As winter approaches, so does the threat of a slew of infections – influenza, common cold, pneumonia and respiratory infections. Many of these infections spread through air droplets as well as fomites, which are any surfaces that can harbour bugs and thus disease like clothes, utensils and furniture. It has been well established that surfaces in public spaces such as seats and handles in public transport, door knobs, locks and toilet taps carry disease-causing organisms and spread them in a community. But one fomite that is often ignored is the automated teller machine or ATM.
Any person who is ill or harbours an infectious pathogen may deposit the organism on the surface of a fomite. Pathogens can live on this surface for extended periods of time, only to move house to the next person who comes in contact with the surface, possibly making him or her ill.
Studies have documented the types of microorganisms that commonly colonise the surface of these public spaces. These include bacteria and viruses that cause respiratory and diarrhoeal diseases. During outbreaks of diarrhoeal illness in a community, bacteria that cause the diarrhoea are commonly found in the water taps and toilet seats and covers. We know that during outbreaks of swine flu, traveling in crowded buses can lead to transmission through contaminated seats and other surfaces. This is one of the main reasons why repeated hand washing is an important preventive measure during outbreaks of influenza and diarrhoeal illnesses.
One more potential surface that is very commonly used, but which no one thinks much about, is the ATM. These machines have number pads and touch screens, which people use without much attention to hand hygiene. They can act as potential fomites for transmission of viruses and bacteria. Usually ATMs are located inside air-conditioned rooms with substantial humidity. Along with the warmth of the electrical activity of the ATM, this provides the ideal conditions for the microorganisms to thrive on this surface. When a customer walks into an ATM, touches the number pad or the touch screen to operate the machine, and then touches his face, nose or mouth, he quickly acquires the infectious microorganism. Especially in times of outbreaks like influenza or diarrhoeal illnesses, the chance of contamination of the ATM and transmission of infection among the public increases multi-fold.
What lurks on an ATM?
Several scientific research studies in India and abroad have examined the type of organisms that grow on the surface of the ATMs. In a 2015 study published in the Journal of Earth, Environmental and Health Sciences, researchers examined ATMs in and around Puducherry and found that 95% of ATM centres had contaminated surfaces. More than 150 bacteria were grown when swabs from these ATMs were incubated in culture media. The most common organism found in the cultures was Klebsiella, a bacterium that belongs to the family called Enterobacteriacea.
Klebsiella bacteria are commonly found in the human large intestine, where they derive nutrition from the intestinal environment but cause no harm. The bacteria are also found in faeces. However, the microorganism has the capacity to produce a very severe infection when it enters the lung, that can sometimes be fatal. Usually, Klebsiella lung infection affects people with depressed immunity due to diseases like diabetes. Klebsiella is also sometimes found in the soil and in drinking water when it is contaminated with faeces. This organism is commonly found on hospital surfaces. It is a common cause of hospital acquired infections of the lungs, urinary tract and blood. The hospital acquired form of Klebsiella infection can sometimes be fatal as hospital-acquired bacteria are resistant to many drugs.
Many physician-researchers have raised questions about the capability of these microorganisms found on ATM surfaces to cause infections. Research has shown that viruses that are present on the surface of fomites for a long time lose their ability to produce severe infection. It is extremely difficult to conduct studies to see whether the presence of viruses and bacteria on these surfaces lead to infections – the development of infection in a human depends on many factors such as the amount of the microorganism present on the surface, its infective ability, temperature, humidity conditions of the surface, general cleanliness of the surface, whether the surface is solid or porous, and susceptibility of the person who is coming into contact with the surface. Given these factors, it may be safer to assume that all microorganisms isolated from ATM surfaces are potentially dangerous and take measures to prevent infections.
Are people careful after using ATMs?
In this connection, a student from the Employees’ State Insurance Corporation Medical College and Postgraduate Institute of Medical Sciences and Research in Chennai conducted a systematic survey among users of ATM in Chennai to understand their awareness, attitudes and hygiene behaviours related to ATM use. She interviewed about 200 people among users of various busy ATMs identified through a systematic sampling method and found that half of them were aware of the possibility of infections spreading through contact with the ATM number pads and touch screen. The level of awareness was directly related to their level of education, with those who were more educated being more aware of the risk.
Despite reasonable awareness about ATMs as a potential source of infection, none of the surveyed individuals practiced any form of hand hygiene after using the ATM, the study showed. They did not use a hand sanitizer or wash their hands after ATM use. The study also explored attitudes of the participants towards the potential ability of ATM to spread infections. The participants exhibited little fear of contamination or unease at using an ATM immediately after another person has used it. They also were not very worried about carrying infections from ATM to other family members at their homes. This distinct disconnect between the awareness, attitudes and hand hygiene practices is a matter of serious concern.
There is a need for heightened awareness about the potential of ATMs to transmit the influenza virus and other infections. This can be effectively prevented by systematic and frequent disinfection of ATM surfaces, number pads and touch screens and by thorough hand hygiene practices following the use of ATMs. ATM should feature as a potent fomite that must be effectively disinfected during outbreak times to systematically interrupt transmission of infection.
The writer is an assistant professor at the department of community medicine, ESIC Medical College & PGIMSR, Chennai. The study on ATM awareness and hygiene behaviour was conducted by Shobana Kanniappan, a third year MBBS student at the ESIC Medical College & PGIMSR, Chennai.
