“Looking after Pseudomonas aeruginosa in chronic ulcers, from a laboratory point of view”

There are a reasonable amount of papers in the medical literature about Pseudomonas aeruginosa in chronic ulcers but not a lot of concrete evidence nor definitive guidelines.


Here are my personal thoughts on the topic:

  • All chronic ulcers will become colonised with bacteria, of which some might be Pseudomonas aeruginosa. Moist lesions full of nutrients are perfect for bacterial breeding. A bacterial swab taken from any chronic ulcer will almost always grow bacteria, which may or may not include Pseudomonas aeruginosa.
  • Whether a chronic ulcer is infected is a clinical judgement. The laboratory result may occasionally affect treatment in a clinically infected ulcer, but should almost never be used to decide whether an ulcer is infected or not.
  • Pseudomonas aeruginosa colonises approximately 10-15% of chronic ulcers. This is my anecdotal experience , but will obviously depend to some extent on the cohort that you are studying.
  • Pseudomonas aeruginosa probably only causes infection in a small minority of ulcers in which it is found. Most chronic ulcers are not infected, including most which grow Pseudomonas aeruginosa. Chronic ulcers may be slow to heal for a variety of other reasons, which is why they are “chronic”!
  • An ulcer colonised with Pseudomonas aeruginosa may have a charcteristic odour and colour. Yes, the distinctive colour and odour of Pseudomonas aeruginosa can be visible on the ulcer. This however does not mean it is necessarily infected, despite what others might say…
  • A heavy load of Pseudomonas aeruginosa is probably associated with slower wound healing. There is some evidence to support this assertion in the literature. However reduction of this load does not necessarily need to be with systemic antibiotic therapy. Various types of dressings, including acetic acid, silver, and medical honey have all shown at least anecdotal evidence of doing this job.
  • I would not feel compelled to report a light growth of Pseudomonas aeruginosa when mixed with other enteric flora. Pseudomonas aeruginosa is enteric flora so no need to report separately unless a heavy growth out of proportion to rest of the flora.
  • I try and avoid doing antimicrobial susceptibility testing on Pseudomonas aeruginosa in chronic ulcers unless specifically requested or some exceptional circumstances, such as pre-grafting, transplant patient etc.. If antimicrobials are routinely reported on Pseudomonas aeruginosa isolates from chronic ulcers, then you can be sure that antimicrobials will be used to treat these ulcers far more often than is clinically necessary. 

Good “management” of Pseudomonas aeruginosa by the laboratory leads to Pseudomonas aeruginosa isolates in the population which are generally susceptible and thus more amenable to treatment when they really do require attention….



5 thoughts on ““Looking after Pseudomonas aeruginosa in chronic ulcers, from a laboratory point of view”

  1. Interesting what they choose to “wash” ulcers out with – acetic acid? Wow, that would be interesting unless they are painless ulcers …. do they still wash with chlorhexidine too?
    I remember one case a few years back where the male patient used to get his dog to lick his leg ulcers because he had heard they had antibacterial saliva. This same patient ended up with a nice little Pasteurella in his blood cultures.

  2. Im interested in studying p.aeruginosa responses to antimicrobials.. im pursuing a research and clinical trials on natural ways of antimicrobials

  3. I have 5 chronic ulcers on both legs , recently 3 of them have turned a deep blue /green colour I was terrified at first thinking it was gangareen!, however wen I looked it up I came to realise that it could well be P aeruginosa, I have tried many dressings to get rid of it but it just seems to be getting worse now, so sore, bleeding around the edges, inflamation and bad headaches every day now, I even tryed scraping it off! as it seems to be fixed to the slough that won’t come off either, my problem is that my doctor won’t change my dressings and the nurse is the same insisting that eventually the intrasite and inadine will get rid of it, but its not working and they will not listen to me!, please give me some advice on what to do,
    Karen g

    1. I sympathise, nothing with chronic ulcers happens quickly unfortunately. A second opinion is always worthwhile, and dressings containing silver ions are always worth a trial in such circumstances. Regards, Michael

  4. I have pseudomonas really bad all the time, it seems to be resinstant to inadine
    and is causing me a lot of pain and distress.
    The nurses that deal with my ulcers wont listen to me, they say they know better than I do, my ulcers are completely blue/green in colour,and very sore!, I’ve asked for new dressings but they say others are too expensive, so I must stay with inadine, I’ve had silver dressings and they help but only have one box a month so that not enough to dress 4 ulcers, soon as I run out the psuedamonas comes back,
    Please can you give any advice, please.

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