Related Experiment Video

Updated: Jul 3, 2026

Experimental Human Pneumococcal Carriage
07:47

Experimental Human Pneumococcal Carriage

Published on: February 15, 2013

Comparison of Typical and Atypical Community Acquired Pneumonia Cases in Hospitalized Patients in Two Tertiary

Abdullah Almufleh1, Abdulrahman Altuwayjiri1, Abdulmalik Alshehri1

  • 1College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh 14611, Saudi Arabia.

Advances in Respiratory Medicine
|December 24, 2025
PubMed
Abstract

Insights

Atypical community-acquired pneumonia (CAP) is uncommon in hospitalized patients, with Mycoplasma pneumoniae being the most frequent cause. Patients with atypical CAP experienced shorter hospital stays and better outcomes, suggesting expanded molecular testing could improve diagnosis and treatment.

Area of Science:

  • Infectious Diseases
  • Pulmonology
  • Microbiology

Background:

  • Community-acquired pneumonia (CAP) presents as typical or atypical forms.
  • Common atypical pathogens include Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila.
  • Typical pathogens commonly include Streptococcus pneumoniae and Haemophilus influenzae.

Purpose of the Study:

  • To compare the prevalence, demographics, and clinical outcomes of hospitalized typical and atypical CAP patients.
  • To assess the utility of molecular testing in identifying CAP pathogens.

Main Methods:

  • A cross-sectional study was conducted from January 2016 to June 2022 in Riyadh, Saudi Arabia.
  • Inclusion criteria: hospitalized patients with CAP diagnosed via imaging and clinical findings (excluding viral cases).
  • Outcomes: pathogen testing, hospitalization duration, ICU stay, and in-hospital mortality.

Main Results:

  • Atypical pathogens were detected in 2.09% of 1238 CAP hospitalizations, with Mycoplasma pneumoniae being most common.
  • Patients with atypical pneumonia had significantly shorter mean hospitalizations (4 days) compared to overall CAP (12 days).
  • No atypical CAP cases required ICU admission or resulted in mortality.

Conclusions:

  • Atypical pneumonia organisms are infrequent causes of CAP in hospitalized patients, despite molecular testing in 65% of cases.
  • Patients with atypical CAP demonstrated more favorable clinical outcomes.
  • Increased utilization of molecular testing may enhance pathogen identification and guide targeted CAP management.
Keywords:
Chlamydia pneumoniaeLegionella pneumophilaMycoplasma pneumoniaeSaudi Arabiaatypical pneumoniacommunity-acquired pneumoniaepidemiologymolecular testingmultiplex PCR

More Related Videos

Murine Oropharyngeal Aspiration Model of Ventilator-associated and Hospital-acquired Bacterial Pneumonia04:32

Murine Oropharyngeal Aspiration Model of Ventilator-associated and Hospital-acquired Bacterial Pneumonia

Published on: June 28, 2018

COVID-19 Seroprevalence Test for IgG Antibody Levels Among Healthy Donors Across Different Pandemic Phases in Jeddah04:43

COVID-19 Seroprevalence Test for IgG Antibody Levels Among Healthy Donors Across Different Pandemic Phases in Jeddah

Published on: June 24, 2025

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...
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:
Acute Pyelonephritis II: Diagnostic Studies and Management01:28

Acute Pyelonephritis II: Diagnostic Studies and Management

Introduction:For diagnosing acute pyelonephritis, a comprehensive patient history is collected to identify symptoms such as dysuria, frequent or urgent urination, flank pain, or costovertebral angle (CVA) tenderness that may suggest a kidney infection.Physical ExaminationDuring the physical examination, CVA tenderness is assessed. This involves gentle percussion over the costovertebral angle, where tenderness often indicates a kidney infection.Diagnostic TestsUrinalysis: Used to identify white...
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 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...