Background: The excessive and irregular use of antibiotics could result in the generation and diffusion of drug-resistant bacteria. The aim of this study was to investigate the inhibitory effect of Zingiber corallinum Hance essential oil (ZCHO) on drug-resistant bacteria, especially on drug-resistant Acinetobacter baumannii.
Material/Methods: Susceptibility testing was used to evaluate the effect of ZCHO on growth inhibition of drug-resistant bacteria by paper disk method. Mice orally administered with ZCHO were used to observe acute toxicity and to determine median lethal dose (LD50) of ZCHO. Broth dilution method was used to determine minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ZCHO on drug-resistant Acinetobacter baumannii.
Results: ZCHO exhibited an obvious inhibitory effect not only on gram-negative drug-resistant bacteria including Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae and Acinetobacter baumannii, but also on gram-positive drug-resistant bacteria including Staphylococcus aureus, Staphylococcus epidermidis and Staphylococcus haemolyticus. The ZCHO containing 79% terpinen-4-ol revealed better bacteriostatic effect than ZCHO with 34% terpinen-4-ol. The LD50 of ZCHO was 1790.427 mg/kg. The MIC and MBC of ZCHO on drug-resistant Acinetobacter baumannii were 1457.81 mg/L.
Conclusions: ZCHO has obvious bacteriostasis and bactericidal effects, especially against drug-resistant Acinetobacter baumannii. Therefore, ZCHO is a promising natural bioactive component with antibacterial effect and satisfactory safety due to its low toxicity.

Keywords: Organ Specificity - drug effects, Phytotherapy, Oils, Volatile - toxicity, Microbial Sensitivity Tests, Lethal Dose 50, Drug Resistance, Bacterial - drug effects, Confidence Intervals, Acinetobacter baumannii - growth & development, Toxicity Tests, Acute, Zingiberaceae - chemistry