Related Experiment Video

Updated: May 6, 2026

Conjunctival Commensal Isolation and Identification in Mice
07:52

Conjunctival Commensal Isolation and Identification in Mice

Published on: May 1, 2021

3.6K

Genotypic characterization of Staphylococcus aureus isolates from cases of keratitis and healthy conjunctival sacs

Saeko Hayashi1, Takashi Suzuki, Satoshi Yamaguchi

  • 1Department of Ophthalmology, Ehime University Graduate School of Medicine, Toon, Japan.

Cornea
|October 23, 2013
PubMed
Abstract

Insights

Specific methicillin-susceptible Staphylococcus aureus (MSSA) clones are more prevalent in keratitis cases than in healthy eyes. Methicillin-resistant S. aureus (MRSA) genotypes appear similar between keratitis and healthy eye isolates in Japan.

Area of Science:

  • Ophthalmology
  • Microbiology
  • Genetics

Background:

  • Staphylococcus aureus is a leading cause of bacterial keratitis.
  • Increasing rates of drug-resistant S. aureus necessitate understanding its epidemiology.
  • Limited data exists on S. aureus keratitis genotypes in Japan.

Purpose of the Study:

  • To characterize the genotypes of methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) from keratitis and healthy conjunctival sacs in Japan.
  • To investigate potential genotypic differences between S. aureus causing keratitis and those found as commensals.

Main Methods:

  • Multilocus sequence typing (MLST) was performed on 30 keratitis isolates (19 MSSA, 11 MRSA) and 18 healthy conjunctival sac isolates (16 MSSA, 2 MRSA).
  • Prevalence of Panton-Valentine leukocidin genes was assessed.

Main Results:

  • MLST revealed ST5 and ST764 as predominant MRSA sequence types in both keratitis and healthy isolates.
  • ST188 was the most common MSSA type in keratitis isolates, while ST8 predominated in healthy commensal isolates.
  • No isolates harbored Panton-Valentine leukocidin genes.

Conclusions:

  • MRSA strains from keratitis and healthy eyes share similar genotypic profiles.
  • Specific MSSA clones are disproportionately represented in keratitis cases compared to commensal strains.
  • Certain MSSA lineages may possess distinct genotypic traits that enhance their ability to cause keratitis.

More Related Videos

A Non-invasive Way to Isolate and Phenotype Cells from the Conjunctiva07:35

A Non-invasive Way to Isolate and Phenotype Cells from the Conjunctiva

Published on: July 5, 2017

14.2K
Genotyping of Staphylococcus aureus by Ribosomal Spacer PCR RS-PCR08:51

Genotyping of Staphylococcus aureus by Ribosomal Spacer PCR RS-PCR

Published on: November 4, 2016

9.1K

Related Concept Videos

Staphylococcal Skin Infections01:29

Staphylococcal 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...
150
Microbiome of the Eye01:22

Microbiome of the Eye

The human eye has a specialized microbiota that reflects its unique anatomical and immunological environment. This low-biomass microbial community predominantly colonizes the conjunctiva and eyelid margins, playing a vital role in ocular surface homeostasis and defense. Despite its proximity to the richly colonized facial skin, the ocular surface maintains a distinct microbial profile due to continuous mechanical and biochemical defense mechanisms.The conjunctival surface hosts fewer microbial...
75
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...
115