Rev Esp Quimioter 2015:28(3):139-144

Role of double strand DNA break repair for quino-lone sensitivity in Escherichia coli: therapeutic implications                                 
 

ROCÍO GONZÁLEZ-SOLTERO, ANA GARCÍA-CAÑAS, ROSA B. MOHEDANO, BELÉN MENDOZA-CHAMIZO, EMILIA BOTELLO              

 

Introduction. Quinolones are one of the types of antibiotics with higher resistance rates in the last years. At molecular level, quinolones block  type II topoisomerases producing double strand breaks (DSBs). These DSBs could play a double role, as inductors of the  quinolone bactericidal effects but also as mediators of the resistance and tolerance mechanisms.
Material and methods. In this work we have studied the molecular pathways responsible for DSBs repair in the quinolone susceptibility: the stalled replication fork reversal (recombination-dependent) (RFR), the SOS response induction, the translesional DNA synthesis (TLS) and the nucleotide excision repair mechanisms (NER). For this reason, at the European University in Madrid, we analysed the minimal inhibitory concentration (MIC) to three different quinolones in Escherichia coli mutant strains coming from different type culture collections.
Results. recA, recBC, priA and lexA mutants showed a significant reduction on the MIC values for all quinolones tested. No significant changes were observed on mutant strains for TLS and NER.
Discussion. These data indicate that in the presence of quinolones, RFR mechanisms and the SOS response could be involved in the quinolone susceptibility.

Rev Esp Quimioter 2015:28(3):139-144 [pdf]