A study led by England’s University of Cambridge and the Wellcome Trust Sanger Institute showed that multidrug-resistant nontuberculous mycobacterium, known to cause serious complications in cystic fibrosis (CF) patients, has spread globally and is becoming more virulent.
The study, “Emergence and spread of a human-transmissible multidrug-resistant nontuberculous mycobacterium,” was published in the journal Science.
The study also indicates that typical cleaning is not enough to eliminate this mycobacterium, which can be transmitted in the air or through contaminated surfaces.
Lung infections with Mycobacterium abscessus, a species of multidrug-resistant nontuberculous mycobacteria, are emerging as an important global threat to people with CF, in whom M. abscessus accelerates inflammatory lung damage, leading to increased morbidity and mortality.
M. abscessus was previously thought to be acquired only by susceptible individuals from the environment, and that transmission between patients never occurred.
Using whole-genome analyses of a global collection of 1,080 clinical isolates of M. abscessus from 517 patients obtained from U.K. cystic fibrosis clinics, as well as CF centers in the U.S., mainland Europe, and Australia, the researchers found that the majority of M. abscessus infections are acquired through transmission that have spread globally.
The researchers also found that the infection may be transmitted via contaminated surfaces and in the air within hospitals.
Using cell-based and mouse models, the team demonstrated that the mycobacteria were more virulent and more likely to cause serious disease in humans.
“This mycobacterium can cause very serious infections that are extremely challenging to treat, requiring combination treatment with multiple antibiotics for 18 months or longer,” Prof. Andres Floto from the Department of Medicine at the University of Cambridge and the Cambridge Centre for Lung Infection at Papworth Hospital NHS Foundation Trust, said in a press release.
“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,” he said.
Prof. Julian Parkhill from the Wellcome Trust Sanger Institute in Cambridgeshire said their 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. Our work has already helped inform infection control policies and provides the means to monitor the effectiveness of these,” Parkhill said.
The Adult Cystic Fibrosis Centre at Papworth Hospital, Cambridgeshire, has led to the development and implementation of new policies aimed at reducing the risk of transmission. These policies have now been adopted in many cystic fibrosis centers.
The findings of this study have also led to the design of a new CF unit at the Papworth Hospital, which will have a novel air handling system. The new CF unit is due to open in 2018.
The researchers are now investigating how the pathogen manages to spread across the globe. The findings of this study have shown that the pathogen can spread not only between individuals within specialist centers, but also across continents. Researchers think that healthy individuals between countries might be carrying the mycobacteria.
The study’s results also opens doors for the development of new drug targets, and the researchers will also explore these in collaboration with teams at the University of Cambridge and Colorado State University.
“This paper highlights the risks posed through transmission of multidrug resistant organisms between people with cystic fibrosis,” said Dr. Janet Allen, director of strategic innovation at the CF Trust. “The team in Cambridge are a world authority in this area. This work demonstrates the global threat of this infection, the risks of cross-infection within and between CF centres, and the need for improved surveillance.
“This study exemplifies the enormous impact of CF Trust-funded Strategic Research Centres, which were designed to generate world-class research with the very highest impact. Without the support of the CF community, this landmark study would not have been possible,” Allen said.