MALDI-TOF MS BIOTYPER AND POLYMERASE CHAIN REACTION FOR RAPID IDENTIFICATION OF STAPHYLOCOCCUS AUREUS AND PSEUDOMONAS AERUGINOSA IN NON-STERILE PHARMACEUTICAL PREPARATIONS

Absence of pathogenic bacteria is a must for passing the microbiological quality control inspection of non-sterile pharmaceutical products. The identification of microbial contaminants by conventional methods is time-consuming and labor-intensive. The overall aim of the study was to test non-conventional methods as polymerase chain reaction (PCR) and Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectroscopy Biotyper (MALDI-TOF) for rapid identification of Pseudomonas aeruginosa and Staphylococcus aureus in topical pharmaceutical preparations. Four different topical preparations and three raw materials were artificially inoculated with tested microorganisms, at an initial cell count of 10º CFU/ml, and were overnight pre-enriched in Tryptic soy broth (TSB). MALDI-TOF was tested for identification of target microorganisms using different sample preparation methods. Duplex PCR targeting oprL (Pseudomonas aeruginosa) and mRNA nuclease gene (Staphylococcus aureus) was also tested. Pseudomonas aeruginosa and Staphylococcus aureus were identified within 18 – 37 h using MALDI-TOF, according to the sample preparation method, and 27 h using duplex PCR; compared to 48 – 72 h for the identification using conventional microbiological methods. Our results revealed that both PCR and MALDI-TOF were sensitive and specific to target microorganisms; MALDI-TOF proved to be a precise, cheap, rapid and high throughput screening method, compared to PCR and conventional methods.