ABSTRACT
To evaluate antibacterial activity and the bioactive compounds of 50% hydroethanolic extract of Alpinia zerumbet (A. zerumbet) rhizomes. Methods: Eight reference microbial strains including two Gram-positive bacteria [Staphylococcus aureus (ATCC 29213) and Enterococcus faecalis (ATCC 29212)] and six Gram-negative bacteria [Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATTC 700603), Proteus mirabilis (DMST 8212), Salmonella enterica subsp. enterica serovar Vellore. (ATCC 15611), Shigella flexneri (ATCC 12022) and Pseudomonas aeruginosa (ATCC 27853)], were used to test antimicrobial susceptibility by the broth microdilution method. Bioactive compounds were analyzed by using HPLC. Results: The minimum inhibitory concentration values of A. zerumbet extract were 8 mg/mL for Staphylococcus aureus, Escherichia coli and Shigella flexneri and 16 mg/mL for Enterococcus faecalis and the other four Gram-negative bacilli. HPLC chromatograms revealed that the A. zerumbet extract contained hydroxybenzoic acids, hydroxycinnamic acids and flavonoids. Conclusions: The constituents of A. zerumbet rhizomes could be a potential source of antibacterial compounds, warranting further study of A. zerumbet extract.
ABSTRACT
Salmonella is an infectious agent of gastrointestinal disease. Rapid isolation and identification of this organism are important for early and effective treatment. Salmonella, as well as other enteric bacteria, shows similar growth and colonies on MacConkey agar and Salmonella-Shigella agar, which are commonly used for isolation of Salmonella in most clinical laboratories. For better isolation and differentiation of this organism from normal enteric flora, modified semi-solid Rappaport-Vassiliadis agar (MSRV) was compared with the routine culture media used in Clinical Microbiology Unit, Srinagarind Hospital. A total of 1,944 rectal swabs were cultured by both methods. It was found that 159 isolates (8.2%) of Salmonella were recovered in this study, 153 isolates (7.9%) from MSRV and 103 isolates (5.3%) from routine medium. Of these, 97 isolates (5.0%) were positive by both methods, 56 isolates (2.9%) were positive by MSRV only, while 6 isolates (0.3%) were positive by routine media only. This study showed that MSRV gave a better result than those of the routine culture media. Therefore, MSRV should be used as additional medium for efficiency of isolation of Salmonella from rectal swab in clinical microbiology laboratories.