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Law J.W.,University of Selangor | Ab Mutalib N.-S.,UKM Medical Molecular Biology Institute UMBI | Chan K.-G.,University of Malaya | Lee L.-H.,University of Selangor
Frontiers in Microbiology | Year: 2015

The incidence of foodborne diseases has increased over the years and resulted in major public health problem globally. Foodborne pathogens can be found in various foods and it is important to detect foodborne pathogens to provide safe food supply and to prevent foodborne diseases. The conventional methods used to detect foodborne pathogen are time consuming and laborious. Hence, a variety of methods have been developed for rapid detection of foodborne pathogens as it is required in many food analyses. Rapid detection methods can be categorized into nucleic acid-based, biosensor-based and immunological-based methods. This review emphasizes on the principles and application of recent rapid methods for the detection of foodborne bacterial pathogens. Detection methods included are simple polymerase chain reaction (PCR), multiplex PCR, real-time PCR, nucleic acid sequence-based amplification (NASBA), loop-mediated isothermal amplification (LAMP) and oligonucleotide DNA microarray which classified as nucleic acid-based methods; optical, electrochemical and mass-based biosensors which classified as biosensor-based methods; enzyme-linked immunosorbent assay (ELISA) and lateral flow immunoassay which classified as immunological-based methods. In general, rapid detection methods are generally time-efficient, sensitive, specific and labor-saving. The developments of rapid detection methods are vital in prevention and treatment of foodborne diseases. © 2015 Law, Ab Mutalib, Chan and Lee. Source


Lee L.-H.,Sunway University | Zainal N.,Sunway University | Zainal N.,University of Malaya | Azman A.-S.,Sunway University | And 3 more authors.
International Journal of Systematic and Evolutionary Microbiology | Year: 2014

A novel actinobacterial strain, designated MUSC 201T, was isolated from a mangrove soil collected from Kuantan, the capital city of Pahang State in Malaysia. The taxonomic status of this strain was determined using a polyphasic approach. Comparative 16S rRNA gene sequence analysis revealed that strain MUSC 201T represented a novel lineage within the class Actinobacteria. Strain MUSC 201T formed a distinct clade in the family Nocardioidaceae and was most closely related to the members of the genera Nocardioides (16S rRNA gene sequence similarity, 91.9-95.1 %), Aeromicrobium (92.7-94.6 %), Marmoricola (92.5-93.1 %) and Kribbella (91.5-92.4 %). The cells of this strain were irregular coccoid to short rod shaped. The peptidoglycan contained LL-diaminopimelic acid as diagnostic diamino acid and the peptidoglycan type was A3c. The peptidoglycan cell wall contained LL-diaminopimelic acid, glycine, glutamic acid and alanine in a molar ratio of 1.5: 0.9: 1.0: 1.5. The cell-wall sugars were galactose and rhamnose. The predominant menaquinone was MK-9(H4). The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphoglycolipid, glycolipid and four unknown phospholipids. The major cellular fatty acids were C18: 1ω9c (30.8 %), C16: 0 (24.1 %), and 10- methyl C18: 0 (13.9 %). The DNA G+C content was 72.0±0.1 mol%. On the basis of phylogenetic and phenotypic differences from members of the genera of the family Nocardioidaceae, a novel genus and species, Mumia flava gen. nov., sp. nov. are proposed. The type strain of Mumia flava is MUSC 201T (=DSM 27763T=MCCC 1A00646T=NBRC 109973T). © 2014 IUMS. Source


Lee L.-H.,University of Selangor | Zainal N.,University of Selangor | Zainal N.,University of Malaya | Azman A.-S.,University of Selangor | And 4 more authors.
International Journal of Systematic and Evolutionary Microbiology | Year: 2014

Two novel actinobacteria, strains MUSC 135T and MUSC 137, were isolated from mangrove soil at Tanjung Lumpur, Malaysia. The 16S rRNA gene sequence similarity and DNA-DNA relatedness between strains MUSC 135T and MUSC 137 were 100% and 83±3.2%, confirming that these two strains should be classified in the same species. Strain MUSC 135T exhibited a broad-spectrum bacteriocin against the pathogens meticillin-resistant Staphylococcus aureus (MRSA) strain ATCC BAA-44, Salmonella typhi ATCC 19430T and Aeromonas hydrophila ATCC 7966T. A polyphasic approach was used to study the taxonomy of MUSC 135T, and it showed a range of phylogenetic and chemotaxonomic properties consistent with those of the genus Streptomyces. The diamino acid of the cell-wall peptidoglycan was LL-diaminopimelic acid. The predominant menaquinones were MK-9(H6), MK-9(H4) and MK-9(H8). Polar lipids detected were a lipid, an aminolipid, a phospholipid, phosphatidylinositol, phosphatidylethanolamine and two glycolipids. The predominant cellular fatty acids (>10.0%) were anteiso-C15 : 0 (20.8%), iso-C16: 0 (18.0%), iso-C15 : 0 (12.2%) and anteiso-C17 : 0 (11.6%). The whole-cell sugars were ribose, glucose and mannose. These results suggested that MUSC 135T should be placed within the genus Streptomyces. Phylogenetic analysis based on the 16S rRNA gene sequence exhibited that the most closely related strains were Streptomyces cinereospinus NBRC 15397T (99.18% similarity), Streptomyces mexicanus NBRC 100915T (99.17%) and Streptomyces coeruleofuscus NBRC 12757T (98.97%). DNA-DNA relatedness between MUSC 135T and closely related type strains ranged from 26.3±2.1 to 49.6±2.5%. BOX-PCR fingerprint comparisons showed that MUSC 135T exhibited a unique DNA profile. The DNA G+C content determined was 70.7±0.3 mol%. Based on our polyphasic study of MUSC 135T, the strain merits assignment to a novel species, for which the name Streptomyces pluripotens sp. nov. is proposed. The type strain is MUSC 135T (=MCCC 1K00252T=DSM 42140T). © 2014 IUMS. Source


Lee L.-H.,University of Selangor | Azman A.-S.,University of Selangor | Zainal N.,University of Selangor | Zainal N.,University of Malaya | And 3 more authors.
International Journal of Systematic and Evolutionary Microbiology | Year: 2015

Strain MUSC 117Twas isolated from mangrove soil of the Tanjung Lumpur forest in Pahang, Malaysia. This bacterium was yellowish-white pigmented, Gram-staining-positive, rod–coccus shaped and non-motile. On the basis of 16S rRNA gene sequence, strain MUSC 117Texhibited highest sequence similarity to Sinomonas atrocyanea DSM 20127T(98.0%), Sinomonas albida LC13T(97.9%) and Sinomonas soli CW 59T (97.8%), and lower (<97.6%) sequence similarity to other species of the genus Sinomonas. DNA–DNA hybridization experiments revealed a low level of DNA–DNA relatedness (less than 27%) between strain MUSC 117Tand closely related species. Chemotaxonomically, the peptidoglycan type was A3α, containing the amino acids lysine, serine, glycine, alanine, glutamic acid and muramic acid. The whole-cell sugars detected were rhamnose, ribose, glucose, galactose and a smaller amount of mannose. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and five unidentified glycolipids. The major fatty acids (.10.0%) of the cell membrane were anteiso-C15: 0(39.4%), C18: 1ω7c (17.7%), anteiso-C17: 0(17.2%) and iso-C16: 0(11.4%). The predominant respiratory quinones detected were MK-9(H2) and MK-9. The DNA G+C content was 67.3 mol%. A comparison of BOX-PCR fingerprints indicated that strain MUSC 117Trepresented a unique DNA profile. Results based on a polyphasic approach showed that strain MUSC 117Trepresents a novel species of the genus Sinomonas, for which the name Sinomonas humi sp. nov. is proposed. The type strain of Sinomonas humi sp. nov. is MUSC 117T(5DSM 29362T=MCCC 1K00410T=NBRC 110653T). © 2015 IUMS. Source


Lee L.-H.,University of Selangor | Azman A.-S.,University of Selangor | Zainal N.,University of Malaya | Eng S.-K.,University of Selangor | And 3 more authors.
International journal of systematic and evolutionary microbiology | Year: 2014

Strain MUSC 115(T) was isolated from mangrove soil of the Tanjung Lumpur river in the state of Pahang, Peninsular Malaysia. Cells of this strain stained Gram-positive and were non-spore-forming, short rods that formed yellowish-white colonies on different agar media. The taxonomy of strain MUSC 115(T) was studied by a polyphasic approach, and the organism showed a range of phylogenetic and chemotaxonomic properties consistent with those of the genus Microbacterium. The cell-wall peptidoglycan was of type B2β, containing the amino acids ornithine, alanine, glycine, glutamic acid and homoserine. The muramic acid was of the N-glycolyl form. The predominant menaquinones detected were MK-12, MK-13 and MK-11. The polar lipids consisted of phosphatidylglycerol, phosphoglycolipid, diphosphatidylglycerol, two unidentified lipids, three unidentified phospholipids and four unidentified glycolipids. The major fatty acids of the cell membrane were anteiso-C15:0 and anteiso-C17:0. The whole-cell sugars detected were ribose, glucose, mannose and galactose. Based on the 16S rRNA gene sequence, strain MUSC 115(T) showed the highest sequence similarity to Microbacterium immunditiarum SK 18(T) (98.1%), M. ulmi XIL02(T) (97.8%) and M. arborescens DSM 20754(T) (97.5%) and lower sequence similarity to strains of other species of the genus Microbacterium. DNA-DNA hybridization experiments revealed a low level of DNA-DNA relatedness (less than 24%) between strain MUSC 115(T) and the type strains of closely related species. Furthermore, BOX-PCR fingerprint comparison also indicated that strain MUSC 115(T) represented a unique DNA profile. The DNA G+C content determined was 70.9 ± 0.7 mol%, which is lower than that of M. immunditiarum SK 18(T). Based on the combination of genotypic and phenotypic data, it is proposed that strain MUSC 115(T) represents a novel species of the genus Microbacterium, for which the name Microbacterium mangrovi sp. nov. is proposed. The type strain is MUSC 115(T) ( = MCCC 1K00251(T) = DSM 28240(T) = NBRC 110089(T)). IUMS. Source

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