An Antibiotic-resistant Bacteria Worsens Bronchiectasis, but Does Not Increase Death Rates, Study Shows

An Antibiotic-resistant Bacteria Worsens Bronchiectasis, but Does Not Increase Death Rates, Study Shows

An antibiotic-resistant Pseudomonas aeruginosa infection worsens bronchiectasis, but does not increase patients’ death rates, a Chinese study shows.

The research, “Antibiotic-resistant Pseudomonas aeruginosa infection in patients with bronchiectasis: prevalence, risk factors and prognostic implications,” was published in the International Journal of Chronic Obstructive Pulmonary Disease.

Bronchiectasis patients often have bacterial infections that increase airway inflammation and accelerate the progression of their disease.

P. aeruginosa is the most common bacteria in bronchiectasis. It leads to deterioration of lung function, lower quality of life, greater risk of hospitalization, and increased mortality.

The bacteria frequently develops resistance to antibiotics. Experts advise doctors to evaluate P. aeruginosa infection and resistance so they can come up with an optimal disease management plan for  bronchiectasis patients.

But limited information has been available on P. aeruginosa-resistant infections’ effect on bronchiectasis.

So Chinese researchers decided to investigate the prevalence, risk factors and long-term effects of the infections on adults hospitalized with bronchiectasis.

The team started by checking the records of bronchiectasis patients with P. aeruginosa who were treated at the First Affiliated Hospital of Zhengzhou University between June 2011 and July 2016. The information researchers looked at included patients’ body mass index, smoking history, whether they had other diseases, results of a lung function test known as spirometry, scores on a shortness of breath test, radio­graphic analysis findings, and the maintenance therapy they were taking for bronchiectasis.

A total of 747 patients were analyzed. P. aeruginosa was found in the sputum of 147, or 20 percent. Eighty-eight, or 60 percent, of the 147 patients had an antibiotic-resistant bacteria, while 59, or 31 percent, had a bacteria that responded to antibiotics.

Fifty-six percent of the patients with P. aeruginosa bacteria were women. The most common additional disease that patients had was pulmonary hypertension, which showed up in 35 percent.

Of the 88 patients with an antibiotic-resistant bacteria, those with multidrug-resistant strains had more hospitalizations beyond the once-a-year minimum. They also had worse shortness of breath, lung function impairment, and a higher prevalence of pulmonary hypertension.

Further analysis identified several factors that increased the risk of a patient having a drug-resistant P. aeruginosa. They included treatment with antibiotics the previous month, three or more bronchiectasis flare-ups in the previous year, worse radiological exam scores, and worse shortness of breath scores. Self-medication due to lack of information could have increased the risk in some patients, the researchers said.

The team followed patients a median of 26 months. Thirty-six died during the follow-up period. Twenty-four, or 67 percent, of the 36 had a drug-resistant bacteria at the start of the study. Its presence did not increase their risk of mortality, however. This prompted researchers to write that a drug-resistant infection “was a marker of more severe disease and more frequent or intensive antibiotic use, but was not associated with greater mortality.”

The team said a number of study limitations mean the findings should be interpreted cautiously. The       limitations included obtaining data from a single hospital, excluding patients younger than 16 years of age from the study, lack of a control group without a P. aeruginosa infection, and the possibility that some patients were put in the wrong infection-related categories.

Nonetheless, the team concluded that a drug-resistant P. aeruginosa infection “is common among bronchiectasis patients, mainly determined by prior exposure to antibiotics, frequent exacerbations, more pronounced dyspnea [shortness of breath] and more severe radiologic involvement. However, PA-R isolate [a P. aeruginosa infection] is not an independent risk factor for all-cause mortality in bronchiectasis.”

The researchers also emphasized that the “assessment of microbiologic profiles in patients with bronchiectasis is urgently needed, which might help clinicians [doctors] better appreciate the effects of PA-R infection on bronchiectasis.”