Authors: Martha Powell & Frances Adlam (Future Science Group)
Last week Infectious Diseases Hub and Future Microbiology attended the second state-of-the-art symposium on nontuberculosis mycobacteria (NTM) infections. The event brought together leading experts in the field who covered a range of topics; from diagnosis to epidemiology, clinical management and treatment.
To begin, we heard Jakko van Ingen (Radboud University, Nijmegen, the Netherlands) reporting on the biology of NTMs, including their distinct characteristics, natural habitat and their propensity towards antibiotic resistance, which Van Ingen highlighted as “most relevant to clinical practice”.
Van Ingen also spoke briefly about his current research designing new antibiotic treatment regimens for NTM disease. Current treatment options typically involve the combination of many antibiotics, which even then reduce infection at a slow rate. Van Ingen has hopes to identify a “Trojan horse”, which could weaken or penetrate the mycobacterial cell wall, consequently improving infection outcomes for patients
The focus then shifted to epidemiology, with Rebecca Prevots, from the National Institute of Allergy and Infectious Diseases (MD, USA), giving an overview of the disease burden caused by NTMs. Despite being relatively rare, she stated, the burden of infection is increasing globally − a trend that highlights the importance of this symposium. In addition to discussing prevalence, Prevots emphasized the species-specific regional variation and the need for more species-specific data moving forwards.
Next, Ken Olivier (National Institutes of Health, MD, USA) delved into host factors associated with NTM infections, discussing the differences between immunocompromised and immunocompetent patients in addition to the possible influences of host genetics.
What is important when diagnosing NTM infections? Michael Loebinger (Royal Brompton Hospital, London, UK) attempted to address this complicated topic in his talk. He stated that “who, when and how to treat is complex”, emphasizing the need to consider extent, progression, significance and patient factors. In addition, Loebinger brought our attention to other diagnostic considerations, such as whether there is the presence of multiple species, and their importance in the decision to treat the NTM infection.
Building on this theme in his discussion of treatment for Mycobacterium Avium complex, David Griffith (University of Texas, TX, US) commented that treatment is “all about context”. Griffith went on to highlight some of the complexities in treating M. Avium complex, for example, the innate resistance of mycobacteria and the lack of understanding around mutational resistance.
Treatment was a continued in the next talk, with Charles Haworth (Papworth hospital, Cambridge, UK) discussing the proposed British Thoratic Society guidelines on NTMs, specifically how these relate to M. abcessus. However, he did also touch on transmission, presenting a worrying case study that highlighted the possibility of within-hospital transmission, and suggesting this issue could be improved with enhanced surveillance, cleaning, ventilation and segregation of NTM patients.
Charles Daley (University of Colorado, CO, USA) was then left with the challenging task of covering treatment for the many other species of NTMs, specifically focusing on M. kansasii, M. simiae, M. malmoense and M. xenopi. He emphasized the difference between treatment outcomes, for example calling M. kansasii the “most treatable NTM” and highlighting the varied outcomes and need for further research in M. xenopi.
Finally, Andres Floto (University of Cambridge, UK) talked about drug discovery and future treatments, asking why we need more antibiotics for NTMs? Floto echoed van Ingen’s earlier talk, discussing the innate resistance mechanisms borne from the mycobacterial cell wall in addition to mentioning the issues with current drugs and the growing problem of antibiotic resistance. Floto went on to suggest the solution was three-fold; borrowing from the tuberculosis pipeline, making old drugs work better and developing new drugs.
To round off the day there was a lively panel discussion with the audience being given an opportunity to highlight difficult topics and ask questions about the NTM treatment guidelines written by some of the panel members. The symposium not only emphasized current research and treatments for NTMs, it was also an opportunity to bring an otherwise often overlooked area to the forefront.
Question from panel discussion: “Over the next few years do you think the focus should be on developing treatments or preventing acquisition?”
Prof Charles Daley: “It takes two to tango! You have to have susceptibility and exposure, and I don’t think we can stop infection but I don’t see why we can’t decrease infection once we better understand where infections are occurring. This is a major failure in our research – we say that it’s in our soil and water, but which soil and which water and when? How much exposure?
“I think that’s what we should be focusing on; prevention and prevention from re-infection. Until we get a better understanding about transmission and where it’s happening it’s hard to come up with effective strategies.”