New Treatment Strategy for Antibiotic-Resistant Bacteria and Infectious Diseases

Scientists use plasmapheresis and antibody replacement to stop P. aeruginosa

A study published in the American Journal of Respiratory and Critical Care Medicine describes a new treatment pathway for antibiotic-resistant bacteria and infectious diseases with benefits for patients and health care providers alike.

Researchers at the University of Birmingham and Newcastle University in the United Kingdom have found that removing antibodies from the blood reduced the effects of chronic infections, the requirement for days spent in the hospital, and the use of antibiotics.

In the study, the team identified two patients with bronchiectasis who also had chronic Pseudomonas aeruginosa infections that were resistant to many antibiotics: a 64-year-old man, diagnosed with bronchiectasis at the age of 15, and a 69-year-old woman who had bronchiectasis since childhood. Both patients volunteered to receive the investigational treatment.

Bronchiectasis is a disease that leads to permanent enlargement of the airways in the lungs. Symptoms are debilitating for patients and typically include a chronic cough, shortness of breath, coughing up blood, and chest pain. Bronchiectasis often affects patients who are beyond the age at which lung transplantation is possible.

Chronic P. aeruginosa lung infections commonly occur in patients suffering from bronchiectasis. P. aeruginosa is a common bacterium that can cause disease and is known as a multidrug-resistant pathogen, recognized for its advanced antibiotic-resistance mechanisms and association with serious illnesses.

Professor Ian Henderson, Director of the Institute of Microbiology and Infection at the University of Birmingham, explained:

“These patients had an excess of a particular antibody in the bloodstream. In contrast to the protective effect normally associated with an antibody, in these patients the antibody stopped the immune system from killing the Pseudomonas aeruginosa bacterium, and this worsened the patients’ lung disease. Perhaps counterintuitively, we decided to remove this antibody from the bloodstream, and the outcomes were wholly positive.”

Co-investigator Dr. Tony De Soyza added: “We needed a brand new way of tackling this problem. Working with kidney and immunology experts, we used a process known as plasmapheresis that is somewhat like kidney dialysis. The plasmapheresis involved the removal, treatment, and return of blood plasma from the circulation, and was done five times in a week in order to remove antibody from the patients. We then replaced antibodies with those from blood donations. This treatment restored the ability of the patients’ blood to kill their infecting Pseudomonas.”

Both patients reported a rapid improvement in health and well-being, greater independence, and improved mobility compared with the previous two years, according to the researchers.

“This shows that we can improve patient well-being significantly by reducing the need for treatment and the numbers of days spent in hospital, which will also help to reduce the reliance on antibiotics,” Henderson said. “The next step is to do longer-term studies to investigate whether an earlier intervention, with slightly less-aggressive therapies, could help prevent disease progression in patients.”

This is the first description of antibody-dependent enhancement of bacterial disease. It may be widely applicable to other bacterial infections and offers hope for the treatment of some antibiotic resistant infections, according to the investigators.

Source: University of Birmingham; March 31, 2017.