Cell free preparations of probiotics exerted antibacterial and antibiofilm activities against multidrug resistant .

The sharp increase in antibiotic resistance imposes a global threat to human health and the discovery of effective antimicrobial alternatives is needed. The use of probiotics to combat bacterial pathogens has gained a rising interest. Pathogenic is causative of multiple clinical syndromes such as diarrheal diseases, meningitis and urinary tract infections. In this work, we evaluated the efficacy of probiotics to control multidrug-resistant and reduce their ability to form biofilms. Six resistant to at least five antibiotics (Ceftazidime, Ampicillin, Clarithromycin, Amoxicillin + Clavulanic Acid and Ceftriaxone) were isolated in this work. Preparations of cell-free spent media (CFSM) of six probiotics belonging to the genus and which were grown in Man-Rogosa-Sharpe (MRS) broth exhibited strong antibacterial activity (inhibition zones of 11.77-23.10 mm) against all isolates. Two isolates, namely WW1 and IC2, which were most resistant to all antibiotics were subjected to antibiofilm experiments. Interestingly, the CFSM of MRS fermented by all probiotics resulted in inhibition of biofilm formation while caused highest inhibition (57.94%) in case of IC2 biofilms and was responsible for 64.57% reduction of WW1 biofilms. On the other hand, CFSM of skim milk fermented by and exhibited a slight inhibitory activity against IC2 isolate (inhibition percentage of 31.52 and 17. 68, respectively) while WW1 isolate biofilms was reduced by CFSM of milk fermented by and (70.81 and 69.49 reduction percentage, respectively). These results support the effective use of probiotics as antimicrobial alternatives and to eradicate biofilms formed by multidrug-resistant .