Related Experiment Video

Updated: Jul 14, 2026

A Robust Pneumonia Model in Immunocompetent Rodents to Evaluate Antibacterial Efficacy against S. pneumoniae, H. influenzae, K. pneumoniae, P. aeruginosa or A. baumannii
09:17

A Robust Pneumonia Model in Immunocompetent Rodents to Evaluate Antibacterial Efficacy against S. pneumoniae, H. influenzae, K. pneumoniae, P. aeruginosa or A. baumannii

Published on: January 2, 2017

Change in pneumococcal susceptibility to azithromycin during treatment for acute otitis media

Philip Toltzis1, Michael Dul, Jeffrey Blumer

  • 1Department of Pediatrics, Rainbow Babies and Children's Hospital, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA. pxt2@case.edu

The Pediatric Infectious Disease Journal
|June 29, 2007
PubMed

Insights

Reducing azithromycin use alone may not stop azithromycin-nonsusceptible Streptococcus pneumoniae (ANSP) spread. Other antibiotic use also contributes to ANSP dissemination, requiring broader antibiotic stewardship strategies.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Pediatrics

Background:

  • Azithromycin-nonsusceptible Streptococcus pneumoniae (ANSP) poses a growing public health concern.
  • Restriction of azithromycin use is proposed to control ANSP spread.
  • Pneumococcal colonization is common in children, particularly those with acute otitis media.

Purpose of the Study:

  • To investigate the acquisition of new or altered Streptococcus pneumoniae strains in children during and after antibiotic treatment for acute otitis media.
  • To determine the impact of azithromycin and beta-lactam exposure on the emergence of ANSP.
  • To evaluate the effectiveness of azithromycin restriction as a sole strategy for ANSP containment.

Main Methods:

  • Prospective study of 83 children with persistent pneumococcal colonization.
  • Microbiological analysis of Streptococcus pneumoniae isolates before, during, and after antibiotic treatment.
  • Assessment of antibiotic susceptibility, including azithromycin and beta-lactam agents.

Main Results:

  • 17 out of 83 children acquired new Streptococcus pneumoniae strains.
  • Nine of these new strains exhibited reduced susceptibility to azithromycin compared to the initial isolates.
  • Emergence of ANSP was observed following exposure to both azithromycin and beta-lactam antibiotics.

Conclusions:

  • Azithromycin-nonsusceptible Streptococcus pneumoniae can emerge even after treatment with other antibiotics.
  • Reducing azithromycin use alone may be insufficient to contain ANSP.
  • Comprehensive antibiotic stewardship, including reduction of other antibiotic classes, is necessary to control ANSP dissemination.

Related Concept Videos

Mechanism of Antibiotic Resistance in MRSA01:25

Mechanism of Antibiotic Resistance in MRSA

Antibiotic resistance in bacteria arises when microorganisms evolve the ability to withstand drugs designed to kill them or inhibit their growth, rendering once-effective treatments useless. This phenomenon, driven by genetic change and selection under antibiotic exposure, poses a profound threat to modern medicine. Mechanisms include drug-inactivating enzymes (e.g., β-lactamases), efflux pumps that eject antibiotics, mutations altering antibiotic targets, decreased drug uptake, and acquisition...
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...
Acute Pharyngitis01:30

Acute Pharyngitis

Introduction
Acute pharyngitis is the inflammation of the back of the throat (pharynx), commonly resulting in a sore throat. It is a frequently encountered condition that prompts individuals to seek medical advice.
Classification
Acute pharyngitis can be categorized based on its underlying cause:
Factors Affecting the Risk of Infection01:26

Factors Affecting the Risk of Infection

The hosts' susceptibility to infection depends on several factors. The integrity of the skin and mucous membranes helps protect the body against microbial attacks. When the skin is altered, the chance of infection, limb loss, and even death increases.
The integrity and count of the white blood cells help the body resist pathogens and fight infection. When impaired, it reduces the body's resistance to pathogens. The acidic pH levels of the gastrointestinal, genitourinary tracts, and skin create...
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...