The Universal Transport Medium (UTM) was prepared according to the formulations published by the Centers of Disease Control and Prevention (CDC) (4). Hank’s Balanced Salt Solution (HBSS) (Gibco™  Waltham, USA) devoid of the pH-indicator phenol red was implemented as the medium’s isotonic solution. The medium was supplemented with sterile heat-inactivated fetal bovine serum (FBS) (Gibco™   Waltham, USA), gentamicin (Gibco™ Waltham, USA), and amphotericin B (Lonza  BioWhittaker™  Walkersville, USA), at final concentrations of 2%, 100μg/ml, and 0.5μg/ml, respectively. Using sterile pipettes, 3 mL of the prepared UTM was dispensed into 15 mL sterile conical centrifuge tubes (Labcon™  Petaluma, USA) and stored at 2-8 °C for one year from the date of production. All UTM production was performed at the Jaber Al-Ahmad Al-Sabah Hospital laboratory, Kuwait.

To maintain the sterility of the reagents and prevent contamination of the UTM, the complete procedure was conducted in class II biosafety cabinets cleansed with 70% alcohol and decontaminated via ultraviolet light before and after each use. The CDC protocol for sterility testing was performed to determine the sterility of the concocted UTM (2). Depending on the number of tubes prepared per batch, tubes were randomly selected from the beginning, middle, and end of each batch made to confirm proper sterility assessment of the entire batch. The sterility of each UTM tube was tested on one blood agar plate. Using a sterile micropipette, 100μL of the prepared UTM was transferred onto blood agar and aseptically spread across the medium using a sterile cell spreader to ensure isolated colony development. The plates were invertedly incubated at 35°C ± 2°C for 48 hours. After incubation, the UTM was deemed as acceptable or rejected based on the presence or absence of microbial growth on the inoculated blood agar plates.