Background: Staphylococcus aureus (S. aureus) is the most common infectious agent in the
community and hospitals. Infections with S. aureus are now becoming difficult to be treated by using
conventional antibiotics due to its emerging methicillin-resistant S. aureus (MRSA) strain.
Objective: In the present study, MRSA was isolated from clinical samples and evaluated for resistance
against different antibiotics, TiO2 nanoparticles, and their combinations.
Methods: Clinical samples were collected from Ayub Medical Complex (AMC), Abbottabad, Pakistan,
and identified by different biochemical tests and polymerase chain reactions (PCR). Kirby-Bauer
disk diffusion method was performed to evaluate antimicrobial susceptibility. Minimum Inhibitory
Concentration (MIC) of ampicillin, ciprofloxacin, erythromycin, and vancomycin was found out by
agar dilution method while the broth dilution method was used for the MIC of TiO2 nanoparticles and
their combinations with erythromycin.
Results: All 13/100 (13%) MRSA were successfully identified. All isolates were susceptible to quinupristin/
dalfopristin, teicoplanin, and vancomycin, while the highest resistance was seen with erythromycin,
penicillin, and tetracycline. MIC showed high resistance against ampicillin (0.25-512 mg/L)
and erythromycin (0.25-1024 mg/L).
Conclusion: The MIC value of 2 mM TiO2 nanoparticles was found to be the most effective concentration
after 12 h of incubation, while the combination of erythromycin with 3 mM TiO2 nanoparticles was
found to be more potent which significantly lowered down the MIC of erythromycin to 2-16 mg/L.