Kasing Apun - Academia.edu (original) (raw)

Papers by Kasing Apun

Research paper thumbnail of Epidemiological study of human intestinal parasites in Sarawak, East Malaysia: A review

Tropical Biomedicine, Aug 30, 2021

Sarawak is the largest state in Malaysia which is nearly as large as the Peninsular Malaysia. It ... more Sarawak is the largest state in Malaysia which is nearly as large as the Peninsular Malaysia. It is situated in the northwest Borneo region and has a complex ethnic and cultural backgrounds (i.e. races and indigenous groups) that comprise approximately 2.656 million population in 2020 (DOSM, 2021). Iban is the largest proportion of this diversity, in addition to the composition of other races which include Malay, Chinese, India and indigenous populations comprising

Research paper thumbnail of Presence of Bacillus cereus s.l. from ready-to-eat cereals (RTE) products in Sarawak

international food research journal, 2013

Bacillus cereus is a soil inhabitant gram positive bacterium, and is known to cause severe food p... more Bacillus cereus is a soil inhabitant gram positive bacterium, and is known to cause severe food poisoning. The objective of this study was to isolate and identify the presence of Bacillus cereus s.l. from selected ready to eat cereals purchased randomly from local supermarkets in Kuching and Kota Samarahan, Sarawak. The result showed that four of the 30 food samples were detected to be contaminated by B. cereus s.l.. Our findings suggested that it is important for the public to be aware of the safety of RTE cereals consumption, as it is possible that B. cereus s.l. may be present in high count number and pose hazardous health effects to the consumers.

Research paper thumbnail of Antibiotic resistance and plasmid profiling of Vibrio parahaemolyticus isolated from cockles (Anadara granosa) at Tanjung Karang, Kuala Selangor

A total of sixty V. parahaemolyticus strains isolated from local cockles (Anadara granosa) were i... more A total of sixty V. parahaemolyticus strains isolated from local cockles (Anadara granosa) were investigated by their antibiotic resistance patterns and plasmid profiles. The isolates showed multiple resistances towards most of the antibiotics tested. All strains of V. parahaemolyticus isolated harbored 1-3 plasmids, with sizes ranging from 2.7 to 54 kb. All V. parahaemolyticus strains showed high multiple antibiotics in frequencies of 0.58-0.94 indicating that the strains were derived from high-risk sources. In addition, no particular plasmid profile was predictive of a particular pattern of antibiotic susceptibility. These findings are essential because of the suggested involvement of seafood especially shellfish and environment in transmission of this pathogen to human. Thus, indicating that seafood may be a source of food-acquired antibiotic resistant bacteria to consumer.

Research paper thumbnail of Summaries of Sessions Human health and biodiversity of natural resources in the Kuroshio region

Summaries of Sessions Human health and biodiversity of natural resources in the Kuroshio region

This session consists of eight topics. Since the following three papers are separately presented,... more This session consists of eight topics. Since the following three papers are separately presented, we do not summarize them: “Spirulina Complex Polysaccharides Suppress the Growth of Glioma in TLymphocytesand Macrophage-dependent Manner” by Akira Tominaga et al., “Rapid Screening for Cytotoxicity and Group Identification of Secondary Metabolites in Methanol Extracts from Four Sponge Species Found in Kapoposang Island, Spermonde Archipelago, Indonesia” by Ajuk Sapar, and “Inventory of Medicinal Plants for Fever Used by Four Dayak Sub Ethnic in West Kalimantan Province, Indonesia” by Fathul Yusro et al.

Research paper thumbnail of Perturbation of the enterobacterial microflora detected by molecular analysis

Perturbation of the enterobacterial microflora detected by molecular analysis

Microbial Ecology in Health and Disease, Sep 1, 1999

ABSTRACT The enterobacterial populations of faecal samples collected from two human subjects duri... more ABSTRACT The enterobacterial populations of faecal samples collected from two human subjects during a twelve-month period were studied. Analysis of the composition of the populations using ribotyping showed that Subject 1 harboured a relatively simple and stable enterobacterial population in which a single Escherichia coli strain predominated. In contrast, the enterobacterial population of Subject 2 underwent a marked change in composition, possibly associated with the administration of amoxicillin, and became dominated by multiple drug resistant E. coli and ampicillin-resistant klebsiella strains.

Research paper thumbnail of Application Of The Multiplex Polymerase Chain Reaction (M-PCR) For The Screening Of Vibrio Spp. From Rivers In Kuching, Sarawak

Borneo Journal of Resource Science and Technology, 1970

The present study was conducted to investigate the occurrence of Vibrio spp. from selected rivers... more The present study was conducted to investigate the occurrence of Vibrio spp. from selected rivers in Kuching, Sarawak (Malaysia) using Multiplex Polymerase Chain Reaction (m-PCR). During the six month study period, 19 samples were collected monthly from seven rivers, followed by simultaneous detection of three Vibrio spp., Vibrio parahaemolyticus, Vibrio cholerae and Vibrio vulnificus, in a single tube PCR reaction. Three sets of primers targeting the thermolabile (tl), outer membrane protein (ompW) and hemolysin/cytolysin genes (vulCulsl) of V. parahaemolyticus, V. cholerae and V. vulnificus, respectively, were used. The results indicated that V. parahaemolyticus was the predominant species, occurring approximately 60.9% throughout the sampling period, followed by V. cholerae (23.1%) and V. vulnificus (16.0%). The months of July and December were found to be the months where all three Vibrio spp. were found to be at higher frequencies in the river samples. Results analyzed also indicated that the rivers with the highest prevalence of the three Vibrio spp. were Tambak Sejingkat, followed by Sungai Jernang and Sungai Tabuan. We conclude that m-PCR is a powerful and useful tool for the rapid and simultaneous detection of V. parahaemolyticus, V. cholerae and V. vulnificus from the riverine environments without the need for isolation and culturing. Furthermore, this method is highly specific, and could be applied in diagnostic laboratories for larger scale epidemiological investigations of Vibrio spp.

Research paper thumbnail of Growth of Ornamental Plants In Constructed Wetlands Of Kuching City: Ecological Sanitation

Two common ornamental plant species Syzygium campanulatum and Ficus microcarpa were planted into ... more Two common ornamental plant species Syzygium campanulatum and Ficus microcarpa were planted into small-scale constructed wetlands receiving grey water. Partially treated black water from septic tanks and grey water are discharged into storm water drains and subsequently into the rivers in Kuching, and discharge from households were the main pollution source ,of the Sarawak River. The option of urban ecological sanitation was explored by the Sarawak Government which involves separating wastewater at the source and recycling of nutrients. Grey water from selected households were channeled to a grease trap and then pumped to biofilters before flowing through a constructed wetland with two species of ornamental plants before discharge. The results indicated no major limitations to the use of municipal wastewater as an irrigation source in urban tree growth. The high photosynthetic rates of both species grown in the constructed wetland compared to the control plants indicated that the plants were able to utilize the available nutrient in the constructed wetland and perform normal physiological processes necessary for plant growth compared to the control plants. Height and dbh of both species wen: relatively higher than the control plants indicating that the wastewater serve as a source of fertilizer for the plants to grow. The growth performance of S. campanulatum was better compared to F. microcarpa in the constructed wetland and both species exhibited better growth performance compared to the control plants.

Research paper thumbnail of Die-off Rates of Escherichia coli in a Silt Loam Soil

Even though animal waste is a resource, fecal contamination of soil is a concern for the public. ... more Even though animal waste is a resource, fecal contamination of soil is a concern for the public. Therefore, in this study, die-off of Escherichia coli (E. coli) was investigated in a silt loam soil under different temperatures and pH. Results indicated that E. c'oU persisted about a month under 30°C and 15 days under 20°C. Persistance of E. coli increased as acidity increased from pH 4 to 6. First order decay model fitted the data well. Die-off rate was highest under 30°C and pH4 and lowest under 20°C and pH6. It is recommended that animal waste be applied during hot season of the year before liming of soil is carried out.

Research paper thumbnail of Survival of Escherichia Coli in pig farm wastewater

Soil is a natural digestion system for animal waste. However, land disposal sites and agricultura... more Soil is a natural digestion system for animal waste. However, land disposal sites and agricultural land pose serious threat to the quality of surface and groundwater. In this study, a clay loam from Sarawak was inoculated with wild strain E. coli isolated from animal waste. Results indicated that first order decay rate increased as temperature increased from 25°C to 35 °c and as moisture decreased from saturation to air-dry. Lag period of the bacteria was found .to be the longest (8 days) in saturated soil at 25°C and the shortest (1 day) in air-dry soil at 35°C. Interaction between temperature and moisture was significant. First order decay model can be used after lag period to estimate E. coli decay. It fit the data the best in cool wet condition. It is recommended that disposal of animal waste be carried out during hot dry season of the year.

Research paper thumbnail of Modelling the survival of an Escherichia Coli in Soil

Research paper thumbnail of Survival of Escherichia coli in soil - Effect of PH and moisture content

Survival of Escherichia coli in soil - Effect of PH and moisture content

Research paper thumbnail of Survival of an Escherichia coli in a Sarawak Soil

Soil is a natural digestion system for animal wastes. However, land disposal sites and agricultur... more Soil is a natural digestion system for animal wastes. However, land disposal sites and agricultural land pose serious threats to the quality of surface and groundwater. In this study, a clay loam, Semongok series, from Sarawak was inoculated with wild strain E. coli isolated from animal wastes. Results indicated that first order decay rate increased as temperature increased from 25°C to 35°C and as moisture decreased from saturation to air-dry. Lag period of the bacteria was found to be the longest (8 days) in saturated soil at 25•C and the shortest (l day) in air-dried soil at 35"C. Interaction between temperature and moisture was significant. First order decay model can be used after lag period to estimate E. coli decay. The best data fit was obtained under cool wet condition. Temperature correction coefficient in the range of25-35°C was !.lS. It is recommended that disposal of animal wastes be. carried out during hot dry seasons of the year.

Research paper thumbnail of Die-off rate of Escherichia coli as a function of pH and temperature

Escherichia coli (E. coli) is a common indicator of fecal pollution of water and soil. To model b... more Escherichia coli (E. coli) is a common indicator of fecal pollution of water and soil. To model bacterial die-off in the soil, knowledge of the relationship between bacteria and environmental factors need to be quantified. First order die-off model is commonly used to predict bacterial die-off in the environment. The die-off rate is a function of environmental conditions. PH and temperature are two key environmental factors affecting E. coli die-off in the soil. In this study, E. coli die-off in a soil was investigated in the laboratory under controlled temperatures and pH conditions. E. coli was isolated from pig waste, grown and inoculated in the soil. The population in the soil was determined for a period of three weeks. Results showed that pH and temperature significantly affected die-off rates. As pH decreases from 7 to 3, die-off rate increased. Die-offrates at 2ifC are generally lower than those at 3ife. It wasfound that there was no significant difference between die-off rates at pH of 6 when compared with that at pH of 7. Simple linear regression shows that the fit of first order die-off model to the experimental data was good with 70% of the coefficients of determination, R2, of 0.90 and higher. Die-offrates were found to range from 0.07 a 1 to 1.60 a l • Between pH 3-5, analysis shows that there was no significant interaction between pH and temperature. Multiple linear regression indicated that both coefficients of temperature and pH are Significant. Relationship of die-off rate as a function of pH was developed. Temperature correction coefficients between 20-3ifC were found to be pH dependent.

Research paper thumbnail of Modelling the survival of an Escherichia Coli in Soil : effect of pH and temperature

Modelling the survival of an Escherichia Coli in Soil : effect of pH and temperature

Survival of E.coli on soils determines its the availability for transport during rainfall events.... more Survival of E.coli on soils determines its the availability for transport during rainfall events. In this study, the survival of E.coli in soil was examined under different pH in saturated condition. Results indicated that first order decay model fit well. Decay rate of E.coli increased when pH of the soil decreased from 7.4 to 3.2 and also when temperature increased from 20 Degree Celsius to 30 Degree Celsius. Survival was prolonged in neutral and cool condition. There is no significant difference between decay rate at pH of 6.4 and 7.4. At pH of 6.4 and 7.4 at 30 Degree Celsius and at pH 7.4 at 20 Degree Celsius, there was evidence of regrowth. Quantitative relationships between decay rate and pH at 20 Degree Celsius and 30 Degree Celsius were developed for use in environmental modeling purposes

Research paper thumbnail of Survival of an indicator bacteria in soil : Effect of temperature and moisture

Survival of an indicator bacteria in soil : Effect of temperature and moisture

Research paper thumbnail of Modelling the Decay of Escherichia Coli in Different Soils

Dalam kajian ini, kadar kematian Escherichia coli (E. coli) dalam tiga jenis tanah tropikal dari ... more Dalam kajian ini, kadar kematian Escherichia coli (E. coli) dalam tiga jenis tanah tropikal dari Sarawak, iaitu tanah gambut, tanah loam berlempung dan tanah loam berkelodak telah dikaji dalam makmal pada suhu yang tetap di bawah keadaan tepu seIama 14 hari. Keputusan kajian ini menunjukkan bahawa kadar kematian min E. coli ialah 0.02 hari-l dalam loam berlempung dan 0.14 haril dalam tanah gambut. Kadar kematian yang rendah dalam loam berlempung mungkin berpunca daripada kuantiti partikellempung di dalam tanah loam berlempung jika dibandingkan dengan tanah loam berkelodak. Kajian ini juga menunjukkan bahawa populasi E. coli kekal selama tiga hari dalam tanah gambut, enam hari dalam tanah loam berkelodak dan sepuluh hari dalam tanah loam berlempung. Walaupun tanah gambut mempunyai bahan organik yang lebih tinggi, kadar kematian E. coli adalah lebih tinggi daripada kematian dalam tanah loam berlempung. lni mungkin disebabkan \ oleh keasidan tanah gambut. Kajian ini menunjukkan bahawa model kematian linear peringkat pertama yang telah diubahsuai untukmempertimbangkan tempoh lamban adalah model yang sesuai digunakan untuk meramalkan kematian E. coli dalam tiga jenis tanah dan dalam tempoh yang telah dikaji. Tambahan pula, terdapat tanda-tanda yang menunjukkan bahawa potensi pencemaran E. coli di negara kawasan tropika adalah lebih tinggi jika dibandingkan dengan negara temperat kerana kemandirian yang lebih tinggi. Oleh yang demooan, amalan pengurusan yang sesuai untuk aplikasi dan pembuangan sisa kumbahan haiwan harns dibentuk dan dilaksanakan.

Research paper thumbnail of Adsorption of Fecal Coliforms, Escherichia coli, in Soils of Sarawak

In this study, fecal bacterial adsorption in three different soils (clay loam, silt loam, sandy l... more In this study, fecal bacterial adsorption in three different soils (clay loam, silt loam, sandy loam) was investigated. A wild strain of &cherichia coli (E. colO isolated from animal wastewater was used in the study. For adsorption kinetics study, adhesion of bacterial cells to soil particles was found to be immediate. Percent adsorption was found to be dependent on the initial concentration of E. coli. Results indicate that at low E. coli concentrations (below I ()3 cfulml), the percent adsorption was very much less in sandy loam than in silt loam and clay loam. However, as the bacterial concentration increased, all the soils tested displayed higher bacteria adsorption with maximum values of 99.9% for clay loam, 99.9% for silt loam and 99.7% for sandy loam. Soil with higher clay content (35.2 % and lower pH (PH 4.5» had significantly higher capacity for adsorbing E. coli. Furthermore, E. coli concentration of I ()6 cfulml in suspension was found to decrease by 2 orders of magnitude in all the three soils. Therefore, land treatment of wastewater from animal farm lagoons should be considered to reduce microbial contamination of rivers.

Research paper thumbnail of Detection and antibiotic susceptibility profiles of Listeria monocytogenes in wildlife and water samples in Kubah National Park, Sarawak, Malaysia

international food research journal, 2016

This study was conducted to detect the presence of Listeria monocytogenes (L. monocytogenes) and ... more This study was conducted to detect the presence of Listeria monocytogenes (L. monocytogenes) and screen for its antibiotic susceptibility characteristic from wildlife and water samples at Kubah National Park, Sarawak, Malaysia. Samples collected were incubated and streaked on selective medium PALCAM agar to confirm the presence of Listeria spp. before they were further tested using molecular analysis. Specific Polymerase Chain Reaction (PCR) assay were performed to target specific virulence gene, haemolysin gene, hlyA to further distinguish the presence of this pathogenic bacteria in the samples. Overall, out of the 30 samples tested, 10 samples were confirmed as to contain L. monocytogenes strains and selected to subsequent antibiotic susceptibility test. Susceptibility patterns to 10 antibiotics were investigated among the L. monocytogenes strains. All strains were uniformly resistant to tetracycline and erythromycin. On the other hand, all strains were sensitive to gentamycin and tobramycin. The multiple antibiotic resistance shown by the strains in this study indicate the potential health hazard associated with the possible transmission between wildlife and water to its surrounding environment especially visitors and workers of

Research paper thumbnail of Spatial and Temporal Disparities of Leptospirosis Transmission in Sarawak (Malaysia), 2011-2018

Borneo Journal of Resource Science and Technology, Dec 31, 2022

This study is to analyse the spatial distribution of leptospirosis and identify its high and low ... more This study is to analyse the spatial distribution of leptospirosis and identify its high and low incidence clusters in Sarawak. The annual incidence rate at the district level was calculated using confirmed report of leptospirosis cases from year 2011 to 2018. Empirical Bayes estimation smoothing of relative risks was used to display the spatial distribution of leptospirosis across the study region. Moran's Global Index and Local Indicators of Spatial Association (LISA) were used to analyse the existence of global and local spatial autocorrelation. Data were analysed using ArcGIS and Geoda software at the district level. The annualised average incidence reported during the study period was 20.83 per 100,000 population, with the highest cases reported in year 2018 (n = 870). The

Research paper thumbnail of Biofilm forming ability of intermediate and saprophytic Leptospira on abiotic and biotic surfaces

Malaysian Journal of Microbiology, Aug 1, 2018

Aims: Leptospira spp. has the ability to develop biofilm communities and this attribute is an ess... more Aims: Leptospira spp. has the ability to develop biofilm communities and this attribute is an essential factor to leptospiral pathogenesis. This study aims to assess and quantify the biofilm forming ability of intermediate and saprophytic Leptospira strains. Methodology and results: The biofilm assay was quantified on microtitre polystyrene plates (abiotic) and wood chips (Jelutong Paya hardwood) over a duration of 11 days. Phase contrast light microscope was used to assess the structure of the on the surface. The biofilm production on wood chips surface were approximately one times higher than on polystyrene plate surface indicating Leptospira strains were capable of forming higher quantity of biofilm on biotic surface compared to abiotic surface by both intermediate and saprophytic Leptospira. A significant difference (p<0.05) exists in biofilms produced by Leptospira on wood surface which formed more biofilm than on polystyrene surface. The strongest biofilm producer is intermediate strain G14 with OD600 of 2.283±0.180 and OD600 of 2.333±0.037, on polystyrene and wood surface, respectively. Visualisation of biofilm by phase-contrast microscopy of two representative strains correlated with the OD values and the colour intensity of stained microtitre plates and wood surfaces. The biofilm formed comprises of a three-step process are adherence (1 th to 24 th h), maturation (6t h to 7 th day) and detachment (9 th to 11 th day) of biofilms. Conclusion, significance and impact of study: The contact time of intermediate pathogenic strains was faster compared to saprophytic strain, indicating the biofilm forming ability is related to the level of pathogenicity of Leptospira strains.

Research paper thumbnail of Epidemiological study of human intestinal parasites in Sarawak, East Malaysia: A review

Tropical Biomedicine, Aug 30, 2021

Sarawak is the largest state in Malaysia which is nearly as large as the Peninsular Malaysia. It ... more Sarawak is the largest state in Malaysia which is nearly as large as the Peninsular Malaysia. It is situated in the northwest Borneo region and has a complex ethnic and cultural backgrounds (i.e. races and indigenous groups) that comprise approximately 2.656 million population in 2020 (DOSM, 2021). Iban is the largest proportion of this diversity, in addition to the composition of other races which include Malay, Chinese, India and indigenous populations comprising

Research paper thumbnail of Presence of Bacillus cereus s.l. from ready-to-eat cereals (RTE) products in Sarawak

international food research journal, 2013

Bacillus cereus is a soil inhabitant gram positive bacterium, and is known to cause severe food p... more Bacillus cereus is a soil inhabitant gram positive bacterium, and is known to cause severe food poisoning. The objective of this study was to isolate and identify the presence of Bacillus cereus s.l. from selected ready to eat cereals purchased randomly from local supermarkets in Kuching and Kota Samarahan, Sarawak. The result showed that four of the 30 food samples were detected to be contaminated by B. cereus s.l.. Our findings suggested that it is important for the public to be aware of the safety of RTE cereals consumption, as it is possible that B. cereus s.l. may be present in high count number and pose hazardous health effects to the consumers.

Research paper thumbnail of Antibiotic resistance and plasmid profiling of Vibrio parahaemolyticus isolated from cockles (Anadara granosa) at Tanjung Karang, Kuala Selangor

A total of sixty V. parahaemolyticus strains isolated from local cockles (Anadara granosa) were i... more A total of sixty V. parahaemolyticus strains isolated from local cockles (Anadara granosa) were investigated by their antibiotic resistance patterns and plasmid profiles. The isolates showed multiple resistances towards most of the antibiotics tested. All strains of V. parahaemolyticus isolated harbored 1-3 plasmids, with sizes ranging from 2.7 to 54 kb. All V. parahaemolyticus strains showed high multiple antibiotics in frequencies of 0.58-0.94 indicating that the strains were derived from high-risk sources. In addition, no particular plasmid profile was predictive of a particular pattern of antibiotic susceptibility. These findings are essential because of the suggested involvement of seafood especially shellfish and environment in transmission of this pathogen to human. Thus, indicating that seafood may be a source of food-acquired antibiotic resistant bacteria to consumer.

Research paper thumbnail of Summaries of Sessions Human health and biodiversity of natural resources in the Kuroshio region

Summaries of Sessions Human health and biodiversity of natural resources in the Kuroshio region

This session consists of eight topics. Since the following three papers are separately presented,... more This session consists of eight topics. Since the following three papers are separately presented, we do not summarize them: “Spirulina Complex Polysaccharides Suppress the Growth of Glioma in TLymphocytesand Macrophage-dependent Manner” by Akira Tominaga et al., “Rapid Screening for Cytotoxicity and Group Identification of Secondary Metabolites in Methanol Extracts from Four Sponge Species Found in Kapoposang Island, Spermonde Archipelago, Indonesia” by Ajuk Sapar, and “Inventory of Medicinal Plants for Fever Used by Four Dayak Sub Ethnic in West Kalimantan Province, Indonesia” by Fathul Yusro et al.

Research paper thumbnail of Perturbation of the enterobacterial microflora detected by molecular analysis

Perturbation of the enterobacterial microflora detected by molecular analysis

Microbial Ecology in Health and Disease, Sep 1, 1999

ABSTRACT The enterobacterial populations of faecal samples collected from two human subjects duri... more ABSTRACT The enterobacterial populations of faecal samples collected from two human subjects during a twelve-month period were studied. Analysis of the composition of the populations using ribotyping showed that Subject 1 harboured a relatively simple and stable enterobacterial population in which a single Escherichia coli strain predominated. In contrast, the enterobacterial population of Subject 2 underwent a marked change in composition, possibly associated with the administration of amoxicillin, and became dominated by multiple drug resistant E. coli and ampicillin-resistant klebsiella strains.

Research paper thumbnail of Application Of The Multiplex Polymerase Chain Reaction (M-PCR) For The Screening Of Vibrio Spp. From Rivers In Kuching, Sarawak

Borneo Journal of Resource Science and Technology, 1970

The present study was conducted to investigate the occurrence of Vibrio spp. from selected rivers... more The present study was conducted to investigate the occurrence of Vibrio spp. from selected rivers in Kuching, Sarawak (Malaysia) using Multiplex Polymerase Chain Reaction (m-PCR). During the six month study period, 19 samples were collected monthly from seven rivers, followed by simultaneous detection of three Vibrio spp., Vibrio parahaemolyticus, Vibrio cholerae and Vibrio vulnificus, in a single tube PCR reaction. Three sets of primers targeting the thermolabile (tl), outer membrane protein (ompW) and hemolysin/cytolysin genes (vulCulsl) of V. parahaemolyticus, V. cholerae and V. vulnificus, respectively, were used. The results indicated that V. parahaemolyticus was the predominant species, occurring approximately 60.9% throughout the sampling period, followed by V. cholerae (23.1%) and V. vulnificus (16.0%). The months of July and December were found to be the months where all three Vibrio spp. were found to be at higher frequencies in the river samples. Results analyzed also indicated that the rivers with the highest prevalence of the three Vibrio spp. were Tambak Sejingkat, followed by Sungai Jernang and Sungai Tabuan. We conclude that m-PCR is a powerful and useful tool for the rapid and simultaneous detection of V. parahaemolyticus, V. cholerae and V. vulnificus from the riverine environments without the need for isolation and culturing. Furthermore, this method is highly specific, and could be applied in diagnostic laboratories for larger scale epidemiological investigations of Vibrio spp.

Research paper thumbnail of Growth of Ornamental Plants In Constructed Wetlands Of Kuching City: Ecological Sanitation

Two common ornamental plant species Syzygium campanulatum and Ficus microcarpa were planted into ... more Two common ornamental plant species Syzygium campanulatum and Ficus microcarpa were planted into small-scale constructed wetlands receiving grey water. Partially treated black water from septic tanks and grey water are discharged into storm water drains and subsequently into the rivers in Kuching, and discharge from households were the main pollution source ,of the Sarawak River. The option of urban ecological sanitation was explored by the Sarawak Government which involves separating wastewater at the source and recycling of nutrients. Grey water from selected households were channeled to a grease trap and then pumped to biofilters before flowing through a constructed wetland with two species of ornamental plants before discharge. The results indicated no major limitations to the use of municipal wastewater as an irrigation source in urban tree growth. The high photosynthetic rates of both species grown in the constructed wetland compared to the control plants indicated that the plants were able to utilize the available nutrient in the constructed wetland and perform normal physiological processes necessary for plant growth compared to the control plants. Height and dbh of both species wen: relatively higher than the control plants indicating that the wastewater serve as a source of fertilizer for the plants to grow. The growth performance of S. campanulatum was better compared to F. microcarpa in the constructed wetland and both species exhibited better growth performance compared to the control plants.

Research paper thumbnail of Die-off Rates of Escherichia coli in a Silt Loam Soil

Even though animal waste is a resource, fecal contamination of soil is a concern for the public. ... more Even though animal waste is a resource, fecal contamination of soil is a concern for the public. Therefore, in this study, die-off of Escherichia coli (E. coli) was investigated in a silt loam soil under different temperatures and pH. Results indicated that E. c'oU persisted about a month under 30°C and 15 days under 20°C. Persistance of E. coli increased as acidity increased from pH 4 to 6. First order decay model fitted the data well. Die-off rate was highest under 30°C and pH4 and lowest under 20°C and pH6. It is recommended that animal waste be applied during hot season of the year before liming of soil is carried out.

Research paper thumbnail of Survival of Escherichia Coli in pig farm wastewater

Soil is a natural digestion system for animal waste. However, land disposal sites and agricultura... more Soil is a natural digestion system for animal waste. However, land disposal sites and agricultural land pose serious threat to the quality of surface and groundwater. In this study, a clay loam from Sarawak was inoculated with wild strain E. coli isolated from animal waste. Results indicated that first order decay rate increased as temperature increased from 25°C to 35 °c and as moisture decreased from saturation to air-dry. Lag period of the bacteria was found .to be the longest (8 days) in saturated soil at 25°C and the shortest (1 day) in air-dry soil at 35°C. Interaction between temperature and moisture was significant. First order decay model can be used after lag period to estimate E. coli decay. It fit the data the best in cool wet condition. It is recommended that disposal of animal waste be carried out during hot dry season of the year.

Research paper thumbnail of Modelling the survival of an Escherichia Coli in Soil

Research paper thumbnail of Survival of Escherichia coli in soil - Effect of PH and moisture content

Survival of Escherichia coli in soil - Effect of PH and moisture content

Research paper thumbnail of Survival of an Escherichia coli in a Sarawak Soil

Soil is a natural digestion system for animal wastes. However, land disposal sites and agricultur... more Soil is a natural digestion system for animal wastes. However, land disposal sites and agricultural land pose serious threats to the quality of surface and groundwater. In this study, a clay loam, Semongok series, from Sarawak was inoculated with wild strain E. coli isolated from animal wastes. Results indicated that first order decay rate increased as temperature increased from 25°C to 35°C and as moisture decreased from saturation to air-dry. Lag period of the bacteria was found to be the longest (8 days) in saturated soil at 25•C and the shortest (l day) in air-dried soil at 35"C. Interaction between temperature and moisture was significant. First order decay model can be used after lag period to estimate E. coli decay. The best data fit was obtained under cool wet condition. Temperature correction coefficient in the range of25-35°C was !.lS. It is recommended that disposal of animal wastes be. carried out during hot dry seasons of the year.

Research paper thumbnail of Die-off rate of Escherichia coli as a function of pH and temperature

Escherichia coli (E. coli) is a common indicator of fecal pollution of water and soil. To model b... more Escherichia coli (E. coli) is a common indicator of fecal pollution of water and soil. To model bacterial die-off in the soil, knowledge of the relationship between bacteria and environmental factors need to be quantified. First order die-off model is commonly used to predict bacterial die-off in the environment. The die-off rate is a function of environmental conditions. PH and temperature are two key environmental factors affecting E. coli die-off in the soil. In this study, E. coli die-off in a soil was investigated in the laboratory under controlled temperatures and pH conditions. E. coli was isolated from pig waste, grown and inoculated in the soil. The population in the soil was determined for a period of three weeks. Results showed that pH and temperature significantly affected die-off rates. As pH decreases from 7 to 3, die-off rate increased. Die-offrates at 2ifC are generally lower than those at 3ife. It wasfound that there was no significant difference between die-off rates at pH of 6 when compared with that at pH of 7. Simple linear regression shows that the fit of first order die-off model to the experimental data was good with 70% of the coefficients of determination, R2, of 0.90 and higher. Die-offrates were found to range from 0.07 a 1 to 1.60 a l • Between pH 3-5, analysis shows that there was no significant interaction between pH and temperature. Multiple linear regression indicated that both coefficients of temperature and pH are Significant. Relationship of die-off rate as a function of pH was developed. Temperature correction coefficients between 20-3ifC were found to be pH dependent.

Research paper thumbnail of Modelling the survival of an Escherichia Coli in Soil : effect of pH and temperature

Modelling the survival of an Escherichia Coli in Soil : effect of pH and temperature

Survival of E.coli on soils determines its the availability for transport during rainfall events.... more Survival of E.coli on soils determines its the availability for transport during rainfall events. In this study, the survival of E.coli in soil was examined under different pH in saturated condition. Results indicated that first order decay model fit well. Decay rate of E.coli increased when pH of the soil decreased from 7.4 to 3.2 and also when temperature increased from 20 Degree Celsius to 30 Degree Celsius. Survival was prolonged in neutral and cool condition. There is no significant difference between decay rate at pH of 6.4 and 7.4. At pH of 6.4 and 7.4 at 30 Degree Celsius and at pH 7.4 at 20 Degree Celsius, there was evidence of regrowth. Quantitative relationships between decay rate and pH at 20 Degree Celsius and 30 Degree Celsius were developed for use in environmental modeling purposes

Research paper thumbnail of Survival of an indicator bacteria in soil : Effect of temperature and moisture

Survival of an indicator bacteria in soil : Effect of temperature and moisture

Research paper thumbnail of Modelling the Decay of Escherichia Coli in Different Soils

Dalam kajian ini, kadar kematian Escherichia coli (E. coli) dalam tiga jenis tanah tropikal dari ... more Dalam kajian ini, kadar kematian Escherichia coli (E. coli) dalam tiga jenis tanah tropikal dari Sarawak, iaitu tanah gambut, tanah loam berlempung dan tanah loam berkelodak telah dikaji dalam makmal pada suhu yang tetap di bawah keadaan tepu seIama 14 hari. Keputusan kajian ini menunjukkan bahawa kadar kematian min E. coli ialah 0.02 hari-l dalam loam berlempung dan 0.14 haril dalam tanah gambut. Kadar kematian yang rendah dalam loam berlempung mungkin berpunca daripada kuantiti partikellempung di dalam tanah loam berlempung jika dibandingkan dengan tanah loam berkelodak. Kajian ini juga menunjukkan bahawa populasi E. coli kekal selama tiga hari dalam tanah gambut, enam hari dalam tanah loam berkelodak dan sepuluh hari dalam tanah loam berlempung. Walaupun tanah gambut mempunyai bahan organik yang lebih tinggi, kadar kematian E. coli adalah lebih tinggi daripada kematian dalam tanah loam berlempung. lni mungkin disebabkan \ oleh keasidan tanah gambut. Kajian ini menunjukkan bahawa model kematian linear peringkat pertama yang telah diubahsuai untukmempertimbangkan tempoh lamban adalah model yang sesuai digunakan untuk meramalkan kematian E. coli dalam tiga jenis tanah dan dalam tempoh yang telah dikaji. Tambahan pula, terdapat tanda-tanda yang menunjukkan bahawa potensi pencemaran E. coli di negara kawasan tropika adalah lebih tinggi jika dibandingkan dengan negara temperat kerana kemandirian yang lebih tinggi. Oleh yang demooan, amalan pengurusan yang sesuai untuk aplikasi dan pembuangan sisa kumbahan haiwan harns dibentuk dan dilaksanakan.

Research paper thumbnail of Adsorption of Fecal Coliforms, Escherichia coli, in Soils of Sarawak

In this study, fecal bacterial adsorption in three different soils (clay loam, silt loam, sandy l... more In this study, fecal bacterial adsorption in three different soils (clay loam, silt loam, sandy loam) was investigated. A wild strain of &cherichia coli (E. colO isolated from animal wastewater was used in the study. For adsorption kinetics study, adhesion of bacterial cells to soil particles was found to be immediate. Percent adsorption was found to be dependent on the initial concentration of E. coli. Results indicate that at low E. coli concentrations (below I ()3 cfulml), the percent adsorption was very much less in sandy loam than in silt loam and clay loam. However, as the bacterial concentration increased, all the soils tested displayed higher bacteria adsorption with maximum values of 99.9% for clay loam, 99.9% for silt loam and 99.7% for sandy loam. Soil with higher clay content (35.2 % and lower pH (PH 4.5» had significantly higher capacity for adsorbing E. coli. Furthermore, E. coli concentration of I ()6 cfulml in suspension was found to decrease by 2 orders of magnitude in all the three soils. Therefore, land treatment of wastewater from animal farm lagoons should be considered to reduce microbial contamination of rivers.

Research paper thumbnail of Detection and antibiotic susceptibility profiles of Listeria monocytogenes in wildlife and water samples in Kubah National Park, Sarawak, Malaysia

international food research journal, 2016

This study was conducted to detect the presence of Listeria monocytogenes (L. monocytogenes) and ... more This study was conducted to detect the presence of Listeria monocytogenes (L. monocytogenes) and screen for its antibiotic susceptibility characteristic from wildlife and water samples at Kubah National Park, Sarawak, Malaysia. Samples collected were incubated and streaked on selective medium PALCAM agar to confirm the presence of Listeria spp. before they were further tested using molecular analysis. Specific Polymerase Chain Reaction (PCR) assay were performed to target specific virulence gene, haemolysin gene, hlyA to further distinguish the presence of this pathogenic bacteria in the samples. Overall, out of the 30 samples tested, 10 samples were confirmed as to contain L. monocytogenes strains and selected to subsequent antibiotic susceptibility test. Susceptibility patterns to 10 antibiotics were investigated among the L. monocytogenes strains. All strains were uniformly resistant to tetracycline and erythromycin. On the other hand, all strains were sensitive to gentamycin and tobramycin. The multiple antibiotic resistance shown by the strains in this study indicate the potential health hazard associated with the possible transmission between wildlife and water to its surrounding environment especially visitors and workers of

Research paper thumbnail of Spatial and Temporal Disparities of Leptospirosis Transmission in Sarawak (Malaysia), 2011-2018

Borneo Journal of Resource Science and Technology, Dec 31, 2022

This study is to analyse the spatial distribution of leptospirosis and identify its high and low ... more This study is to analyse the spatial distribution of leptospirosis and identify its high and low incidence clusters in Sarawak. The annual incidence rate at the district level was calculated using confirmed report of leptospirosis cases from year 2011 to 2018. Empirical Bayes estimation smoothing of relative risks was used to display the spatial distribution of leptospirosis across the study region. Moran's Global Index and Local Indicators of Spatial Association (LISA) were used to analyse the existence of global and local spatial autocorrelation. Data were analysed using ArcGIS and Geoda software at the district level. The annualised average incidence reported during the study period was 20.83 per 100,000 population, with the highest cases reported in year 2018 (n = 870). The

Research paper thumbnail of Biofilm forming ability of intermediate and saprophytic Leptospira on abiotic and biotic surfaces

Malaysian Journal of Microbiology, Aug 1, 2018

Aims: Leptospira spp. has the ability to develop biofilm communities and this attribute is an ess... more Aims: Leptospira spp. has the ability to develop biofilm communities and this attribute is an essential factor to leptospiral pathogenesis. This study aims to assess and quantify the biofilm forming ability of intermediate and saprophytic Leptospira strains. Methodology and results: The biofilm assay was quantified on microtitre polystyrene plates (abiotic) and wood chips (Jelutong Paya hardwood) over a duration of 11 days. Phase contrast light microscope was used to assess the structure of the on the surface. The biofilm production on wood chips surface were approximately one times higher than on polystyrene plate surface indicating Leptospira strains were capable of forming higher quantity of biofilm on biotic surface compared to abiotic surface by both intermediate and saprophytic Leptospira. A significant difference (p<0.05) exists in biofilms produced by Leptospira on wood surface which formed more biofilm than on polystyrene surface. The strongest biofilm producer is intermediate strain G14 with OD600 of 2.283±0.180 and OD600 of 2.333±0.037, on polystyrene and wood surface, respectively. Visualisation of biofilm by phase-contrast microscopy of two representative strains correlated with the OD values and the colour intensity of stained microtitre plates and wood surfaces. The biofilm formed comprises of a three-step process are adherence (1 th to 24 th h), maturation (6t h to 7 th day) and detachment (9 th to 11 th day) of biofilms. Conclusion, significance and impact of study: The contact time of intermediate pathogenic strains was faster compared to saprophytic strain, indicating the biofilm forming ability is related to the level of pathogenicity of Leptospira strains.