Related Experiment Video
Updated: Jun 23, 2026
09:03
Multiplex PCR Assay for Typing of Staphylococcal Cassette Chromosome Mec Types I to V in Methicillin-resistant Staphylococcus aureus
Published on: September 5, 2013
Reclassification of Staphylococcus aureus nasal carriage types
Alex van Belkum1, Nelianne J Verkaik, Corné P de Vogel
1Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands.
The Journal of Infectious Diseases
|May 8, 2009
Summary
Persistent Staphylococcus aureus nasal carriers are distinct from intermittent carriers and noncarriers. Persistent carriers show longer colonization, higher bacterial loads, and different antibody responses, suggesting two carrier types.
Area of Science:
- Microbiology
- Immunology
- Infectious Diseases
Background:
- Persistent Staphylococcus aureus nasal carriage is linked to higher infection risk.
- Intermittent carriers and noncarriers share a similar low risk of infection.
Purpose of the Study:
- To investigate differences in Staphylococcus aureus nasal carriage types.
- To understand the factors contributing to persistent S. aureus colonization.
Main Methods:
- Artificial colonization of volunteers with S. aureus strains.
- Comparison of intranasal S. aureus survival between carriage groups.
- Analysis of antistaphylococcal antibody levels in relation to carriage state.
Main Results:
- Persistent carriers selectively re-established their own S. aureus strain.
- Persistent carriers maintained colonization longer (154 days) than intermittent (14 days) or noncarriers (4 days).
- Persistent carriers exhibited higher S. aureus colony-forming units and distinct antibody profiles (IgG, IgA).
Conclusions:
- Intermittent carriers and noncarriers share similar S. aureus nasal elimination and antibody profiles.
- A paradigm shift suggests two main nasal carrier types: persistent and others.
- This classification aids in understanding Staphylococcus aureus infection susceptibility.
Related Concept Videos
01:29Staphylococcal Skin Infections
Staphylococcus aureus is a Gram-positive coccus that resides harmlessly on the skin and mucous membranes of healthy individuals. When the skin barrier is breached, it can shift from a commensal to an opportunistic pathogen. This transition is facilitated by surface adhesins, such as clumping factor B and S. aureus surface protein G (SasG), which bind to structural proteins, including loricrin and cytokeratin, in the damaged epidermis. Protein A, another key factor, binds the Fc region of...
01:25Clinical 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...
01:29Microbiota of the Respiratory Tract
The human respiratory tract, comprising the upper and lower segments, serves as a critical interface with the external environment. The upper respiratory tract (URT)—including the nostrils, sinuses, pharynx, and oropharynx—is heavily colonized by microbes, while the lower respiratory tract (LRT), composed of the larynx, trachea, bronchi, and lungs, was long thought to be sterile. However, recent molecular studies have revealed that the lungs are not devoid of microbes but act more like...
01:25Mechanism 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...
01:24Microbial Classification System
Classification is the process of organizing organisms into hierarchically inclusive groups based on their phenotypic similarities or evolutionary relationships. A species comprises one or more strains, and closely related species are grouped into genera. Genera are further classified into families, families into orders, orders into classes, and so forth, up to the domain level, which is the broadest taxonomic rank derived from a combination of phenotypic and genotypic data.The nomenclature of...
01:28Methods of Classification and Identification
Bacterial identification relies on a diverse array of techniques to classify and understand microorganisms, each tailored to uncover specific characteristics. Traditional morphological approaches, while still valuable, are limited for closely related or structurally simple organisms. Modern methods integrate biochemical, serological, genetic, and advanced molecular tools to achieve greater accuracy.Morphological and Biochemical TechniquesMorphological characteristics, such as cell shape and...