Related Experiment Video

Updated: Aug 15, 2026

Characterization of Inflammatory Responses During Intranasal Colonization with Streptococcus pneumoniae
09:12

Characterization of Inflammatory Responses During Intranasal Colonization with Streptococcus pneumoniae

Published on: January 17, 2014

Virulence in mice of pneumococcal clonal types with known invasive disease potential in humans

Andreas Sandgren1, Barbara Albiger, Carlos J Orihuela

  • 1Swedish Institute for Infectious Disease Control, Solna, Sweden.

The Journal of Infectious Diseases
|August 10, 2005
PubMed

Insights

Different Streptococcus pneumoniae clones cause varying disease severity and host responses in mice. Serotype 4 clones caused severe invasive disease, while serotype 1 clones caused mild bacteremia, highlighting the importance of clonal type and host factors.

Area of Science:

  • Microbiology
  • Immunology
  • Infectious Diseases

Background:

  • Streptococcus pneumoniae causes significant human disease.
  • Specific serotypes and clonal types are associated with invasive potential.
  • Host factors influence disease development.

Purpose of the Study:

  • To investigate the impact of different Streptococcus pneumoniae clonal types on disease development in mice.
  • To compare disease severity and host responses between various serotypes and clonal types.
  • To explore the role of host genetics in pneumococcal meningitis susceptibility.

Main Methods:

  • Infection of C57BL/6 and BALB/c mice with S. pneumoniae isolates of serotypes 1, 4, 6B, 7F, 14, and 19F.
  • Assessment of nasopharyngeal colonization, bacterial load, and disease severity.
  • Monitoring of host immune responses, including tumor necrosis factor (TNF) production.
  • Comparison of disease kinetics and outcomes between different clonal types and mouse strains.

Main Results:

  • Most S. pneumoniae isolates colonized the nasopharynx; ST162 (serotype 19F) showed higher bacterial numbers.
  • Serotype 4 clones induced the most severe invasive disease, while serotype 1 clones caused minimal bacteremia.
  • BALB/c mice exhibited higher susceptibility to meningitis compared to C57BL/6 mice.
  • Disease kinetics and TNF responses varied significantly among clonal types, with some serotype 1 and 7F isolates eliciting weak responses.

Conclusions:

  • Capsular serotype, clonal properties, and host factors are critical determinants of pneumococcal disease development and severity.
  • Distinct clonal types of S. pneumoniae can elicit differential host immune responses.
  • Mouse models reveal strain-specific variations in colonization, invasion, and host response to pneumococcal infections.

More Related Videos

Following in Real Time the Impact of Pneumococcal Virulence Factors in an Acute Mouse Pneumonia Model Using Bioluminescent Bacteria11:32

Following in Real Time the Impact of Pneumococcal Virulence Factors in an Acute Mouse Pneumonia Model Using Bioluminescent Bacteria

Published on: February 23, 2014

Inducing Meningococcal Meningitis Serogroup C in Mice via Intracisternal Delivery10:03

Inducing Meningococcal Meningitis Serogroup C in Mice via Intracisternal Delivery

Published on: November 5, 2019

Related Concept Videos

Determinants of Bacterial Pathogenicity and Virulence01:20

Determinants of Bacterial Pathogenicity and Virulence

Pathogenic bacteria employ a variety of strategies to establish infections, including the secretion of extracellular enzymes that act as potent virulence factors. These enzymes facilitate bacterial colonization of host tissues and help evade immune surveillance. By targeting structural components of host tissues and interfering with immune mechanisms, these enzymes play a pivotal role in disease progression.Extracellular Enzymes Facilitating Tissue Invasion: Several bacterial pathogens secrete...
Bacterial Meningitis01:24

Bacterial Meningitis

Bacterial meningitis is a severe infectious disease involving inflammation of the meninges, the protective membranes surrounding the brain and spinal cord. It occurs when pathogenic bacteria cross the blood–brain barrier and enter the cerebrospinal fluid. Common causative organisms include Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae type b, Listeria monocytogenes, and Escherichia coli K1. The exact route of entry varies by pathogen and host condition.Routes of Entry...
Atypical Pneumonia01:14

Atypical Pneumonia

Atypical pneumonia, often caused by Mycoplasma pneumoniae, is a form of pulmonary infection that differs from the classical presentation of bacterial pneumonia in both its cause and clinical symptoms. Mycoplasma pneumoniae is a pleomorphic bacterium notable for its lack of a rigid cell wall. This structural characteristic imparts resistance to beta-lactam antibiotics and significantly influences the bacterium’s behavior within the human host.Other pathogens responsible for the disease include...
Clinical Significance of Antibiotic Resistance01:25

Clinical Significance of Antibiotic Resistance

Methicillin-resistant Staphylococcus aureus (MRSA) presents a critical public health threat, arising from its capacity to resist β-lactam antibiotics due to acquisition of the mecA gene within the staphylococcal cassette chromosome mec (SCCmec). This gene encodes penicillin-binding protein 2a (PBP2a), which impairs binding efficacy of methicillin and other β-lactams. MRSA has evolved into distinct clonal lineages impacting humans and animals alike, reinforcing its significance within the One...
Bacterial Meningitis II: Pathophysiology01:26

Bacterial Meningitis II: Pathophysiology

Bacterial meningitis typically begins when pathogens such as Neisseria meningitidis and Streptococcus pneumoniae colonize the nasopharynx and invade the bloodstream. This process is facilitated by bacterial virulence factors, such as polysaccharide capsules, which resist phagocytosis and complement-mediated killing. Less commonly, bacteria reach the central nervous system via contiguous spread from infections like otitis media or sinusitis, through congenital or acquired dural defects, or...