Related Experiment Video

Updated: Jul 29, 2026

Following in Real Time the Impact of Pneumococcal Virulence Factors in an Acute Mouse Pneumonia Model Using Bioluminescent Bacteria
11:32

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

Published on: February 23, 2014

Genetic relatedness among nontypeable pneumococci implicated in sporadic cases of conjunctivitis

J H Barker1, D M Musher, R Silberman

  • 1Department of Medicine, Baylor College of Medicine, Houston, Texas.

Journal of Clinical Microbiology
|November 24, 1999
PubMed

Insights

Nontypeable Streptococcus pneumoniae causes epidemic conjunctivitis. Some sporadic cases are linked to epidemic strains, while others show genetic diversity, indicating varied origins of bacterial conjunctivitis.

Area of Science:

  • Microbiology
  • Ophthalmology
  • Epidemiology

Background:

  • Nontypeable Streptococcus pneumoniae is a frequent cause of epidemic conjunctivitis.
  • A specific clone of this bacterium was previously identified as responsible for a recent conjunctivitis outbreak.

Purpose of the Study:

  • To investigate the genetic relationship between pneumococci causing sporadic conjunctivitis and the previously identified epidemic strain.
  • To determine the clonal relatedness of nontypeable pneumococcus isolates from sporadic conjunctivitis cases.

Main Methods:

  • Molecular fingerprinting using arbitrarily primed BOX-PCR was employed.
  • Ten isolates of nontypeable Streptococcus pneumoniae from sporadic conjunctivitis cases were analyzed.

Main Results:

  • Five of the ten sporadic isolates were found to be clonal and closely related to the epidemic strain.
  • The remaining five sporadic isolates exhibited significant genetic diversity, suggesting different origins.

Conclusions:

  • Sporadic cases of conjunctivitis caused by nontypeable Streptococcus pneumoniae can originate from the same clonal strains responsible for outbreaks.
  • However, other genetically diverse strains also contribute to sporadic bacterial conjunctivitis, highlighting the complex epidemiology of this infection.

More Related Videos

Capsular Serotyping of Streptococcus pneumoniae by Latex Agglutination09:11

Capsular Serotyping of Streptococcus pneumoniae by Latex Agglutination

Published on: September 25, 2014

Constructing Mutants in Serotype 1 Streptococcus pneumoniae strain 519/4306:06

Constructing Mutants in Serotype 1 Streptococcus pneumoniae strain 519/43

Published on: September 11, 2020

Related Concept Videos

Pneumonia I: Introduction01:30

Pneumonia I: Introduction

Pneumonia is an acute respiratory infection that targets the lungs, specifically the alveoli. These tiny air sacs, essential for oxygen exchange, become engorged with pus and fluid, severely hindering breathing, decreasing oxygen absorption, and causing significant pain and discomfort during respiration.
Risk Factors
Various factors influence the likelihood of developing pneumonia. Age plays a crucial role, with infants, children under two, and individuals over 65 at increased risk due to their...
Phylogenetic Species Concept in Microbiology01:22

Phylogenetic Species Concept in Microbiology

The phylogenetic species concept (PSC) is a framework used to delineate species based on evolutionary relationships, emphasizing shared ancestry and diagnosable genetic traits. Unlike morphological or biological species concepts, the PSC is particularly advantageous for microbial taxonomy, where traditional reproductive or phenotypic criteria often fall short due to the prevalence of asexual reproduction, minimal morphological differentiation, and widespread horizontal gene transfer among...
Streptococcal Pharyngitis01:27

Streptococcal Pharyngitis

Streptococcal pharyngitis, commonly known as “strep throat,” is an acute infection of the oropharyngeal tissues caused by the Gram‑positive Group A Streptococcus (Streptococcus pyogenes). Transmission occurs primarily through respiratory droplets expelled during coughing, sneezing, or talking.Mechanisms of Host Entry and Immune EvasionUpon entering the host, S. pyogenes adheres to the mucosal epithelial cells of the pharynx via surface proteins, notably lipoteichoic acid and the antiphagocytic...
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...
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...
Pneumonia I: Introduction01:29

Pneumonia I: Introduction

Pneumonia is an infection of the lower respiratory tract that leads to inflammation of the lung parenchyma, often resulting in the accumulation of inflammatory exudate in the alveoli and airways. Unlike the watery, low-protein fluid exudate in pulmonary edema, the exudate in this case is a thick fluid rich in immune cells, proteins, and debris produced during infection and inflammation.This impairs gas exchange and can lead to consolidation of lung tissue. The infection may be caused by a...