Related Experiment Video

Updated: Feb 8, 2026

Implementation of In Vitro Drug Resistance Assays: Maximizing the Potential for Uncovering Clinically Relevant Resistance Mechanisms
08:46

Implementation of In Vitro Drug Resistance Assays: Maximizing the Potential for Uncovering Clinically Relevant Resistance Mechanisms

Published on: December 9, 2015

11.2K

Pneumococcal resistance to the third-generation cephalosporins: clinical, laboratory and molecular aspects

K P Klugman1

  • 1Department of Medical Microbiology, University of the Witwatersrand and SAIMR, P.O. Box 1038, Johannesburg 2000, South Africa.

International Journal of Antimicrobial Agents
|March 1, 1994
PubMed

Insights

Widespread cephalosporin use drives resistance in pneumococci, impacting meningitis treatment. New breakpoints and MIC testing are recommended for accurate detection of resistant strains.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Pharmacology

Background:

  • Third-generation cephalosporins are crucial for treating bacterial meningitis.
  • Increasing resistance in Streptococcus pneumoniae poses a therapeutic challenge.
  • Previous resistance mechanisms are not fully understood in the context of cephalosporin failure.

Purpose of the Study:

  • To investigate the emergence and mechanisms of third-generation cephalosporin resistance in Streptococcus pneumoniae.
  • To propose new clinical breakpoints for cephalosporin resistance in pneumococcal meningitis.
  • To evaluate diagnostic methods for identifying resistant strains.

Main Methods:

  • Analysis of clinical isolates of Streptococcus pneumoniae.
  • Determination of minimum inhibitory concentrations (MICs) for cephalosporins.
  • Genetic analysis of penicillin-binding proteins (PBPs) including PBP 2X and PBP 1A.
  • Evaluation of oxacillin disk diffusion tests.

Main Results:

  • Widespread use of third-generation cephalosporins has selected for resistant pneumococci.
  • Proposed breakpoints: 0.5 mg/l for intermediate and 2 mg/l for full resistance in pneumococcal meningitis.
  • Oxacillin disk tests do not reliably detect these resistance levels.
  • PBP 2X gene rearrangements confer low-level resistance; PBP 1A rearrangements confer full resistance.

Conclusions:

  • Cephalosporin resistance in pneumococci necessitates revised treatment guidelines for meningitis.
  • MIC or E test confirmation is crucial for strains showing initial resistance to oxacillin.
  • Understanding genetic mechanisms of resistance aids in developing targeted therapies and diagnostics.

More Related Videos

Investigating the Effects of Probiotics on Pneumococcal Colonization Using an In Vitro Adherence Assay09:20

Investigating the Effects of Probiotics on Pneumococcal Colonization Using an In Vitro Adherence Assay

Published on: April 28, 2014

13.1K
Experimental Human Pneumococcal Carriage07:47

Experimental Human Pneumococcal Carriage

Published on: February 15, 2013

16.3K

Related Concept Videos

Resistivity01:22

Resistivity

When a voltage is applied to a conductor, an electrical field is generated, and charges in the conductor feel the force due to the electrical field. The current density that results depends on the electrical field and the properties of the material. In some materials, including metals at a given temperature, the current density is approximately proportional to the electrical field. In these cases, the current density can be modeled as:
4.6K
Resistance01:19

Resistance

When a current moves through any conductor, the conductor causes some level of difficulty for the current to flow. The measure of that difficulty is known as the resistance of the material and is represented by R. Every material has its own resistance. In the case of conductors, heat is emitted whenever a current passes through them. Resistance depends on the resistivity of the material. Resistivity is a characteristic of the material used to fabricate electrical components, whereas the...
6.0K
Quantitative Aspects of Drug-Receptor Interaction01:30

Quantitative Aspects of Drug-Receptor Interaction

The receptor occupancy theory connects a drug's response to the number of occupied receptors. With higher drug concentrations, more receptors are occupied, leading to increased responses. The formation of drug-receptor complexes involves association and dissociation rates, which reach equilibrium when the forward and backward reactions are equal. The equilibrium association constant (Ka) and its inverse, the equilibrium dissociation constant (Kd), indicate drug affinity. Higher Ka and lower...
1.8K
Molecular Models02:00

Molecular Models

Physical models representing molecular architectures of chemical compounds play essential roles in understanding chemistry. The use of molecular models makes it easier to visualize the structures and shapes of atoms and molecules.
43.8K
Molecular Orbital Theory II03:51

Molecular Orbital Theory II

Molecular Orbital Energy Diagrams
27.6K
Molecular Orbital Theory I02:35

Molecular Orbital Theory I

Overview of Molecular Orbital Theory
47.7K