Cystic Fibrosis Patients Can Transmit Antibiotic-resistant Infections to Each Other

People with cystic fibrosis (CF) live with a manageable but difficult condition, and now, new findings reveal additional complications. Researchers in the United Kingdom have found that multi-drug resistant infections, which are becoming increasingly prevalent in those with CF, are transmitted more often between patients than was previously known.

Cystic fibrosis is a genetic disease that primarily affects the lungs and digestive system of an individual. Due to a deficient gene, the cells normally involved in mucus, sweat, and digestion secretions do not work properly, failing to lubricate the lungs and pancreas, thus causing tubes and ducts to get plugged up. Along with other symptoms, those living with CF have persistent coughs, wheezing, and shortness of breath, and are susceptible to infections of the lungs, such as pneumonia and bronchitis. Bacterial respiratory infections are the greatest killer among individuals with CF. Lifelong treatment, which includes antibiotics and other therapies, are prescribed in an effort to keep the lungs functioning properly, by preventing mucus build-up and the development of dangerous infections. In 2013, the Centers for Disease Control and Prevention published a study on these infections in their journal, Emerging Infectious Diseases, in which a team of researchers reported on the increasing incidence of NTM pulmonary infections.

Researchers from the University of Cambridge in Cambridge, United Kingdom, and the Wellcome Trust Sanger Institute in Hinxton, United Kingdom, recently investigated the rising occurrence of a particularly virulent type of lung infection in CF patients caused by a drug-resistant nontuberculous mycobacteria (NTM) called Mycobacterium abscessus. The new paper, published in the journal, Science, examined how individuals with CF are acquiring M. abscessus infections. Previous to this study, researchers believed individuals with the condition were largely exposed to and picking up these infections from the environment. The researchers note that, in the United Kingdom, the disease is the most lethal genetic disorder of white individuals in the country. They also found a recent diagnosis of NTM infections in 5.0% of 3,805 adults and in 3.3% of 3,317 children with the chronic condition. In their investigation, M. abscessus was the second most common species of NTM to cause lung infections in those with CF.

Infections from M. abscessus are of increasing concern to doctors and researchers specializing in CF treatment and study, as the bacteria has shown resistance to a wide range of antibiotics, raising questions pertaining to which antibiotic agents and combination therapies would be best for fighting the pathogen. The study team looked at 1,080 isolates of bacteria collected from 517 patients from the United Kingdom, the United States, Ireland, Denmark, Sweden, Netherlands, and Australia. Although many isolates showed the large genetic differences that indicated that the patients picked these up independently from their environments, many of the samples from different geographic locations were nearly identical. According to the authors, this is a sign of widespread transmission within CF patients, what they call, “frequent and widespread infection of patients with closely related isolates.” In addition, the researchers found the most recent isolates to be most virulent and drug-resistant.

The research team attributes the transmission of M. abscessus between CF patients to contaminated surfaces and airborne transmission in hospitals. In a press release, the authors offered both a sober assessment of these life-threatening infections and some hope that the new findings can help reduce these infections.

“This mycobacterium can cause very serious infections that are extremely challenging to treat, requiring combination treatment with multiple antibiotics for 18 months or longer,” according to study author and professor Andres Floto, PhD, from the University of Cambridge and the Cambridge Centre for Lung Infection at Papworth Hospital NHS Foundation Trust. “The bug initially seems to have entered the patient population from the environment, but we think it has recently evolved to become capable of jumping from patient to patient, getting more virulent as it does so.”

“Our research should provide a degree of hope: now that we know the extent of the problem and are beginning to understand how the infection spreads, we can start to respond,” added Wellcome Trust Sanger Institute professor Julian Parkhill, PhD. “Our work has already helped inform infection control policies and provides the means to monitor the effectiveness of these.”