Related Experiment Video

Updated: Jun 23, 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

Severity of pneumococcal pneumonia associated with genomic bacterial load

Jordi Rello1, Thiago Lisboa1, Manel Lujan2

  • 1Critical Care Department, Hospital Universitari Joan XXIII, Tarragona, Spain; University Rovira i Virgili, IISPV, Tarragona, Spain; Centro de Investigacíon Biomedica en Red Enfermedades Respiratorias (CIBERes), Tarragona, Spain.

Chest
|May 13, 2009
PubMed
Abstract

Insights

Bacterial load in Streptococcus pneumoniae pneumonia correlates with increased mortality and risk of septic shock. Measuring bacterial DNA can help assess disease severity in patients with community-acquired pneumonia.

Area of Science:

  • Infectious Diseases
  • Critical Care Medicine
  • Molecular Diagnostics

Background:

  • Community-acquired pneumonia (CAP) requires objective markers for risk stratification.
  • Current methods lack precision in identifying patients with high risk for septic shock and adverse outcomes.
  • Bacterial load is hypothesized to correlate with outcomes in pneumococcal pneumonia.

Purpose of the Study:

  • To investigate the association between Streptococcus pneumoniae bacterial load and clinical outcomes in CAP patients.
  • To determine if bacterial DNA levels can serve as a predictive marker for disease severity.

Main Methods:

  • Prospective study of 353 patients admitted with CAP symptoms.
  • Real-time polymerase chain reaction (rt-PCR) used to quantify S. pneumoniae DNA in whole blood.
  • Analysis of outcomes including mortality, septic shock, and mechanical ventilation.

Main Results:

  • S. pneumoniae identified in 93 patients (36.5%); rt-PCR positive in these cases.
  • Higher S. pneumoniae DNA levels significantly correlated with increased mortality (OR 7.08), shock (OR 6.29), and mechanical ventilation (OR 7.96).
  • Bacterial load independently predicted septic shock (aOR 2.42) and mechanical ventilation (aOR 2.71). A load >= 10^3 copies/mL showed heightened risk for shock, ventilation, and mortality.

Conclusions:

  • Bacterial load in pneumococcal pneumonia is a significant predictor of mortality, septic shock, and need for mechanical ventilation.
  • High S. pneumoniae genomic load may serve as a valuable tool for assessing disease severity.
  • Objective bacterial quantification can improve risk stratification in CAP patients.

More Related Videos

Experimental Human Pneumococcal Carriage07:47

Experimental Human Pneumococcal Carriage

Published on: February 15, 2013

Related Concept Videos

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...
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...
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...
Pneumonia II: Pathophysiology01:29

Pneumonia II: Pathophysiology

The pathophysiology of pneumonia involves the following steps:
Pneumonia III: Complications and Assessment01:30

Pneumonia III: Complications and Assessment

Pneumonia poses the potential for numerous complications that warrant consideration. These complications include the following:
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...