
Candida Auris ◽  
Once Daily ◽  
Content Type ◽  
Fungal Burden

ABSTRACT The in vitro and in vivo activity of the arylamidine T-2307 against Candida auris was evaluated. T-2307 demonstrated in vitro activity (MIC ranges ≤ 0.008 to 0.015 μg/ml at 50% inhibition; 0.125 to >4 μg/ml at 100% inhibition). Treatment with T-2307 (3 mg/kg subcutaneous [SC] once daily) also significantly improved survival (70% at 21 days postinfection) and reduced kidney fungal burden (5.06 log10 CFU/g) compared to control (0% survival and 7.09 log10 CFU/g) (P < 0.01).

scholarly journals Thiol Peroxidase Is an Important Component of Streptococcus pneumoniae in Oxygenated Environments

2012 ◽  
Vol 80 (12) ◽  
pp. 4333-4343 ◽  
Author(s):  
Barak Hajaj ◽  
Hasan Yesilkaya ◽  
Rachel Benisty ◽  
Maayan David ◽  
Peter W. Andrew ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Mass Spectrometry Analysis ◽  
Activity Levels ◽  
Content Type ◽  
Spectrometry Analysis ◽  
Cellular Processes ◽  
Thiol Peroxidase ◽  
Fine Tune

ABSTRACTStreptococcus pneumoniaeis an aerotolerant Gram-positive bacterium that causes an array of diseases, including pneumonia, otitis media, and meningitis. During aerobic growth,S. pneumoniaeproduces high levels of H2O2. SinceS. pneumoniaelacks catalase, the question of how it controls H2O2levels is of critical importance. Thepsalocus encodes an ABC Mn2+-permease complex (psaBCA) and a putative thiol peroxidase,tpxD. This study shows thattpxDencodes a functional thiol peroxidase involved in the adjustment of H2O2homeostasis in the cell. Kinetic experiments showed that recombinant TpxD removed H2O2efficiently. However,in vivoexperiments revealed that TpxD detoxifies only a fraction of the H2O2generated by the pneumococcus. Mass spectrometry analysis demonstrated that TpxD Cys58undergoes selective oxidationin vivo, under conditions where H2O2is formed, confirming the thiol peroxidase activity. Levels of TpxD expression and synthesisin vitrowere significantly increased in cells grown under aerobic versus anaerobic conditions. The challenge with D39 and TIGR4 with H2O2resulted intpxDupregulation, whilepsaBCAexpression was oppositely affected. However, the challenge of ΔtpxDmutants with H2O2did not affectpsaBCA, implying that TpxD is involved in the regulation of thepsaoperon, in addition to its scavenging activity. Virulence studies demonstrated a notable difference in the survival time of mice infected intranasally with D39 compared to that of mice infected intranasally with D39ΔtpxD. However, when bacteria were administered directly into the blood, this difference disappeared. The findings of this study suggest that TpxD constitutes a component of the organism's fundamental strategy to fine-tune cellular processes in response to H2O2.

scholarly journals Implications of the EUCAST Trailing Phenomenon inCandida tropicalisfor theIn VivoSusceptibility in Invertebrate and Murine Models

2018 ◽  
Vol 62 (12) ◽  
Author(s):  
K. M. T. Astvad ◽  
D. Sanglard ◽  
E. Delarze ◽  
R. K. Hare ◽  
M. C. Arendrup
Keyword(s):  
Susceptibility Testing ◽  
Galleria Mellonella ◽  
Growth Control ◽  
Resistant Isolate ◽  
Murine Models ◽  
Wild Type ◽  
Content Type ◽  
Gradual Loss

ABSTRACTCandida tropicalisisolates often display reduced but persistent growth (trailing) over a broad fluconazole concentration range during EUCAST susceptibility testing. Whereas weak trailing (<25% of the positive growth control) is common and found not to impair fluconazole efficacy, we investigated if more pronounced trailing impacted treatment efficacy. Fluconazole efficacy against two weakly (≤25% growth), two moderately (26% to 50% growth), and one heavily (>70% growth) trailing resistant isolate and one resistant (100% growth) isolate were investigatedin vitroandin vivo(in aGalleria mellonellasurvival model and two nonlethal murine models).CDR1expression levels andERG11sequences were characterized. The survival in fluconazole-treatedG. mellonellawas inversely correlated with the degree of trailing (71% to 9% survival in treatment groups). In mice, resistant and heavily trailing isolates responded poorly to fluconazole treatment.CDR1expression was significantly higher in trailing and resistant isolates than in wild-type isolates (1.4-fold to 10-fold higher). All isolates exhibitedERG11wild-type alleles. Heavily trailing isolates were less responsive to fluconazole in allin vivomodels, indicating an impact on fluconazole efficacy.CDR1upregulation may have contributed to the observed differences. Moderately trailing isolates responded less well to fluconazole in larvae only. This confirms clinical data suggesting fluconazole is effective against infections with such isolates in less severely ill patients and supports the current 50% growth endpoint for susceptibility testing. However, it is still unclear if the gradual loss of efficacy observed for moderately trailing isolates in the larva model may be a reason for concern in selected vulnerable patient populations.

scholarly journals Characterization of Pit, a Streptococcus pneumoniae Iron Uptake ABC Transporter

2002 ◽  
Vol 70 (8) ◽  
pp. 4389-4398 ◽  
Author(s):  
Jeremy S. Brown ◽  
Sarah M. Gilliland ◽  
Javier Ruiz-Albert ◽  
David W. Holden
Keyword(s):  
Streptococcus Pneumoniae ◽  
Abc Transporter ◽  
Iron Uptake ◽  
Systemic Infection ◽  
Iron Chelator ◽  
Iron Deficient ◽  
Deficient Medium ◽  
Mutant Strains

ABSTRACT Bacteria frequently have multiple mechanisms for acquiring iron, an essential micronutrient, from the environment. We have identified a four-gene Streptococcus pneumoniae operon, named pit, encoding proteins with similarity to components of a putative Brachyspira hyodysenteriae iron uptake ABC transporter, Bit. An S. pneumoniae strain containing a defined mutation in pit has impaired growth in medium containing the iron chelator ethylenediamine di-o-hydroxyphenylacetic acid, reduced sensitivity to the iron-dependent antibiotic streptonigrin, and impaired virulence in a mouse model of S. pneumoniae systemic infection. Furthermore, addition of a mutation in pit to a strain containing mutations in the two previously described S. pneumoniae iron uptake ABC transporters, piu and pia, resulted in a strain with impaired growth in two types of iron-deficient medium, a high degree of resistance to streptonigrin, and a reduced rate of iron uptake. Comparison of the susceptibilities to streptonigrin of the individual pit, piu, and pia mutant strains and comparison of the growth in iron-deficient medium and virulence of single and double mutant strains suggest that pia is the dominant iron transporter during in vitro and in vivo growth.

scholarly journals Dynamic Changes in the Streptococcus pneumoniae Transcriptome during Transition from Biofilm Formation to Invasive Disease upon Influenza A Virus Infection

2014 ◽  
Vol 82 (11) ◽  
pp. 4607-4619 ◽  
Author(s):  
Melinda M. Pettigrew ◽  
Laura R. Marks ◽  
Yong Kong ◽  
Janneane F. Gent ◽  
Hazeline Roche-Hakansson ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Influenza A Virus ◽  
Influenza A ◽  
Lactate Production ◽  
Invasive Disease ◽  
Content Type ◽  
Induced Changes ◽  
Upregulated Genes

ABSTRACTStreptococcus pneumoniaeis a leading cause of infectious disease globally. Nasopharyngeal colonization occurs in biofilms and precedes infection. Prior studies have indicated that biofilm-derived pneumococci are avirulent. However, influenza A virus (IAV) infection releases virulent pneumococci from biofilmsin vitroandin vivo. Triggers of dispersal include IAV-induced changes in the nasopharynx, such as increased temperature (fever) and extracellular ATP (tissue damage). We used whole-transcriptome shotgun sequencing (RNA-seq) to compare theS. pneumoniaetranscriptome in biofilms, bacteria dispersed from biofilms after exposure to IAV, febrile-range temperature, or ATP, and planktonic cells grown at 37°C. Compared with biofilm bacteria, actively dispersedS. pneumoniae, which were more virulent in invasive disease, upregulated genes involved in carbohydrate metabolism. Enzymatic assays for ATP and lactate production confirmed that dispersed pneumococci exhibited increased metabolism compared to those in biofilms. Dispersed pneumococci also upregulated genes associated with production of bacteriocins and downregulated colonization-associated genes related to competence, fratricide, and the transparent colony phenotype. IAV had the largest impact on the pneumococcal transcriptome. Similar transcriptional differences were also observed when actively dispersed bacteria were compared with avirulent planktonic bacteria. Our data demonstrate complex changes in the pneumococcal transcriptome in response to IAV-induced changes in the environment. Our data suggest that disease is caused by pneumococci that are primed to move to tissue sites with altered nutrient availability and to protect themselves from the nasopharyngeal microflora and host immune response. These data help explain pneumococcal virulence after IAV infection and have important implications for studies ofS. pneumoniaepathogenesis.

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