Objectives. The increasing prevalence of antibiotic-resistant Staphylococcus aureus, besides the inadequate numbers of effective antibiotics, emphasises the need to find new therapeutic agents against this lethal pathogen. Methods. In this study, to obtain antibody fragments against S. aureus, a human single-chain fragment variable (scFv) library was enriched against living methicillin-resistant S. aureus (MRSA) cells, grown in three different conditions, that is human peripheral blood mononuclear cells with plasma, whole blood and biofilm. The antibacterial activity of scFvs was evaluated by the growth inhibition assay in vitro. Furthermore, the therapeutic efficacy of anti-S. aureus scFvs was appraised in a mouse model of bacteraemia. Results. Three scFv antibodies, that is MEH63, MEH158 and MEH183, with unique sequences, were found, which exhibited significant binding to S. aureus and reduced the viability of S. aureus in in vitro inhibition assays. Based on the results, MEH63, MEH158 and MEH183, in addition to their combination, could prolong the survival rate, reduce the bacterial burden in the blood and prevent inflammation and tissue destruction in the kidneys and spleen of mice with MRSA bacteraemia compared with the vehicle group (treated with normal saline). Conclusion. The combination therapy with anti-S. aureus scFvs and conventional antibiotics might shed light on the treatment of patients with S. aureus infections.

Breast cancer is the most common cancer diagnosed in women, with an estimated 12% of women in the United States affected during their lifetime. Researchers have demonstrated that early detection, diagnosis, and treatment are pivotal to increasing survival. The advent of nanotechnology has yielded several novel advances and available modern methods within the clinic to detect and treat breast cancer. Inorganic nanoparticles are broadly utilized for cancer diagnosis and therapeutic purposes. Interestingly, these nanoparticles can also be attached to tumor-specific ligands and used to deliver chemotherapeutic or hormonal agents with high levels of tumor selectivity. Iron oxide nanoparticles are one of the most commonly used nanomaterials, which have attracted much attention to detect and treat breast cancers, owing to their superparamagnetic characteristics. Computerized tomography and magnetic resonance imaging (MRI) utilizing iron-based magnetic nanoparticles are promising approaches for the radiological detection of breast cancer. Here, we discuss the roles and recent applications of iron oxide nanoparticles in diagnosing and treating breast cancer.

Background Staphylococcal superantigens are virulence factors that help the pathogen escape the immune system and develop an infection. Toxic shock syndrome toxin (TSST)-1 is one of the most studied superantigens whose role in toxic shock syndrome and some particular disorders have been demonstrated. Inhibiting TSST-1 production with antibiotics and targeting TSST-1 with monoclonal antibodies might be one of the best strategies to prevent TSST-1-induced cytokines storm followed by lethality. Results A novel single-chain variable fragment (scFv), MS473, against TSST-1 was identified by selecting an scFv phage library on the TSST-1 protein. The MS473 scFv showed high affinity and specificity for TSST-1. Moreover, MS473 could significantly prevent TSST-1-induced mitogenicity (the IC50 value: 1.5 µM) and cytokine production. Conclusion Using traditional antibiotics with an anti-TSST-1 scFv as a safe and effective agent leads to deleting the infection source and preventing the detrimental effects of the toxin disseminated into the whole body.