Related Experiment Video
Updated: May 30, 2026
07:44
Time-Lapse Epifluorescence Microscopy Imaging of Pseudomonas aeruginosa and Staphylococcus aureus Heterogeneous Phenotypes
Published on: February 14, 2025
Ophthalmic antibiotic use and multidrug-resistant staphylococcus epidermidis: a controlled, longitudinal study
Sarita B Dave1, Hassanain S Toma, Stephen J Kim
1Department of Ophthalmology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
Ophthalmology
|August 23, 2011
Summary
Repeated topical antibiotic use, including fluoroquinolones and azithromycin, significantly increases multidrug resistance in conjunctival Staphylococcus epidermidis. This co-resistance extends to other antibiotic classes, posing a clinical challenge.
Area of Science:
- Ophthalmology
- Microbiology
- Infectious Diseases
Background:
- Staphylococcus epidermidis is a common cause of ocular infections.
- Antibiotic resistance is a growing global health concern.
- Topical antibiotics are frequently used in ophthalmology, particularly for intravitreal injections.
Purpose of the Study:
- To investigate the development of multidrug-resistant Staphylococcus epidermidis following repeated conjunctival exposure to topical macrolide or fluoroquinolone antibiotics.
- To analyze changes in antibiotic susceptibility patterns of S. epidermidis in eyes undergoing serial intravitreal injections.
Main Methods:
- Prospective, controlled, longitudinal study with 1-year follow-up.
- 24 patients received serial unilateral intravitreal injections for choroidal neovascularization.
- Conjunctival cultures and antibiotic susceptibility testing (Kirby-Bauer disc diffusion) were performed on treated and control eyes.
Main Results:
- Repeated exposure to fluoroquinolones or azithromycin led to a significant increase in multidrug-resistant S. epidermidis.
- S. epidermidis in treated eyes showed increased resistance to third- and fourth-generation fluoroquinolones, macrolides, trimethoprim/sulfamethoxazole, gentamicin, clindamycin, and doxycycline.
- Resistance to 3 or more antibiotics increased from 69% in control eyes to 90% in treated eyes after 4 treatments.
Conclusions:
- Topical fluoroquinolone and azithromycin antibiotics promote rapid resistance development in conjunctival S. epidermidis.
- Observed co-resistance to other antibiotic classes highlights the broader impact of targeted antibiotic use.
- Findings underscore the need for judicious antibiotic use in ophthalmic practice to mitigate resistance.
Related Concept Videos
01:22Microbiome 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...
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...
01:23Ophthalmic Drug Delivery Systems
Ophthalmic drug delivery faces major limitations due to poor absorption across the corneal membrane. This process is primarily driven by diffusion and is influenced by two main factors: the physicochemical properties of the drug and tear drainage. Most ophthalmic drugs, such as pilocarpine, epinephrine, atropine, and local anesthetics, are weak bases. They are typically formulated at an acidic pH to enhance chemical stability. However, this leads to high ionization, reducing their ability to...
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...
01:25Mechanism 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...
01:30Development of Antibiotic Resistance
Antibiotic resistance is a major public health concern that arises when bacteria evolve mechanisms to withstand the effects of antibiotic treatments. This resistance can be intrinsic, acquired through genetic mutations, or transferred between bacteria via horizontal gene transfer. The development of antibiotic resistance poses significant challenges in treating bacterial infections and necessitates ongoing research to develop new therapeutic strategies.Intrinsic resistance occurs when bacterial...