P. aeruginosa Adapt in Lungs to Make Mucus Harder to Clear, Study Finds

P. aeruginosa Adapt in Lungs to Make Mucus Harder to Clear, Study Finds

Pseudomonas aeruginosa, the most common bacterial infection found in bronchiectasis patients, can adapt in the lungs and acquire a mucoid state that makes sputum harder to clear, new research shows. Bacteria that mutate in this way are also linked to more severe disease.

The study, “Mucoid Pseudomonas aeruginosa alters sputum viscoelasticity in patients  with non-cystic fibrosis bronchiectasis,” was published in the journal Respiratory Medicine.

Mucus that lubricates the bronchi — the conducting airways — is produced and expelled continuously, but in people with bronchiectasis an excessive production and changes in the mucus’ mechanical properties make it harder to clear. This creates the perfect conditions for infections, of which the bacteria Pseudomonas aeruginosa is one of the most common.

Mutations in the gene mucA in P. aeruginosa make the bacteria transition from a non-mucoid to a mucoid state that is characterized by an excessive production of the exopolysaccharide alginate. Alginate is used by the bacteria to form biofilms — in which bacteria grow as a ‘community’ attached to a surface — a feature that contributes to the establishment of chronic infections.

Researchers in Spain investigated how non-mucoid and mucoid P. aeruginosa affect the viscosity and elasticity of mucus, and ultimately how it impacts clinical outcomes in bronchiectasis patients.

The team analyzed a total of 48 sputum (mucus) samples: 17 from bronchiectasis patients with mucoid P. aeruginosa, 14 from those with non-mucoid bacteria, and 17 from patients with no bacterial infection.

To measure sputum viscoelasticity, researchers used a technique called rheology that uses mechanical forces to detect changes in behavior.

Elasticity is the mechanical property that measures the tendency of a material to return to its original form after being deformed, while viscosity measures how much the material resists the tendency to flow. Hence, mucus with a high viscosity and low elasticity is more likely to remain intact and not move when air at high velocity passes through it.

Researchers found that, compared with infection-free patients, those with mucoid P. aeruginosa showed a tendency to have higher sputum viscosity (median 2.40 vs. 1.5 1rad/s), elasticity (median 10.30 vs. 5.70 1rad/s), and stiffness (median 10.70 vs. 6.0 1rad/s).

This trend might explain why patients with mucoid bacteria had more exacerbations or flares, and more pus (purulence) in their sputum than patients without infection.

Patients with chronic colonization with mucoid bacteria also had worse lung function, a higher level of dyspnea (shortness of breath), and more severe disease.

The team concluded that mucoid P. aeruginosa bacteria are “associated with increased elasticity, viscosity, and stiffness of bronchiectatic sputum” that “correlated with worse severity outcomes.”

Sputum “viscoelasticity assessment with rheology could be a new clinical tool in order to optimize and personalize bronchiectasis management,” and used “as a marker of poor mucociliary clearance,” the researchers added, noting that further studies are needed to confirm these findings.

Patricia holds a Ph.D. in Cell Biology from University Nova de Lisboa, and has served as an author on several research projects and fellowships, as well as major grant applications for European Agencies. She has also served as a PhD student research assistant at the Department of Microbiology & Immunology, Columbia University, New York.
Patricia holds a Ph.D. in Cell Biology from University Nova de Lisboa, and has served as an author on several research projects and fellowships, as well as major grant applications for European Agencies. She has also served as a PhD student research assistant at the Department of Microbiology & Immunology, Columbia University, New York.
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  1. Grandma Horsey says:

    My treatment and it works:
    Vicks Vapor rub in jar
    original formula
    It will take some looking to find this
    Flush nose with saline nose drops
    Take cue tip little rub on it put

    • Nila atkins says:

      Acetylcysteine this thins out your sputum, I use this and it works like a dream. You have to have it prescribed, Great mucoloid.

  2. They interesting, I have suffered with bronchietasis for 15 years, have had asthma 25 years. Last winter I developed pneumonia. Prior to that it was under control, but my stamina, and as a result mental health, has deteriorated dramatically. I’ve gone from being reasonably active to almost sedatory. When I feel well I try to do the things that came naturally to me prior to my pneumonia but I pay for it the following day feeling absolutely exhausted. It does now seem to effect my legs, feeling heavy and having no strength.
    I use a seretide 250 mcg two puffs twice daily
    I have recently been treated with levofloxacin 500mg twice daily for two weeks
    Also a short course of corticosteroids
    My overall health has not improved
    Result of chest X-ray taken 4th July 2019
    “No active lung lesion identified. There is some focal segmental bronchiectasis of the left mid zone on a background of fribrous scarring. No accompanying soft tissue mass lesions seen. There is generalised wall thickening at this level. No large pleural effusion. Cardiomediastinal are within normal limits.”

    • Jon Olsen says:

      Have you tried going on a five day run out of 40 mg of prednisone is early in the morning as possible? That might jump start your energy level the main side effect which I hate is severe insomnia that can be helped by melatonin and Benadryl but I still wake up quite often check your diet also I shouldn’t be that extreme

    • Grandma Horsey says:

      Hi Angela
      Stamina is a problem for me also!
      I eat protein at every meal either fruit with
      bacon or eggs for breakfast always have snacks after exercise too!
      carved turkey sandwich for lunch with cheese stick
      Lean Cuisine Spaghetti and meatballs for dinner
      is normal for me also I drink comforts advantage care electrolyte solution with zinc or you can use pedialyte for adults 1 glass when I feel fatigued

  3. Grandma Horsey says:

    Hi Barry,
    I don’t know if I am infected with that bacteria or not
    I live in N.Nevada and medicare is provided mostly by clinics seeing a real doctor is rare. I was referred to a pulmonary specialist and we have had a hard time getting a culture grown in a lab seems they just give the sputum the 10 min test and that’s all I get which is not what my doctored ordered but that’s what you get if you live in Nevada. So I decided to analyze my history I have had pneumonia 6 to 7 times brought on by sinus infections and allergies also I live on 3 acres of dusty desert property
    to survive I use a air purifier in my bedroom for 1-2 hours than a humidifier for 1-2 hours before bedtime flush my nose with saline nose drops then vicks right under the nostrils a little around the tip inside of the nose the humidity here is only 7% so I have to do all this to breathe!

  4. Nila atkins says:

    I was first diagnosed with Bronchiectasis at age 26 That was also when I had to have resection of my lower left lung. I am now 55 and am still living with Bronch. I have had pneumonia more times than I care to mention. I have psudomona areuginosa colonized in my lungs and have to do a 28 day course of Gentamicin nebulized ever other month. and various other nebulized meds. I use the vest 3 x a day to clear out the excess of mucus. I use 3 liters of concentrated air at night because I have sleep apnea. I take many pills and a multi vitamin . Use Acetylcystine which is a mucloid , this works like a dream to get rid me of excess mucus . I too also deal with Shortness of breath. I have to use O2 when I am active. I am involved in Pulmonary rehab to try to strengthen what lungs I do have left.
    I wish the best for all of you out there with Bronchiectasis It is a daily battle .

  5. Janet Ball says:

    I have bronchiectasis and also been diagnosed with pseudomonas areuginosa. Have been given no specific antibiotics for this except 100mg Doxycycline daily.
    Sputem is getting more difficult to eliminate. Nebuliser with salbutamol 3 times daily and also been advised to add about 7 drops of 0.9% sodium chloride for injection.
    Any views on this. Thank you.

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