The Microbiology Section of the Therapeutic Goods Administration conducts risk-based compliance
and investigative testing of therapeutic goods to verify microbiological quality with regulatory
requirements. Identification of microorganisms presents challenges due to the variety of
environmental organisms encountered, the slow-growing nature of some organisms and the
potential for organisms to be sub-lethally damaged by exposure to sterilising or antimicrobial agents.
To determine if an organism poses a risk to patient safety or product spoilage, it is vital that
identification is correct with a high degree of confidence.
Matrix Assisted Laser Desorption/Ionisation Time of Flight Mass Spectrometry (MALDI-TOF MS)
systems are established as rapid and reliable identification systems in many fields of microbiology.
Performance qualification (PQ) of a Bruker Maldi Biotyper® 4.0 system was conducted to investigate
its suitability to identify with a high degree of confidence, bacteria likely to be encountered during
testing of therapeutic goods.
PQ comprised four separate phases: specificity, reproducibility, robustness and accuracy. A total of
1474 data point identifications were analysed: 94.2% were correct to species level, 2.4% were
correct to genus level only, 2.1% resulted in no identification, 1.1% resulted in a not reliable
identification and 0.3% were identified incorrectly.
Results indicate reliable capability of the system to rapidly identify many of the PQ microorganisms
to genus or species level, with known limitations evident for some organisms, e.g. some species of
Bacillus and Streptococcus. Extension of PQ studies will further investigate suitability of the system
for identification of other relevant organisms e.g. yeasts and probiotic bacteria.