Examination of the growth rates of environmental isolates compared with compendial strains

For some years there has been a regulatory drive for microbiology laboratories to use environmental isolates for media quality control and for the incorporation into method suitability studies. Where these organisms are included in testing regimes, do they take longer to grow? This paper assesses the growth rates of environmental isolates in comparison with compendial recommended cultures. The research presented here finds that environmental isolates do take slightly longer to grow compared with laboratory strains, yet this time difference was within the recommended incubation times of each test type. Therefore, microbiologists should generally expect slower growth but test methods may not need to be adapted to compensate.