Pneumonia-causing bacteria can be spread by nose picking and rubbing

October 11, 2018, European Lung Foundation
Streptococcus pneumoniae. Credit: CDC/Dr. M.S. Mitchell

Pneumonia-causing bacteria can be spread through picking and rubbing the nose, according to new research published in the European Respiratory Journal.

Pneumococcus, the that can cause pneumonia, is known to be spread through inhalation of airborne droplets containing the bacteria, for example in coughs and sneezes. This study is the first to show that transmission can also occur via contact between the nose and the hands after exposure to pneumococcus bacteria.

The study found that bacteria can spread at the same rate whether it is dry or wet, and at the same rate when a person picks or pokes their nose as when they rub their nose. The results suggest that ensuring good hygiene and keeping toys clean could help to protect young children from catching and spreading the bacteria on to other children and their elderly relatives, who may be more susceptible to infection.

Lead researcher Dr. Victoria Connor, a clinical research fellow at the Liverpool School of Tropical Medicine and Royal Liverpool Hospital, explained: "Pneumococcal infection is a major cause of death around the world, and it is estimated that it is responsible for 1.3 million deaths in children under five years annually. The elderly and people with other causes of impaired immunity, such as chronic illness, are also at an increased risk of pneumococcal infections.

"Our current understanding of the transmission of pneumococcus is poor, so we wanted to look at how it may be spread in the community. Having a clearer understanding of how the bacteria is spread will allow for better advice on how transmission can be reduced, so that there is greater prevention of pneumococcal infections."

To assess the potential for hand-to-nose contact to cause pneumococcus bacteria to spread into the nose, 40 healthy adult volunteers were randomly allocated to four groups that were exposed to pneumococcus bacteria using different hand-to-nose methods.

One group had water containing pneumococcus bacteria applied to their hands and were then asked to sniff their hands ("wet sniff"). A second group were asked to sniff air-dried pneumococcus bacteria from the back of the hand ("dry sniff"). The third and fourth group were asked to pick or poke their nose with a finger that was either exposed to wet pneumococcus bacteria ("wet poke") or exposed to air-dried pneumococcus bacteria ("dry poke").

Two different detection methods were then used to test for pneumococcus, to confirm the presence of the bacteria in the participants' noses. These included a test to see if they could grow pneumococcus bacteria from wash samples of the participants' noses (culture), and whether they could detect the presence of bacterial DNA (qPCR).

The results showed that the highest rates of bacteria spread were among participants in the "wet poke" group, followed by the "wet sniff" group.

The researchers say that participants were just as likely to get pneumococcus bacteria in their noses whether they were exposed using wet or dry samples, but the total number of bacteria passed on was higher in the wet groups; the authors suggest this may be because the air-drying process leads to the death of some bacteria.

The tests also showed that the same amount of transmission occurred when the participants poked or picked their nose as when they rubbed their nose with the back of their hand.

Dr. Connor said: "It might not be realistic to get children to stop picking, poking and rubbing their noses, and presence of the bacteria can sometimes boost the immune system of children and can reduce their chances of carrying it again later in life, so it is unclear if completely reducing the spread of pneumococcus in children is the best thing.

"But for parents, as this research shows that hands are likely to spread pneumococcus, this may be important when children are in contact with elderly relatives or relatives with reduced immune systems. In these situations, ensuring good hand hygiene and cleaning of toys or surfaces would likely reduce transmission, and reduce the risk of developing such as pneumonia."

The researchers highlight that using real people as part of the study design enabled them to test the survival of pneumococcus and the viability of transmission methods in a safe and controlled way.

Professor Tobias Welte, from Hannover University, Germany, is President of the European Respiratory Society and was not involved in the study. He said: "This pilot study is the first to confirm that pneumococcus bacteria can be spread through direct contact, rather than just through breathing in .

"For clinicians, the findings reinforce the message that we must promote rigorous hand hygiene and basic infection control measures such as avoidance of sharing food, drink and mobile phones, in order to potentially reduce the transmission of respiratory bacterial pathogens such as pneumococcus. Pneumococcal vaccination is the best method for limiting the spread of S. pneumoniae in to the sinuses and lower airways, but vaccination rates are below 50% for those for whom it is recommended. To improve this is one of the major tasks for healthcare policy."

The researchers note that the bacteria samples used in the tests were given at a dose which may not represent a real-life scenario, so the results may be treated with caution. They plan to look at how pneumococcus is shed from the nose, and if hand washing reduces the spread from hand to .

Explore further: 1.45 million children's lives saved by HiB and pneumococcal vaccines since 2000

More information: Victoria Connor et al, Hands are vehicles for transmission of Streptococcus pneumoniae in novel controlled human infection study, European Respiratory Journal (2018). DOI: 10.1183/13993003.00599-2018

Related Stories

1.45 million children's lives saved by HiB and pneumococcal vaccines since 2000

June 11, 2018
Childhood deaths from two leading bacterial causes of pneumonia and meningitis, pneumococcus and Hib, declined sharply during the period 2000 to 2015, especially as vaccines against these pathogens were introduced in high-burden ...

Mechanism that prevents lethal bacteria from causing invasive disease revealed

July 7, 2014
An important development in understanding how the bacterium that causes pneumonia, meningitis and septicaemia remains harmlessly in the nose and throat has been discovered at the University of Liverpool's Institute of Infection ...

Drop in childhood pneumococcal, Hib deaths from 2000 to 2015

July 12, 2018
(HealthDay)—Streptococcus pneumoniae and Haemophilus influenzae type b (Hib) deaths in children decreased between 2000 and 2015, following introduction of the pneumococcal conjugate vaccine (PCV) and Hib vaccine, according ...

Bacterial respiratory tract colonization prior to catching the flu may protect against severe illness

July 10, 2014
Many studies have shown that more severe illness and even death are likely to result if you develop a secondary respiratory infection after developing influenza. Now, however, a team of researchers based at The Wistar Institute ...

Recommended for you

New hope for cystic fibrosis

October 19, 2018
A new triple-combination drug treatment being trialled at the Mater Hospital in Brisbane could increase the life expectancy of patients with cystic fibrosis.

Bug guts shed light on Central America Chagas disease

October 18, 2018
In Central America, Chagas disease, or American trypanosomiasis, is spread by the "kissing bug" Triatoma dimidiata. By collecting DNA from the guts of these bugs, researchers reporting in PLOS Neglected Tropical Diseases ...

Rapid genomic sequencing of Lassa virus in Nigeria enabled real-time response to 2018 outbreak

October 18, 2018
Mounting a collaborative, real-time response to a Lassa fever outbreak in early 2018, doctors and scientists in Nigeria teamed up with researchers at Broad Institute of MIT and Harvard and colleagues to rapidly sequence the ...

Researchers cure drug-resistant infections without antibiotics

October 17, 2018
Biochemists, microbiologists, drug discovery experts and infectious disease doctors have teamed up in a new study that shows antibiotics are not always necessary to cure sepsis in mice. Instead of killing causative bacteria ...

Infectious disease consultation significantly reduces mortality of patients with bloodstream yeast infections

October 17, 2018
In a retrospective cohort study conducted at the University of Alabama at Birmingham Division of Infectious Diseases, patients with candidemia—a yeast infection in the bloodstream—had more positive outcomes as they relate ...

How drug resistant TB evolved and spread globally

October 17, 2018
The most common form of Mycobacterium tuberculosis (TB) originated in Europe and spread to Asia, Africa and the Americas with European explorers and colonialists, reveals a new study led by UCL and the Norwegian Institute ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.