The effectiveness of an improved combination therapy for experimental Staphylococcus aureus keratitis

Staphylococcus aureus Keratitis: Incidence, Pathophysiology, Risk Factors and Novel Strategies for Treatment

Bacterial keratitis is a devastating condition that can rapidly progress to serious complications if not treated promptly. Certain causative microorganisms such as Staphylococcus aureus and Pseudomonas aeruginosa are notorious for their resistance to antibiotics. Resistant bacterial keratitis results in poorer outcomes such as scarring and the need for surgical intervention. Thorough understanding of the causative pathogen and its virulence factors is vital for the discovery of novel treatments to avoid further antibiotic resistance. While much has been previously reported on P. aeruginosa, S. aureus has been less extensively studied. This review aims to give a brief overview of S. aureus epidemiology, pathophysiology and clinical characteristics as well as summarise the current evidence for potential novel therapies.

Novel Antibacterial Strategies for Combating Bacterial Multidrug Resistance

BACKGROUND

Antibacterial multidrug resistance has emerged as one of the foremost global problems affecting human health. The emergence of resistant infections with the increasing number of multidrug-resistant pathogens has posed a serious problem, which required innovative collaborations across multiple disciplines to address this issue.

METHODS

In this review, we will explain the mechanisms of bacterial multidrug resistance and discuss different strategies for combating it, including combination therapy, the use of novel natural antibiotics, and the use of nanotechnology in the development of efflux pump inhibitors.

RESULTS

While combination therapy will remain the mainstay of bacterial multi-drug resistance treatment, nanotechnology will play critical roles in the development of novel treatments in the coming years.

CONCLUSION

Nanotechnology provides an encouraging platform for the development of clinically relevant and practical strategies to overcome drug resistance in the future.

Eradication of methicillin-resistant Staphylococcus aureus infection by nanoliposomes loaded with gentamicin and oleic acid

CONTEXT

Methicillin-resistant Staphylococcus aureus (MRSA) infection with its high incidence is responsible for nosocomial infections. MRSA strains resistant to multiple antibiotics have emerged increasingly. Recently, combination therapy and efficient drug delivery systems are developed to treat infections.

OBJECTIVE

The aim of the present study was to evaluate antibacterial activities of combination of oleic acid and gentamicin against MRSA, in both free and liposomal forms, and in comparison with vancomycin.

MATERIALS AND METHODS

The antibacterial activities against MRSA ATCC 43300 were assessed by the determination of minimum inhibitory concentration (MIC), MBC, and Fractional Inhibitory Concentration Index (FICI). The time-kill assays were performed to evaluate the potency of antibacterial agents. Nanoliposomal formulations of gentamicin, oleic acid, and combination of gentamicin with oleic acid were prepared by the dehydration-rehydration (DRV) method and characterized for size, zeta potential, and encapsulation efficiency.

RESULTS

MIC values of gentamicin and oleic acid were 19.5 and >250 µg/ml, respectively. Synergetic effects were observed by the gentamicin and oleic acid combination; FICI was 0.5. Following incorporation of gentamicin into liposomal gentamicin and liposomal combination, the MIC values were reduced 15- and 27-fold, respectively. In comparison with vancomycin, liposomal combination was more effective in bacterial inhibition and killing. Liposomal combination was the most effective formula in time-kill study.

DISCUSSION AND CONCLUSION

Liposomal formulation showed a higher antibacterial activity in comparison with the free forms and vancomycin. These carriers can improve antimicrobial activity as well as reducing the effective concentration required and inducing rapid bacterial clearance.