Gentamycin

Antibiotic susceptibility testing was performed for 17 drugs covering all the nine antimicrobial categories comprising aminoglycosides, ansamycins, fluoroquinolones, folate pathway inhibitors, tetracyclines, glycopeptides, oxazolidinones, macrolides and incosamidesl were determined using the disc diffusion susceptibility test according to clinical and laboratory standards institute (CLSI) guidelines. Commercial antibiotic discs of rifampin (5 μg), linezolid (30 μg), ciprofloxacin (5 μg), levofloxacin (5 μg), minocyclin (30 μg), doxycycline (30 μg), tetracycline(10 μg), gentamycin (10 μg), tobramycin (10 μg), amikacin(1 μg), erythromycin(15 μg), azithromycin (15 μg), clarithromycin (15 μg),clindamycin (2 μg) trimethoprim/sulfamethoxazole (1.25/23.75 μg),(MAST Diagnostics, Merseyside UK) were used in disc diffusion test. Then, MDR/XDR/PDR phenotype of these isolates was established according to the results obtained from the disc diffusion test. Briefly, multidrug-resistance (MDR) was defined as resistance to at least three or more different classes, extensive drug-resistance (XDR) was defined as resistance to at least one agent in all but two or fewer antimicrobial categories and pan drug-resistance (PDR) was defined as resistance to all agents in all antimicrobial categories.16,17