HomeHealth articlesbacterial infectionWhat Respiratory Bacterial Infections Are Common In Cystic Fibrosis?

Respiratory Bacterial Infections in Cystic Fibrosis

Verified dataVerified data

4 min read


Respiratory bacterial infections remain the most prominent cause of increased morbidity and mortality in cystic fibrosis. Read the article below to know more.

Medically reviewed by

Dr. Kaushal Bhavsar

Published At November 3, 2022
Reviewed AtJuly 27, 2023


Cystic fibrosis is an autosomal recessive disorder that causes sticky, thick, hyper-viscous mucus to build up in the lungs. This mucus secretion is not removed. Instead, the secretions plug up ducts and the airways leading to difficulty breathing and increasing the risk of infections. It is a defect in the cystic fibrosis transmembrane regulator (CFTR) gene. The CFTR is an epithelial anion channel in the alveolar ducts that facilitates the transfer of chloride and bicarbonate ions along with water to pass through it.

How Does the Immune System Detect the Infection?

Bacterial products and components are named pathogen-associated molecular patterns (PAMPS) and are detected by the immune cells' pattern recognition receptors (PRR). The detection of PAMPs and their subsequent activation results in an innate and acquired inflammatory response. One such PRR is the toll-like receptor(TLR), characterized by its ligand specificity.

What Are the Different Bacterial Infections in Cystic Fibrosis?

The most common bacterial infections in cystic fibrosis are:

  • Staphylococcal aureus.

  • Pseudomonas aeruginosa.

  • Burkholderia cepacia complex.

  • Nontuberculous mycobacterial infections.

  • Haemophilus influenzae.

Cystic fibrosis patients are predominantly infected by specific pathogens, of which Staphylococcal aureus and Pseudomonas aeruginosa are the most prevalent.

Staphylococcal Aureus:

It is the first non-fastidious Gram-positive pathogen to infect and colonize the airways of cystic fibrosis patients, specifically seen in children. It is a co-infective pathogen associated with Pseudomonas aeruginosa. The inflammatory process becomes more intense due to the additive effect of the two pathogens. Methicillin-resistant Staphylococcus aureus (MRSA) has become a major nosocomial pathogen with an increased prevalence in cystic fibrosis patients. MRSA can cause serious infections that usually present multi-resistance to several antibiotics.

Symptoms of MRSA:

  • Pneumonia.

  • Osteomyelitis- It is an infection of the bone and bone marrow.

  • Lung abscess.

  • Empyema- Accumulation of pus in between the lung and chest wall.

  • Sepsis- It is an infection in the blood.

  • Endocarditis - Inflammation of the inner layer of the heart.

If the infection spreads into the body, a person can experience high fever, chills, dizziness, confusion, and body ache.

Lab Diagnosis:

Blood culture is an important tool in the diagnosis of Staphylococcal aureus.


The broad-spectrum anti-MRSA cephalosporins, such as Ceftaroline and Ceftobiprole, have shown a marked ability to limit MRSA biofilm formation.

Pseudomonas Aeruginosa:

It is a non-capsulated, non-sporing oxidase-positive gram-negative motile bacillus that most commonly affects the lower respiratory tract. It is an opportunistic pathogen in cystic fibrosis patients. It is more prevalent in adult cystic fibrosis patients.

Laboratory Investigations:

The standard method for assessing respiratory infections with pseudomonas are:

  • Bacterial culture of sputum.

  • Oropharyngeal swabs.

  • Bronchoalveolar lavage.

Bacterial culture and oropharyngeal swabs are the most frequently used to establish Pseudomonas infection. Bronchoalveolar lavage is an invasive method considered a standard laboratory diagnosis as it reflects colonization of the lower respiratory tract.


The Pseudomonas infections can range in severity from colonization to severe necrotizing bronchopneumonia. The extended-spectrum Penicillins, Aminoglycosides, Cephalosporins, Fluoroquinolones, and Monobactams are the most commonly used. An Aminoglycoside with beta-lactam Penicillin is considered to be the first-line treatment. Nebulised delivery of antipseudomonal antibiotics is thought to prevent recurrent exacerbations, reduce antibiotic usage and maintain lung function, particularly in cystic fibrosis patients.

Burkholderia Cepacia Complex:

It is an aerobic, mesophilic gram-negative bacillus. It is one of the most opportunistic bacterial pathogens of cystic fibrosis patients. It is linked to a more rapid decline in lung function and increases morbidity and mortality.

Symptoms of Burkholderia Are:

  • Fever.

  • Cough.

  • Congestion.

  • Shortness of breath.

  • Wheezing

Cepacia Syndrome:

If the infection disseminates throughout the body, causing cepacia syndrome, which is characterized by fulminating pneumonic infection along with fever and respiratory failure, and occasional association with septicemia. If left untreated, it can lead to death within weeks.

Lab Investigation:

The best way to confirm Burkholderia infection is to get a sputum culture and a bronchoscopy.


It is highly resistant to antibiotic therapy because its genome is very plastic, shows several mutations, and adapts itself, making it difficult to treat. Isolated pathogenic colonization often loses its characteristic phenotype or growth conditions, leading to difficulty in accurate identification. To overcome this problem, molecular identification is required to distinguish species within the Burkholderia cepacia complex (Bcc). Thorough molecular targets for identification are not reliable when used individually. A multi-target approach is essential to improve the identification of Bcc and non-Bcc organisms. It often requires combination therapy to eradicate the bacteria.

Nontuberculous Mycobacterium (NTM):

It is a group of microorganisms that is common in chronic pulmonary diseases. The most common NTM infecting cystic fibrosis patients is Mycobacterium abscessus. It is particularly resistant to therapy.


  • Persistent cough.

  • Haemoptysis.

  • Fever.

  • Night sweats.

  • Shortness of breath during activity.

  • Weight loss.

  • Fatigue.

Lab Diagnosis:

Sputum culture: Rapidly growing medium is an agar-based, selective culture medium designed to isolate nontuberculous Mycobacteria from the sputum of cystic fibrosis patients. Bronchoscopy and imaging tests such as chest X-ray and computed tomography (CT) scans can help confirm the signs of NTM infection.


A combination of three antibiotics is given: Azithromycin, Ethambutol, and Rifampicin.

Haemophilus Influenzae:

It is a gram-negative Coccobacillus that usually infects younger patients between 6-12 years old. This bacterium undergoes hyper mutation making itself resistant to antibiotics and making the treatment more difficult.


  • Cough.

  • Fever and chills.

  • Excessive fatigue.

  • Shortness of breath.

  • Chest pain.

  • Muscle pain and headache.

Lab investigation:

Blood culture and spinal fluid, joint fluid, and pleural fluid culture can be done to confirm the presence of the bacteria.


Haemophilus infections are treated with antibiotics such as Cephalosporins, Azithromycin, Amoxicillin, Clarithromycin, and fluoroquinolones.


Pseudomonas aeruginosa remains the most common pathogen in adults, whereas Staphylococcal aureus is the most common pathogen in children. Expanded culturing and culture-independent molecular methods are used for such polymicrobial respiratory infections. With proper physical examinations along with lab investigation, one can come to a diagnosis in a cystic fibrosis patient.

Frequently Asked Questions


Which Bacterial Infection Is the Most Common in the Cystic Fibrosis Airway?

Pseudomonas aeruginosa is the most common bacterial infection in the cystic fibrosis airway. This bacteria can cause chronic lung infections and progressive lung damage in people with cystic fibrosis.


What Causes Respiratory Infections in People With Cystic Fibrosis?

People with cystic fibrosis are prone to respiratory infections because the thick mucus that accumulates in their airways serves as a breeding ground for bacteria to grow and thrive, resulting in chronic infections. In addition, a defective CFTR gene, the underlying cause of cystic fibrosis, also affects the body's ability to clear mucus and fight infections, contributing to respiratory problems.


What Are the Most Common Respiratory Pathogens in Cystic Fibrosis Patients?

Bacteria such as Pseudomonas, Staphylococcus, Haemophilus influenzae, Burkholderia cepacia complex, and non-tuberculous mycobacteria are the most common respiratory pathogens in cystic fibrosis patients.


What Happens if a CF Patient Develops Pneumonia?

If a cystic fibrosis patient gets pneumonia, it can worsen their lung function, make breathing more difficult, and lead to complications like lung abscesses, sepsis, and respiratory failure. It is also difficult to treat because many cystic fibrosis patients have chronic lung infections, making it difficult to identify and target the specific bacteria causing pneumonia.


What Respiratory Pathogens Are Common in Cystic Fibrosis Patients, and How Do They Change?

Bacteria such as Staphylococcus aureus, Pseudomonas aeruginosa, Haemophilus influenzae, Burkholderia cepacia complex, and non-tuberculous mycobacteria are common respiratory pathogens in cystic fibrosis patients. These pathogens evolve, some becoming more common and others becoming extinct due to treatment. In cystic fibrosis patients, the emergence of antibiotic-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Pseudomonas aeruginosa is also a concern.


What Is the Most Common Cause of Death in People With Cystic Fibrosis?

Respiratory failure caused by chronic infections and inflammation is the most common cause of death in people with cystic fibrosis. This can result in severe breathing difficulties, low oxygen levels, and respiratory failure. Other risk factors for death in people with cystic fibrosis include malnutrition, liver disease, and diabetes.


What Is Cystic Fibrosis?

Cystic fibrosis is an inherited genetic disorder that affects multiple organs caused by the production of thick, sticky mucus that clogs airways and ducts, resulting in chronic lung infections, poor growth, and malnourishment, among other complications.


What Are the Most Severe Cystic Fibrosis Symptoms?

Chronic lung infectious diseases, respiratory arrest, malnourishment, developmental delay, and male infertility are the most severe cystic fibrosis symptoms. Other symptoms include a persistent cough, wheezing, shortness of breath, gastrointestinal issues such as diarrhea (vomiting and loose motions), constipation, and stomach pain. The severity of symptoms varies between individuals and may be determined by the genetic mutation that causes the disease.


What Are Two Fascinating Facts About Cystic Fibrosis?

- Cystic fibrosis is known to cause the production of sticky mucus, which can clog airways. Still, it can also cause thicker and stickier sperm in men with the disease, resulting in infertility .
 - People with cystic fibrosis are much more likely to develop osteoporosis, a bone-weakening condition, due to various factors such as inflammation, malnutrition, and medication use.


Antibiotics Are Safe to Take if One Has Cystic Fibrosis?

Infections in people with cystic fibrosis can be treated safely and effectively with antibiotics. To reduce the risk of antibiotic resistance and other side effects, it is important to use them correctly and under the supervision of a healthcare professional.


Why Can Not Two Cystic Fibrosis People Live Together?

Two people with cystic fibrosis should avoid living together because they can share bacteria and infections that can harm each other, potentially worsening their respiratory symptoms and decreasing their life expectancy. In addition, they can develop infections with antibiotic-resistant bacteria that can be more challenging to treat.


What Is the Average Age of Cystic Fibrosis Patients?

Because of advances in medical treatments and care, the average age of cystic fibrosis patients has risen. It is now estimated to be in the mid-40s in many developed countries. However, life expectancy varies depending on several factors, including the genetic mutation that causes the disease and the severity of symptoms.


Is Cystic Fibrosis Caused by a Virus or a Bacterial Infection?

A virus or bacterial infection does not cause cystic fibrosis. Instead, it is a genetic disease caused by CFTR gene mutations that produce thick and sticky mucus in various organs such as the lungs, pancreas, and liver. On the other hand, people with cystic fibrosis are more likely to develop respiratory infections due to mucus buildup in the lungs, which can foster the growth of bacteria and other pathogens.


Does a Respiratory Infection Cause Cystic Fibrosis?

No, a respiratory infection does not cause cystic fibrosis. It is a genetic disease caused by CFTR gene mutations that affect the production and function of the CFTR protein, which regulates salt and water transport in various organs, including the lungs. However, respiratory infections in people with cystic fibrosis can be more common and severe due to the accumulation of thick and sticky mucus in the airways, which can trap bacteria and other pathogens and increase the risk of inflammation and lung damage.
Source Article IclonSourcesSource Article Arrow
Dr. Kaushal Bhavsar
Dr. Kaushal Bhavsar

Pulmonology (Asthma Doctors)


bacterial infectioncystic fibrosis
Community Banner Mobile
By subscribing, I agree to iCliniq's Terms & Privacy Policy.

Source Article ArrowMost popular articles

Do you have a question on

bacterial infection

Ask a doctor online

*guaranteed answer within 4 hours

Disclaimer: No content published on this website is intended to be a substitute for professional medical diagnosis, advice or treatment by a trained physician. Seek advice from your physician or other qualified healthcare providers with questions you may have regarding your symptoms and medical condition for a complete medical diagnosis. Do not delay or disregard seeking professional medical advice because of something you have read on this website. Read our Editorial Process to know how we create content for health articles and queries.

This website uses cookies to ensure you get the best experience on our website. iCliniq privacy policy