الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
MRSA has been recognized as an increasingly important pathogen in both hospital
and community settings worldwide.(1) It was initially described in 1961 and has emerged in
the last decade as one of the most important healthcare associated pathogens.(2)
By far the most important reservoir for MRSA and the most important source for
spread and subsequent infections is colonized patients with no signs of infection.(5) The
anterior nares are the most important sites of colonization.(6) Evidence suggests that the
exposure to the hospital environment for a prolonged duration may cause an increase in
carriage of MRSA among hospital personnel.(7)
The several and serious side effects of commonly used antibiotics, together with the
development of drug resistant human pathogens against most of the commonly used
antibiotics; necessitates the search for new and alternative antimicrobial agents from other
sources including plants.
The present work aimed at studying the occurrence of MRSA nasal carriage among
patients, HCWs and community individuals, together with testing the effect of tea extracts
on detected S.aureus isolates.
This cross sectional study that was followed by an experimental study was conducted
during a 7 months period from November 2012 to June 2013. It 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 done by culture of collected nasal swabs on
mannitol salt agar plates that were incubated aerobically at 37°C for 24- 48 hours. S.aureus
isolates were identified according to the standard microbiological methods. Methicillin
resistance was determined by disk diffusion method using both oxacillin and cefoxitin
disks, according to the CLSI recommendations.
In addition, a total of 6 tea samples (black and green) were purchased from different
markets in Alexandria and were extracted. The antibacterial effect of these tea extracts was
tested against identified MRSA isolates using agar gel diffusion method.
The study revealed the following results:
1. Of the 1021 studied individuals, 53.7% were males and 46.3% were females.
2. More than half of the community cases (52.1%) were of age group 21-40 years,
followed by those aged 41-60 years old (35.1%).
3. Of the 191 HCWs, 156 (81.7%) belonged to the age group 21-40 years, while 40.8%
of patients were aged 41-60 years old.
4. Of the1021 studied individuals, 128 were found to be S. aureus nasal carriers with an
overall S. aureus nasal carriage rate of 12.5%; distributed as 7.9% MRSA and 4.6%
MSSA.
5. All 81 detected MRSA isolates were resistant to both oxacillin and cefoxitin discs.
6. The rates of MRSA nasal carriage among HCWs, patients and community cases were
10.5%, 8.1%, and 6.8%, respectively.
Summary and Conclusions
60
7. MRSA was found among 72.2% of healthcare setting cases aged 21-40 years old.
Of the 26 cases aged 41-60 years old; 69.2% were MRSA carriers. On the other hand,
MSSA was encountered among 66.7% of those aged 20 years and less.
8. MRSA nasal carriage rate among community carriers aged 21-40 years old was 65.4%.
9. About 75% of HCWs with MRSA nasal carriage were of age group 21-40 years.
10. MRSA carriage rate among patients aged 41-60 years old was found to be 72.2%.
11. Half of the 34 male community cases with S. aureus nasal carriage were MRSA
carriers, and half were MSSA carriers (50% each).
12. MRSA colonized 70% of female patients with S.aureus nasal carriage, while MSSA
colonized only 30%.
13. Of the 61 studied nurses, 21.6% were MRSA carriers and only 1.6% yielded MSSA
isolates. Technicians yielded 8.3% MRSA and 2.8% MSSA isolates. On the other
hand, all the 20 studied physicians and 4 pharmacists showed no S.aureus nasal
carriage (zero % each).
14. Of the 128 individuals with S. aureus nasal carriage, 22 (17.2%) were smokers and
106 (82.8%) were non smokers.
15. Of the 57 community cases with S.aureus nasal carriage, 55 were tea consumers and
only 2 were non consumers. The 55 consumers were distributed as 58.2% MRSA
nasal carriers and 41.8% MSSA carriers, while the 2 non consumers yielded only
MSSA isolates.
16. Two thirds (66.7%) of community cases who had associated diseases were MRSA
carriers and only one third (33.3%) were MSSA carriers. On the other hand, MRSA
and MSSA had equal percentages among those with no associated diseases (50%
each).
17. The four community cases who had taken antibiotics within 2 weeks of the study were
all MRSA carriers (100%). On the other hand, of the 53 community cases with
S.aureus nasal carriage who didn’t take any antibiotics within the same period, 52.8%
were MRSA carriers and 47.2% were MSSA carriers.
18. Of the 128 cases with S. aureus nasal carriage, 22 (17.2%) were smokers and 106
(82.8%) were non smokers. Of the 13 community smokers with S.aureus nasal
carriage, MRSA accounted for 53.8% and MSSA represented 46.2%.
19. Seventy percent of HCWs at the surgery department were negative for S.aureus, 23.3%
were MRSA carriers and 6.7% were MSSA carriers.
20. Of the 360 patients, 99 were admitted to the internal medicine department, distributed
as 11.1% MRSA carriers and 3% MSSA carriers.
21. MRSA was of highest percentages among patients with length of hospital stay of 4
days and less, followed by those of 5-8 days (65.5% and 27.6%, respectively).
22. Eighty % of the patients who had internal medicine problems yielded MRSA isolates
and 20% were MSSA carriers.
23. Black tea had a weak effect on 62.5% of the MRSA isolates from community cases
and an intermediate effect on 37.5% of them, while it had no strong effect on any of 32
isolates (0%). On the other hand, Green tea had no weak effect on any of these isolates
(0%). It showed an intermediate effect on 53.1% of these isolates and a strong effect
on 46.9% of them. The difference between these results was found to be statistically
significant with P-value less than 0.001.
Summary and Conclusions
61
24. Black tea had a weak effect on 68% of MSSA isolates from community cases, an
intermediate effect on 28%, and a strong effect on only 4% of them. On the other
hand, green tea had a strong effect on more than half (56%) of MSSA isolates, an
intermediate effect on 40% and a weak effect on only 4% of these isolates.
25. For MRSA isolates from patients, black tea had a weak effect on 82.8% and an
intermediate effect on only 17.2% of these isolates. Green tea showed no weak effect
on any of these MRSA isolates, an intermediate effect on 58.6% and a strong effect on
41.4%. The difference between these results was found to be statistically significant
with P-value less than 0.001.
26. Black tea didn’t have any strong effect on MRSA and MSSA isolates from HCWs (zero
%). Regarding MRSA isolates; black tea had a weak effect on 60% of these isolates
and an intermediate effect on 40% of them. On the other hand, green tea had no weak
effect on any of MRSA isolates, an intermediate effect on 45% and a strong effect on
55% of these isolates. The difference between these results was statistically significant
with P-value less than 0.001.
27. Of the 8 MSSA HCWs isolates, black tea had a weak effect on 75% of these isolates
and an intermediate effect on 25% of them. No strong effect was detected. Green tea
showed an intermediate effect on half of the tested MSSA isolates from HCWs and a
strong effect on the other half (50% each).
from the results of this study, it could be concluded that:
1. Among all tested individuals, HCWs had the highest percentage of MRSA nasal
carriage.
2. The majority of HCWs and community cases with MRSA nasal carriage were of age
group 21-40 years, while most of the patient carriers were aged 41-60 years old with a
higher carriage rate among males.
3. Nurses showed the highest rate of MRSA nasal carriage among HCWs.
4. The highest percentage of MRSA nasal carriage was among patients with length of
hospital stay of 4 days and less.
5. MRSA nasal carriage rates were higher than MSSA rates among tea consumers in all
studied cases.
6. Most of the community cases with S.aureus nasal carriage were tea consumers.
7. The majority of S. aureus nasal carriers were nonsmokers.
8. The majority of studied patients who had internal medicine problems were MRSA
carriers.
9. Tea extracts had an inhibitory effect with varying degrees on tested S.aureus (MRSA
and MSSA) isolates.
10. Green tea had a significantly stronger inhibitory effect than black tea on almost all
tested isolates.