Evaluation of the Nutritive Capacity of Soybean Tryptic Agar for Environmental Control in the Pharmaceutical Industry

Abstract

Introduction: An environmental monitoring program is key to ensure aseptic production areas where sterile pharmaceutical products can be produced under environmental conditions that prevent the introduction, generation and retention of contamination. According to Brazilian guidelines, the exposure time of agar plates for environmental monitoring should be ≤4 h and industries should evaluate whether the culture medium used presents satisfactory nutritive capacity for use in this period of time.

Objective: To evaluate the nutritive capacity of tryptic soybean agar for environmental monitoring in the pharmaceutical industry in different exposure periods.

Methods: Seven microorganisms Aspergillus brasiliensis ATCC 16404, Bacillus spizizizenii ATCC 6633, Candida albicans ATCC 10231, Pseudomonas aeruginosa ATCC 9027, Staphylococcus aureus ATCC 6538; and Klebsiella oxytoca and Staphylococcus epidermidis (in house strains) that were previously characterized by VITEK®2 and complete sequencing of the 16S rRNA gene were used. Microorganism suspensions were prepared to achieve less than 100 colony forming unit. Plates were exposed inside biological safety cabinet for 2, 3, 4 and 5 h and then transferred to another biological safety cabinet where each suspension was spread on two tryptic soy agar plates. Plates inoculated with Aspergillus. brasiliensis and Candida albicans were incubated at 22.5 ± 2.5 °C/5 days and the others were incubated at 32.5 ± 2.5 °C/3 days. Two uninoculated plates were used as controls. Colony forming units were counted and compared with positive controls.

Results: The percentage recovery of strains was ≥50 % in all periods (50 to 189 %).

Conclusions: The nutritive capacity of soy tryptone agar was adequate for use in environmental monitoring tests up to 4 h.