What is pseudomonas aeruginosa?

A case report of community-acquired Pseudomonas aeruginosa pneumonia complicated with MODS in a previously healthy patient and related literature review

This patient was diagnosed with severe community-acquired pneumonia (CAP) due to P. aeruginosa, which progressed to septic shock quickly. It was complicated by secondary hematogenous CNS infection and MODS involving cardiovascular, hematologic, central nervous, and gastrointestinal systems. During treatment, the pathogen developed resistance to carbapenems quickly and the antibiotic regimen was adjusted accordingly. The patient ended up with symptomatic improvement and was discharged from hospital, though unilateral structural lung damage and multiple cavities remained.

In CAP, P. aeruginosa is rarely identified as the pathogenic agent, accounting for only 0.4–6.9% in reported cases of CAP requiring hospitalization and 1.8–8.3% in CAP requiring ICU admission . It is very rare in previously healthy patients since P. aeruginosa usually causes infections in patients who have lung structural change, are immunocompromised, or have other specific risk factors. In the English-language literature reported from 1966 to 2000, Todd F et al. identified only 11 publications describing a total of 13 cases.

Most P. aeruginosa-caused CAP is seen in patients with structural lung diseases, chronic obstructive pulmonary disease (COPD) or cystic fibrosis. Therefore, the 2007 American Thoracic Society (ATS) / Infectious Diseases Society of America (IDSA) guidelines recommended empirical treatment against P. aeruginosa in community-acquired pneumonia (CAP) patients with the following specific risk factors: 1) structural lung disease, like bronchi, 2) recurrent exacerbations of COPD requiring corticosteroid/antibiotic treatment, 3) antibiotic use before admission,4) immunocompromised status. However, by analyzing the data of 402 cases, ORIOL SIBILA et al. found that current risk factors for CAP due to P. aeruginosa in the CAP guidelines identified only one-third of the patients admitted with CAP due to P. aeruginosa, with the other two-thirds undetected. They also found that chronic heart failure, cerebrovascular disease, advanced age and smoking were risk factors for CAP due to P. aeruginosa. Catia Cillóniz et al. found that malnutrition was another important risk factor for P. aeruginosa-caused CAP. Several studies also found that fatal P. aeruginosa pneumonia in previously healthy patients was associated with contaminated hot tubs. Influenza may be a risk factor for P. aeruginosa infection, there are some reports of P. aeruginosa co-infection with influenza A (H1N1). Influenza viral infection contributes to respiratory epithelial cell dysfunction and death through disruption of protein synthesis and induction of apoptosis, allowing for increased bacterial adherence and invasion .

Compared to pneumonia caused by other pathogens, P. aeruginosa CAP exhibits rapid progression, high severity and poor prognosis. P. aeruginosa CAP usually has a higher CURB-65 score and pneumonia severity index (PSI) than pneumonia caused by other pathogens, with mortality approximately 18–61% . In severe P. aeruginosa CAP, mortality of those who developed progressive septic shock and MODS can reach as high as 50–100% . In death cases, Todd F reported a median time of 11 h from admission to death. Advanced age(>65y), chronic liver disease, acute renal failure, requirement of ICU admission, and improper initial antibiotic use might be risk factors for poor prognosis. Even in survival cases, the foci of infection usually develop into fibrous scar tissue, or repeated infections requiring long-term antibiotic treatment. In our case, the patient developed necrotic pneumonia with cavity formation.

The progression and prognosis of such cases might be associated with various pathogeneses of P. aeruginosa :1)P. aeruginosa secretes toxins into the extracellular environment and into host cells. For example, through the type III secretion system (TTSS), P. aeruginosa injects toxins (e.g, ExoS, ExoT, ExoU) that change host cell activities and disrupt host cell actin cytoskeletons, block phagocytosis, and cause cell death; 2) Bacterial surface factors such as flagella, pili and lipopolysaccharide induce host inflammatory responses; 3) QS (quorum sensing), functioning as the connection between neighboring bacteria, plays a role in the regulation of a wide variety of processes including biofilm formation and production of numerous toxins; 4) P. aeruginosa secretes various enzymes and cytotoxins, such as elastase, alkaline protease and exotoxin A, that either disrupt the integrity of the epithelial barrier by disrupting epithelial cell tight junctions or cause direct tissue damage and necrosis.

The patient in this case developed rapid antimicrobial resistance to carbapenems. Despite a number of studies on antimicrobial resistance of hospital-acquired P. aeruginosa infection, the number of studies on resistance of community-acquired P. aeruginosa is limited. After analyzing drug sensitivity reports of 77 P. aeruginosa CAP cases, researchers found 32% were multi-drug resistant strains and 68% were sensitive strains . During treatment, these bacteria acquire antimicrobial resistance by several mechanisms, including reduced permeability, enzymatic degradation, and active efflux . Development of resistance is also associated with gene mutations. For example, repressed oprD expression leads to carbapenem resistance; mexX mutation causes resistance to aminoglycosides and fluoroquinolones . Mutations of gyrA and gyrB(gyrase) also result in resistance to fluoroquinolones . In addition, biofilm formation also contributes to antimicrobial resistance in P. aeruginosa. Biofilms are bacterial cities, highly organized, microbial communities encased in a polysaccharide matrix and attached to the surfaces of implants or airways. These multi-drug resistant variants in these colonies contribute to the high resistance of biofilms to antimicrobials.

Regarding treatment of P. aeruginosa CAP, guidelines recommend empirical treatment for these who have risk factors for P. aeruginosa infection. Early administration of proper antibiotics may improve the outcomes for such patients . For patients with suspected P. aeruginosa-caused severe pneumonia, combination antibiotic therapy should be administered within an hour . For critically ill patients admitted to the ICU, guidelines recommend use of an antipseudomonal β-lactam (piperacillin-tazobactam, cefepime, imipenem, or meropenem) plus an antipseudomonal fluoroquinolone; or the above β-lactam plus an aminoglycoside and azithromycin; or the aboveβ-lactam plus an aminoglycoside and a fluoroquinolone . Once P. aeruginosa is confirmed to be the pathogenic agent, antibiotic regimen should be adjusted to be more targeted. Targeted therapy recommended by guidelines includes an antipseudomonal β-lactam plus an aminoglycoside or a fluoroquinolone, with the alternative being an aminoglycoside plus a fluoroquinolone. According to a study by Cillóniz , inappropriate therapy occurred in 64 and 77% cases of P. aeruginosa CAP and multi-drug resistant P. aeruginosa CAP, respectively. In light of the high severity and rapid progression, patients with such conditions should be monitored closely and should receive frequent organ function evaluations.

According to our case and related literature review, we conclude that more attention should be paid to community-acquired Pseudomonas aeruginosa pneumonia because of its rapid progression and poor prognosis.

Pseudomonas skin infections


Infection of the skin or soft tissues by Pseudomonas aeruginosa or other Pseudomonas species tend to be serious and complex because these bacteria are both invasive and toxigenic.

What causes Pseudomonas skin infections?

Pseudomonas aeruginosa can be commonly found on the skin, especially in the axillary and anogenital regions. However, healthy people do not normally develop Pseudomonas infection. Pseudomonas is considered to be opportunistic and more frequently causes disease in those who are immunocompromised.

Pseudomonas can be easily transmitted from hospital workers to their patients in absence of proper hand hygiene and is responsible for approximately 10% of all nosocomial infections.

Who is at risk for Pseudomonas skin infections?

Patients at higher risk for this infections include those with:

  • Malignancies
  • HIV/AIDs
  • Burns
  • Diabetes
  • Intravenous catheter
  • Indwelling urinary catheter
  • Surgery
  • Trauma.

What are the signs and symptoms of a Pseudomonas skin infection?

Signs and symptoms of Pseudomonas infection can vary widely depending upon the site of the infection, but can include:

  • Erythematous (red) lesions that can be haemorrhagic or necrotic
  • Deep abscess
  • Subcutaneous nodules
  • Cellulitis
  • Necrotising fasciitis
  • Black or purple discoloration or eschar (in case of infected thermal burns)
Pseudomonas skin infection

What are the different types of Pseudomonas skin infections?

Pseudomonas skin infections include:

  • Puncture wounds of the foot. These can frequently become infected with Pseudomonas species and the patient will present with drainage with a sweet, fruity-smelling discharge. Cellulitis and osteomyelitis are common complications.
  • Thermal burn wounds. If eschar is present, Pseudomonas bacteria can populate beneath this protected layer. It can often result in bacteraemia (bacteria in the blood stream), a complication with a high mortality rate.
  • Chronic leg ulcers. Colonisation with Pseudomonas is recognised by malodorous greenish superficial crust.
  • Spa pool folliculitis. This Pseudomonas infection is acquired in inadequately chlorinated hot tubs. Patients present with itchy follicular papules and pustules on any part of the body submerged in the tub.
  • External otitis. This is the most common form of Pseudomonas infection of the ear and is most commonly found in the tropics: patients present with pain, swelling and redness of the external portions of the ear as well as purulent discharge. Malignant external otitis is more serious. This affects diabetic patients and can cause severe pain and damage to the cranial nerve.
  • Ecthyma gangrenosum. Patients with ecthyma gangrenosum are frequently neutropaenic. They develop erythematous, ulcerated, purple or black skin lesions in the axillary, inguinal or anogenital areas.
  • Chronic paronychia and onycholysis. Greenish discolouration may be due to colonisation by Pseudomonas.

Pseudomonas nail infection

What are the complications from Pseudomonas skin infections?

The most common complication of a Pseudomonas skin or soft tissue infection is bacteraemia; this usually comes from contaminated intravenous fluids, drugs or antiseptics used during placement of an intravenous line.

How are Pseudomonas skin infections diagnosed?

Pseudomonas infections are suspected on physical examination when there is a a greenish or blackish, fruity-smelling discharge. They are confirmed by laboratory studies of cultures taken from the affected area.

What are the treatments for Pseudomonas skin infections?

Treatment is based on the site of the Pseudomonas infection and its severity. It may include:

  • Antibiotics
  • Irrigation with a 1% acetic acid solution in cases of otitis media along with topical polymyxin B, colistin, or fluoroquinolones in cases of a more severe infection
  • Debridement of necrotic tissue and/or drainage of abscesses as an adjuvant to antibiotic therapy
  • Amputation of affected limb (in rare cases).

Pseudomonas infection

Pseudomonas is a type of bacteria that can cause lung infections. It mainly affects people who already have a lung condition or who have a problem with their immune system. It doesn’t respond to commonly-used antibiotics, which means infections can be hard to treat.

If you have a lung condition and have repeated chest infections, or chest infections that don’t go away with your usual treatment, ask your health care professional about having a test to see if you have Pseudomonas in your sputum.

If you have cystic fibrosis or bronchiectasis, it’s important to have effective antibiotic treatment as soon as Pseudomonas is found to prevent it from becoming long-term.

On this page we will answer:

  • What is Pseudomonas?
  • What infections does it cause?
  • Who is at risk?
  • How is it diagnosed?
  • How is it treated?
  • How can I avoid a Pseudomonas infection?

What is Pseudomonas?

Pseudomonas is a common type of bacteria usually found in soil and water. It rarely causes problems in people with healthy lungs.

Pseudomonas can be difficult to treat, as it’s resistant to commonly-used antibiotics, like penicillin, doxycycline and erythromycin. You may need to take different antibiotics if you have Pseudomonas.

Sometimes antibiotics are unable to clear Pseudomonas from the lungs. When this happens, you may need to have long-term oral or inhaled antibiotic treatment to keep the bacteria at a low level.

What infections does Pseudomonas cause?

Pseudomonas bacteria can cause a variety of infections, not limited to lung infections, including:

  • pneumonia
  • urinary tract infections
  • wound infections
  • septicaemia
  • gastro-intestinal system infection

Sometimes people without existing lung conditions carry Pseudomonas in their lungs without causing an infection. This means it’s not always necessary to have treatment.

Who is at risk of a Pseudomonas infection?

People more likely to get a Pseudomonas infection include those with long-term conditions like:

  • cystic fibrosis
  • bronchiectasis
  • COPD

It can also cause an infection in people with problems with their immune system.

Pregnant women are at a greater risk of getting a Pseudomonas infection. This is due to hormone changes affecting their immune system.

How is a Pseudomonas infection diagnosed?

A sample will be taken from your lungs to see if Pseudomonas is present. This is usually through a sputum sample.

But occasionally you may have a bronchoscopy, when a narrow tube is inserted through your nose or mouth, down into your lungs, while you are sedated.

How is a Pseudomonas infection treated?

If you have a Pseudomonas infection, it can usually be treated effectively with antibiotics. But sometimes the infection can be difficult to clear completely.

This is because many standard antibiotics don’t work on Pseudomonas. The only type of tablet that works is ciprofloxacin. Other antibiotics in the same group whose names end in -floxacin are also effective. This kind of antibiotic can occasionally cause tendon problems – if you start to get heel pain while taking it, stop the medication and let your health care professional know immediately.

It’s important to finish your antibiotic course

This is because:

  • your infection becomes harder to treat as the Pseudomonas bacteria can become resistant to the antibiotics you were taking
  • you may need to take more medication
  • you may need to have injections as well as tablets

If your infection is resistant to this antibiotic, or you can’t take it because of side effects, you may need to have intravenous antibiotics, and may need to be admitted to hospital for this.

If you have a long-term Pseudomonas infection that persists despite antibiotics, you may need to take antibiotics regularly. This is to keep the infection at a low level and to prevent flare-ups of your symptoms. This is usually prescribed by a consultant and you’ll have regular reviews. This might include tablets or inhaled antibiotics taken through inhalers or a nebuliser.

Pseudomonas grow in mucus so keeping your airways clear makes it harder for the bacteria to grow. Ask your health care professional about seeing a physiotherapist who can recommend airway clearance techniques.

How can I avoid a Pseudomonas infection?

The main thing you can do is follow good hygiene rules:

  • regularly wash your hands with soap and water
  • always cough into a tissue
  • clean contaminated surfaces with a bleach-based cleaner
  • wash contaminated clothes and sheets separately at the highest possible temperature.

Also, if you smoke, it’s important to stop as smoking damages your lung’s immune defences.

BrodexTrident Blog

The chances are you may never have heard of Pseudomonas aeruginosa, and even if the name sounds familiar, you may not be au fait with exactly what it is and how it might affect someone. Thankfully this is where we step in, and inform you that Pseudomonas aeruginosa (there are other strains of pseudomonas, yet the majority have been found to spawn in a similar manner when clinically presented) is a commonly occurring bacterium discovered across the globe; and typically rooted in soil, plants and water sources. What’s more (and admittedly a little gross sounding), it’s not unheard of for seemingly healthy people to have variations on the common pseudomonas theme alive and kicking MUCH closer to home. So much so, that certain strains – or series of events/eventualities – can take hold and prosper on host’s skin, particularly moist parts of the human anatomy (like armpits and/or the genital area for example).

So, What Are the Specific and Recognised Signs of Pseudomonas Aeruginosa to be Made Aware of?

Turning our attentions to the key symptoms normally associated with the onset of Pseudomonas aeruginosa, and a lot depends on whereabouts the infection establishes itself. Pseudomonas is no respecters of persons per se and have a habit of making their presence felt in numerous areas within the body; including the bloodstream, lungs, stomach, urinary tract or tendons. In addition to this, existing skin wounds could also become possible breeding grounds for pseudomonas, taking into account pressure sores and burns which might also become infected. In terms of identifying symptoms to be vigilant for (and moreover, locations on the body where infection tends to occur), the following are universally cited as amongst the core examples.

  • Ears (pain and discharge)
  • Eyes (pain, redness, swelling)
  • Skin (rash, which can include pimples filled with pus) – Pseudomonas does not grow on dry skin, however has a propensity to flourishes on moist skin. Green nail syndrome is a paronychia-type infection that can develop in individuals whose hands are frequently submerged in water, while secondary wound infections occur in patients with decubiti, eczema, and tinea pedis. These infections may have a characteristic blue-green exudate with a fruity odour. Pseudomonas is a common cause of hot tub or swimming pool folliculitis, as many patients present with pruritic follicular, maculopapular, vesicular, or pustular lesions on any part of the body that was immersed in water.
  • Bones or joints (joint pain and swelling; neck or back pain that lasts weeks) – The most common sites of involvement are the vertebral column, the pelvis, and the sternoclavicular joint
  • Wounds (green pus, or discharge that may have a fruity smell)
  • Gastrointestinal/Digestive Tract ((headache, diarrhoea) – Pseudomonal infections can affect every portion of the GI tract. The disease is often underestimated but usually affects very young children and adults with hematologic malignancies and chemotherapy-induced neutropenia
  • Lungs (pneumonia; severe coughing and congestion)
  • Fever (also acknowledged as a sign of a severe pseudomonas infection)
  • Urinary tract infections – Pseudomonal urinary tract infections usually require a spell of hospitalisation and are associated with catheterization, instrumentation and surgery. These infections can involve the urinary tract through an ascending infection or through bacteremic spread
  • …..Meanwhile the central nervous system can be attacked by a particularly virulent strain of Pseudomonas aeruginosa, which can in turn lead to the onset of critical health issues such as meningitis and/or brain abscess.

Picking up on the Above, Who Are Considered Most at Risk from the Advent of Pseudomonas Aeruginosa?

Those most at risk include people who;

  • Have a wound from surgery
  • Are being treated for burns
  • Use a breathing machine, catheter, or other medical device
  • Suffer from diabetes or Cystic Fibrosis
  • Have a disorder that weakens their immune system (such as HIV)
  • Take medications that suppress their immune system (like those that treat cancer)

Further to this, below we have outlined health conditions which are classed as predisposing to pseudomonal infections (and major manifestations);

  • Diabetes – Malignant otitis externa
  • Drug dependency/addiction – Endocarditis, osteomyelitis
  • Leukaemia – Sepsis, Typhlitis
  • Cancer – Pneumonia, sepsis
  • Burn wound – Cellulitis, sepsis
  • Cystic Fibrosis – Pneumonia
  • Surgery involving CNS – Meningitis
  • Tracheostomy – Pneumonia
  • Neonatal period – Diarrhoea
  • Corneal ulcer – Panophthalmitis
  • Vascular catheterization – Bacteraemia, suppurative thrombophlebitis
  • Urinary catheterization – UTI

How is Pseudomonas Aeruginosa Diagnosed, and What Treatment is Subsequently Offered by the Medical Profession?

In the event of a GP suspecting the presence of any pseudomonas, they’ll ask to take a blood sample (or another bodily fluid) and send it for the appropriate tests at a lab to determine whether or not an individual has contracted Pseudomonas aeruginosa; and to ultimately ascertain which type of antibiotics would be best suited to fight the infection. With mild forms of pseudomonas, a course of antibiotics is traditionally prescribed, and based on where the infection has been identified the medicine could take the form of a cream, eye drops, ear drops or orally-ingested tablets, all of which comprise of antibiotic qualities. Similar to influenza in some respects, every pseudomonas bacteria is slightly different from the other, with strains perpetually changing; which makes infections a challenge to treat on some occasions. It’s not beyond the realms of possibility that a sufferer is required to take more than one kind of antibiotic, whilst in severe cases antibiotics might be administered courtesy of an IV tube/feed.

What Measures Can I Adopt to Avoid Succumbing to a Pseudomonas Infection?

Basically, good hygiene form will stand anyone in good stead when it comes to consciously side-stepping a potential pseudomonas Infection. In a nut shell it’s imperative to be aware that germs can prosper in certain situations, ergo take a more pro-active approach to personal hygiene both at home and when out and about. This includes;

  • Ensure you wash your hands often. If you’re in the hospital, make sure that doctors and nurses always clean their hands before touching you, too
  • Always rinse fruits/vegetables before eating. Even salad greens should be given a good wash
  • Always subject water bottles to a regular clean between uses. Sterilize with boiling water ideally
  • Try to avoid unclean pools and hot tubs. Pseudomonas will thrive in them unless they’re cleaned often and the chlorine and pH are well-controlled

Ensuring you have an effective water hygiene monitoring programme can help prevent & control the risk of your domestic water system harbouring bacteria such as pseudomonas and legionella. Check out our free audit checklist to make sure you have effective controls in place.

What Is Pseudomonas Aeruginosa?

Some superbug strains of Pseudomonas aeruginosa cause infections that are resistant to nearly all types of antibiotics.

Pseudomonas is a group of bacteria that can cause various types of infections.

Pseudomonas aeruginosa is the most common disease-causing species, according to the Centers for Disease Control and Prevention (CDC).

Serious infections from P. aeruginosa generally occur only in healthcare (nosocomial) settings, but people can also develop mild infections in other environments.

In the United States, there are an estimated 51,000 healthcare-associated P. aeruginosa infections each year, according to the CDC.

This translates to about 8 percent of all healthcare-associated infections — of any type — reported to the CDC.

P. Aeruginosa Transmission and Risks

In healthcare settings, P. aeruginosa is spread through improper hygiene, such as from the unclean hands of healthcare workers or via contaminated medical equipment that wasn’t fully sterilized.

Common hospital-associated P. aeruginosa infections include bloodstream infections, pneumonia (lung infection), urinary tract infections, and surgical wound infections.

These infections typically affect people who are ill in the hospital, particularly those with weakened immune systems from diseases or long-term treatments.

When hospitalized, you have a higher risk for a serious, life-threatening P. aeruginosa infection if you have surgical wounds or burns, or are being treated with a breathing machine, such as a mechanical ventilator, or other medical devices, such as urinary or intravenous catheters.

Exposure to contaminated water can also cause mild P. aeruginosa infections in healthy people outside of healthcare settings.

For instance, inadequately chlorinated hot tubs and swimming pools can cause P. aeruginosa ear infections (most common in children) and skin rashes. They can also cause eye infections in users of extended-wear contact lenses.

Pseudomonas Aeruginosa Symptoms

Symptoms of P. aeruginosa vary based on the type of infection.

Bloodstream infections can cause various symptoms, including:

  • Fever and chills
  • Body aches
  • Light-headedness
  • Rapid pulse and breathing
  • Nausea and vomiting
  • Diarrhea
  • Decreased urination

Pneumonia can cause:

  • Fever and chills
  • Difficulty breathing
  • Cough, sometimes with yellow, green, or bloody mucus

Urinary tract infections can cause:

  • Strong urge to urinate frequently
  • Painful urination
  • Unpleasant odor in urine
  • Cloudy or bloody urine

Wound infections can cause:

  • Inflamed wound site
  • Fluid leakage from wound

Ear infections can cause:

  • Ear pain
  • Hearing loss
  • Dizziness and disorientation

Pseudomonas Aeruginosa Treatment

Mild, water-related P. aeruginosa infections are generally treated easily with certain antibiotics.

Treating severe hospital-associated P. aeruginosa infections is becoming more difficult, however, because some bacterial strains show resistance to nearly all classes of powerful antibiotics, including:

  • Aminoglycosides
  • Cephalosporins
  • Fluoroquinolones
  • Carbapenems (antibiotics of last resort)

In fact, about 13 percent of severe healthcare-associated P. aeruginosa infections are caused by multidrug-resistant strains, according to the CDC.

These drug-resistant superbugs cause roughly 400 deaths a year.

Treating these tough infections requires sending samples to a laboratory to test the bacteria against different antibiotics in hope of finding drugs that are effective against it.

Pseudomonas Infections: Matching Causes and Prevention

Peter L. Salgo, MD: I heard something else that I think we need to at least mention. I think it was you who said that if you have pseudomonas colonization, we then have pseudomonas infection and invasive disease. What’s the difference?
Jason Pogue, PharmD, BCPS-AQID: The clear thing is that a lot of patients are colonized with all kinds of microbiology, but we’re only concerned with patients who actually develop clinical infections from the same place. Colonization will often precede infection occurring, but certainly we’re concerned about the patients once they develop the pneumonia from them having that longstanding colonization of the organism.
Peter L. Salgo, MD: I want to bring it back full circle then, which goes to what I was saying. You can be colonized with pseudomonas, but in order to get an invasive infection with pseudomonas, don’t you need to be sicker? Don’t you need to be one of those patients who’s already, in some way, really ill? Or can you just get pseudomonas out of the blue?
Marin Hristos Kollef, MD: Generally, healthy patients in the community don’t develop pseudomonal infection for the most part. There may be a few exceptions to that rule, but to develop a true pseudomonal infection, it really requires certain host factors. I think that’s what we’ve been commenting on.
Peter L. Salgo, MD: Right.
Marin Hristos Kollef, MD: In addition to the host factors, I think it is important to recognize that it’s a very virulent organism, and I think the audience really needs to be clear on that particular point. Because it’s a virulent organism and it has certain virulent mechanisms in place, antibiotic therapy does become important. We don’t have mechanisms for treating the virulence of the pathogen, so we have to really err on the side of treating it with an appropriate antibiotic regimen.
Peter L. Salgo, MD: Death to bugs; death to pseudomonas.
Marin Hristos Kollef, MD: Death to pseudomonas, but focusing on the antimicrobial aspect of it, since we have limited options for tackling the virulence factors.
Peter L. Salgo, MD: Right.
Andrew Shorr, MD: More importantly, focusing on prevention. There are things that we can do to prevent severe infection in our critically ill patients, whether it’s early ambulation, early liberation from the ventilator, less sedation, or chlorhexidine bathing. One place where we take infection prevention very seriously in the hospital is actually the ICU, where we have bundles of protocols that are evidence based and have been shown in randomized trials to effectively prevent some severe infections. And so, if you’re going to work in an environment where you know it’s enriched for the risk and bad outcomes associated with the bug you’re describing, then it’s incumbent upon all of us to actually start this conversation at, what are we doing for prevention?

Peter L. Salgo, MD: You want to back off. Before we even talk about antibiotics, if we could prevent people from becoming infected—or if they’re colonized, we could prevent it from becoming invasive—that’s the ideal.
Andrew Shorr, MD: Correct.
Peter L. Salgo, MD: We have techniques for that. Whether it’s a VAP (ventilator-associated pneumonia) bundle or something else—as you said, chlorhexidine—that would be ideal, right?
Andrew Shorr, MD: The data for chlorhexidine are more controversial than they used to be. We’ve got a positive trial, but we’ve got some follow-up on negative trials.
Peter L. Salgo, MD: I heard a chuckle on the right side of me.
Andrew Shorr, MD: Your patient smells better if they’re bathed in chlorhexidine every day, but I think it speaks to the fact that people are striving to find good, effective, inexpensive strategies, some of which have abundant evidence in support, some of which are controversial when you make a decision about the risk-benefit tradeoff.
Jason Pogue, PharmD, BCPS-AQID: I think with some of the most invasive things that we do, there’s a conscious effort in the ICU to shorten the duration. So, ventilation might be an option for that.
Peter L. Salgo, MD: Absolutely.
Jason Pogue, PharmD, BCPS-AQID: Pulling in the central line sooner on these patients. Those are known risk factors for hospital-acquired infections, chlorhexidine in particular. And so, I think a lot of effort to prevention comes along those lines.
Peter L. Salgo, MD: By the way, I think the correct phrase now is health care facility associated infection. It’s morphed again.
Yoav Golan, MD: Obviously, another component that is very important in our efforts to prevent infection is our use of antibiotics. What antibiotics are we choosing as a matter of protocol? We’re going to discuss this later, but a lot of that is actually in our hands.
Peter L. Salgo, MD: We talk about pseudomonas as if it affects 1 organ system. People always think about pseudomonas pneumonia, which is common, but there are lots of other pseudomonas infections, too, right?
Andrew Shorr, MD: Pseudomonas is a pathogen that, once it sets up shop in your hospital, can cause any kind of infection because it’s a bug-host interaction. It can certainly be a leading pathogen in a ventilator-associated or hospital-acquired pneumonia, but it can still be a leading pathogen in bloodstream infection. My colleagues in the surgical ICU see surgical-site infections in postoperative mediastinitis after CABG (coronary artery bypass graft). If pseudomonas is around, pseudomonas will find a place to get in, and it’s very much the same way with acinetobacter. If it has set up shop, it’s not specific for 1 infection or 1 organ infection. It causes infections in any of those syndromes, even including urinary tract infection. You need to be vigilant.
Peter L. Salgo, MD: Is there one infection that’s worse than others?
Yoav Golan, MD: Before that, just to add to what Andy says, I think it’s important to understand the biology of pseudomonas when you try to predict the kinds of infections. It’s important to remember that pseudomonas is ubiquitous. It’s a moisture type of bacteria. It can exist in the environment. It tends to colonize people, particularly people who get antibiotics and are in health care institutions, particularly on mucosa surfaces. And anything you do to violate the integrity of the mucosa—by putting a line that breaks the mucosa going into the vein, by using a urinary catheter that dilates the mucosa of the urinary tract, by using endotracheal tubes, and so forth—will provide pseudomonas with an opportunity. So, you tell me what kind of violation of the mucosa you had with your patient and I’ll tell you what the patient is going to be vulnerable to develop.

Peter L. Salgo, MD: But that’s not unique to pseudomonas. You can say that that for staph infections. You can say that for anybody, right?
Yoav Golan, MD: Absolutely. This is not unique to pseudomonas. What is unique to pseudomonas are a few factors. One is, as Andy said, that once you get colonized with it, it’s really hard to get rid of it. It’ a long-term colonization. If you look at the risk of infections, it’s right into colonization and how long you are going to be colonized with the bacteria. What is the ability of this bacteria to survive the antibiotics in the environment, as pseudomonas has a great ability? Pseudomonas is not unique in principle, but it’s more quantitative. That makes it more likely to infect those patients.
Peter L. Salgo, MD: What scares you guys more? Is it pseudomonas pneumonitis? Pseudomonas cystitis? Pseudomonas something else? Is there 1 organ system that, when infected with pseudomonas, is worse than all the others?
Yoav Golan, MD: What scares me the most is once it infects my sickest patients. Because they are the least able to tolerate infection and they’re the ones who require the most aggressive approach.
Peter L. Salgo, MD: Aren’t they the ones who are most likely to get it? That’s what makes this bug so nasty, among other things.
Andrew Shorr, MD: Right, but it is in some way a tautology, right?
Peter L. Salgo, MD: Right.
Andrew Shorr, MD: I think about Yoav’s point about it being a function of the patient, not a function of the bug. If you’ve had a kidney transplant, I’m worried about an ascending tract infection from pseudomonas.
Peter L. Salgo, MD: Sure.
Andrew Shorr, MD: If you’ve been on a ventilator with acute lung injury from flu or on ECMO (extracorporeal membrane oxygenation) for 2 weeks, I’m worried about pneumonia. It is a pathogen that goes where the host offense is weakest. Can I say that pneumonia is associated with the highest accrued mortality rate pseudomonas versus urinary tract infections? Yes, sure, but that’s because it’s easy to eradicate pus in the bladder and it’s hard to eradicate pus in the lung. So, that’s also true for every other pathogen. To stay informed on the latest in infectious disease news and developments, please sign up for our weekly newsletter.

Infections caused by pseudomonas

Pseudomonas can cause a variety of infections, including:

  • pneumonia (chest infections)
  • urinary tract infections
  • wound infections
  • septicaemia (blood infection)
  • infection of the gastro-intestinal system

Pseudomonas may also be found on the skin of some people and not necessarily cause infection. This is known as colonisation.

For these people, a risk assessment is undertaken. Treatment may be given in some cases if the person is at risk of developing an infection.

People vulnerable to pseudomonas infection

Pseudomonas rarely causes infection in people who are in good health. It is more likely to infect patients who are already very sick.

It can cause a range of infections, particularly among immunocompromised people (weakened immune symptom). This includes:

  • people who have HIV
  • people with cancer
  • people with severe burns
  • people with diabetes
  • people with cystic fibrosis


During pregnancy a woman’s body undergoes changes promoted by hormones, and changes to the immune system. These changes occur to promote a healthy pregnancy, and help protect the developing baby.

As a result of these changes, pregnant women can be more likely to experience some infections, such as urine infections.

As a result, women who are pregnant may have an increased risk of getting a pseudomonas infection.

When to seek medical advice

In general, if you, or your child, have a weakened immune system and develop any signs of infection, such as a temperature, or symptoms of any of the infections listed above, you should seek medical advice urgently.

It may not necessarily be pseudomonas infection, but should be investigated and treated without delay.

If you have a weakened immune system, have recently been treated in a healthcare setting, and develop an infection, your GP will want to find out what is causing it – to see for example, if pseudomonas is present.

Causes of pseudomonas infection

Pseudomonas infection is caused by the bacterium Pseudomonas aeruginosa, in a patient that is at risk (see above).

It is a tough bacterial strain, and is able to survive in harsh environments. This makes it difficult to get rid of completely.

It rarely causes illness outside a hospital or healthcare setting.

Infection control departments in hospitals are constantly taking measures to prevent spread and outbreaks.

Screening for pseudomonas

In Northern Ireland, steps are taken to control and minimise the spread of pseudomonas by screening for presence of the bacterium on the parts of the body where it can be found.

Screening is usually done in hospital by taking swabs from different areas of the body. The areas swabbed may involve:

  • the nose/throat secretions
  • armpit
  • groin/ perineum
  • sometimes the navel (belly button)

Treatment of pseudomonas

If screening test results (see screening section above) show you have a pseudomonas infection, you will be contacted, and your treatment will be discussed with you.

Infections caused by pseudomonas are usually treated using an appropriate antibiotic in hospital.

Pseudomonas colonisation (when it is found only on the skin) may not necessarily require treatment.

Hospital staff take special precautions with patients who have pseudomonas in order to stop it spreading.

How to stop germs spreading

You can reduce your risk of picking up or spreading germs by practising good hygiene, both at home and in healthcare settings.

The following can help:

  • if you have an illness, stay at home until at least 48 hours after your symptoms have cleared up
  • wash your hands regularly with soap and water, particularly after going to the toilet and before eating – use liquid rather than bar soap and don’t use flannels or nail brushes
  • clean contaminated surfaces – such as the toilet, flush handle, light switches and door handles – with a bleach-based cleaner after each use
  • don’t share towels and flannels
  • wash contaminated clothes and sheets separately from other washing at the highest possible temperature
  • when visiting someone in hospital, follow visiting guidelines, avoid taking any children under the age of 12, and wash your hands with liquid soap and water when entering and leaving ward areas – avoid visiting hospital if you’re feeling unwell or have recently had diarrhoea
  • Read more about preventing germs from spreading

Who stands to benefit from this research and how?

Helping prevent, diagnose and treat infection

The researchers are hoping to identify the bacterial genes that make Pseudomonas aeruginosa so deadly to vulnerable people. This work is of fundamental importance to the future development of better ways to prevent, diagnose and treat Pseudomonas infections. It may lead to new screening tools that can tell us whether people have been infected with a particularly nasty strain of the bacteria. Researchers believe this could save lives by allowing better infection control procedures, as well as early and aggressive antibiotic therapy when needed. The discovery of disease-causing genes may also contribute to the development of new antibiotics, a vital area of need as Pseudomonas bacteria are increasingly resistant to most currently available antibiotics. Everyone who is at risk of Pseudomonas infection may benefit in the future. Pseudomonas aeruginosa causes an estimated 10% of all hospital-acquired infections in the UK.4,7,8 Those most at risk include the elderly, people with cancer, severe burns or weakened immune systems, and people who need artificial ventilation. People with cystic fibrosis may benefit too. More than 7,000 people in the UK have cystic fibrosis,11 with the much-dreaded Pseudomonas bacteria being a leading cause of death.

1. Shaw MJ. 2005. Ventilator-associated pneumonia. Curr Opin Pulm Med 11:236-41.

2. Chastre J, Fagon JY. 2002. Ventilator-associated pneumonia. Am J Respir Crit Care Med 165: 867-903.

3. Van Delden C. 2007. Pseudomonas aeruginosa bloodstream infections: how should we treat them? Int J Antimicrob Agents 30 Suppl 1: S71-5.

4. Spencer RC. 1996. Predominant pathogens found in the European Prevalence of Infection in Intensive Care Study. Eur J Clin Microbiol Infect Dis 15:281-5.

5. Hoiby N, Frederiksen B, and Pressler T. 2005. Eradication of early Pseudomonas aeruginosa infection. J Cyst Fibros 4 Suppl 2:49-54.

6. Murray TS, Egan M, and Kazmierczak BI. 2007. Pseudomonas aeruginosa chronic colonization in cystic fibrosis patients. Curr Opin Pediatr 19:83-8.

7. Jones RN, Kirby JT, Beach ML, Biedenbach DJ, and Pfaller MA. 2002. Geographic variations in activity of broad-spectrum beta-lactams against Pseudomonas aeruginosa: summary of the worldwide SENTRY Antimicrobial Surveillance Program (1997-2000). Diagn Microbiol Infect Dis 43:239-43.

9. Mayor S. 2000. Hospital-acquired infections kill 5000 patients a year in England. BMJ 321:1370.

10. Doring G, Conway SP, Heijerman HGM, Hodson ME, Hoiby N, Smyth A, Touw DJ for the Consensus Committee. 2000. Antibiotic therapy against Pseudomonas aeruginosa in cystic fibrosis: a European consensus. Eur Respir J 16:749-67. 11. UK CF Database / Cystic Fibrosis Trust, Annual Data Report 2004, University of Dundee,

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