In vitro activity of garlic oil and four diallyl sulphides against antibiotic-resistant Pseudomonas aeruginosa and Klebsiella pneumoniae

The in vitro antibacterial activities of garlic oil and four diallyl sulphi des naturally occurring in this oil were studied against Pseudomonas aerugi nosa and Klebsiella pneumoniae (total 237 clinical isolates). Garlic oil at 4 x MIC could reduce original inoculum to less than or equal to2 log(10) i n both P. aeruginosa and K, pneumoniae within 8 h, The MIC values of four d iallyl sulphides against these two pathogens followed the order diallyl mon osulphide > diallyl disulphide > diallyl trisulphide (DAT) > diallyl tetras ulphide (DATS) (P < 0.05). Most interactions of ceftazidime, gentamicin, im ipenem and meropenem with DAT or DATS, determined according to the fraction al inhibitory concentration index, showed synergic or additive effects. The se results suggest that garlic oil, DAT and DATS may have potential for the prevention or treatment of nosocomial, antibiotic-resistant bacterial infe ctions.