Methicillin Resistant Staphylococcus aureus: Molecular Mechanisms Underlying Drug Resistance Development and Novel Strategies to Combat

Antimicrobial resistance (AMR) represents a major threat to global health. Infection caused by Methicillin-resistant Staphylococcus aureus (MRSA) is one of the well-recognized global public health problem globally. In some regions, as many as 90% of S. aureus infections are reported to be MRSA, which cannot be treated with standard antibiotics. WHO reports indicated that MRSA is circulating in every province worldwide, significantly increasing the risk of death by 64% compared to drug-sensitive forms of the infection which is attributed to its antibiotic resistance. The emergence and spread of antibiotic-resistant MRSA strains have contributed to its increased prevalence in both healthcare and community settings. The resistance of S. aureus to methicillin is due to expression of penicillin-binding protein 2a (PBP2a), which renders it impervious to the action of β-lactam antibiotics including methicillin. The other is through the production of beta-lactamases. Although the treatment options for MRSA are limited, there are promising alternatives to antibiotics to combat the infections. Innovative therapeutic strategies with wide range of activity and modes of action are yet to be explored. The review highlights the global challenges posed by MRSA, elucidates the mechanisms underlying its resistance development, and explores mitigation strategies. Furthermore, it focuses on alternative therapies such as bacteriophages, immunotherapy, nanobiotics, and antimicrobial peptides, emphasizing their synergistic effects and efficacy against MRSA. By examining these alternative approaches, this review provides insights into the potential strategies for tackling MRSA infections and combatting the escalating threat of AMR. Ultimately, a multifaceted approach encompassing both conventional and novel interventions is imperative to mitigate the impact of MRSA and ensure a sustainable future for global healthcare.

Comparing Watchful Waiting Approach vs. Antibiotic Therapy in Children with Nonsevere Acute Otitis Media: A Randomized Clinical Trial

Objective

To compare both approaches for the treatment of nonsevere acute otitis media (AOM) in Iran.

Methods

This randomized clinical trial was performed at a pediatric infectious diseases clinic in Buali tertiary hospital in Sari, north of Iran, from 2016 to 2018. All participants in this study were previously healthy children with AOM diagnosis, who were 6 months to 6 years old. The patients were randomly assigned into two groups: the intervention (80 mg/kg/day amoxicillin for 7-10 days) and the control group (watchful waiting approach). AOM recovery and adverse drug reactions were evaluated after 72 hours, and the patients were followed for the frequency of AOM and middle ear effusion 1 and 3 months' postintervention.

Results

A total of 396 children have participated in this study. AOM recovery was significantly different in the two groups (73% vs. 44% in the intervention and control groups, respectively). Recurrence of AOM and middle ear effusion (MEE) persistence, one month following the intervention, have not shown any significant differences between the two groups. However, the AOM recurrence between 1 and 3 months was more frequent in the control group. The frequency of diarrhea was also higher in the intervention group compared to the control but no significant difference was found between the two groups regarding vomiting and skin rash.

Conclusion

The faster recovery from AOM is achieved when an antibiotic treatment regimen is applied, although the risk of potential side effects should be considered.

Evaluation of in-situ gel-forming eye drop containing bacteriophage against Pseudomonas aeruginosa keratoconjunctivitis in vivo

Introduction: Eradication of Pseudomonas aeruginosa has become increasingly difficult due to its remarkable capacity to resist antibiotics. Bacteriophages have been suggested as an alternative treatment for bacterial infections. Methods: In-situ gel-forming eye drop containing phage against P. aeruginosa keratoconjunctivitis was prepared. The Cystoviridae phage was formulated as in-situ gel-forming formulation which is a solution formulation but turns into gel when it contacts the eye. Therapeutic effectiveness of the in-situ gel forming formulation was evaluated by histological examination on day 12 post-infection. Results: The viscosity of selected formulation increased when it was instilled into the eye. The histological results showed edema, abscesses, and destruction of the stromal structure of cornea in groups where no in-situ gel-forming formulation was used. In the group where in-situ gel forming formulation was used, re-epithelialization and normal corneal structure were observed. Conclusion: In-situ gel-forming ophthalmic formulation containing phage can be effective in the treatment of P. aeruginosa keratoconjunctivitis.