Nanopore sequencing of anti-FASII-adapted versus non-treated Staphylococcus aureus

Antibiotics that target the fatty acid synthesis (FASII) pathway block FASII synthesis, but do not prevent multiplication of the major Gram-positive pathogen Staphylococcus aureus. Bacteria can bypass inhibition by using exogenous fatty acids as present in animal hosts and food, making the anti-FASII an ineffective single-treatment method. The presence of serum favors adaptation to anti-FASII. We previous determined that no point mutation occurs during the adaptation period, which ranges from 6 - 8 hours according to conditions (https://doi.org/10.1016/j.celrep.2019.11.071). Here we performed genome sequencing by the nanopore method (realized by Eurofins Genomics Europe Sequencing GmbH, Germany) to determine whether genomic rearrangements occur during the adaptation event. Experiments were done using the USA300-FPR3757 strain called JE2. DNA was extracted from i- a control culture grown in 10% mouse serum (MS_col_1), and a second control culture grown in 10% newborn calf serum containing free fatty acids (170 µM each of C14:0, C16:0, C18:1) (SFA_col_1), and from ii- 2 independent anti-FASII-adapted cultures grown in 10% mouse serum + AFN-1252 (0.5 µg/ml) (MS A_col_1B and MS A_col_2), and 2 independent anti-FASII-adapted cultures grown in 10% newborn calf serum containing free fatty acids (170 µM each of C14:0, C16:0, C18:1) + AFN-1252 (0.5 µg/ml) (SFA_A_col_1 and SFA_A_col_2). Our results indicate that no genomic rearrangements are responsible for anti-FASII adaptation in the tested Staphylococcus aureus strain and conditions.