Use of LIPA Mycobacteria (Innogenetics) to identify mycobacteria in a routine laboratory

The test consists in the PCR amplification of the DNA region coding for the 16S~23S rRNA
space! of Mycobacterium species followed by the hybridization and the stringent wash of the
amplified product with species specific probes immobilized on a strip. Thirteen different probes
are placed on the strip enabling the specific identification of the most frequent mycobacterial
strains isolated in clinical samples.
One hundred twenty strains isolated from clinical specimens on Lowenstein-Jensen medium
were included in the evaluation study. Lipa. identification of all the 120 strains was in agreement
with identification obtained by other methods like classical bacteriological tests) Gen Probe
hybridization tests, species specific PCRs. PeR-restriction fragment length polymorphism
analysis ofthe fup65 gene (PRA) and, in some cases, DNA sequencing of an amplified fragment
ofthe 168 rRNA gene.
On the other hand, 35 early growing Bactec cultures from clinical specimens, taken at a GI as
low as 9, were analysed by Lips Mycobacteria. 69 % ofthem could be identified on the aliquot
taken when the GI was between 9 to 50. The remaining cultures could be identified on an
aliquot ofBaetec mediwn taken one or 2 days later.
In comparison to the other identification methods. Lipa Mycobacteria gives results by far faster
than bacteriological tests and is easier to perfonn than PRA and DNA sequencing. It takes
longer to perform than the Gen Probe hybridization test (lh30 PeR plus 3h30 hybridizationwashing procedure versus 2h for the Gen Probe test), but it allows, in the same procedure, identification of 9 different mycobacterial species though Gen Probe hyridiution only identifies 1 or maximum 2 species. Lipa Mycobacteria is also usable on early growing Bactec cultures.