Bacterial Growth in Contrast Agents

Dense, homogenous suspensions of the microorganisms E.coli, S. aureus, M. smegmatis and F. necrophorum were prepared in Müller–Hinton Broth. The growth time in Müller–Hinton broth growth was 8–12 h for E. coli and S. aureus and 24 h for M. smegmatis. According to our earlier experiments, these species are in the log growth phase after this time span. Then the cultures were transferred into a minimal medium M9 supplemented with 2% glucose (produced in-house in its own media production unit). The bacteria were cultured in this medium until dense suspensions were reached. Next, 1.5 mL was taken out and pelleted by centrifugation. The pellet was washed with PBS and transferred into minimal medium M9. A quantity of 100 µL of all bacterial strains in the two media were placed onto a microplate and incubated with 100 µL of each contrast agent (Ultravist, Iopamiro, Telebrix Gastro, Visipaque, Multihance and Dotarem). Negative and positive controls were included. The plates were covered by a film and incubated at 37 °C aerobic conditions for E. coli, S. aureus and M. smegmatis and anaerobic conditions for F. necrophorum.