| Popis: |
The isolation of Legionella species from environmental specimens has multiple steps subject to many potential errors, which have a cumulative effect. The growth medium is relatively complex and contains heat-sensitive ingredients, and the preparation involves multiple aseptic additions after autoclaving. The selective media and pretreatments do not suppress all background flora, and the recognition of colonies of Legionella, particularly non-L. pneumophila species, requires experience. In addition background bacterial flora can sometimes suppress the growth of colonies of Legionella completely. It is important that all laboratories in different countries produce equivalent reliable results. To achieve this, each laboratory needs a comprehensive quality assurance program including good internal quality control and participation in external quality assurance (EQA) schemes. The beneficial effects of belonging to an EQA scheme have been demonstrated by the gradual improvement in the consistency of the laboratories. This in turn is leading to more reliable quantification, which is important for monitoring the effectiveness of control measures throughout the world. |
