Evaluation of Various Culture Media for Detection of Rapidly Growing Mycobacteria from Patients with Cystic Fibrosis.
Isolation of nontuberculous mycobacteria (NTM) from the sputum of patients with cystic fibrosis (CF) is challenging due to overgrowth by rapidly growing species that colonize the lungs of patients with CF. Extended incubation on Burkholderia cepacia selective agar (BCSA) has been recommended as an expedient culture method for the isolation of rapidly growing NTM in this setting. The aim of this study was to assess five selective media designed for the isolation of Burkholderia cepacia complex, along with two media designed for the isolation of mycobacteria (rapidly growing mycobacteria [RGM] medium and Middlebrook 7H11 agar), for their abilities to isolate NTM. All seven media were challenged with 147 isolates of rapidly growing mycobacteria and 185 isolates belonging to other species. RGM medium was then compared with the most selective brand of BCSA for the isolation of NTM from 224 sputum samples from patients with CF. Different agars designed for the isolation of B. cepacia complex varied considerably in their inhibition of other bacteria and fungi. RGM medium supported the growth of all isolates of mycobacteria and was more selective than any other medium. NTM were recovered from 17 of 224 sputum samples using RGM medium, compared with only 7 samples using the most selective brand of BCSA (P = 0.023). RGM medium offers a superior option, compared to other selective agars, for the isolation of rapidly growing mycobacteria from the sputum of patients with CF. Furthermore, the convenience of using RGM medium enables routine screening for rapidly growing NTM in all submitted sputum samples from patients with CF.
Microbiology Department, Freeman Hospital, Newcastle upon Tyne, United Kingdom.|Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom.
Clair L
CL
Preece
Institute of Medical Microbiology and Infection Control, University Hospital Frankfurt, Frankfurt am Main, Germany.
Thomas A
TA
Wichelhaus
Microbiology Department, Freeman Hospital, Newcastle upon Tyne, United Kingdom.
Audrey
A
Perry
Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom.
Amanda L
AL
Jones
Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom.
Stephen P
SP
Cummings
Microbiology Department, Freeman Hospital, Newcastle upon Tyne, United Kingdom john.perry@nuth.nhs.uk.|Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom.
John D
JD
Perry
Institute of Medical Microbiology and Infection Control, University Hospital Frankfurt, Frankfurt am Main, Germany.
Michael
M
Hogardt
D000328:Adult; D001431:Bacteriological Techniques / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D003470:Culture Media / Q000737:chemistry*; D003550:Cystic Fibrosis / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods; D009165:Mycobacterium Infections, Nontuberculous / Q000175:diagnosis*; D009170:Nontuberculous Mycobacteria / Q000302:isolation & purification*; D013183:Sputum / Q000382:microbiology*
D003470:Culture Media