1.Synthesis, characterization, anti-mycobacterial activity and in silico study of new 2,5-disubstituted-1,3,4-oxadiazole derivatives
Azmi, M.N. ; Hasmaruddin, N.S. ; Mat Ali, N.A. ; Osman, H. ; Mohamad, S. ; Parumasivam, T. ; Hassan, M.Z. ; Abd Ghani, M.S. ; Awang, K.
Tropical Biomedicine 2022;39(No.3):467-475
A series of new 2,5-disubstituted-1,3,4-oxadiazole derivatives (5a-j and 6a-j) have been designed and
synthesized in four-steps. Sixteen compounds among the twenty compounds are reported for the first
time. The compounds were characterized and confirmed by the FTIR, 1D- and 2D-NMR and HRMS
analyses, and were tested against Mycobacterium smegmatis and Mycobacterium tuberculosis H37Ra.
Compound 5d was the most active against M. smegmatis with MIC value of 25 µM, and exhibited
cidal activity with MBC of 68 µM, respectively. The time-kill assay showed the good killing rate at 77%
with the combination of isoniazid (INH). In addition, checkboard assay confirmed the interaction of
compound 5d was categorised as additive. Docking simulation has been performed to position 5d into
the pantothenate synthetase active site with binding free energy value –8.6 kcal mol-1. It also occupied
the same active site as that of standard native ligand with similar interactions, which clearly indicate
their potential as pantothenate synthetase inhibitor.
2.Survival of antibiotic resistant Escherichia coli in vacuum-packed keropok lekor: Food safety alert among SME keropok lekor producers
Wan-Hamat, H. ; Lani, M.N. ; Hamzah, Y. ; Alias, R. ; Hassan, Z. ; Mahat, N.A.
Tropical Biomedicine 2020;37(No.1):103-115
The microbiological quality of thirty ready-to-eat (RTE) keropok lekor (a sausage shape Malaysian fish product) was evaluated in comparison to microbiological guidelines for ready to eat foods. The two E. coli isolates were subjected to DNA sequencing, identified and tested for their resistance towards fifteen different antibiotics. The survival and growth of the isolated E. coli strains inoculated in keropok lekor at atmospheric air and vacuum packaging were also evaluated. Results revealed that four samples (13.33%) contained Enterobacteriaceae counts that exceeded the recommended allowable counts of 4.0 log10 CFU/g. Unsatisfactory level of coliforms (> 1.7 log10 CFU/g) was also observed in ten of the samples; two of which contained E. coli (2.1 ± 0.17 and 3.7 ± 0.02 log10 CFU/g), suggesting of poor hygiene and sanitation practices. While the ‘Possible E10’ E. coli strain was observably resistant towards Nalidixic acid (30µg) alone, B10 E. coli isolate was worryingly resistant towards Ampicillin (10µg), Ceftazidime (30µg), Ciprofloxacin (5µg), Ceftriaxone (30µg), Nalidixic acid (30µg) and Tetracycline (30µg). This study also revealed that the growth and survival of the ‘Possible E10’ and B10 E. coli strains were not significantly affected by vacuum packaging when stored at both 4°C and 28°C. Therefore, intervention programmes to alert and educate smallmedium enterprisers (SMEs) of keropok lekor producers on food safety as well as potential health risks that can be associated due to inappropriate handling procedures of such product, merits consideration.
3.Gastrointestinal parasitic infections of buffaloes (Bubalus bubalis) in Sarawak Borneo: Prevalence, risk factors, and farming practices
Harizt, A.M. ; Malahubban, M. ; Syed-Hussain, S.S. ; Ramanoon, S.Z. ; Sadiq, M.B. ; Sarbini, S.R. ; Hassan, M.N. ; Mustafa, S. ; Aziz, N.A.A. ; Isa, N.M.M. ; Nating, W.R. ; Asut, R. ; Kamaludeen, J.
Tropical Biomedicine 2021;38(No.3):318-326
The objectives of this study were to investigate the prevalence and associated risk factors for gastrointestinal (GI) parasites in buffaloes from various areas of Sarawak, and to assess current management practices of GI parasites among farmers. Faecal samples were collected from 15 farms and 129 animals, as well as data on farm and animal-based characteristics. A total of 129 faecal samples were examined for GI parasites using a modified McMaster and sedimentation. Association between potential risk factors and the prevalence of GI parasites was investigated using Chi-square statistic. The prevalence of Paramphistomum sp., strongyles, and coccidia were 75.2% (95% CI±7.5), 52.7% (95% CI±8.6) and 48.1% (95% CI±8.6), respectively. Farms which had a grazing area less than 50 acres in size had significantly higher prevalence of strongyles (70.5%, χ² = 8.34, P = 0.004) and paramphistomes (88.6%, χ² = 6.46, P = 0.01) relative to farms with a larger grazing area (43.5% and 68.2%, respectively). Prevalence of strongyles was lower in farms that did not implement a cut- and-carry system (45.6%, χ² = 4.17, P = 0.04) in comparison to those that did (64%). The prevalence of paramphistomes was higher on farms with more than 40 animals (80.6%, χ² = 3.18, P = 0.05) relative to farms with fewer animals. The majority of farmers surveyed (67.9%) showed awareness of GI parasite infection and reported that they recognized the associated symptoms. Most farmers practised deworming, and ivermectin was the most commonly used anthelminthic (60.4%); only 1.9% of farmers used albendazole. Overall this study revealed a high prevalence of GI parasites in buffalo in Sarawak. Although farmers report they are aware of parasitic diseases, further education is still required. This could include how they can successfully implement on-farm changes to reduce the prevalence of GI parasites in their herds.