2.Vancomycin-resistant Enterococcus faecium of multi locus sequence type 18 in Malaysia
Poh Leng Weng ; Rukman Awang Hamat ; Yoke Kqueen Cheah ; Norita Zainol ; Muhammad Nazri Aziz
The Medical Journal of Malaysia 2012;67(6):639-640
Vancomycin-resistant Enterococcus faecium (VREF) in
human infections mostly belong to the high-risk, epidemic,
clonal complex-17 (CC17) group. Treatment limitation and
high conjugation frequency makes it dominant in hospitals
worldwide. We investigated positive cultures by Pulse-field
gel electrophoresis (PFGE), multi locus sequence typing
(MLST). DNA of two strains (A2 and C) appeared to be
clonally related by PFGE. Three strains were of ST 18 type
(A1, B and C) and strain A2 is of a new ST 596. This ST 18
type strain found in our study is crucial and is believed to be the first in Malaysia.
3.Characterization and antimicrobial activities of two Streptomyces isolates from soil in the periphery of Universiti Putra Malaysia
Nurul Zarith Mohamad Zin ; Nor Asmara Tasrip ; Mohd Nasir Mohd Desa,* ; Cheah Yoke Kqueen ; Zainul Amiruddin Zakaria ; Rukman Awang Hamat ; Mariana Nor Shamsudin,
Tropical Biomedicine 2011;28(3):651-660
This study was to assess the identification and antimicrobial activities of two
actinomycete isolates. The two isolates designated as B8 and C2, were isolated from a patch
of soil in the peripheral area of Universiti Putra Malaysia by streaking on starch casein agar
after standard serial dilution procedures. Their antimicrobial activities were first evaluated
against eight clinical laboratory strains namely Bacillus sp., Enterococcus sp., Escherichia
coli, Klebsiella sp., Pseudomonas sp., Salmonella sp., Staphylococcus aureus, and
Staphylococcus epidermidis by perpendicular streak method on Mueller Hinton and Tryptic
Soy agar. In both media, a broad-spectrum antibacterial activity was observed for both
isolates, with B8 against all the test bacteria and C2 against five of them (Bacillus sp., E. coli,
Pseudomonas sp., S. aureus and S. epidermidis). Re-assessment against E. coli ATCC 25922
and S. aureus ATCC 25923 strains by similar method showed antibacterial activities by
isolate B8 against both ATTC strains while C2 only against S. aureus ATCC 25923. Streptomyces
griseus ATCC 10137 was included in the later experiment and showed antibacterial activity
against both ATCC strains. Subsequently, the two isolates were identified by PCR/sequencing
techniques and phylogenetic analysis to be Streptomyces species (>93% homology based on
16S rRNA and rpoB genes). Characterization on cultural characteristic and viable count at
different temperatures (37ºC and 28ºC), on different microbiological media (AIA, ISP-2, MHA,
NA, PDA and TSA), were performed. More morphological features were observed on ISP-2 for
both isolates. A higher growth yield was also observed at 28ºC in all media but in comparing
that between the two isolates, isolate B8 outnumbered C2 at all experimental conditions. The
observed variation in cultural traits and growth yield indicate unique properties between the
two antibiotic-producing isolates
4.Comparative aspects of microRNA expression in canine and human cancers
Kabiru SAHABI ; Gayathri T SELVARAJAH ; Rasedee ABDULLAH ; Yoke Kqueen CHEAH ; Geok Chin TAN
Journal of Veterinary Science 2018;19(2):162-171
MicroRNAs (miRNAs) have important roles in all biological pathways in multicellular organisms. Over 1,400 human miRNAs have been identified, and many are conserved among vertebrates and invertebrates. Regulation of miRNA is the most common mode of post-transcriptional gene regulation. The miRNAs that are involved in the initiation and progression of cancers are termed oncomiRs and several of them have been identified in canine and human cancers. Similarly, several miRNAs have been reported to be down-regulated in cancers of the two species. In this review, current information on the expression and roles of miRNAs in oncogenesis and progression of human and canine cancers, as well the roles miRNAs have in cancer stem cell biology, are highlighted. The potential for the use of miRNAs as therapeutic targets in personalized cancer therapy in domestic dogs and their possible application in human cancer counterparts are also discussed.
Animals
;
Biology
;
Carcinogenesis
;
Dogs
;
Gene Expression
;
Humans
;
Invertebrates
;
MicroRNAs
;
Neoplastic Stem Cells
;
Stem Cells
;
Vertebrates
5.pncA Mutations in the Specimens from Extrapulmonary Tuberculosis.
Jaechun LEE ; Yeo Jun YUN ; Cheah Yoke KQUEEN ; Jong Hoo LEE ; Hee Youn KIM ; Young Ree KIM ; Yoon Hoh KOOK ; Keun Hwa LEE
Tuberculosis and Respiratory Diseases 2012;72(6):475-480
BACKGROUND: Pyrazinamide (PZA) is an effective antitubercular drug that becomes toxic to Mycobacterium tuberculosis when converted to pyrazinoic acid by pyrazinamidase (PZase), encoded by mycobacterial pncA. A strong association was noted between the loss of PZase activity and PZA resistance. The causative organisms in extrapulmonary tuberculosis are rarely cultured and isolated. To detect pncA mutations in specimens from extrapulmonary tuberculosis as confirmative diagnosis of mycobacterial infection and alternative susceptibility test to PZA. METHODS: Specimens were collected from clinically proven extrapulmonary tuberculosis. pncA was sequenced and compared with wild-type pncA. RESULTS: pncA from 30 specimens from 23 donors were successfully amplified (56.6% in specimens, 59% in donors). Six mutations in pncA were detected (20.0% in amplified specimens, 26.1% in specimen donors) at nucleotide positions of 169, 248 and 419. The mutation at position 169 results in substitution of aspartic acid for histidine, a possible allelic variation of M. bovis that have intrinsic PZA resistance. The mutation at position 248 changes proline into arginine and that at position 419, arginine into histidine. CONCLUSION: DNA-based diagnosis using pncA may be simultaneously useful for the early diagnosis of mycobacterial infection and the rapid susceptibility to PZA in extrapulmonary tuberculosis. A potential implication of pncA allelic variation at 169 might be suggested as a rapid diagnostic test for M. bovis infection or Bacille Calmette-Guerin (BCG) reactivation.
Amidohydrolases
;
Antitubercular Agents
;
Arginine
;
Aspartic Acid
;
Diagnostic Tests, Routine
;
Early Diagnosis
;
Histidine
;
Humans
;
Mycobacterium bovis
;
Mycobacterium tuberculosis
;
Proline
;
Pyrazinamide
;
Tissue Donors
;
Tuberculosis
6.Tumour Growth Inhibition and Systemic Responses of ΔsopBΔsopDΔpipD Disrupted Salmonella Agona and Salmonella Typhimurium in Mice
Ubaidah Naim Taraq Naem Zia ; Emy Sarah Ng Amar Ng ; Mohd Amirudin Sidik ; Mohamad Fauzi Mohd Idris ; Khoo Chai Hoon ; Sabrina Sukardi ; Yeap Swee Keong ; Cheah Yoke Kqueen
Malaysian Journal of Medicine and Health Sciences 2021;17(No.2):63-71
Introduction: Bacteria had long been known to have tumour-targeting and tumour inhibition capabilities and have
re-emerged into the limelight of cancer research as a possible alternative treatment for solid tumours. Conventional
therapies for solid tumours are either by surgery, chemotherapy, radiotherapy, which are very invasive and non-specific to the tumours and results in various adverse effects on the patients. Bacterial Mediated Tumour Therapy often
utilises attenuated bacteria as therapeutic agents to ensure reduced pathogenicity of the strains. However, this often
results in lower invasiveness towards the tumours itself. In this study, we studied the tumour inhibition capabilities
of Salmonella Pathogenicity Island (SPI) attenuated Salmonella Typhimurium (S. Typhimurium) and Salmonella Agona (S. Agona), specifically with attenuation of sopB, sopD, and pipD genes. Methods: Balb/c mice bearing CT26
tumours were inoculated with S. Typhimurium and S. Agona, both unattenuated and ΔsopBΔsopDΔpipD attenuated
strains. Tumour volumes were monitored daily. Organs and blood were collected for plasma liver enzyme analysis
and histopathology studies on testis, liver, kidneys and brain. Results: The ΔsopBΔsopDΔpipD S. Agona treated
group showed improved inhibition of tumour growth with 51.11% tumour volume reduction compared to unattenuated S. Agona. The ΔsopBΔsopDΔpipD strains have also shown lesser systemic effects as observed in plasma and
histopathological studies) compared to its unattenuated counterparts. Conclusion: The present study showed that
ΔsopBΔsopDΔpipD S. Agona has a great potential to be utilised as tumour therapeutic agent as it exerts lesser systemic effect while having similar tumour inhibition capabilities as the well-studied S. Typhimurium strain.
7.Analysis of Internal Transcribed Spacer (ITS) region and D1/D2 domain coupled with Random Amplified Polymorphic DNA (RAPD) reveal the inter- and intraspecific relationships of Diutina rugosa and Diutina mesorugosa isolated from Malaysian patients
Sri Raja Rajeswari Mahalingam ; Thiba Peremalo ; Priya Madhavan ; Sharina Hamzah ; Leslie Thian Lung Than ; Pei Pei Chong ; Yoke Kqueen Cheah ; Jacinta Santhanam ; Jasper Elvin James
Malaysian Journal of Microbiology 2023;19(no.3):261-273
Aims:
This study was aimed to characterise nine clinical isolates in our culture collection that were categorized as Diutina species based on their molecular genetic profiles. D. rugosa is a species complex comprising four taxa., i.e., D. rugosa sensu stricto, D. pseudorugosa, D. neorugosa and D. mesorugosa. The most commonly used phenotypic identification methods for yeasts often lead to the misidentification of this species complex.
Methodology and results:
The Diutina isolates were received from two local referral hospitals as pure cultures. Species confirmation was performed using conventional phenotypic methods; CHROMagar and RapID Yeast Plus Kit. To study the inter- and intraspecific relationships among the clinical isolates, ITS region, D1/D2 domain and random amplified polymorphic DNA (RAPD) analyses were performed. The results were further validated using the housekeeping gene sequence similarity technique coupled with pairwise sequence alignment. The results from phenotypic methods results were ambiguous and inconclusive. The sequence analyses of ITS regions and D1/D2 domains revealed that the samples consisted of three yeast species; D. rugosa complex: D. rugosa (n=1), D. mesorugosa (n=6), Candida
pararugosa (n=1) and Meyerozyma guilliermondii (n=1). The RAPD analysis with random primers, OPG4, OPG11 and OPA18, demonstrated good banding patterns that could distinguish between the Diutina isolates. The pairwise sequence alignment revealed that the Diutina isolates were genetically similar to D. rugosa ATCC 10571.
Conclusion, significance and impact of study
The molecular methods, D1/D2 domain, ITS1 and ITS4 region, and RAPD analyses have proven helpful for accurately identifying the yeasts, especially closely related species; D. rugosa and D. mesorugosa.