Thirty one Vibrio cholera isolates recovered from cholera outbreak in Bintulu, Sarawak (Malaysia) were detected with the presence of ctx gene by using specific PCR. These isolates were further characterized and differentiated by using the Enterobacterial Repetitive Intergenic Consensus PCR (ERIC-PCR) and BOX-PCR to determine their genomic fingerprints. The specific PCR result confirmed the identities of 27 isolates out of 31 as pathogenic V. cholerae. The ERIC-PCR generated several genetic profiles consisting of 4-6 bands with sizes in the range of 100 to 600 bp, while the BOX-PCR produced profiles numbering 2-7 bands in the sizes between 200 to 1000 bp. Based on the dendrogram generated from the DNA fingerprinting profiles (ERIC-PCR and BOX-PCR), all of the isolates can be divided into 2 main clusters that is further divided into 2 sub-clusters. The low genetic diversity of the isolates indicated the outbreak of V. cholerae in the study area was due to the contamination from a single or few sources of V. cholerae.
Cholera

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.

Aims: Bacillus cereus is a Gram-positive, rod-shaped and spore-forming bacterium. It is a ubiquitous bacterium which is widely distributed in several environments such as soil and plants and is commonly isolated from food and its processing environment. This study was aimed to determine the genetic diversity and antibiotic resistance of B. cereus isolated from sago processing in Sarawak. Methodology and results: Out of 120 samples, 42 B. cereus isolates were detected with the presence of hly gene of B. cereus by using specific polymerase chain reaction (PCR). Twenty B. cereus isolates were randomly selected and further characterized by pulsed-field gel electrophoresis (PFGE) of chromosomal DNA digested with NotI to examine the genetic diversity. The result of the PFGE analysis confirmed that the B. cereus strains in sago processing were genetically diverse. Based on the dendrogram generated, B. cereus strains were grouped into two major clusters and these clusters were grouped together based on sources of isolation. The investigation on the antibiotic resistance of B. cereus strains revealed that the B. cereus strains were uniformly highly resistant to penicillin and ampicillin and highly susceptible to imipenem and norfloxacin. Conclusion, significance and impact of study The results of this study suggest that the B. cereus isolated from sago processing derived from a mixture of sensitive and resistant strains with diverse genetic contents.

Aims: Cholera epidemics have been occurred in Malaysia since 1991 till 2003 which can be proved from the records by the Infectious Diseases Division of the Ministry of Health. Moreover, there were also course of cholera epidemics from the year 1994 to 2003 which had been happened in Sarawak. Cholera outbreaks in Malaysia mostly caused by the El Tor O1 Vibrio cholerae serogroup. The aims of this study were to detect the presence of V. cholerae in clinical and environmental samples (n=28) from Limbang, Sarawak by collaboration with Sarawak Government Hospital and to detect the toxin genes from the isolates. Methodology and results: All the isolates were sub-cultured in alkaline peptone water (APW). The boiled-cell method was used for DNA extraction. The total DNA extracted was amplified by polymerase chain reaction (PCR). Two types of PCR were used in this study which are 16S rRNA PCR and multiplex PCR. The results obtained from the study found out that 16 out of 28 (57.14%) samples were confirmed to be V. cholerae species. Four primers specific for V. cholerae were used in multiplex PCR (O1 type, O139 type, ctxA and ctxAB) to confirm the species type and the toxin genes. All samples shown positive for V. cholerae O1 serotype and 100% positive to all genes for the identification of ctxA and ctxAB genes. Conclusion, significance and impact of study From this study, it showed that multiplex PCR can be used for research purposes in molecular genetics field involving cholera outbreak.
Vibrio cholerae--genetics ; Cholera Toxin