Characterization of Vibrio Parahaemolyticus Isolated From Local Cockles (Anadara Granosa) From Tanjung Karang, Kuala Selangor

Vibrio parahaemolyticus is widespread in occurrence and has been recognized as a cause of gastroenteritis related to consumption of raw or improperly cooked seafood. Outbreaks of V. parahaemolyticus food poisoning are most common in Taiwan, Japan and Southeast Asia. In this study, V. parahaemolyticus was isolated from 62 of 100 (62%) samples of cockles (Anadara granosa) collected from Tanjong Karang, Kuala Selangor. A total of 62 strains were studied for the presence or absence of regulatory gene (toxR), virulence genes (tdh and trh), their antibiotic resistance, the occurrence of plasmids and their molecular fingerprints by Randomly Amplified Polymorphic DNA – Polymerase Chain Reaction (RAPD-PCR) and Enterobacterial Repetitive Intergenic Consensus - Polymerase Chain Reaction (ERIC-PCR) assays. All 62 strains were positive for the regulatory gene (toxR) of V. parahaemolyticus. The PCR analysis for the detection of tdh or trh genes showed two (3.2%) positive strains carrying tdh gene and eleven (17.7%) strains had trh gene. The MPN value for all samples was more than 1100 MPN/g. This study has shown that all strains were multiple resistant to three or more of the seventeen antibiotics tested with the MAR indices ranging from 0.58-0.94. All isolates of V. parahaemolyticus were highly resistant towards the antibiotics tested, except one strain that was sensitive towards norfloxacin. Plasmids were found in 80% of the strains analyzed and 18 different plasmid profiles were observed. The plasmid size ranged from 2.7 to more than 54 kb. Two molecular typing methods were used in this study to examine the genetic relatedness among the V. parahaemolyticus strains. In the analysis by RAPD-PCR and ERIC-PCR, the size of RAPD and ERIC fragments ranged from 0.25 to 10.0 kb with an average number of ten and eight bands, respectively. Sixty-two genotypes among the 62 V. parahaemolyticus strains were generated using RAPD and ERIC-PCR which indicates that the strains were very diverse. Hence, this study, demonstrated that the local cockles are potential source for pathogenic V. parahaemolyticus

Isolation and Molecular Characterisation of Listeria Monocytogenes and Listeria Innocua from Poultry Meat

Thirty isolates of Listeria monocytogenes (12) and Listeria innocua (18) were isolated from poultry meat. All isolates were confirmed by Microbact (Medvet, Australia) identification kits. All the isolates were subjected to chromosomal and plasmid DNA screening and antibiotic resistance test. Based on the antibiotic resistance profiles, Listeria monocytogenes and Listeria innocua were differentiated into 10 and 9 profiles respectively. The antibiotyping procedure discriminated the Listeria monocytogenes and Listeria innocua into 10 and 3 different groups respectively. Most of the isolates were resistant to nalidixic acid (100%), c1indamycin (97%), spectinomycin (97%), cefuroxime (93%), cefriaxone (80%), cephalothin (73%), cefotaxime (67%), novobiocin (37%), chloramphenicol (27%), kanamycin (20%), rifampicin (20%), tobramycin (17%), norfloxacin (13%), netilmicin(10%) and imipenem (3%). The results of the plasmid profiles and antibiotyping show that there is no correlation between them. RAPD-PCR has been used to generate polymorphic genomic fingerprints to discriminate the Listeria isolates. Primer GEN15009 was chosen whereby it produced reproducible and typeable results in all isolates examined with the bands ranging from 0.25 to 3.0 kilobase pairs. From the dendrogram generated L. monocytogenes were separated from L. innocua and the strains in each species were differentiated as well. The data indicate that RAPD-PCR based approaches is a valid means of discriminating strain differences among isolates of L. monocytogenes and L. innocua and as an adjunct to differentiate among Listeria spp

Synthesis and Characterization of Cordierite and Mullite composite

Cordierite-mullite composite has been prepared from rice husk derived silica; Magnesium sulphate derived magnesium oxide, and calcined alumina powder. Phase formation behavior of the sample has been studied from the XRD pattern of the sintered sample. The densification behaviour of the composite has been studied using dilatometer. The densification behavior of the composite as a function of sintering temperature has also been reported. Flexural strength as a function of sintering temperature and mullite content in the composite has also been studied

Molecular typing of Bacillus cereus isolated from sago processing mills in Sarawak.

Bacillus cereus is an ubiquitous bacteria which is commonly found in soil and plant-based food. In this study, thirty-nine Bacillus cereus isolates were detected with the presence of hly gene by using specific PCR. These isolates were further characterized and differentiated by using the Enterobacterial Repetitive Intergenic Consensus PCR (ERIC-PCR) to determine their genomic fingerprints. The ERIC-PCR generated several genetic profiles consisting of 1 to 7 bands with sizes in the range of 120 bp to 990 bp. Based on the dendrogram generated from the DNA fingerprinting profiles (ERIC-PCR), all of the isolates can be divided into 2 main clusters that is further divided into few sub-clusters. The heterogeneity of the isolates indicated the crosscontamination of Bacillus cereus occurred in sago processing mills in Sarawak

Detection of Bacillus cereus in formula milk and ultra high temperature (UHT) treated milk products

Ultra high temperature (UHT) treated milk products and formula milk are known to be frequently contaminated with Bacillus cereus. Presence of B. cereus in these milk products is of particular concern considering the majority of consumers are infants and children. Possible sources of contamination are contaminated raw milk, cross-contamination during processing, under-processing and mishandling of milk products. This study was conducted to detect the presence of B. cereus in both formula milk (n=12) and UHT milk (n=20) sold in selected retail markets. The approach consisted of enumerating by MPN/g followed by PCR assay aimed at detecting gyrB gene in B. cereus, that encode for the subunit B protein of DNA gyrase (topoisomerase type II). Contamination level of B. cereus in both types of samples examined ranged from 1100 MPN/g. The contamination level of B. cereus was found to be highest in full cream UHT milk (> 1100 MPN/g) and formula milk (> 1100 MPN/g). The PCR analysis showed that 41.7% (5/12) formula milk and 30% (6/20) UHT milk samples were detected with B. cereus, respectively. This is the first report of such study demonstrating the presence of B. cereus in formula milk from Malaysia. Therefore, constant surveillance of these milk products would reduce the potential risk of B. cereus-linked outbreaks

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

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

Characterization of Escherichia coli isolated from cultured catfish by antibiotic resistance and RAPD analysis

Antibiotic susceptibility and genetic diversity of E. coli isolated from cultured catfish and their surrounding environment were determined. The levels of resistance of the E. coli isolates towards six different antibiotics tested differed considerably. Though the isolates displayed resistance towards some of the antibiotics tested, none of the isolates showed resistant towards norfloxacin, sulphametoxazole/trimethoprim and chloramphenicol. RAPD-PCR analysis using single primer and primers combination clustered the E. coli isolates into 3 and 5 groups, respectively. The results of this study suggest that the E. coli isolates from the catfish and their surrounding environment derived from a mixture of sensitive and resistant strains with diverse genetic contents. The use of the RAPD analysis is sufficiently discriminatory for the typing of the E. coli isolates

Identification of Vibrio parahaemolyticus isolates by PCR targeted to the toxR gene and detection of virulence genes

Vibrio parahaemolyticus is a gram negative bacterium and causes gastrointestinal illness in humans. In this study, twenty five out of fifty cockle samples from Padang, Indonesia produced purple colonies when they were grown on selective medium, CHROMagarTM Vibrio. Specific–PCR for toxR gene detection gave positive results in which a band with 368 base pairs size appeared on the gel for all the isolates that confirmed the presence of V. parahaemolyticus. In the virulence properties test, all the isolates showed negative results for tdh and trh genes detection. The results indicate that the isolates under this study do not contain virulence properties that correlate to the ability of infection and diseases, which means that they are nonpathogenic

Simultaneous Reclamation of Sago Starch Processing Effluent Water and Rhizopus oligosporus Cultivation at Different pH Conditions

Industrial sago starch extraction from the sago palm (Metroxylon sagu) generates large volumes of wastewater, known as sago effluent that is generally discharged into nearby water bodies without proper treatment. This practice has led to severe environmental pollution that prompts the development of biotechnological treatments of sago effluent. In this study, Rhizopus oligosporus was grown in sago effluent at several initial pHs (pH 4, 5, and 6) during submerged fermentation to determine the optimum pH for high protein fungal biomass (HPFB) production while simultaneously reducing the starch content and high organic loads of sago effluent. Our results showed that the growth of R. oligosporus was the highest (3.8 g/L) when the initial pH of the sago effluent was 4. The same pH also gave the best reduction of starch, biochemical oxygen demand and chemical oxygen demand of the sago effluent following the R. oligosporus fermentations, which were 96.70%, 89.81%, and 78.30%, respectively. In addition, nitrate concentration was found to be reduced from 0.266 to 0.257 g/L, while the nitrite level dropped from 0.040 to 0.029 g/L. The present findings presented the potential of R. oligosporus for the production of HPFB as well as for treating sago effluent

Impact of Different Land Uses on the Escherichia coli Concentrations, Physical and Chemical Water Quality Parameters in a Tropical Stream

Rural streams are important source of water for the nearby communities. However, bacterial contamination from agriculture and human settlement may render the water unsuitable for drinking and body contact recreation. Hence, the objective of this study was to determine the impact of different land uses such as animal farming and human settlement on E. coli concentrations in the Serin River, a tropical stream. Samplings were conducted at 9 stations from September 2009 to March 2010. Results showed that E. coli concentrations ranged from 2,000-6,900,000 CFU/100 mL with E. coli concentrations in fish aquaculture water exceeding the WHO standard. Animal and crop farming stations showed the highest E. coli concentrations in the tributaries. Re-suspension from stream sediment and non-point sources such as runoff contributed to the high concentrations observed in the main river. Multiple linear regressions indicated that total suspended solids and dissolved oxygen were significant water quality parameters and they explained 68.1% of the total E. coli variations observe