Displaying publications 1 - 20 of 105 in total

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  1. Molecular diversity of the ammonia-oxidizing bacteria community in disused tin-mining ponds located within Kampar, Perak, Malaysia
    Sow SL, Khoo G, Chong LK, Smith TJ, Harrison PL, Ong HK
    World J Microbiol Biotechnol, 2014 Feb;30(2):757-66.
    PMID: 24078113
    Disused tin-mining ponds make up a significant amount of water bodies in Malaysia particularly at the Kinta Valley in the state of Perak where tin-mining activities were the most extensive, and these abundantly available water sources are widely used in the field of aquaculture and agriculture. However, the natural ecology and physicochemical conditions of these ponds, many of which have been altered due to secondary post-mining activities, remains to be explored. As ammonia-oxidizing bacteria (AOB) are directly related to the nutrient cycles of aquatic environments and are useful bioindicators of environmental variations, the focus of this study was to identify AOBs associated with disused tin-mining ponds that have a history of different secondary activities in comparison to ponds which were left untouched and remained as part of the landscape. The 16S rDNA gene was used to detect AOBs in the sediment and water sampled from the three types of disused mining ponds, namely ponds without secondary activity, ponds that were used for lotus cultivation and post-aquaculture ponds. When the varying pond types were compared with the sequence and phylogenetic analysis of the AOB clone libraries, both Nitrosomonas and Nitrosospira-like AOB were detected though Nitrosospira spp. was seen to be the most ubiquitous AOB as it was present in all ponds types. However, AOBs were not detected in the sediments of idle ponds. Based on rarefaction analysis and diversity indices, the disused mining pond with lotus culture indicated the highest richness of AOBs. Canonical correspondence analysis indicated that among the physicochemical properties of the pond sites, TAN and nitrite were shown to be the main factors that influenced the community structure of AOBs in these disused tin-mining ponds.
    Matched MeSH terms: Bacteria/classification*
  2. Diversity of microbiota associated with symptomatic and non-symptomatic bacterial wilt-diseased banana plants determined using 16S rRNA metagenome sequencing
    Suhaimi NSM, Goh SY, Ajam N, Othman RY, Chan KG, Thong KL
    World J Microbiol Biotechnol, 2017 Aug 21;33(9):168.
    PMID: 28828756 DOI: 10.1007/s11274-017-2336-0
    Banana is one of the most important fruits cultivated in Malaysia, and it provides many health benefits. However, bacterial wilt disease, which attacks bananas, inflicts major losses on the banana industry in Malaysia. To understand the complex interactions of the microbiota of bacterial wilt-diseased banana plants, we first determined the bacterial communities residing in the pseudostems of infected (symptomatic) and diseased-free (non-symptomatic) banana plants. We characterized the associated microorganisms using the targeted 16S rRNA metagenomics sequencing on the Illumina MiSeq platform. Taxonomic classifications revealed 17 and nine known bacterial phyla in the tissues of non-symptomatic and symptomatic plants, respectively. Cyanobacteria and Proteobacteria (accounted for more than 99% of the 16S rRNA gene fragments) were the two most abundant phyla in both plants. The five major genera found in both plant samples were Ralstonia, Sphingomonas, Methylobacterium, Flavobacterium, and Pseudomonas. Ralstonia was more abundant in symptomatic plant (59% out of the entire genera) as compared to those in the non-symptomatic plant (only 36%). Our data revealed that 102 bacterial genera were only assigned to the non-symptomatic plant. Overall, this study indicated that more diverse and abundant microbiota were associated with the non-symptomatic bacterial wilt-diseased banana plant as compared to the symptomatic plant. The higher diversity of endophytic microbiota in the non-symptomatic banana plant could be an indication of pathogen suppression which delayed or prevented the disease expression. This comparative study of the microbiota in the two plant conditions might provide caveats for potential biological control strategies.
    Matched MeSH terms: Cyanobacteria/classification; Bacteria/classification*; Proteobacteria/classification
  3. Nitrification of high-strength ammonium landfill leachate with microbial community analysis using fluorescence in situ hybridization (FISH)
    Yusof N, Hassan MA, Yee PL, Tabatabaei M, Othman MR, Mori M, et al.
    Waste Manag Res, 2011 Jun;29(6):602-11.
    PMID: 21447612 DOI: 10.1177/0734242X10397581
    Nitrification of mature sanitary landfill leachate with high-strength of N-NH(4) + (1080-2350 mg L(-1)) was performed in a 10 L continuous nitrification activated sludge reactor. The nitrification system was acclimatized with synthetic leachate during feed batch operation to avoid substrate inhibition before being fed with actual mature leachate. Successful nitrification was achieved with an approximately complete ammonium removal (99%) and 96% of N-NH(4) + conversion to N-NO(-) (3) . The maximum volumetric and specific nitrification rates obtained were 2.56 kg N-NH(4) (+) m(-3) day(-1) and 0.23 g N-NH(4) ( +) g(-1) volatile suspended solid (VSS) day(-1), respectively, at hydraulic retention time (HRT) of 12.7 h and solid retention time of 50 days. Incomplete nitrification was encountered when operating at a higher nitrogen loading rate of 3.14 kg N-NH(4) (+) m(-3) day(-1). The substrate overloading and nitrifiers competition with heterotrophs were believed to trigger the incomplete nitrification. Fluorescence in situ hybridization (FISH) results supported the syntrophic association between the ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria. FISH results also revealed the heterotrophs as the dominant and disintegration of some AOB cell aggregates into single cells which further supported the incomplete nitrification phenomenon.
    Matched MeSH terms: Bacteria/classification
  4. Fulltext Epidemiology and clinical characteristics of hospitalized patients with pandemic influenza A (H1N1) 2009 infections: the effects of bacterial coinfection
    Dhanoa A, Fang NC, Hassan SS, Kaniappan P, Rajasekaram G
    Virol J, 2011;8:501.
    PMID: 22050645 DOI: 10.1186/1743-422X-8-501
    Numerous reports have described the epidemiological and clinical characteristics of influenza A (H1N1) 2009 infected patients. However, data on the effects of bacterial coinfection on these patients are very scarce. Therefore, this study explores the impact of bacterial coinfection on the clinical and laboratory parameters amongst H1N1 hospitalized patients.

    Study site: Hospital Sultanah Aminah Johor Bahru
    Matched MeSH terms: Bacteria/classification
  5. Microbial biodiversity in the throats of pulmonary tuberculosis patients and tuberculin skin test (TST) positive and negative healthy individuals in Malaysia
    Semail N, Suraiya S, Calero R, Mirabal M, Carrillo H, Ezzeddin Kamil MH, et al.
    Tuberculosis (Edinb), 2020 09;124:101965.
    PMID: 32692651 DOI: 10.1016/j.tube.2020.101965
    The purpose of this study was to investigate the composition of throat microbiota in pulmonary tuberculosis patients (PTB) in comparison to healthy tuberculin skin test positive (TSTp) and negative (TSTn) individuals. Throat swabs samples were collected, and the microbiota was characterized. Richer operational taxonomic units (OTUs) were present in PTB group, compared to TSTp and TSTn. Regarding alpha diversity analysis there was a higher community diversity in TSTn compared to TSTp. Beta diversity analysis showed different species composition in TSTp compared to TSTn and PTB. There was higher presence of Firmicutes in PTB and TSTn compared to TSTp group at phylum level. At the genus level, Leuconostoc and Enterococcus were higher in TSTn compared to TSTp and Pediococcus, Chryseobacterium, Bifidobacterium, Butyrivibrio, and Bulleidia were higher in PTB compared to TSTn. Streptococcus was higher in TSTn compared to PTB and Lactobacillus in PTB compared to TSTp. At species level, Streptococcus sobrinus and Bulleidia moorei were higher in PTB compared to TSTn individuals, while Lactobacillus salivarius was higher in PTB compared to TSTp. The differences in the microbiome composition could influence the resistance/susceptibility to Mtb infection.
    Matched MeSH terms: Bacteria/classification
  6. Fulltext Bacterial constituents of indoor air in a high throughput building in the tropics
    Li TC, Ambu S, Mohandas K, Wah MJ, Sulaiman LH, Murgaiyah M
    Trop Biomed, 2014 Sep;31(3):540-56.
    PMID: 25382482 MyJurnal
    Airborne bacteria are significant biotic constituents of bioaerosol. Bacteria at high concentrations in the air can compromise indoor air quality (IAQ) and result in many diseases. In tropical environments like Malaysia that extensively utilize air-conditioning systems, this is particularly significant due to continuous recirculation of indoor air and the potential implications for human health. Currently, there is a lack of knowledge regarding the impact of airborne bacteria on IAQ in Malaysia. This study was prompted by a need for reliable baseline data on airborne bacteria in the indoor environment of tropical equatorial Malaysia, that may be used as a reference for further investigations on the potential role played by airborne bacteria as an agent of disease in this region. It was further necessitated due to the threat of bioterrorism with the potentiality of release of exotic pathogenic microorganisms into indoor or outdoor air. Before scientists can detect the latter, a gauge of the common microorganisms in indoor (as well as outdoor) air needs to be ascertained, hence the expediency of this study. Bacterial counts from the broad-based and targeted study were generally in the order of 10(2) colony-forming units (CFU) per m(3) of air. The most prevalent airborne bacteria found in the broad-based study that encompassed all five levels of the building were Gram-positive cocci (67.73%), followed by Gram-positive rods (24.26%) and Gram-negative rods (7.10%). Gram-negative cocci were rarely detected (0.71%). Amongst the genera identified, Kytococcus sp., Micrococcus sp., Staphylococcus sp., Leifsonia sp., Bacillus sp. and Corynebacterium sp. predominated in indoor air. The most dominant bacterial species were Kytococcus sedentarius, Staphylococcus epidermidis and Micrococcus luteus. The opportunistic and nosocomial pathogen, Stenotrophomonas maltophilia was also discovered at a high percentage in the cafeteria. The bacteria isolated in this study have been increasingly documented to cause opportunistic infections in immuno-compromised patients, sometimes with fatal outcomes. Furthermore, some of them are becoming increasingly resistant to antibiotics. Hence, we propose that indoor reservoirs of these bacteria and their associated clinical and more subtle health effects, if any, be investigated further.
    Matched MeSH terms: Bacteria/classification*
  7. Fulltext Back to basic: bio-burden on hands of health care personnel in tertiary teaching hospital in Malaysia
    Wong JL, Siti Azrin AH, Narizan MI, Norliah Y, Noraida M, Amanina A, et al.
    Trop Biomed, 2014 Sep;31(3):534-9.
    PMID: 25382481 MyJurnal
    Hands of Health Care Personnel (HCP) are one of the most common vehicles for the transmission of infection. Microorganisms can survive well on the hands of HCP for a certain duration. Therefore, the purpose of this study is to bring awareness to HCP that their hands can actually be contaminated with many microorganisms. These microbes on the hands of HCP can potentially infect their patients if they do not comply with the proper hand hygiene practice. This cross-sectional study was conducted at a randomly selected Intensive Care Unit (ICU) and general ward in a hospital. Twenty five HCP from each ward were randomly selected and their hands were imprinted on blood culture plates. Microorganism growth were quantified and identified. Data were analyzed and presented as descriptive analysis. One hundred blood agar plates were processed and analyzed. Majority (71%) of the samples had more than 50 colony-forming units (CFU) and only 17% of the samples had less than 25 CFU. Microorganisms identified include Staphylococcus spp., Acinetobacter spp., Enterobacteriaceae, Pseudomonas spp., Moraxella, Delftiaacidovorans and fungi. All isolated microorganisms were antibiotic sensitive strain. This study showed that the hands of HCP were contaminated with many microorganisms. Therefore, it is imperative that HCP must practice proper hand hygiene when taking care of their patients in the wards.
    Matched MeSH terms: Bacteria/classification
  8. Fulltext An eight-year review of blood culture and susceptibility among sepsis cases in an emergency department in Northeastern Malaysia
    Hashairi F, Hasan H, Azlan K, Deris ZZ
    Trop Biomed, 2011 Dec;28(3):599-605.
    PMID: 22433889 MyJurnal
    An understanding of common pathogens and their antibiotic sensitivity patterns is critical for proper management of sepsis in Emergency Department (ED). The goal of the study was to identify common organisms isolated from blood cultures of patients attended to ED and their antimicrobial susceptibility. Beginning from 2002, all cases of positive blood culture collected by the ED, Hospital Universiti Sains Malaysia (HUSM) were recorded and analysed. Over the period of eight years, we documented 995 cases of positive blood cultures. Of these samples, 549 (55.2%) were Gram-negative bacteria; 419 (42.1%) were Gram-positive bacteria; 10 (1.0%) were anaerobic organisms; 10 (1.0%) were fungus; and 7 (0.7%) cases were mixed organisms. Gram-negative bacteria were observed to develop more resistance to antimicrobial agents, especially those commonly used in an outpatient setting with less than 80% sensitivity to ampicillin, cotrimoxazole and ciprofloxacin. By contrast, there has been no marked change in the sensitivity trends of Gram-positive bacteria over the same period. In conclusion, ED physicians are more equipped to initiate empirical antimicrobial therapy especially when dealing with possibility of Gram-negative sepsis.
    Study site: Emergency department, Hospital Universiti Sains Malaysia (HUSM), Kelantan, Malaysia
    Matched MeSH terms: Bacteria/classification
  9. Fulltext Prospective surveillance of nosocomial device-associated bacteremia in three adult intensive units in Malaysia
    Gopal Katherason S, Naing L, Jaalam K, Kamarul Iman Musa K, Nik Abdullah NM, Aiyar S, et al.
    Trop Biomed, 2010 Aug;27(2):308-16.
    PMID: 20962730 MyJurnal
    Nosocomial blood stream infection (or nosocomial bacteremia) is a common problem in hospitals worldwide, including Malaysia. A three-year prospective cohort study (October 2003-March 2007) of the incidences, risk factors, and patterns of the microorganisms causing bacteremia was conducted using a validated surveillance form in three intensive care units (ICUs) in Malaysia. Center for Disease Control criteria were used to diagnose bacteremia. Patients were monitored from admission until the end point of study, which was the first detection of bacteremia in the blood in each patient. The frequency of occurrence of bacteremia with clinical symptoms was 10.7% (n=23). Bacteremia was observed to occur within a mean length of stay of 10 days in ICU. The rate of device-related infection was 10.4% per device utilization days with a device utilization rate of 95.9%/1000 patient days. The total number of patient days was 2309 and the period of device utilization was 2211 days. The common bacteria detected were extended-spectrum beta-lactamases (ESBLs) Klebsiella pneumoniae (n=6); Pseudomonas aeruginosa (n=6); Acinetobacter species (n=5); Methicillin-resistant Staphylococcus aureus (MRSA)(n=3); and (non- ESBL) Klebsiella pneumoniae (n=2). Multivariable analysis using Cox Proportional Hazard Model showed that the predictors for developing bacteremia were cancer, MRSA carriage, duration of central venous catheter (CVC) infusion, frequency change of CVC, and the administration of hydrocortisone drugs. These results indicate that a combination of nursing and medical interventions as well as patients' severity of illness could lead to bacteremia in ICU. Strategic implementation of quality assurance measures in ICUs could help to control this problem.
    Matched MeSH terms: Bacteria/classification
  10. Fulltext Detection of protozoan and bacterial pathogens of public health importance in faeces of Corvus spp. (large-billed crow)
    Lee HY, Stephen A, Sushela D, Mala M
    Trop Biomed, 2008 Aug;25(2):134-9.
    PMID: 18948884
    Parasites and bacteria are reported in the faeces of birds in the current study. Fresh faecal samples of the large-billed crow (Corvus spp.) were collected from the study site at Bangsar, an urban setting in Kuala Lumpur, Malaysia. These samples were transported to laboratory and analysed for parasites and bacteria. Pre-prepared XLD agar plates were used for culturing the bacteria in the laboratory. Using the API 20ETM Test Strips, 9 different species of bacteria were identified belonging to the family Enterobacteriacea. They were Citrobacter freundii, Enterobacter cloacae, Proteus mirabilis, Klebsiella pneumoniae, Kluyvera ascorbata, Salmonella arizonae, Salmonella typhi, Shigella flexneri and Shigella sonnei. The protozoan parasites detected include Cryptosporidium spp., Cyclospora spp., Blastocystis spp., and Capillaria hepatica and Ascaris lumbricoidus ova. Environmental air samples collected on agar plates using an air sampler in the area only produced fungal colonies. Some of these pathogens found in the crows are of zoonotic importance, especially Cryptosporidium, Blastocystis, Cyclopsora, Salmonella, Shigella and Kluyvera. The finding of Kluyvera spp. in crows in our current study highlights its zoonotic potential in an urban setting.
    Matched MeSH terms: Bacteria/classification
  11. Fulltext Bacteria fauna from the house fly, Musca domestica (L.)
    Nazni WA, Seleena B, Lee HL, Jeffery J, T Rogayah TA, Sofian MA
    Trop Biomed, 2005 Dec;22(2):225-31.
    PMID: 16883292 MyJurnal
    The house fly, Musca domestica has long been considered a potential agent for disease transmission ever since its existence. The general truth of this assertion remains undisputed till the present day in spite of increasing awareness toward an improved sanitation and better hygiene. The habitual movement of house fly from filthy substrata such as human faeces, animal excreta, carcasses, garbage, etc. makes them ideal candidates for disease transmission such as cholera, shigellosis, salmonellosis and others when settling on food. Fly as a potential mechanical vector of pathogenic bacteria was elucidated in this study by examining flies from various breeding sites such as food courts, dumping ground, food processing areas and poultry farm in Peninsular Malaysia. The flies were baited with 10% sugar solution on a glass slide in the field. All materials used for collection of samples were sterile. Bacteria from fly sample were isolated using the normal isolation technique. Bacillus sp., Coccobacillus sp., Staphylococcus sp., Microccus sp., Streptococcus sp., Acinetobacter sp., Enterobacter sp., Proteus sp., Escherichia sp., Klebsiella sp. and yeast cells were isolated from feaces, vomitus, external surfaces and internal organs of house fly. Newly emerged house fly did not harbour any bacteria.
    Matched MeSH terms: Bacteria/classification
  12. Fulltext In vitro screening of five local medicinal plants for antibacterial activity using disc diffusion method
    Zaidan MR, Noor Rain A, Badrul AR, Adlin A, Norazah A, Zakiah I
    Trop Biomed, 2005 Dec;22(2):165-70.
    PMID: 16883283 MyJurnal
    Medicinal plants have many traditional claims including the treatment of ailments of infectious origin. In the evaluation of traditional claims, scientific research is important. The objective of the study was to determine the presence of antibacterial activity in the crude extracts of some of the commonly used medicinal plants in Malaysia, Andrographis paniculata, Vitex negundo, Morinda citrifolia, Piper sarmentosum, and Centella asiatica. In this preliminary investigation, the leaves were used and the crude extracts were subjected to screening against five strains of bacteria species, Methicillin Resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli, using standard protocol of Disc Diffusion Method (DDM). The antibacterial activities were assessed by the presence or absence of inhibition zones and MIC values. M. citrifolia, P. sarmentosum and C. asiatica methanol extract and A. paniculata (water extract) have potential antibacterial activities to both gram positive S. aureus and Methicillin Resistant S. aureus (MRSA). None of the five plant extracts tested showed antibacterial activities to gram negative E. coli and K. pneumoniae, except for A. paniculata and P. sarmentosum which showed activity towards P. aeruginosa. A. paniculata being the most potent at MIC of 2 g/disc. This finding forms a basis for further studies on screening of local medicinal plant extracts for antibacteria properties.
    Matched MeSH terms: Gram-Negative Bacteria/classification
  13. Bacterial profiling of head lice isolated from the Orang Asli: A first report in Malaysia
    Abd Majid MA, Khoo JJ, Lim FS, Khor CS, Loong SK, Low VL, et al.
    Trop Biomed, 2020 Dec 01;37(4):884-895.
    PMID: 33612742 DOI: 10.47665/tb.37.4.884
    This study was carried out to determine from bacterial profiling to the bacterial profiles of head lice among the Orang Asli communities. The head lice were collected from Orang Asli community volunteers. The surface sterilized head lice pools were subjected to genomic DNA extraction while next generation sequencing of the 16S rRNA gene was performed using the Illumina MiSeq platform. Six female and three male head lice identified as Pediculus humanus capitis were collected. A total of 111 368 number of NGS sequencing reads were recorded while another 223 bacterial taxa sequences were obtained. Symbiotic bacteria showed the highest number of reads, with Arsenophonus and Rhodococcus sequences being the most abundant genera in the female and male samples, respectively. The female head lice contained a more distinct microbial diversity. Amongst the pathogenic bacterial species sequences noted were the methicillin-resistant Staphylococcus aureus, Streptobacillus moniliformis, Haemophilus influenzae, Bordetella pertussis and Acinetobacter baumannii. The 16S rRNA genome sequencing revealed a number of rare and pathogenic bacterial species within the head lice of the Orang Asli. The socio-economic practices of the community which involved forest foraging and hunting, and their poor living conditions potentially facilitated the transmission of zoonotic bacterial pathogens, including those found within the head lice. Hence, there is the possibility that the head lice could serve as vectors for the transmission of pathogenic bacteria. This study highlighted the diverse microbial community found within the head lice's gut of the Orang Asli, with the detection of multiple rare and pathogenic bacteria capable of causing severe infections.
    Matched MeSH terms: Bacteria/classification*
  14. Detection of periodontal microorganisms in coronary atheromatous plaque specimens of myocardial infarction patients: A systematic review and meta-analysis
    Joshi C, Bapat R, Anderson W, Dawson D, Hijazi K, Cherukara G
    Trends Cardiovasc Med, 2021 01;31(1):69-82.
    PMID: 31983534 DOI: 10.1016/j.tcm.2019.12.005
    BACKGROUND: Microbial translocation from inflamed periodontal pockets into coronary atheroma via systemic circulation is one of the proposed pathways that links periodontitis and myocardial infarction (MI). The purpose of this systematic review is to determine the reported prevalence of periodontal microorganisms in coronary atheroma and/or aspirated clot samples collected from MI patients with periodontal disease.

    METHODOLOGY: The "Preferred Reporting Items for Systematic Reviews and Meta-Analyses" (PRISMA) guidelines were followed. Six databases were systematically searched using Medical Subject Headings/Index and Entree terms. After a thorough screening, fourteen publications spanning over ten years (2007-2017) were eligible for this systematic review and meta-analysis.

    RESULTS: Out of 14 included studies, 12 reported presence of periodontal bacterial DNA in coronary atherosclerotic plaque specimens. Overall, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans were the most frequently detected periodontal bacterial species. Meta-analysis revealed that the prevalence of P. gingivalis was significantly higher than A. actinomycetemcomitans in coronary atheromatous plaque samples. Apart from periodontal microbes, DNA from a variety of other microbes e.g. Pseudomonas fluorescens, Streptococcus species, Chlamydia pneumoniae were also recovered from the collected samples.

    CONCLUSION: Consistent detection of periodontal bacterial DNA in coronary atheroma suggests their systemic dissemination from periodontal sites. It should further be investigated whether they are merely bystanders or induce any structural changes within coronary arterial walls.

    Matched MeSH terms: Bacteria/classification
  15. Fulltext The bacterial aetiology of adult community-acquired pneumonia in Asia: a systematic review
    Peto L, Nadjm B, Horby P, Ngan TT, van Doorn R, Van Kinh N, et al.
    Trans R Soc Trop Med Hyg, 2014 Jun;108(6):326-37.
    PMID: 24781376 DOI: 10.1093/trstmh/tru058
    Community-acquired pneumonia (CAP) is a major cause of adult mortality in Asia. Appropriate empirical treatment depends on knowledge of the pathogens commonly responsible. However, assessing the aetiological significance of identified organisms is often difficult, particularly with sputum isolates that might represent contamination with oropharyngeal flora.
    Matched MeSH terms: Bacteria/classification
  16. Bacterial communities in Haemaphysalis, Dermacentor and Amblyomma ticks collected from wild boar of an Orang Asli Community in Malaysia
    Lim FS, Khoo JJ, Tan KK, Zainal N, Loong SK, Khor CS, et al.
    Ticks Tick Borne Dis, 2020 03;11(2):101352.
    PMID: 31866439 DOI: 10.1016/j.ttbdis.2019.101352
    Ticks are hematophagous vectors of arthropod-borne disease agents globally. In Malaysia, despite seroprevalence studies indicating the presence of tick-borne diseases among the indigenous people, the etiological agents of these diseases are still unclear. These indigenous people, also known as the Orang Asli, still live in forested areas with frequent contact with wildlife. Wild boar are ubiquitously found in the forested areas where the Orang Asli communities are located and are commonly hunted as a food supplement. In this study, we aim to determine the tick species parasitizing wild boar from an Orang Asli community, and explore the tick-associated bacterial communities using 16 s rRNA amplicon sequencing on the Ion Torrent PGM™ platform. A total of 72 ticks were collected from three wild boar and were morphologically identified as Haemaphysalis hystricis (n = 32), Dermacentor compactus (n = 15), Amblyomma testudinarium (n = 13), Dermacentor steini (n = 10) and Dermacentor atrosignatus (n = 2). Across all tick samples, 910 bacterial taxa were identified. Although the bacterial communities were not significantly distinct between tick species in beta-diversity analyses, Coxiella, Rickettsia and Francisella were detected at high relative abundance in H. hystricis, D. compactus and D. steini respectively. Many other bacterial genera, including those that have been described in many different tick species, were also identified, including Pseudomonas, Acinetobacter, Staphylococcus and Corynebacterium. Beta-diversity analyses also showed that the bacterial communities were separated based on the animal host from which the ticks were collected from, suggesting that the bacterial communities here may be influenced by the animal skin microflora, host blood or the environment. PCR screening confirmed the presence of Rickettsia sp. related to spotted fever group Rickettsia in some of the ticks. This study provides baseline knowledge of the microbiome of H. hystricis, D. atrosignatus, D. compactus, D. steini and A. testudinarium parasitizing wild boar in this region. The information gained in this study provides the basis to target our efforts in H. hystricis, D. compactus and D. steini for the future investigation of vector competence and the zoonotic potential for the Coxiella, Rickettsia and Francisella detected here, as well as their implications for the risks of tick-borne diseases among the Orang Asli communities.
    Matched MeSH terms: Bacteria/classification
  17. Increasing atmospheric deposition nitrogen and ammonium reduced microbial activity and changed the bacterial community composition of red paddy soil
    Zhou F, Cui J, Zhou J, Yang J, Li Y, Leng Q, et al.
    Sci Total Environ, 2018 Aug 15;633:776-784.
    PMID: 29602116 DOI: 10.1016/j.scitotenv.2018.03.217
    Atmospheric deposition nitrogen (ADN) increases the N content in soil and subsequently impacts microbial activity of soil. However, the effects of ADN on paddy soil microbial activity have not been well characterized. In this study, we studied how red paddy soil microbial activity responses to different contents of ADN through a 10-months ADN simulation on well managed pot experiments. Results showed that all tested contents of ADN fluxes (27, 55, and 82kgNha-1 when its ratio of NH4+/NO3--N (RN) was 2:1) enhanced the soil enzyme activity and microbial biomass carbon and nitrogen and 27kgNha-1 ADN had maximum effects while comparing with the fertilizer treatment. Generally, increasing of both ADN flux and RN (1:2, 1:1 and 2:1 with the ADN flux of 55kgNha-1) had similar reduced effects on microbial activity. Furthermore, both ADN flux and RN significantly reduced soil bacterial alpha diversity (p<0.05) and altered bacterial community structure (e.g., the relative abundances of genera Dyella and Rhodoblastus affiliated to Proteobacteria increased). Redundancy analysis demonstrated that ADN flux and RN were the main drivers in shaping paddy soil bacteria community. Overall, the results have indicated that increasing ADN flux and ammonium reduced soil microbial activity and changed the soil bacterial community. The finding highlights how paddy soil microbial community response to ADN and provides information for N management in paddy soil.
    Matched MeSH terms: Bacteria/classification
  18. Metagenomics profiling for assessing microbial diversity in both active and closed landfills
    Zainun MY, Simarani K
    Sci Total Environ, 2018 Mar;616-617:269-278.
    PMID: 29117585 DOI: 10.1016/j.scitotenv.2017.10.266
    The municipal landfill is an example of human-made environment that harbours some complex diversity of microorganism communities. To evaluate this complexity, the structures of bacterial communities in active (operational) and closed (non-operational) landfills in Malaysia were analysed with culture independent metagenomics approaches. Several points of soil samples were collected from 0 to 20cm depth and were subjected to physicochemical test, such as temperature, pH, and moisture content. In addition, the heavy metal contamination was determined by using ICPMS. The bacterial enumeration was examined on nutrient agar (NA) plates aerobically at 30°C. The soil DNA was extracted, purified and amplified prior to sequence the 16S rRNA gene for statistical and bioinformatics analyses. As a result, the average of bacteria for the closed landfill was higher compared to that for the active landfill at 9.16×107 and 1.50×107, respectively. The higher bacterial OTUs sequenced was also recorded in closed landfills compared to active landfill i.e. 6625 and 4552 OTUs respectively. The data from both landfills showed that the predominant phyla belonged to Proteobacteria (55.7%). On average, Bacteroidetes was the second highest phylum followed by Firmicutes for the active landfill. While the phyla for communities in closed landfill were dominated by phyla from Acidobacteria and Actinobacteria. There was also Euryarchaeota (Archaea) which became a minor phylum that was detected in active landfill, but almost completely absent in closed landfill. As such, the composition of bacterial communities suggests some variances between the bacterial communities found in active and closed landfills. Thus, this study offers new clues pertaining to bacterial diversity pattern between the varied types of landfills studied.
    Matched MeSH terms: Bacteria/classification
  19. Bacterial diversity associated with empty oil palm fruit bunch compost as revealed by cultivation-independent analyses of PCR-amplified 16S rRNA genes
    Liew PW, Jong BC, Goh CM, Ahmad M
    J Gen Appl Microbiol, 2009 Jun;55(3):233-40.
    PMID: 19590151
    Matched MeSH terms: Bacteria/classification*
  20. In vitro fermentation of commercial α-gluco-oligosaccharide by faecal microbiota from lean and obese human subjects
    Sarbini SR, Kolida S, Gibson GR, Rastall RA
    Br J Nutr, 2013 Jun;109(11):1980-9.
    PMID: 23116939 DOI: 10.1017/S0007114512004205
    The fermentation selectivity of a commercial source of a-gluco-oligosaccharides (BioEcolians; Solabia) was investigated in vitro. Fermentation by faecal bacteria from four lean and four obese healthy adults was determined in anaerobic, pH-controlled faecal batch cultures. Inulin was used as a positive prebiotic control. Samples were obtained at 0, 10, 24 and 36 h for bacterial enumeration by fluorescent in situ hybridisation and SCFA analyses. Gas production during fermentation was investigated in non-pH-controlled batch cultures. a-Gluco-oligosaccharides significantly increased the Bifidobacterium sp. population compared with the control. Other bacterial groups enumerated were unaffected with the exception of an increase in the Bacteroides–Prevotella group and a decrease in Faecalibacterium prausnitzii on both a-gluco-oligosaccharides and inulin compared with baseline. An increase in acetate and propionate was seen on both substrates. The fermentation of a-gluco-oligosaccharides produced less total gas at a more gradual rate of production than inulin. Generally, substrates fermented with the obese microbiota produced similar results to the lean fermentation regarding bacteriology and metabolic activity. No significant difference at baseline (0 h) was detected between the lean and obese individuals in any of the faecal bacterial groups studied.
    Matched MeSH terms: Bacteria/classification
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