Cross infection

Cross infection, or cross contamination, occurs when one person spreads an infection to another, either directly or indirectly. Find out how cross infection affects people with cystic fibrosis, and what is done to combat the issue.

What is cross infection?

People with cystic fibrosis are vulnerable to different bacteria or 'bugs', which grow in their lungs. While these bugs are usually harmless to people who don't have cystic fibrosis, they can settle in the lungs (colonise) and be harmful to people who have CF. These bugs can be easily transmitted from one person with cystic fibrosis to another.

Cross infection occurs when one person spreads these dangerous bacteria to another either directly, such as with physical contact, or indirectly, such as coughing or when someone touches something that another person with cystic fibrosis has touched – such as a glass, cutlery or medical equipment.

The risk of cross infection increases the longer people with cystic fibrosis are in close proximity to one another. It is recommended that people with cystic fibrosis do not have physical contact with each other.

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How is cross infection managed?

This issue is taken extremely seriously in the CF community and often the wider community are not aware of these risks. Children’s hospitals in New Zealand require young CF patients to wear a mask during appointments to protect them and reduce the risk of transmitting these bugs. Many adults also choose to wear masks during hospitalisation to reduce the risk of cross infection.



It's recommended individuals with cystic fibrosis wear a surgical mask rather than the fabric-based environmental mask such as a Vog mask. This is because Vog masks are not approved to protect against the spread of pathogens in a clinic or hospital setting. These masks are intended for use against environmental particles such as dust, pollen, and other particles found in air pollution.

At school

Ideally only one child with CF will be enrolled at a school, but with New Zealand being such a small country it's inevitable that two children with CF may need to attend the same school.

In this instance the families should be aware that there are two (or more) children with CF at the school and a strict plan needs to be in place to minimise the risk of the children coming into close contact with each other.

See our CF at School page for more information.

Safe distances

There is less risk of transmission of 'bugs' in an outdoor environment, but meeting indoors, travelling with other people with cystic fibrosis or spending time with them socially has a high level of risk. We recommend people with cystic fibrosis do not have physical contact with each other, and in situations where this is not possible, we recommend keeping a safe distance.

The safest way for people with cystic fibrosis to speak to each other is online, over the phone or through text messages. We have dedicated Facebook pages to facilitate online conversations.

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Which bugs can be passed on through cross infection?

Pseudomonas aeruginosa

Pseudomonas aeruginosa is a ‘bug’ that people with CF get mostly from their environment. This can usually be kept under control with early antibiotic treatment. Most people with cystic fibrosis with acquire this infection during their lives. Unfortunately, it can become resistant to antibiotics and cause problems.

There are concerns that people with cystic fibrosis can be more at risk from Pseudomonas they pick up from each other than the strains they get from their environment. That’s one of the reasons why people with CF are kept separate at hospital clinics.

Burkholderia cepacia complex

This is an extremely serious infection because these bugs cause serious harm and are hard to treat.

It's not always easy to determine how people with CF become infected with B. cepacia complex. Research has shown people with CF can get B. cepacia from other people who are infected with these bacteria. These germs are transmitted via direct contact such as kissing, or indirectly from touching objects with the bacteica such as doorknobs.

In many cases having burkholderia cepacia can prevent a person with cystic fibrosis being offered a lung transplant because of the risk of a poorer result.

Nontuberculous Mycobacterium (NTM) abscesses

The group of bacteria that make up the different types of NTM are ‘cousins’ to the bacteria that cause tuberculosis (TB). These infections are very hardy and can survive many disinfectants and harsh environmental conditions.

The symptoms caused by NTM infection can vary between people, from causing no symptoms to causing symptoms such as a severe cough, fatigue and weight loss.

Further information

Cross infection is taken very seriously by both Cystic Fibrosis New Zealand and the CF community. If you’d like to know more about cross infection, have any concerns or would like some advice, please contact your local CF field worker. 

We also have a Cross Infection at Events Fact Sheet which provides further information.