Prevalence And Molecular Characteristics Of Aeromonas Species Isolated From Fish, Shrimp And Waters

Aeromonas species are ubiquitous aquatic micro-organisms which are opportunistic pathogens that have been associated to wound infections, gastroenteritis, septicemia, and traveler’s diarrhea in humans and hemorrhagic septicaemia in fish. The main routes of exposure in humans are ingestion of contaminated foods and drinking water, or direct contact with recreational waters. In this study, a total of 450 samples were obtained from different sources and locations in Malaysia. Two hundred fifty samples of fresh water were obtained from ponds in UPM (n=150) and in tiger prawn farm in Malacca (n=150), respectively. In addition, 100 samples of shrimps (Penaeus indicus) were purchased from different wet markets in Selangor state: Seri Kembangan (35), Kajang (35) and Bangi (30). Hundred samples of fish (Clarias batrachus) (n=50) and Tiger prawn (Penaeus monodon) (n=50) were obtained from UPM and tiger prawn farm in Malacca, respectively. 238 (52.8%) of the 450 samples were tested positive for the isolation of Aeromonas species, 49 (10.8% ), 43 (9.5%),33 (7.3%), 37 (8.4%), 25 (5.5%), 23 (5.1%), 19 (4.2%), 15 (3.3%) and 2% harbored A. veronii, A. allosacharophila, A. hydrophila, A. caviae, A. enterpelogenes, A. encheleia, A. trota, A. media like DNA and A. veronii biovar sobria, respectively. All the strains of A. hydrophila, A. caviae and A. veronii biovar sobria were tested for resistance to 15 antibiotics and 98.8% and 94.1% of the strains were resistant to amoxcillin and penicillin, respectively, followed by teicoplanin (89.4%), penicillin (81.1%) and 12.9% of the strains were found resistant to chloramphenicol. The Multiple Antibiotic Resistance Indexing (MAR) and the bionumeric analysis of A. hydrophila, A. caviae and A. veronii biovar sobria, showed that all of them originated from high-risk sources. Two molecular typing methods were used in this study to examine the intra/inter-specific genetic relatedness among the A. hydrophila, A. caviae and A. veronii biovar sobria strains. In the analysis by RAPD-PCR and ERIC-PCR, the size for RAPD and ERIC fragments ranged from 0.25 to 10.0 kb with an average number of sixteen and eight bands, respectively. Eighty five genotypes among the 85 A. hydrophila, A. caviae and A. veronii biovar sobria isolates were generated using RAPD and ERIC-PCR which indicated that the strains were very diverse. The PCR analysis for detection of aerolysin (aer) and hemolysin (hly) showed that 50.5% of the isolates carried hemolysin (hly) gene and 45.9% of the isolates carried aerolysin (aer) gene. The nucleotide blast results of aerolysin gene sequences representative A. hydrophila, A. caviae and A. veronii biovar sobria revealed a high homology of 94%, 95% and 95% for A. hydrophila, A. caviae and A. veronii biovar sobria published sequences, respectively. The protein blast also showed homology (97%, 94% and 96%) as compared with the Genbank database of National Centre for Biotechnology Information (NCBI). The present study demonstrates the high intra/inter-specific diversity within the Aeromonas species and reveals a clear differentiation of strains according to their ecological origin. Increasing presence of haemolysin-producing multiple antibiotic resistant A. hydrophila, A. caviae and A. veronii biovar sobria in food and environment may become a potential human health hazard. In conclusion, the research undertaken has contributed significantly to our knowledge of Aeromonas by providing new information on its distribution, its specific detection by PCR and inter/intra-species relationship

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

Molecular typing of Aeromonas species using RAPD and ERIC-PCR fingerprinting

Two molecular typing methods were used in this study to examine the intra/inter-specific genetic relatedness among the A. hydrophila, A. caviae and A. veronii biovar sobria strains. In the analysis by RAPDPCR and ERIC-PCR, the size for RAPD and ERIC fragments ranged from 0.25 to 10.0 kb with an average number of sixteen and eight bands, respectively. For the inter-species similarity, RAPD could generate 16 major clusters and 36 single isolates at the similarity of 30%. 10 clusters are significant since it grouped the strains according to their own species, however, ERIC-PCR could discriminate the strains into 4 significant clusters and 64 single isolates at the similarity of 50%. Moreover, there was no genetic similarity between food and environmental strains of Aeromonas sp. isolated from different geographical areas as well as from the same geographical area. Eighty five genotypes among the 85 A. hydrophila, A. caviae and A. veronii biovar sobria isolates were generated using RAPD and ERIC-PCR which indicated that the strains were very diverse

Bioactivity studies and chemical constituents of Murraya paniculata (Linn) Jack

Murraya paniculata (Linn) Jack (Orange Jasmine), known as "Kemuning Putih" in Malaysia, has been widely used as food flavor additive in cuisine by local residences. This is due to the strong fragrances of the leaves which make it suitable to be used in Indian and Malay dishes. Besides as a flavoring, leaves, branches, stem barks and roots of the plant are used in folk medicine to treat dysentery and morning sickness. Flowers of the plants are used in cosmetics. Since 1970's, flavonoids and coumarins were isolated from Murraya paniculata, but no further bioactivity has been tested from the isolated compounds. The aim of this paper is to review and update the research related to chemical constituents and bioactivities of Murraya paniculata (L) Jack

In vivo antidiabetic and acute toxicity of spray-dried Vernonia amygdalina water extract

The spray-dried Vernonia amygdalina water extract was evaluated for antidiabetic effect using normoglycaemic, glucose induced hyperglycaemic and streptozotocin induced diabetic mice. This effect was compared with an oral dose of Momordica charantia. Besides, acute toxicity of the extract was also evaluated at concentration 2000 and 5000 mg/kg body weight. The extract was able to reduce blood glucose level in glucose and streptozotocin induced hyperglycaemic mice without causing hypoglycemic effect on fasting normoglycaemic mice. Moreover, mice appeared to be normal and no mortality was observed in the acute toxicity study after treated with up to 5000mg/kg of extract. These results indicated that the spray-dried Vernonia amygdalina water extract was a potential antidiabetic agent which does not induce hypoglycemic and acute toxicity on normal subject

Synthesis and anti-microbial potencies of 1-(2-hydroxyethyl)-3-alkylimidazolium chloride ionic liquids: microbial viabilities at different ionic liquids concentrations

Three 1-(2-hydroxyethyl)-3-alkylimidazolium chloride room temperature ionic liquids (ILs) [2OHimCn][Cl]; (n=0, 1, 4) have been synthesized from the appropriate imidazole precursors and characterized by IR and NMR spectroscopies and elemental analysis. Their anti-microbial activities were investigated using the well-diffusion method. The viabilities of Escherichia coli, Aeromonas hydrophila, Listeria monocytogenes and Salmonella enterica as a function of IL concentrations were studied. The minimal inhibitory concentrations (MICs) and EC50 values for the present ILs were within the concentration range from 60 to 125 mM and 23 to 73 mM. The anti-microbial potencies of the present ILs were compared to a standard antibiotic, gentamicin. The finding affords additional perspective on the level of ILs toxicity to aquatic lifeforms and yet, this characteristic can be readily harnessed to detect microbial growth and activity

Immunomodulatory role of Rhaphidophora korthalsii methanol extract on human peripheral blood mononuclear cell proliferation, cytokine secretion and cytolytic activity.

Rhaphidophora korthalsii methanol extract induce the immunomodulatory effect on human peripheral blood mononuclear cell (PBMC). The present study was performed to investigate the immunomodulatory potential of the extract through different tests: MTT assay, BrdU proliferation assay, Trypan blue direct cell counting, cytokine (IL-2, IL-12 and IFN-γ) ELISA assay and Annexin V cytotoxicity assay. Concanavalin A (Con A) and lipopolysaccharide (LPS) were used as positive control. The observed results from all MTT assay, BrdU proliferation assay and Trypan blue direct cell counting showed that the plant extract stimulated the PBMC at 48 and 72 h where 25 μg/ml was the optimum concentration. On the other hand, the results of the cytokines study showed that 25 μg/ml induced the secretion of IL-2 (433 ± 25 pg/ml) and IFN-γ (7336 ± 131.79 pg/ml) but not IL-12 at 72 h only. The activated PBMC also directed the effector cell (K562) in mix culture to undergo apoptosis (12.96 ± 0.57% of early apoptosis and 10.60 ± 0.21% of late apoptosis) at the ratio of 2/1 of PBMC/K562. The present results indicate that R. korthalsii extract showed evidences of immunomodulating activity which may be potential to use as an immunotherapy agent