Low Rate of Phagocylosis and Overwheiming Inflammatory Reactions Cortribute to Mortality Rate in a Murine Model of Streptococcus Pneumoniae Pneumonia

1995 ◽  
Vol 17 (2) ◽  
pp. 128
Author(s):  
A. M. DESLAURIERS ◽  
Y. BERGERON ◽  
M. OLIVIER ◽  
D. BEAUCHAMP ◽  
P. GOURDE ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Mortality Rate ◽  
Murine Model ◽  
Inflammatory Reactions ◽  
Low Rate

scholarly journals Synthetic acylsugars and their effects on the control of arthropod pests

2017 ◽  
Vol 41 (2) ◽  
pp. 201-208
Author(s):  
Anni Cristini Silvestri Gomes ◽  
Maria das Graças Cardoso ◽  
Juliano Vilela Resende ◽  
Sérgio Scherrer Thomasi ◽  
Luana Isac Soares ◽  
...  
Keyword(s):  
Mortality Rate ◽  
Biological Effect ◽  
Sodium Acetate ◽  
Spectroscopic Techniques ◽  
Agricultural Pests ◽  
Wild Tomato Species ◽  
Tomato Species ◽  
Biological Tests ◽  
Arthropod Pests ◽  
Low Rate

ABSTRACT One of the main problems facing agriculture is the loss of production as a result of the attack of agricultural pests. Alternative ways to work around this problem are being sought. There are substances called acylsugars that are naturally produced by the wild tomato species S. pennellii and affect arthropod pests. The objectives of this work were to synthesize two acylsugars and assess the biological effect of these on the arthropod pests Bemissia tabaci and Tetranycus urticae. The syntheses were performed via the reactions of glucose and sucrose (saccharose) with acetic anhydride using sodium acetate as the catalyst. The products of these reactions were sucrose octa-acetate and glucose penta-acetate, the structures of which were confirmed by spectroscopic techniques. In a resistance test against the mite, a linear correlation between the concentration of the synthesized substances, and the dislocation of the mite was obtained. A delay in the hatching of the arthropod eggs was observed, causing a mortality rate of approximately 95% in the 1st instar larvae of mites that was confirmed in adults. In the biological tests with Bemisia tabaci, there was a low rate of hatching and emergence, and the effect on the nymphs was the deformation of the emergent adults.

scholarly journals Experimental Evolution In Vivo To Identify Selective Pressures during Pneumococcal Colonization

mSystems ◽  
2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Vaughn S. Cooper ◽  
Erin Honsa ◽  
Hannah Rowe ◽  
Christopher Deitrick ◽  
Amy R. Iverson ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Murine Model ◽  
Experimental Evolution ◽  
Nasal Colonization ◽  
Content Type ◽  
Selective Pressures ◽  
Specific Tissue ◽  
Tissue Tropisms ◽  
Insight Into

ABSTRACT Experimental evolution is a powerful technique to understand how populations evolve from selective pressures imparted by the surrounding environment. With the advancement of whole-population genomic sequencing, it is possible to identify and track multiple contending genotypes associated with adaptations to specific selective pressures. This approach has been used repeatedly with model species in vitro, but only rarely in vivo. Herein we report results of replicate experimentally evolved populations of Streptococcus pneumoniae propagated by repeated murine nasal colonization with the aim of identifying gene products under strong selection as well as the population genetic dynamics of infection cycles. Frameshift mutations in one gene, dltB, responsible for incorporation of d-alanine into teichoic acids on the bacterial surface, evolved repeatedly and swept to high frequency. Targeted deletions of dltB produced a fitness advantage during initial nasal colonization coupled with a corresponding fitness disadvantage in the lungs during pulmonary infection. The underlying mechanism behind the fitness trade-off between these two niches was found to be enhanced adherence to respiratory cells balanced by increased sensitivity to host-derived antimicrobial peptides, a finding recapitulated in the murine model. Additional mutations that are predicted to affect trace metal transport, central metabolism, and regulation of biofilm production and competence were also selected. These data indicate that experimental evolution can be applied to murine models of pathogenesis to gain insight into organism-specific tissue tropisms. IMPORTANCE Evolution is a powerful force that can be experimentally harnessed to gain insight into how populations evolve in response to selective pressures. Herein we tested the applicability of experimental evolutionary approaches to gain insight into how the major human pathogen Streptococcus pneumoniae responds to repeated colonization events using a murine model. These studies revealed the population dynamics of repeated colonization events and demonstrated that in vivo experimental evolution resulted in highly reproducible trajectories that reflect the environmental niche encountered during nasal colonization. Mutations impacting the surface charge of the bacteria were repeatedly selected during colonization and provided a fitness benefit in this niche that was counterbalanced by a corresponding fitness defect during lung infection. These data indicate that experimental evolution can be applied to models of pathogenesis to gain insight into organism-specific tissue tropisms.

Short-course Gemifloxacin Therapy is Effective Against Streptococcus pneumoniae in a Murine Model of Pneumonia

CHEST Journal ◽  
2004 ◽  
Vol 126 (4) ◽  
pp. 847S
Author(s):  
Darrin J. Bast ◽  
Xueynn Chen ◽  
Ryan Goren ◽  
Mei Yue ◽  
Carla L. Duncan ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Murine Model ◽  
Short Course

scholarly journals Factors Associated With 30-Day Mortality Rate in Respiratory Infections Caused by Streptococcus pneumoniae

2017 ◽  
Vol 66 (8) ◽  
pp. 1282-1285 ◽  
Author(s):  
Matthew P Cheng ◽  
Isaac I Bogoch ◽  
Karen Green ◽  
Agron Plevneshi ◽  
Wallis Rudnick ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Mortality Rate ◽  
Respiratory Infections ◽  
Factors Associated

Biphasic lung injury during Streptococcus pneumoniae infection in a murine model

2018 ◽  
Vol 48 (2) ◽  
pp. 103-113
Author(s):  
A. Prevotat ◽  
C. Rouyer ◽  
P. Gosset ◽  
E. Kipnis ◽  
K. Faure ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Lung Injury ◽  
Murine Model

scholarly journals Streptococcus pneumoniaemeningitis in Alberta pre- and postintroduction of the 7-valent pneumococcal conjugate vaccine

2011 ◽  
Vol 22 (4) ◽  
pp. 137-141 ◽  
Author(s):  
Jennie Johnstone ◽  
Gregory J. Tyrrell ◽  
Thomas J. Marrie ◽  
Sipi Garg ◽  
James D. Kellner ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Mortality Rate ◽  
Conjugate Vaccine ◽  
Invasive Pneumococcal Disease ◽  
High Mortality ◽  
Clinical Characteristics ◽  
Pneumococcal Disease ◽  
Laboratory Data ◽  
Appropriate Therapy ◽  
Meningitis In Children

The objective of this study was to describe the epidemiology, clinical characteristics, microbiology and outcomes of patients of all ages withStreptococcus pneumoniaemeningitis between 2000 and 2004; two years pre- and postintroduction of anS pneumoniae7-valent conjugate vaccine program in Alberta in children younger than two years of age. The high mortality rate associated withS pneumoniaemeningitis, despite appropriate therapy, suggests that prevention ofS pneumoniaemeningitis is critical. Despite implementation of a PCV-7 program in Alberta, rates ofS pneumoniaemeningitis in children younger than two years of age is still high. Thus, continued research into safe and efficacious vaccines covering a broader range ofS pneumoniaeserotypes is necessary.OBJECTIVE: To describe the epidemiology, clinical characteristics, microbiology and outcomes of patients of all ages withStreptococcus pneumoniaemeningitis two years pre- and postintroduction of aS pneumoniae7-valent conjugate vaccine program in Alberta in children <2 years of age.METHODS: Between 2000 and 2004, all cases of invasive pneumococcal disease in Alberta were identified. From this cohort, patients withS pneumoniaemeningitis were identified by chart review. Clinical data, laboratory data and in-hospital outcomes were collected.RESULTS: Of the 1768 cases of invasive pneumococcal disease identified between 2000 and 2004, 110 (6.2%) hadS pneumoniaemeningitis. The overall incidence was 0.7 per 100,000 persons and remained unchanged over the study period. The rate in children <2 years of age appeared to fall over time, from 10.5 per 100,000 persons in 2000 to five per 100,000 persons in 2004, although there was insufficient evidence of a statistically significant time trend within any age group. Overall, the mean age was 30 years and 47% were male. In-hospital mortality was 20%, ranging from 6% in those ≤2 years of age to 31% for those ≥18 years of age, despite appropriate antimicrobial therapy.CONCLUSION: The high mortality rate associated withS pneumoniaemeningitis suggests that prevention by vaccination is critical. In children <2 years of age, there was a downward trend in the rate ofS pneumoniaemeningitis after implementation of theS pneumoniae7-valent conjugate vaccine program, but rates were still high.

A triad of endocarditis, endophthalmitis, and meningitis

Open Medicine ◽  
2013 ◽  
Vol 8 (6) ◽  
pp. 795-798
Author(s):  
Aušra Kavoliūnienė ◽  
Regina Jonkaitienė ◽  
Laura Urbonaitė
Keyword(s):  
Cerebrospinal Fluid ◽  
Streptococcus Pneumoniae ◽  
Infective Endocarditis ◽  
Mortality Rate ◽  
Aortic Valve ◽  
Aortic Valve Replacement ◽  
Transesophageal Echocardiography ◽  
Rare Case ◽  
Antibacterial Treatment ◽  
Infective Complications

AbstractStreptococcus pneumoniae is an uncommon cause of infective endocarditis; it often requires prolonged antibacterial treatment and involves a high mortality rate. We report a rare case of pneumococcal endocarditis manifesting with unusual complications — meningitis and endophthalmitis. Streptococcus pneumoniae species grew from the cerebrospinal fluid. The diagnosis of native aortic valve infective endocarditis was confirmed after some delay by transesophageal echocardiography. The patient’s eye was lost because of infective complications, but his life was saved following an aggressive antibacterial therapy in combination with an immediate aortic valve replacement.

scholarly journals Experimental Evolution in vivo to Identify Selective Pressures During Pneumococcal Colonization

2020 ◽  
Author(s):  
Vaughn S. Cooper ◽  
Erin Honsa ◽  
Hannah Rowe ◽  
Christopher Deitrick ◽  
Amy R. Iverson ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Murine Model ◽  
Experimental Evolution ◽  
Nasal Colonization ◽  
Environmental Niche ◽  
Selective Pressures ◽  
Specific Tissue ◽  
Tissue Tropisms ◽  
Insight Into

AbstractExperimental evolution is a powerful technique to understand how populations evolve from selective pressures imparted by the surrounding environment. With the advancement of whole-population genomic sequencing it is possible to identify and track multiple contending genotypes associated with adaptations to specific selective pressures. This approach has been used repeatedly with model species in vitro, but only rarely in vivo. Herein we report results of replicate experimentally evolved populations of Streptococcus pneumoniae propagated by repeated murine nasal colonization with the aim of identifying gene products under strong selection as well as the population-genetic dynamics of infection cycles. Frameshift mutations in one gene, dltB, responsible for incorporation of D-alanine into teichoic acids on the bacterial surface, evolved repeatedly and swept to high frequency. Targeted deletions of dltB produced a fitness advantage during initial nasal colonization coupled with a corresponding fitness disadvantage in the lungs during pulmonary infection. The underlying mechanism behind the fitness tradeoff between these two niches was found to be enhanced adherence to respiratory cells balanced by increased sensitivity to host-derived antimicrobial peptides, a finding recapitulated in the murine model. Additional mutations were also selected that are predicted to affect trace metal transport, central metabolism and regulation of biofilm production and competence. These data indicate that experimental evolution can be applied to murine models of pathogenesis to gain insight into organism-specific tissue tropisms.ImportanceEvolution is a powerful force that can be experimentally harnessed to gain insight into how populations evolve in response to selective pressures. Herein we tested the applicability of experimental evolutionary approaches to gain insight into how the major human pathogen Streptococcus pneumoniae responds to repeated colonization events using a murine model. These studies revealed the population dynamics of repeated colonization events and demonstrated that in vivo experimental evolution resulted in highly reproducible trajectories that reflect the environmental niche encountered during nasal colonization. Mutations impacting the surface charge of the bacteria were repeatedly selected during colonization and provided a fitness benefit in this niche that was counterbalanced by a corresponding fitness defect during lung infection. These data indicate that experimental evolution can be applied to models of pathogenesis to gain insight into organism-specific tissue tropisms.

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