Objective: To evaluate antibacterial activity and the bioactive compounds of 50％ hydro-ethanolic 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.

Background: With limited information available, the association among urinary tract infections, urease-producing bacteria and the presence of magnesium ammonium phosphate (MAP) urolithiasis in canines in Thailand requires more study. Objectives: This study aimed to investigate the association between demographic characteristics of canines and the presence of MAP urolithiasis in canines, and to evaluate antimicrobial susceptibility patterns of bacteria isolated from canine uroliths. Methods: A total of 56 canines admitted for treatment with surgical removal of uroliths were recruited. Demographic characteristics and clinical chemistry data were recorded.Bacteria isolated from the removed uroliths were identified. Chemical compositions of the uroliths were analyzed by Fourier transform infrared spectrometer. Potential risk factors were determined with univariable and multivariable logistic regression analyses. Results: Of 56 canine urolithiasis, bacteria were isolated from uroliths of 38 canines (27 MAP and 11 non-MAP) but not from uroliths of 18 canines (5 MAP and 13 non-MAP). The most common bacteria found in nidus of MAP uroliths was Staphylococcus pseudintermedius (approximately 51%). An antimicrobial resistance was frequently found in Staphylococci isolates (42.86%). Multivariate logistic regression analysis showed that the predictors of MAP urolith in canine urolithiasis were being female (p = 0.044; adjusted odds ratio [OR], 10.22; 95% confidence interval [CI], 1.06– 98.24) and the positive urolith culture (p = 0.012; adjusted OR, 8.60; 95% CI, 1.60–46.30). Conclusions Our results indicate that S. pseudintermedius (a urease-producing bacterium) is the major causative bacteria of MAP uroliths. A positive urolith culture and being female are risk factors of MAP urolithiasis in canines.

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.

Objective: To analyze antioxidant and antibacterial properties of selected weeds commonly found in Northeast Thailand including Ageratum conyzoides L., Alysicarpus vaginalis L., Commelina bengalensis L., Euphorbia hirta L., Hyptis suaveolens L., Parthenocissus quinquefolia L., and Trianthema portulacastrum L. Methods: Ferric reducing antioxidant power and radical scavenging activity of the aqueous and ethanol weed extracts were determined. Phytochemical screening, total phenolic and flavonoid contents were done. Antibacterial activity against Aeromonas hydrophila, Aeromonas caviae, Edwardsiella tarda, Plesiomonas shigelloides, Ralstonia spp., Xanthomonas campestris pv. Vesicatoria, Salmonella spp. and Shigella spp. was performed by disc diffusion assay. Results: The results showed that Euphorbia hirta extract had the highest total phenolic contents and was the most effective against most of the test organisms compared to the other weed extracts. Hyptis suaveolens ethanol extract weakly inhibited Ralstonia spp. and Salmonella spp. (10.42% and 9.84% inhibition, respectively). Trianthema portulacastrum ethanol extract had 20.10% inhibition against Shigella spp. Parthenocissus quinquefolia aqueous extract strongly inhibited Aeromonas caviae and Aeromonas hydrophila with 55.90% and 59.68% inhibition, respectively. Conclusions: These weeds may be serving as a potential source of antibacterial agents.

Objective: To compare biofilm formation in trimethoprim/sulfamethoxazole (SXT)- susceptible Escherichia coli (E. coli) (SSEC) and SXT-resistant E. coli (SREC) isolated from patients with urinary tract infections, and study the motile ability and physical characteristics of the isolates. Methods: A total of 74 E. coli isolates were tested for antimicrobial susceptibility with the disc diffusion assay. Based on the SXT-susceptibility test, the E. coli isolates were divided into SSEC (N = 30) and SREC(N = 44) groups. All E. coli isolates were examined for motile ability by using a motility test medium, and for checking biofilm formation a scanning electronmicroscope was used. Bacterial colony size was measured with a vernier caliper and bacterial cell length was measured under a light microscope. The bacterial growth rate was studied by plotting the cell growth (absorbance) versus the incubation time. Results: The frequencies of non-motility and biofilm formation in the SREC group were significantly higher than that in the SSEC group (P < 0.01). The SREC bacterial cell length was shorter than that in the SSEC group [(1.35 ± 0.05) vs. (1.53 ± 0.05) mm, P < 0.05)], whereas the bacterial colony size and mid-log phase of the growth curve were not significantly different. Conclusions: The present study indicated that biofilm formation and phenotypic change of uropathogenic E. coli can be attributed to the mechanism of E. coli SXT resistance.