Asthma Linked to E. Coli Bloodstream Infections

Asthma patients found to have higher risk of developing bacterial bloodstream infection

(RxWiki News) People with asthma tend to have a higher risk of developing breathing-related infections. But it seems asthma also may be associated with other types of bacterial infections.

A recent study found that people with a history of asthma had a higher risk of getting an E. coli bloodstream infection than those without asthma.

The researchers concluded that the reasons behind this link remain unknown, therefore more research is needed.

"Talk to your doctor about the risks of asthma."

The lead author of this study was Young J. Juhn, MD, from the Department of Pediatric and Adolescent Medicine at the Mayo Clinic in Rochester, Minnesota.

The researchers selected 259 people who had recorded cases of community-acquired E. coli bloodstream infection. All participants lived in Olmsted County, Minnesota and had the condition between January 1, 1998 and December 31, 2007.

Of the participants, 69 percent were women, 96 percent were 18 years old or older, and 86 percent were Caucasian.

The researchers also selected 259 comparison subjects who matched each person in the participant group by birthday, gender and residency.

Asthma diagnoses in both the participant and the comparison groups were determined by reviewing medical records for symptoms that matched a list of criteria for asthma.

The researchers found that 14 percent of the participant group (those who had recorded cases of E. coli infection) had a history of asthma. A total of 6 percent of the comparison group had a history of asthma.

The researchers determined that the participants with a history of asthma were almost three times more likely to have E. coli bloodstream infection than the participants who had not had asthma.

The researchers discovered that these results were not influenced by outside risk factors such as age, gender, follow-up time, ethnicity, educational level or co-occurring conditions.

"This interesting study from the Mayo Clinic examined a group of patients living in Olmsted County, Minnesota who suffered an infection of E. coli and found that almost three fold greater likelihood of infection was seen in those with asthma," John Oppenheimer, MD, Physician at Pulmonary and Allergy Associates in New Jersey, told dailyRx News.

"This leaves us with many yet unanswered questions. Is this finding the result of some change in the immune system related to the asthma, is it a consequence of illnesses that occur more commonly in people with asthma (such as suffering from allergy) or related to the medicines that the asthmatic patients are using," said Dr. Oppenheimer.

"One thing is for sure — further research is needed!" he said.

The underlying reason behind the association between asthma and E. coli bloodstream infection is not yet known; therefore the researchers believe more research is needed.

The authors noted a few limitations of their study.

First, the researchers used previously recorded participant data, so they could not find out certain information that may have influenced the results, such as atopic sensitivity (how sensitive a person is to a certain allergen) or cigarette smoking history. Second, the researchers determined asthma diagnoses using a certain criteria of symptoms, rather than a recorded diagnosis.

Third, the participants were mostly white, so these results may not be applicable to other ethnicities. Lastly, the participants were generally older and had many co-occurring conditions.

This study was published in the October edition of BMJ Open.

The Mayo Foundation, the National Institute of Aging and the National Institute of Allergy and Infectious Diseases provided funding.

Review Date: 
October 15, 2013