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Antibiotics susceptibility of Burkholderia species of Sarawak origin

Lua Viana Pangau ; Flowrence Vianney Sylvester ; Yuwana Podin

Malaysian Journal of Microbiology.2018;14(4):305-308. doi:10.21161/mjm.144181

Aims: The Burkholderia species is comprised of more than 70 members which co-exist in the same ecological niche including Burkholderia pseudomallei, which causes fatal melioidosis infections in humans and animals. Many of the members of the Burkholderia species share similarities in their biochemical and morphological profiles. B. pseudomallei is intrinsically resistant to a myriad of antibiotics and hence, the treatment of melioidosis involves various types of antibiotics with prolonged prescription. Apart from B. pseudomallei which has been widely described due to its clinical importance, little is known about the antibiotics mechanisms and susceptibility profile of Burkholderia species. This leads to the question of whether the antibiotics susceptibility profile of the Burkholderia species is similar to that of B. pseudomallei. Methodology and results: In this study, Burkholderia species isolated from environmental samples were tested for their susceptibility against gentamicin, ceftazidime, cotrimoxazole (trimethoprim/sulfamethoxazole) and azithromycin using the disk diffusion test method. The antibiogram profiles Burkholderia species isolates tested in this study suggested that the antibiogram profile of Burkholderia spp. resembles that of B. pseudomallei for some antibiotics while totally different for other antibiotics. Conclusion, significance and impact of study The actual mechanisms which render these observations and whether the interaction of these subspecies within the same ecological niche attribute to these observations warrant further investigation.

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Molecular characterisation of rice tungro bacilliform virus isolated from Bario, Sarawak

Magdline Sia Henry Sum ; Siew Fung Yee

Malaysian Journal of Microbiology.2018;14(4):309-312. doi:10.21161/mjm.144182

Aims: Rice tungro disease is one of the most damaging and destructive diseases of rice in South and Southeast Asia. The disease is caused by the co-infection of two viruses, the Rice tungro bacilliform virus (RTBV) and Rice tungro spherical virus (RTSV). The symptoms and severity of the disease depend on these two viral agents, if rice is coinfected by both viruses, it will show the typical severe symptoms of yellow-orange leaf discoloration, plant stunting and reduced in yield. On the other hand, if rice is infected only with RTBV, it shows milder symptoms and in contrast, rice plants will show no symptoms if they are infected only with RTSV. The disease had been detected in Malaysia since the 1930s. However, the first incursion of the disease was only reported in Sarawak in 2012. Since the disease was not seen in the Sarawak until recently, very little information on local virus isolate is available. This study was conducted to obtain and record the nucleotide sequence of partial coat protein gene of two primary isolates of RTBV collected from Bario, Sarawak in 2012 and 2013. Methodology and results: Based on the phylogenetic analysis, the isolates cluster with the Southeast Asia group with sequence identity at nucleotide and amino acid level of 91.1 to 95.1% and 98.6 to 99.5% respectively. Conclusion, significance and impact of study This study provide the first genetic information on RTBV isolates from Sarawak. This data is important for future reference of the virus variants and diversity for epidemiological and diagnosis purposes.

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

Kasing Apun ; Jennifer Jalan ; Chai Fung Pui ; Lesley Maurice Bilung ; Hashimatul Fatma Hashim ; Anisa Aina Nadiah Md Ahsan ; Rennielyn Rupert

Malaysian Journal of Microbiology.2018;14(4):313-319. doi:10.21161/mjm.144183

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.

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Detection, genetic diversity and antibiotic resistance profiles of Bacillus cereus isolated from sago processing plants in Malaysia

Lesley Maurice Bilung ; Jasmine Jaraee ; Cirilo Nolasco-Hipó ; lito ; Micky Vincent

Malaysian Journal of Microbiology.2018;14(4):320-324. doi:10.21161/mjm.144184

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.

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Overexpression of recombinant domain III envelope protein of Zika virus

Sylvia Empiang Andrew ; Easther Manye Kennedy ; Magdline Sia Henry Sum

Malaysian Journal of Microbiology.2018;14(4):325-328. doi:10.21161/mjm.144185

Aims: Zika virus (ZIKV) is a member of the Flaviviridae family and is transmitted to humans by mosquitoes. In humans, it causes disease known as Zika fever. The severity of the infection ranged from asymptomatic to mild disease and to infection associated with neurological disorders and congenital anomaly. The common symptoms are maculopapular rash, fever, arthralgia, myalgia, headache and conjunctivitis. The flavivirus genome consists of structural and nonstructural proteins. The envelope (E) glycoprotein is the major structural protein which is responsible for virus entry and represents a major target for neutralizing antibodies. The E protein consists of three distinct domains: domain I, domain II and domain III. The domain III (DIII) of the E protein has shown to be useful as antigen for flavivirus serologic diagnosis and immunization in animal model. Hence, the aim of this work is to express the DIII of E protein (EDIII) of ZIKV for immunoreactivity study Methodology and results: The EDIII of ZIKV was cloned into pET SUMO cloning vector and transformed into Mach-T1 competent E. coli cells. Positive clone was selected, verified and transformed into BL21 (DE3) competent E. coli for protein expression. The expression of the recombinant protein was analysed on SDS-PAGE and western blot. The recombinant fusion protein of EDIII/SUMOHIS (rEDIII) was successfully expressed at a molecular weight of approximately 38.2 kDa. Conclusion, significance and impact of study The expression of the protein was confirmed by detection with antihistidine and a flavivirus antiserum, HPR.

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Screening and characterisation of two Pseudomonas aeruginosa from aquaculture and water environment

Seng Chiew Toh ; Samuel Lihan ; Khar Mun Soh ; Natalia Uyub ; Lay Ching Chai ; Moritz Mü ; ller

Malaysian Journal of Microbiology.2018;14(4):329-334. doi:10.21161/mjm.144186

Aims: Pseudomonas has been associated with diseases occurring in people with weakened or compromised immune system after exposure to contaminated water. The diseases are commonly treated with antibiotics. However, the bacteria had developed resistances to commonly used antibiotics making treatment a difficult task. Therefore, the continuous surveillance of susceptibility of Pseudomonas especially for the human pathogen P. aeruginosa to commonly clinical and aquaculture farming used antibiotics is important to ensure that serious infections remain susceptible to those antibiotics. Methodology and results: In this study, the bacteria were screened from water, sediment and fish from rivers and aquaculture farms around Kuching, Sarawak. A total number of 38 presumptive P. aeruginosa were isolated using CHROMagar TM Pseudomonas and subjected to a series of biochemical tests. Out of all the isolates tested, only two isolates designated as AS-R10(S) and BK2-OLT2(S) fulfilled the biochemical characteristics of P. aeruginosa. 16S rRNA gene sequencing further confirmed these two isolates as P. aeruginosa based on their 100% similarity with P. aeruginosa strain GD1 and P. aeruginosa strain PA1201 in NCBI database. These two isolates were tested for their susceptibilities against nine common antibiotics used in both clinical and aquaculture farming nowadays: imipenem, piperacillin, meropenem, amikacin, gentamicin, ciprofloxacin, ceftazidime, tobramycin and norfloxacin according to CLSI standard using disk diffusion method. Conclusion, significance and impact of study The two isolates exhibited total susceptibility to all the antibiotics analysed, suggesting the effectiveness of the antimicrobial agents towards P. aeruginosa isolated from aquaculture and water environment in the study area.

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Isolation and characterisation of Arbuscular mycorrhizal (AM) fungi spores from selected plant roots and their rhizosphere soil environment

Seng Chiew Toh ; Samuel Lihan ; Bryan Chuan Wang Yong ; Bi Ren Tiang ; Rakiya Abdullahi ; Rebicca Edward

Malaysian Journal of Microbiology.2018;14(4):335-343. doi:10.21161/mjm.144187

Aims: Arbuscular mycorrhizal (AM) fungi or previously known as the vesicular-arbuscular mycorrhizal (VAM) fungi, is a type of endomycorrhiza that closely associates with most species of plants. Meanwhile, they significantly improve the nutrients uptake in exchange of photosynthates and decrease the stress caused by both biotic and abiotic factors through symbiosis relationship. However, the understanding of indigenous AM fungi species present in its host plants are comparatively inadequate, hence this research study concentrated on indigenous AM fungi population in some selected plants that contribute to agricultural sector in Malaysia and phytochemical properties of soil that affect the colonization rate of AM fungi. Methodology and results: Bamboo, banana, coconut, sugarcane, papaya, lemongrass, pandan and tapioca plant were selected in this study. The soil and plant roots were sampled and the fungi spores were extracted by applying Wet sieves and decantation techniques then further purified by sucrose density centrifugation. Genera Glomus, Funneliformis, Rhizophagus, Acaulospora and Dentiscutata were isolated and Glomus was determined as the dominant genera followed by Acaulospora in these selected plants. Soil pH were found to be significantly affecting the AM fungi population and the root colonization percentage of AM fungi in the plants analysed. Conclusion, significance and impact of study From this study, tapioca recorded the highest percentage of AM fungi root colonization rate with 20.00% in root while banana recorded the lowest rate of 3.33% only. Based on this study, tapioca is recommended for the propagation of AM fungi for biofertilizer usage in agricultural sector in future.

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Production of pigments by Rhodotorula mucilaginosa

Wai Xian Lau ; Octavio Carvajal-Zarrabal ; Cirilo Nolasco-Hipó ; lito ; Mizuno Kohei ; Zayn Al-Abideen Gregory ; Mohammad Omar Abdullah ; Seng Chiew Toh ; Samuel Lihan

Malaysian Journal of Microbiology.2018;14(4):344-350. doi:10.21161/mjm.144188

Aims: Pigments have a large and growing market in the world. Drawbacks in their production such as raw materials availability and low productivity prompt the search for fermentation routes for industrial production. A carotenoid-producing yeast identified as Rhodotorula mucilaginosa was isolated in our laboratory. The aim of this study was to investigate the growth and carotenoid production capacity of the yeast. Methodology and results: A cost-effective substrate of sago starch hydrolysate (SSH) derived from sago fiber waste was used for the fermentation. The fermentation was carried out for 96 h at 27 °C in batch mode. The biomass produced during 5 days of fermentation was 9.6 g/L, which contained a carotenoid concentration of 8.1 mg/L and a specific yield of 845.9 g/g. Conclusion, significance and impact of study The results demonstrated the capacity of R. mucilaginosa yeast to produce carotenoids and its potential for larger-scale production.

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Prevalence and antibiotic sensitivity profiles of Staphylococcus aureus nasal carriage among preclinical and clinical medical students in a Malaysian university

Isabel Lim Fong ; Efa Ezan binti Abdul Razak ; Janice Tham Jia Mei ; Nurul Akmal binti Safian ; Ong Sheng Tian ; Ng Poh Peng ; Helmy Hazmi

Malaysian Journal of Microbiology.2018;14(4):351-355. doi:10.21161/mjm.144189

Aims: Prevalence of Methicillin-resistant Staphylococcus aureus (MRSA) strains in healthcare (HA-MRSA) and community (CA-MRSA) incurred costly morbidity and mortality. This study assessed the prevalence and antibiotic sensitivity profile of S. aureus and MRSA isolates from medical students. Methodology and results: A cross-sectional study of nasal swabs from 60 medical students yielded 93% positive S. aureus. In this study, erythromycin, fusidic acid, gentamicin, penicillin, vancomycin and methicillin were used. The most significant antibiotic sensitivity against S. aureus was fusidic acid (p-value=0.0042). The S. aureus and MRSA isolates from clinical students were more resistant than those of preclinical students against erythromycin (44%; 15%), fusidic acid (33.3%; 10%), penicillin (85%; 86.9%), vancomycin (11.1%;-) and methicillin (19.4%; 15%) respectively while the isolates from preclinical students were more resistant than those of clinical students against gentamicin (5%;-). Conclusion, significance and impact of study In this study, gender, age and duration of clinical exposure had no significant bearing on the prevalence of nasal S. aureus and MRSA respectively. No MRSA infections were detected in preclinical (15%) and clinical (19%) students positive for MRSA, suggesting that these students may be carriers of CA-MRSA. A larger study will be implemented to provide baseline data for monitoring CA-MRSA infections, genotyping and constructing of phylogenetic tree.

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Isolation of thermotolerant xylose-utilizing yeasts for ethanol and xylitol production

Khadijah Hanim Abdul Rahman ; Nazalan Najimudin ; Ku Syahidah Ku Ismail

Malaysian Journal of Microbiology.2018;14(5):372-380. doi:10.21161/mjm.110517

Aims: The implementation of simultaneous saccharification and co-fermentation (SScF) and consolidated bioprocessing (CBP) is highly anticipated for industrial bioethanol applications. Thus, microorganisms capable of utilizing hexose and pentose sugars, as well as thermotolerant, are considered advantageous for optimum ethanol production. Methodology and results: Thermotolerant yeast strains were isolated from wastewater ponds of ethanol-producing facility as well as empty fruit bunch composting area and screened for xylose- and glucose-fermenting ability. Five out of 24 total isolates were able to grow at 40 ºC and were found positive for ethanol production from xylose. Based on their high efficiency of xylose and glucose utilization, two isolates were chosen for further characterization. They were identified as Kluyveromyces marxianus UniMAP 1-1 and Schwanniomyces etchellsii UniMAP 1-7 based on the D1/D2 region of the large subunit ribosomal DNA. The growth kinetics of each isolate on xylose and glucose at 40 °C were determined. The two isolates were able to ferment xylose to ethanol at a maximum concentration between 0.533  0.415 and 1.243  0.246 g/L with concomitant xylitol production between 9.932  0.303 and 12.933  0.505 g/L. Fermentation of glucose to ethanol was also tested for these isolates and the yields were and 0.361 and 0.118 g/g for UniMAP 1-1 and UniMAP 1-7, respectively. Conclusion, significance and impact of study The potential of these thermotolerant microbes to be used for xylitol and bioethanol production from lignocelluloses are evident from this study.

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