What Is Stenotrophomonas Maltophilia? What Can Be Done About It?

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Stenotrophomonas maltophilia is a rare bacterial infection that often infects hospitalized patients. It’s part of a growing problem of resistant bacteria that results from the overuse of antibiotics in both healthcare and agriculture.

What Is Stenotrophomonas Maltophilia?

Stenotrophomonas maltophilia is a multidrug-resistant bacteria that causes respiratory infections. It’s also been implemented in soft tissue infection, endocarditis (infection of the tissues around the heart), meningitis, septic arthritis, and other conditions. It’s a naturally-occurring bacteria that has historically only affected individuals with compromised immune systems, but has more recently become a wider problem. Lastly, hospitalized patients with immune system issues or those with medical implants develop it.

The bacterium is generally transmitted through fluids, including irrigation solutions. It is highly resistant to common antibiotics, and there is some evidence that it can survive in chlorinated water. This makes it a hard bacteria to deal with and prevent. However, it is not particularly virulent and does not pass from person to person. In fact, it technically does not infect patients so much as colonize bodily fluids.

What Are the Symptoms of Infection?

As already mentioned, S. maltophilia can cause a variety of infections, although it most commonly affects the lungs or blood. When it infects the lungs, it causes bacterial pneumonia, and the exact infectious agent may not immediately be identified. Symptoms include cough with mucus, shortness of breath, and fever.

Symptoms of blood infection might include fever, elevated heart rate, low blood pressure, nausea, diarrhea, confusion, and abdominal pain. However, the bacteria can infect any part of the body. Endocarditis can occur if the patient has had valve replacement surgery, and this may result in the need to replace the new valve earlier.

Because of this, diagnosis is generally not based off of symptoms, but by combining them with risk factors. Generally, body fluid cultures identify bacteria. Cultures may also be taken from IV catheters, urinary catheters, breathing machines, etc. Then, these cultures are tested to establish what antibiotics to use. More research is being done on better ways to treat multi-drug resistant infections in general, so it’s very likely that treatment protocols will change significantly in the future.

S. maltophilia may sometimes be present in the body without causing disease, especially if you’re healthy. In general, most people exposed to the bacteria will not get sick unless their immune system is compromised.

How Is Stenotrophomonas Maltophilia Treated?

Because S. maltophilia is resistant to many antibiotics, treatment options are somewhat limited. In some cases, the infection may be life-threatening, and an infectious disease specialist will need to be brought in to choose the right antibiotic(s) to treat the specific strain. Currently, the first choice is an antibiotic called trimethoprim-sulfamethoxazole, but doctors may use combination therapy (more than one antibiotic), especially for severe infections. Clinical trials haven’t yet proved the efficacy, but it does appear to work.

There is no vaccine available to prevent the infection, and as yet no specific therapy that can be guaranteed to work. Instead, specialists may have to try more than one antibiotic to isolate an effective treatment.

As mentioned, S. maltophilia can be life threatening, especially in immunocompromised patients. Incorrect or inappropriate use of antibiotics can contribute to mortality, although this is a tricky infection to treat. However, in some cases, prompt removal of the medical device that is infected can be enough to treat without needing antibiotics.

What Causes the Infection?

S. maltophilia is an environmental bacteria. This puts it in a class of pathogens called “opportunistic” – although they don’t always, or even often, cause illness, if somebody’s immune system is compromised then they may be affected. The risk factors for S. maltophilia infection include:

  1. Invasive medical devices. This might include heart replacement valves, IV or urinary catheters, etc. Basically, any medical device that is inside the body can provide a vector for the bacteria. Urinary catheters seem to present a higher risk.
  2. Prior use of broad-spectrum antibiotics to deal with a different infection. Doctors should never be quick to prescribe broad-spectrum antibiotics, and patients should be inclined to question whether this treatment is necessary. (If you are prescribed antibiotics, make sure to finish the course even if you think you are “better”.)
  3. Hematopoietic stem cell transplantation has emerged as a risk factor. This treatment is for some blood cancers.
  4. Immunosuppression, such as from corticosteroids or chemotherapy.
  5. Certain chronic conditions, including HIV and cystic fibrosis.
  6. Lengthy stays in hospital.
  7. Recent surgery, especially abdominal surgery.

What Are the Next Steps?

a patient being handed antibiotics for Stenotrophomonas Maltophilia

If you or a loved one experienced S. maltophilia infection, then it may or may not be from hospital mistakes. As a common environmental bacteria, S. maltophilia is nearly impossible to keep out of hospitals. However, some doctors are too quick to perform invasive procedures and far too quick to prescribe antibiotics. Considered these risk factors before you decide if you have a medical malpractice case.

How long were urinary catheters and other devices left in? At the first sign of trouble, were they promptly removed? Hospital-acquired infections cannot always be prevented, but if the hospital seems to be having a rash of them or you have any concern about how you or your loved one are being treated, you should speak up.


If you have reason to believe the conduct of hospital staff or other personnel contributed to a S. maltophilia infection (or any other bacterial infection), then you should contact a lawyer. At Weltcheck Mallahan & Weltchek, we specialize in medical malpractice. Thus, we can help you establish if you have a chance of winning a case and getting the compensation you deserve. Contact us for a free initial consultation.

Who Can You Trust with Your Case?

Have you or a loved one been injured due to negligence? We want to help. Don’t hesitate to contact us if you believe you have a case; time is an important factor. Interested in learning more? Get in touch with us so we can better evaluate and serve your needs in getting the justice your loved one deserves. You may very well be entitled to compensation.


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