Non-antibiotic antibacterial agents: Has their time come?

New Delhi, May 3, 2018:

The discovery of penicillin ushered in the antibiotic era, which dramatically cut down the prevailing infection rate. Since then, antibiotics have successfully treated and prevented many infections and saved countless lives as a result.

But now, several bacteria have developed resistance to these ‘wonder drugs’ reducing their effectiveness. The emergence of resistance to antibiotics was perhaps a development ‘waiting to happen’ inevitable given their indiscriminate use since they were first discovered. With no new antibiotics in the pipeline, a ‘pre-antibiotic era’ looms ahead, where many common infections might no longer have a cure and, once again, become a threat to human life.

Antimicrobial resistance (AMR) is rapidly increasing worldwide and has now become a global public health issue.

Given this background coupled with the undesirable side effects of systemic antibiotics, it is time perhaps to look at and explore some non-antibiotic antibacterial alternatives, some of which are available in nature.

Sunlight is a potent bactericide. It is also a natural disinfectant. A review examining the roles of sunlight and natural ventilation for controlling infection published in the Journal of Hospital Infection in 2013 states as follows: “The majority of microbes that cause airborne infections cannot tolerate sunlight”. The article further says, “The World Health Organization refers to sunlight in guidance on preventing hospital infections.”

The WHO also promotes natural ventilation design for infection control in health care in its 2009 guidelines on natural ventilation for infection control in health-care settings.

Many foods such as garlic, turmeric, ginger, honey, oregano act as natural antibiotics with antibacterial action; some of them like garlic may also have antiviral and/or antifungal properties. Oregano has a strong antifungal action.

Then there are medicinal plants or herbs. The all-familiar neem comes foremost in the list. Each part of the neem tree such as the leaves, twigs, seeds have been used for their healing effect. Neem leaves have been used in skin infections. The herb Echinacea is a natural antibiotic, which can treat bacterial infections. Tulsi has antibacterial, anti-viral and anti-fungal activity. The Indian Ginseng (Withania somnifera), locally known as Ashwagandha, has antibiotic, antioxidant, immunomodulatory, antistress and adaptogenic activity.

Use of topical antiseptics on wounds is another approach to prevent and treat infection. Unlike topical antibiotics, antiseptics have the advantage of a broad-spectrum antimicrobial activity, faster onset of action that is long-lasting, good tolerance and less likelihood for resistance.

Then there are some innovative technologies, which have been shown to have antimicrobial effects. These may well become feasible options in the near future, though their long term effect is yet to be studied.

The use of copper-coated uniforms to fight E. coli infection in hospitals has been reported this year in the Journal of Nanomaterials. Researchers have created a ‘durable and washable, concrete-like’ composite material made from antibacterial copper nanoparticles. They have also developed a way of binding the composite to wearable materials such as cotton and polyester. These cotton and polyester coated-copper fabrics showed excellent antibacterial resistance against Staph aureus and E. coli, even after being washed 30 times. Doctors could soon be wearing their white coats and scrubs made of this material.

Researchers have developed silver-nanoparticle-embedded antimicrobial paints. Silver is antibacterial. Surfaces coated with silver-nanoparticle-embedded antimicrobial paints have shown excellent antimicrobial properties by killing both Gram-positive (Staph aureus) and Gram-negative (E. coli) bacteria. These paints may be used in hospitals to fight off infections.

Prevention is better than cure. There is no time like now to re-emphasize that hand hygiene is the single most effective and economical means to prevent the spread of infections.

-Dr K K Aggarwal, President Heart Care Foundation of India