In vitro antimicrobial efficacy of Cassia alata (Linn.) leaves, stem, and root extracts against cellulitis causative agent Staphylococcus aureus

Abstract Background. Cellulitis is a common skin disease encountered in medical emergencies in hospitals. It can be treated using a combination of antibiotics therapy; however, the causative agent Staphylococcus aureus has been reported to develop resistance towards the currently used antibiotics. Therefore, the search for more alternative herbal origin antimicrobial agents is critical. Aim: In this study, maceration and Soxhlet extraction of the whole plant of Cassia alata Linn. (leaves, roots, and stem) were performed using four solvents with diferent polarities, namely n-hexane, ethyl acetate, ethanol and distilled water. The crude extracts were screened using agar well difusion, colorimetric broth microdilution, grid culture and bacterial growth curve analysis against Staphylococcus aureus. The phytochemicals in the crude extracts were identifed using Gas Chromatography-Mass Spectrometry (GC–MS). Results. Agar-well difusion analysis revealed that extraction using ethyl acetate showed the largest inhibition zone with an average diameter of 15.30 mm (root Soxhlet extract) followed by 14.70 mm (leaf Soxhlet extract) and 13.70 mm (root maceration extract). The lowest minimum inhibitory and minimum bactericidal concentration in root Soxhlet extract using ethyl acetate was 0.313 and 0.625 µg µL−1 , respectively. Our study proved that crude extract of the plant suppressed the growth of S. aureus as evidenced from a signifcant regression extension (p<0.06,p=0.00003) of lag phase for 6 h after the treatment with increased concentration. Based on the GC–MS analysis, 88 phytochemicals consist of fatty acids, esters, alkanes, phenols, fatty alcohols, sesquiterpenoids and macrocycle that possibly contributed to the antimicrobial properties were identifed, 32 of which were previously characterized for their antimicrobial, antioxidant, and anti-infammatory activities. Conclusion. Ethyl acetate crude extract was better than the other investigated solvents. The root and stem of C. alata showed signifcant antimicrobial efcacy against S. aureus in this study. The remaining 56 out of 88 phytochemicals of the plant should be intensively studied for more medicinal uses. Keywords. Cassia alata, Skin bacteria, Maceration and Soxhlet extraction, Antimicrobial, Phytochemicals, GC–MS

Isolation and molecular characterization of bacterial species from Sikog waterfall, Padawan, Sarawak

Aims: Bacteria are microorganisms that are commonly distributed in any environment. They are also found abundantly in marine environments such as waterfalls and rivers. Some bacteria participate in various biological activities and possess no health risk; however, other species could be pathogenic and have been directly associated with various diseases in animals and humans. Therefore, it is crucial to analyze the antibiotic resistance profiles of bacteria in the research area based on regularly used antibiotics in clinical and agricultural contexts to establish a data baseline for health providers and public usage. Methodology and results: Water samplings were done twice and collected from upstream, midstream, and downstream of the Sikog waterfall. A total of ninety isolates were isolated and analyzed using (GTG)5 genetic fingerprinting to determine the genetic similarities. Based on the dendrogram generated using Gelj Version 2.0 software, 41 bacterial isolates were subjected to 16S rRNA gene sequencing for species identification. The Kirby-Bauer disk diffusion method was implemented to determine the level of susceptibility toward certain antibiotics. Sequence analysis was performed using BLAST, revealing that the isolates constitute 17 genera, including Pseudomonas, Alcaligenes, Stenotrophomonas, Staphylococcus, Bacillus, Lysinibacillus, Rossellomorea, Citrobacter, Enterobacter, Kosakonia, Klebsiella, Escherichia, Serratia, Cronobacter, Aeromonas, Chromobacterium and Kocuria. According to the overall antibiotic susceptibility analysis, streptomycin (10 µg) exhibited the highest rate of resistance among bacterial isolates, with 36.84%, followed by penicillin (10 units) (36.36%), rifampicin (5 µg) (27.27%) and ampicillin (10 µg) (26.32%). Conclusion, significance and impact of study: The research findings revealed the predominant bacteria found in the recreational water of Sikog waterfall and their antibiotic susceptibility, which could be helpful in the treatment of bacterial infections for future clinical reference. Simultaneously, the public, particularly communities in the study area, should be informed about the potential health risk associated with diverse resistant enteric bacteria in the recreational water

Isolation and Characterisation of Salmonella spp. from Water in Aquaculture Farms

Aquaculture has become one of the world largest industries due to high demand of aquaculture products as a part of food supply. In Malaysia, aquaculture especially in freshwater pond aquaculture has developed quickly and become an important activity. In spite of that, chloramphenicol, one of the banned antibiotics in aquaculture, is illegal used of this antibiotic become a major concern due to the safety of consumer which depends on the development of drug resistant strains in bacterial Salmonella spp. Due to the circumstances stated above, the objectives of this study were to isolate the Salmonella spp. from water in both traditional and commercial farm, to detect the chloramphenicol resistance gene in Salmonella spp. isolated from both traditional and commercial farm and to determine the susceptibility of Salmonella spp. towards chloramphenicol by using antibiotic susceptibility test. Salmonella spp. that isolated from aquaculture farms were grown selectively on XLD agar and assessed for antibiotic susceptibility test using chloramphenicol disks. The corresponding chloramphenicol resistance genes in the isolates were detected by specific PCR which targeted the catP gene. The chloramphenicol susceptibility test showed that 15 (79%) isolates were susceptible towards chloramphenicol, while 4 (21 %) isolates were intermediate resistance to chloramphenicol. Based on this study, 17 out of 20 isolates including the Salmonella spp. control were detected with catP gene. These findings provided information on chloramphenicol resistance profiles of Salmonella spp. in aquaculture farms to control the usage of antibiotics in aquacultur