title: Fresh Garlic Extract Enhances the Antimicrobial Activities of Antibiotics on Resistant Strains in Vitro.
abstract: BACKGROUND
  Infections caused by strains with multi-drug resistance are difficult to treat with standard antibiotics. Garlic is a powerful remedy to protect against infections of many bacteria, fungi and viruses. However, little is known about the potentials of fresh garlic extract (FGE) to improve the sensitivity of multi-drug resistant strains to antibiotics.
  
  
  OBJECTIVE
  In this study, we used the disk diffusion method to investigate the antimicrobial activities of FGE and the combination of antibiotics with FGE, on methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Candida albicans, to evaluate the interactions between antibiotics and FGE.
  
  
  METHODS
  Clinical isolates were isolated from clinical specimens obtained from the inpatients at the First Affiliated Hospital of Xi'an Jiaotong University Health Science Center. The isolates consisted of MRSA, (n = 30), C. albicans (n = 30) and P. aeruginosa (n = 30). Quality control for CLSI (Clinical and Laboratory Standards Institute) disk diffusion was performed using S. aureus ATCC®25923, C. albicans ATCC®90028 and P. aeruginosa ATCC®27853. The 93 microorganisms were divided into four groups in a factorial design: control (deionized water), FGE, antibiotics without FGE, and antibiotics with FGE. Next, antibacterial activity was evaluated by measuring the diameter of inhibition zones according to performance standards for antimicrobial susceptibility testing of the Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS).
  
  
  RESULTS
  Fresh garlic extract displayed evident inhibition properties against C. albicans and MRSA, yet weak inhibition properties against P. aeruginosa. Additionally, FGE showed the potential to improve the effect of antibiotics on antibiotic resistant pathogens. The synergism of fluconazole and itraconazole with FGE on C. albicans yielded larger sized inhibition zones compared with fluconazole and itraconazole without FGE (P < 0.01). The factorial analysis represents intense positive interaction effects (P < 0.01). The synergism of cefotaxime and ceftriaxone with FGE on P. aeruginosa yielded larger sized inhibition zones than cefotaxime and ceftriaxone without FGE (P < 0.01). The factorial analysis represents intense positive interaction effects (P < 0.01).
  
  
  CONCLUSIONS
  The results suggest that FGE can improve the antibiotic sensitivity of these pathogens to some antibiotics.
authors.affiliation: The First Affiliated Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, China.
authors.forename: Guoliang
authors.initials: G
authors.lastname: Li
authors.affiliation: The First Affiliated Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, China.
authors.forename: Xudong
authors.initials: X
authors.lastname: Ma
authors.affiliation: Department of Pathogen Biology and Immunology, College of Basic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, China.
authors.forename: Lisha
authors.initials: L
authors.lastname: Deng
authors.affiliation: Department of Pathogen Biology and Immunology, College of Basic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, China.
authors.forename: Xixi
authors.initials: X
authors.lastname: Zhao
authors.affiliation: The First Affiliated Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, China.
authors.forename: Yuejiao
authors.initials: Y
authors.lastname: Wei
authors.affiliation: Department of Pathogen Biology and Immunology, College of Basic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, China.
authors.forename: Zhongyang
authors.initials: Z
authors.lastname: Gao
authors.affiliation: The First Affiliated Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Jia
authors.affiliation: Department of Pathogen Biology and Immunology, College of Basic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, China.
authors.forename: Jiru
authors.initials: J
authors.lastname: Xu
authors.affiliation: The First Affiliated Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, China.
authors.forename: Chaofeng
authors.initials: C
authors.lastname: Sun
keywords: Candida albicans; Drug Resistance, Microbial; Garlic; Methicillin-Resistant Staphylococcus aureus; Pseudomonas aeruginosa