Anyone who has ever commuted knows that public transport is far from hygienic. This has now been thrown into stark relief after swabs were taken from across the London Underground, bus network and taxis.
Interactive data compiled by Staveley Head and collected by microbiologists at London Metropolitan University brings this invisible bacteria into startling clarity.
Using UV lighting, the London Under the Microscope project highlights 121 different bacteria and mould strains on public transport – including nine bacteria species associated with antibiotic-resistant superbugs. Out of the twelve superbug families identified by the World Health Organisation (WHO), London is home to some of the most dangerous.
London’s filthiest tube lines
- Victoria line is the worst with 22 bacteria found.
- Circle line – 20 bacteria found.
- Piccadilly line – 20 bacteria found.
- Jubilee line – 18 bacteria found.
- Northern Line – 18 bacteria found.
- District Line – 17 bacteria found.
- Central line – 16 bacteria found.
- Waterloo and City line – 16 bacteria found.
- Hammersmith and City – 14 bacteria found.
- Bakerloo line – 13 bacteria found.
Microbiologist Paul Matewele took 80 swabs across the capital to test for bacteria. He tested hand rails, seats, doors and the walls of public transport services and studied these findings to discover levels of antibiotic resistance. What he found was an unprecedented layer of dangerous bacteria, including traces of superbugs that “antibiotics cannot fight and can be extremely harmful.”
An estimated 2.29 billion people use London buses every year, with 1.34 billion using the underground. With so many people from across the world, the germ traces are rich with disgusting variety.
Through the interactive data, the London Underground is shown as the dirtiest form of transport. When exploring different tube lines in such grim detail, it’s clear the Victoria line ranks as the most unhygienic – a haven of 22 different types of living bacteria, including four of the world’s most threatening.
Staphylococcus Aureus (the bacteria responsible for toxic shock syndrome), E.coli, Klebsiella Pneumoniae and Serratia were found. The latter two strains are resistant to antibiotics and known to cause serious blood, chest and urine infections.
Klebsiella is one of the most threatening bacteria.
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Its microbes can cause the Klebsiella Pneumoniae infection which is a superbug antibiotics cannot fight. It killed 16 patients in a UK hospital in 2014, leaving 62 people to suffer from serious blood poisoning. It is also responsible for the death of a Nevada woman in America – the infection having run rampant through her body regardless of all 26 antibiotic varieties at the disposal of the CDC.
Public Health England is reluctant to give exact figures as to how many people have contracted superbug infections, but the figures are growing. From 2003 to 2014, infections of carbapenemase-producing Enterobacteriaceae (CPE) rose from 3 to over 2,000 from 2003 to 2015. Of the drugs that have developed resistance to the carbapenems – ‘last resort’ antibiotics that are used in serious infections when other drugs will not work – KPC (Klebsiella pneumoniae carbapenemase) joins the ranks of NDM (New Delhi Metallo-beta-lactamase).
Small but deadly: most dangerous bacteria found on public transport
- Acinetobacter baumannii
- Commonly found in soil and water, Acinetobacter baumannii accounts for about 80 per cent of reported infections.
- Pseudomonas aeruginosa
- Pseudomonas infection is caused by strains of bacteria found widely in the environment. Those with weakened immune systems are most susceptible but healthy people can also develop mild illnesses with Pseudomonas aeruginosa, especially after exposure to dirty water.
- Enterobacteriaceae: Klebsiella, E. coli, Serratia, Proteus
- CRE or carbapenem-resistant Enterobacteriaceae, is a family of germs that are difficult to treat because it has high levels of resistance to antibiotics. Klebsiella species and Escherichia coli (E. coli) are examples of Enterobacteriaceae, a normal part of the human gut bacteria, that can become resistant. This is because the enzymes break down the drugs, rendering them ineffective. While healthy people do not usually get this infection, it has been found to contribute to death in up to 50 per cent of patients who become infected.
- Enterococcus faecium
- Bacteria existing in the human intestinal lining, this strain has developed antibiotic resistance.
- Staphylococcus aureus
- Staph bacteria can cause a wide range of infections, from relatively minor skin infections such as boils, to more serious infections of the blood, lungs and heart.
- Most people infected with Salmonella develop diarrhoea, fever, and abdominal cramps 12 to 72 hours after infection. While symptoms usually pass from 4 to 7 days, hospitalisation can be required in some cases.
As well as drug-resistant bacteria, human faeces can be seen spread against hand rails and across seats. Other germs are shown in a cacophany of colour, spread out like spray-paint across London public transport systems. Bacteria from rats and mice were found on tube lines, along with traces of bacteria from sewage.
Doctor Matewele told WIRED of his shock at the sheer variety of bacteria he found. “[Surprise] is an understatement. We were totally confounded. The diversity of bacteria growing on the media was quite a shock,” he said.
While the antibiotic susceptibility tests that were carried out were limited, if these observations were to be realised on a wider scale, it could hint at a serious problem.
“Not only did we find potentially life-threatening bacteria’s which behaved like superbugs when tested against antibiotics, but other forms of mould and bacteria that can be harmful to human health were discovered as part of this research,” added Dr Matewele.
“The bacteria doesn’t usually affect healthy people. It’s mainly a problem if transmitted between sick patients in hospitals and between people with weakened immune systems. The infection can cause urinary tract infections, pneumonia, septicemia, meningitis, and diarrhoea. Therefore, proper hygiene is a must.”
Taxis in the capital were found to be cleaner than tube lines – with 14 living bacteria found on average in each cab tested. Of these bacteria, teams found Staphylococcus Aureus, Aeromonas Veronii, which can cause pneumonia and meningitis. Traces of faeces and salmonella were also detected.
Overall, buses that came out as the cleanest transport option in the capital, with the least number of bacteria found – 37 in total. The tube lines held 95 different varieties, and taxis in London have around 40.
So far the only class of bacteria isolated was what’s known as class II. Matewele warns of a potential problem when this bacteria changes. “If class III bacteria were to be isolated, then resistance transfer may become a major issue. Immunologically compromised individuals are at risk and so are vulnerable people in wards if visited by carriers of some the bacteria.”
Doctor Matewele hopes the results of these swabs lead to improved cleanliness on public transportation: “It may help London Transport to check and monitor their disinfection procedures,” he says, “They can check if the methods and chemicals used are effective.”
The next time you travel through the heart of this fair city, remember its dirty underbelly.