The bacterium Staphylococcus aureus, which is increasingly becoming resistant to methicillin, an antibiotic, is a major cause of severe and fatal infections in the U.S. More than 6,500 people died of infections from methicillin-resistant Staphylococcus aureus (MRSA) in 2005. Persistent harboring of bacteria in the body is known as carriage. The nose is a common site for carriage of MRSA. In the present study, the researchers examined the effect of drinking tea, coffee and other beverages on nasal MRSA carriage. It was found that those who consumed hot tea or coffee had a lower likelihood of being carriers of MRSA.
Many in vitro studies on tea and coffee as well as studies on the topical application of extracts of tea and coffee have shown that these have antibacterial properties. They have been found to be particularly effective against E. coli, Salmonella, and Staphylococcus aureus. So far, very few studies have been conducted to evaluate the systemic antibacterial actions of tea and coffee. Owing to a steady increase in the incidence of MRSA-related infections, researchers are constantly looking for substances, especially plant extracts, which reduce the carriage of these bacteria and thus decrease the prevalence of MRSA-related infections. This study was carried out to find out whether an association exists between the consumption of tea and coffee and the nasal carriage of MRSA.
* The data for the present study was collected from the 2003-2004 National Health and Nutrition Examination Survey (NHANES), which provided highly representative medical information on the non-hospitalized population of the US.
* Nasal carriage of MRSA was assessed in 5,555 participants by culturing the nasal samples in mannitol salt agar, and then assessing their sensitivity to methicillin by a standard diffusion technique.
* The participants were given questionnaires to assess the consumption of tea, coffee, and other beverages. They were particularly asked whether they consumed hot or cold beverages.
* Data regarding confounding factors such as age, sex, race, poverty status, recent antibiotic use, and health status were also collected.
* Overall, 1.4 percent of the participants were nasal carriers of MRSA. About 48 percent of the participants consumed tea, while 61 percent participants consumed coffee.
* “Individuals who consumed hot tea had a slightly more than one-half reduction in the likelihood of MRSA nasal carriage relative to their counterparts who reported consuming no hot tea.” Similar findings were observed with the consumption of hot coffee as well. These findings remained the same even after considering all the confounding factors.
* Consumption of cold tea or cold coffee and other beverages did not reduce the nasal MRSA carriage.
In the present study, data was collected only once. Follow-up studies are necessary to confirm the antibacterial effects of tea and coffee. The researchers of the present study did not collect information on the timing of consumption of tea or coffee. Further studies are necessary to identify the components in tea and coffee, which are responsible for their antibacterial effects.
In 2005, more than 278,000 Americans suffered from MRSA infections. Nasal carriage is thought to be the primary source of infection in all these cases. The present study has shown that carriage is about 50 percent less in those who consume hot tea or coffee. Hence, consumption of hot tea and coffee is an easy, inexpensive and safe method to prevent infection from MRSA. Trigonelline and glyoxal present in coffee and tannic acid and catechin present in tea are probably responsible for the antibacterial activity of these beverages. The reason for the lack of antibacterial activity of cold tea/coffee in contrast to hot tea/coffee cannot be ascertained. However, the authors assume that the antimicrobial compounds in hot tea and coffee reach the nose in vapor form, which is not possible in cold tea and coffee. An earlier study has shown that consumption of tea reduces the duration of hospitalization of patients with MRSA-related pneumonia from 85 days to 51 days. The findings of the present study reinforce the results obtained from prior studies.
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Tea and Coffee Consumption and MRSA Nasal Carriage
Publication Journal: Annals of Family Medicine, July 2011
By Eric M. Matheson, MD; Arch G. Mainous, PhD; Medical University of South Carolina, Charleston