The International Journal of Mycobacteriology

LETTER TO EDITOR
Year
: 2021  |  Volume : 10  |  Issue : 3  |  Page : 344--345

Mind the gap!: Need for improved harmonization of antibiotic susceptibility testing of the nontuberculous mycobacteria between cystic fibrosis clinical guidelines and Mycobacterium antibiotic susceptibility testing laboratories


John Edmund Moore1, Mark Smyth2, Steven Caskey3, Beverley Cherie Millar1,  
1 Laboratory for Disinfection and Pathogen Elimination Studies, Northern Ireland Public Health Laboratory, Belfast City Hospital, UK
2 Department of Medical Microbiology, Northern Ireland Regional Mycobacterium Reference Laboratory, The Royal Group of Hospitals, Belfast, Northern Ireland, UK
3 Northern Ireland Regional Adult Cystic Fibrosis Centre, Level 8, Belfast City Hospital, Belfast, Northern Ireland, UK

Correspondence Address:
John Edmund Moore
Laboratory for Disinfection and Pathogen Elimination Studies, Northern Ireland Public Health Laboratory, Belfast City Hospital, Belfast, BT9 7AD
UK




How to cite this article:
Moore JE, Smyth M, Caskey S, Millar BC. Mind the gap!: Need for improved harmonization of antibiotic susceptibility testing of the nontuberculous mycobacteria between cystic fibrosis clinical guidelines and Mycobacterium antibiotic susceptibility testing laboratories.Int J Mycobacteriol 2021;10:344-345


How to cite this URL:
Moore JE, Smyth M, Caskey S, Millar BC. Mind the gap!: Need for improved harmonization of antibiotic susceptibility testing of the nontuberculous mycobacteria between cystic fibrosis clinical guidelines and Mycobacterium antibiotic susceptibility testing laboratories. Int J Mycobacteriol [serial online] 2021 [cited 2022 Jan 21 ];10:344-345
Available from: https://www.ijmyco.org/text.asp?2021/10/3/344/325490


Full Text



The last two decades has seen an increase in the incidence of nontuberculous mycobacteria (NTM) in people with cystic fibrosis (CF) where these organisms have now become established as important organisms within CF.[1],[2],[3] The CF Foundation in their latest annual report (2019) describes that of the 15,497 individuals with CF examined for the presence of mycobacterial organisms, 2149 (13.9%) had a mycobacterial species isolated one or more times.[4] Of the mycobacterial organisms identified, Mycobacterium avium complex was the most frequently isolated (1057/2059; 51.3%), followed by Mycobacterium abscessus/Mycobacterium chelonae (888/2059; 43.1%), Mycobacterium gordonae (65/2059; 3.2%), Mycobacterium fortuitum (27/2059; 1.3%), Mycobacterium tuberculosis (12/2059; 0.6%), and Mycobacterium kansasii (10/2059; 0.5%). Due to their clinical significance in terms of related disease severity along with the resistance to many antibiotics resulting in treatment dilemmas, several national and international clinical guidelines have been published to help give guidance as to the best way to diagnose and management such patients.[5],[6]

These guidelines detail several antibiotics, belonging to several different classes of antibiotic, which are advocated for the treatment of NTM-related infection. Given the high degree of antibiotic resistance observed with these isolates, clinicians are eager to first check the sensitivity of antibiotics that they are planning to use with the patient, to avoid the employment of agents where the clinical response may be potentially diminished due to existing onboard resistance. Therefore, clinicians will first check with their supporting microbiology laboratory or with the receiving NTM reference laboratory.

In general, such NTM testing laboratories will have their own established panel of antibiotics that they will test against the submitted CF NTM isolate. Given that the evolution of antibiotic susceptibility testing assays in the laboratory will have a different origin and timeline to the clinical guidelines, sometimes, those antibiotics detailed in the clinical guidelines do not align with those tested in the reference laboratory and vice versa. The downside of such a misalignment is that antibiotic assay reports are returned with susceptibility to several antibiotics missing, which the clinician would have liked to have seen, to support NTM antibiotic choice on the commencement of therapy.

An example of such a scenario are those antibiotics listed in the British Thoracic Society guidelines for the management of nontuberculous mycobacterial pulmonary disease, for the treatment of M. abscessus,[6] which include amikacin, tigecycline, imipenem, clarithromycin, azithromycin, clofazimine, linezolid, minocycline, moxifloxacin, and cotrimoxazole. Antibiotic sensitivities routinely reported for rapid growing NTM in the National Mycobacterium Reference Service-South User Manual[7] include amikacin, tobramycin, cefoxitin, cotrimoxazole, clarithromycin, linezolid, ciprofloxacin, moxifloxacin, and doxycycline but do not include tigecycline, imipenem, clofazimine nor minocycline.

Remedial action may be taken to specifically re-request that the reference laboratory re-tests with specific antibiotics as defined by the CF clinician, but this requires a retest which may take several weeks due to the slow-growing nature of several NTM species, thereby potentially delaying the initiation of anti-NTM therapy, until sensitivity results are available from the reference laboratory, to guide antibiotic choice.

Therefore, we advocate the need for better communication between CF clinicians and microbiologists, to align those NTM antibiotics detailed in clinical guidelines with those tested de facto in NTM reference laboratories, to support well-informed and appropriate antibiotic choice.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Richards CJ, Olivier KN. Nontuberculous mycobacteria in cystic fibrosis. Semin Respir Crit Care Med 2019;40:737-50.
2Degiacomi G, Sammartino JC, Chiarelli LR, Riabova O, Makarov V, Pasca MR. Mycobacterium abscessus, an emerging and worrisome pathogen among cystic fibrosis patients. Int J Mol Sci 2019;20:5868.
3Martiniano SL, Nick JA, Daley CL. Nontuberculous mycobacterial infections in cystic fibrosis. Thorac Surg Clin 2019;29:95-108.
4Patient Registry. Annual Data Report. Cystic Fibrosis Foundation; 2019. Available from: https://www.cff.org/Research/Researcher-Resources/Patient-Registry/2019-Patient-Registry-Annual-Data-Report.pdf. [Last accessed on 2021 May 12].
5Floto RA, Olivier KN, Saiman L, Daley CL, Herrmann JL, Nick JA, et al. US Cystic Fibrosis Foundation and European Cystic Fibrosis Society. US Cystic Fibrosis Foundation and European Cystic Fibrosis Society consensus recommendations for the management of non-tuberculous mycobacteria in individuals with cystic fibrosis. Thorax 2016;71 Suppl 1:i1-22.
6Haworth CS, Banks J, Capstick T, Fisher AJ, Gorsuch T, Laurenson IF, et al. British Thoracic Society guidelines for the management of non-tuberculous mycobacterial pulmonary disease (NTM-PD). Thorax 2017;72:i1-64.
7National Mycobacterium Reference Service-South (NMRS-South) User Handbook. National Infection Service Public Health England. Available from: https://www.gov.uk/government/publications/national-mycobacterium-reference-laboratory-nmrl-user-manual. [Last accessed on 2021 May 13].