title: Antibacterial and synergy of berberines with antibacterial agents against clinical multi-drug resistant isolates of methicillin-resistant Staphylococcus aureus (MRSA).
abstract: Antibacterial activity of berberine (Ber) and 8-acetonyl-dihydroberberine (A-Ber) alone and combined uses with antibacterial agents ampicillin (AMP), azithromycin (AZM), cefazolin (CFZ) and levofloxacin (LEV) was studied on 10 clinical isolates of SCCmec III type methicillin-resistant Staphylococcus aureus (MRSA). Susceptibility to each agent alone was tested using a broth microdilution method and the chequerboard and time-kill tests for the combined evaluations, respectively. The alone MICs/MBCs (μg/mL) ranges were 32-128/64-256 (Ber) and 32-128/128-512 (A-Ber). Significant synergies were observed for the Ber (A-Ber)/AZM and Ber (A-Ber)/LEV combinations against 90% of the tested MRSA strains, with fractional inhibitory concentration indices (FICIs) values ranged from 0.188 to 0.500. An additivity result was also observed for the Ber/AZM combination by time-kill curves. These results demonstrated for the first time that Ber and A-Ber enhanced the in vitro inhibitory efficacy of AZM and LEV to a same extent, which had potential for further investigation in combinatory therapeutic applications of patients infected with MRSA.
authors.affiliation: Research Center for Natural Medicines, Kunming General Hospital, PLA, Kunming 650032, China.
authors.forename: Guo-Ying
authors.initials: GY
authors.lastname: Zuo
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Han
authors.forename: Gen-Chun
authors.initials: GC
authors.lastname: Wang
authors.forename: Yun-Ling
authors.initials: YL
authors.lastname: Zhang
authors.forename: Zhong-Qi
authors.initials: ZQ
authors.lastname: Bian
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017963:Azithromycin / Q000494:pharmacology; D001599:Berberine / Q000494:pharmacology*; D002437:Cefazolin / Q000494:pharmacology; D004338:Drug Combinations; D004347:Drug Interactions; D024901:Drug Resistance, Multiple, Bacterial; D004357:Drug Synergism; D064704:Levofloxacin; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D015242:Ofloxacin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D004338:Drug Combinations; D001599:Berberine; D064704:Levofloxacin; D000667:Ampicillin; D017963:Azithromycin; D015242:Ofloxacin; D002437:Cefazolin