Nasal carriage of methicillin-resistant Staphylococcus aureus and the effect of tea extracts on isolates.

ABSTRACT

OBJECTIVES: This study aimed to determine the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage among patients, healthcare workers (HCWs), and community individuals, as well as to test the effect of tea extracts on detected S. aureus isolates. MATERIALS AND METHODS: This cross-sectional study that was followed by an experimental study included a total of 1021 nasal swab samples that were collected from 470 community cases, 191 HCWs, and 360 patients. Isolation of S. aureus and MRSA was carried out on mannitol salt agar plates. S. aureus isolates were identified according to standard microbiological methods. Methicillin resistance was determined by disc-diffusion method according to the Clinical and Laboratory Standard Institute recommendations. A total of six tea samples (black and green) were purchased from different markets in Alexandria and were extracted. The antibacterial effects of these tea extracts were tested against identified MRSA isolates using agar gel diffusion method. RESULTS: The overall S. aureus nasal carriage rate was 12.5%, distributed as 7.9% MRSA and 4.6% methicillin-susceptible S. aureus. The rates of MRSA nasal carriage among HCWs, patients, and community cases were 10.5, 8.1, and 6.8%, respectively. Green tea had a strong effect on more than half of the isolates (55%) and an intermediate effect on 45% of them. It had no weak effect on any of the MRSA isolates. CONCLUSION: Among all tested individuals, HCWs had the highest percentage of MRSA nasal carriage. Green tea had a significantly stronger inhibitory effect than black tea on almost all tested isolates.