Related Experiment Video
Updated: May 15, 2026
06:36
Improved Enzyme Protection Assay to Study Staphylococcus aureus Internalization and Intracellular Efficacy of Antimicrobial Compounds
Published on: September 8, 2021
Ultrasonically enhanced rifampin activity against internalized Staphylococcus aureus
Si-Feng Shi1, Xian-Long Zhang, Chen Zhu
1Department of Orthopaedic Surgery, Shanghai Sixth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200233, P.R. China.
Experimental and Therapeutic Medicine
|December 20, 2012
Summary
Low-frequency ultrasound enhances rifampin
Area of Science:
- Microbiology
- Biomedical Engineering
- Cell Biology
Background:
- Staphylococcus aureus (S. aureus) is the primary cause of osteomyelitis, leading to 80% of human cases.
- Intracellular S. aureus within osteoblasts evades immune responses and antibiotic treatments.
- Ultrasound technology can enhance cell membrane permeability, potentially improving drug delivery.
Purpose of the Study:
- To investigate the efficacy of combining low-frequency ultrasound with rifampin against S. aureus internalized in human osteoblasts.
- To assess the impact of ultrasound on osteoblast viability.
- To explore ultrasound-enhanced antibiotic delivery for treating intracellular bacterial infections.
Main Methods:
- Internalization assays were performed to quantify S. aureus within osteoblasts.
- Low-frequency, low-power ultrasound was applied in combination with rifampin.
- Antibacterial effects were measured using Tryptic Soy Agar (TSA), and cell viability was assessed with a Cell Counting Kit-8 (CCK-8) assay.
Main Results:
- Rifampin demonstrated effectiveness in penetrating osteoblasts and eliminating internalized S. aureus.
- Low-frequency ultrasound significantly enhanced the antibacterial activity of rifampin.
- Ultrasound exposure caused minimal and reversible damage to osteoblast cell viability.
Conclusions:
- Combining low-frequency ultrasound with rifampin is a promising strategy for targeting intracellular S. aureus in osteomyelitis.
- This approach enhances antibiotic efficacy against bacteria residing within osteoblasts.
- Ultrasound-enhanced antibiotic therapy may offer a novel method for controlling chronic S. aureus infections and reducing recurrence.
Related Concept Videos
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...
01:25Mechanism 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...
01:27Combined Effects of Drugs: Synergism
Synergism is a useful mechanism where combining two or more drugs is more effective than each constituent used alone. Such combinations are also called supra-additive interactions. The drugs collectively enhance the final therapeutic effect by acting on different targets. Another advantage is that the low dose of each constituent drug is sufficient to achieve the desired effect. This helps reduce the duration of therapy and lower the adverse effects of these drugs.
Such synergistic combinations...
Such synergistic combinations...
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...
01:25Inhibitors of Bacterial Protein Synthesis
Aminoglycosides constitute a highly potent class of bactericidal antibiotics that exert their antimicrobial effects by targeting the bacterial ribosome, specifically disrupting protein synthesis. These polycationic molecules consist of amino-modified sugars linked via glycosidic bonds to an aminocyclitol core such as 2-deoxystreptamine or streptamine. Their strong positive charges facilitate tight binding to the negatively charged phosphate backbone of ribosomal RNA (rRNA), primarily at the 16S...