1.Decrease in RT-PCR Ct values among SARS-CoV-2 positive samples during the emergence of B.1.617.2 (Delta) variant in Malaysia
Che-Kamaruddin N. ; Teoh B.T. ; Tan K.K. ; Tan J.Y. ; Wong J.E. ; Tiong V. ; Abd-Jamil J. ; Nor&rsquo ; e S.S. ; Khor C.S. ; Johari J. ; Yaacob C.N. ; Zulkifli M.M.S. ; CheMatSeri A. ; Mahfodz N.H. ; Azizan N.S. ; AbuBakar S.
Tropical Biomedicine 2025;42(No. 1):1-9
Reverse transcription-polymerase chain reaction (RT-PCR) cycle threshold (Ct) value in detecting the
Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection is inversely proportionate to
the virus load in the patient’s specimen. These values could be beneficial in the epidemic trajectory
at the population level. The SARS-CoV-2 B.1.617.2 (Delta) variant which emerged in late 2020, caused
an unprecedented exponential increase in SARS-CoV-2 infection cases worldwide. In Malaysia, the
surge in coronavirus disease 2019 (COVID-19) cases and the inclining positivity rate contributed to the
epidemic waves in late May 2021. Sudden surge in cases was suggested to be associated with increased
transmission caused by the emergence of the B.1.617.2 variant. In the present study, Ct value distribution
of the positive COVID-19 samples from 2020 and 2021 was tabulated against SARS-CoV-2 genomic
variants determined from genomic sequencing. A significant decreasing pattern of median Ct values
from overall 2020 and 2021 samples was evident (p<0.01). However, notable variability was observed
in the Ct values between 2020 and 2021, which samples showing lower median Ct values in 2021. The
percentages of SARS-CoV-2 genomic variants B.1.36 and B.1.524 were 31.6% and 68.4%, respectively,
for samples obtained in October and December 2020. Whereas samples obtained in June and July 2021
were 100% of the B.1.617.2 variant. The population neutralizing antibody against SARS-CoV-2 during
the initial peak of B.1.617.2 was low, however, increased during the B.1.617.2 wave. A decreasing trend
in the Ct value distribution from samples tested in our laboratory correlated well with the increasing
weekly COVID-19 cases reported by the Malaysia national data, which was subsequently attributed to
the emergence of B.1.617.2 variant. This study proposes that analyzing Ct value distribution in screened
SARS-CoV-2 samples could reveal population-level transmission dynamics and emerging variants.
Coupled with genomic sequencing, it supports early control strategies against new SARS-CoV-2 strains.
2.Computed Tomographic Study of Occipital Thickness in Ethnic Malays
Yusof MI ; Sadagatullah AN ; Johari J ; Salim AA ; Govindasamy M
Malaysian Orthopaedic Journal 2022;16(No.2):15-22
Introduction: Occipitocervical fusion is performed to
address craniocervical and atlantoaxial instability. A screw of
at least 8mm is needed for biomechanical stability. Occipital
thickness of Malay ethnicity is unknown, and this study
presents the optimal screw placement positions for occiput
screw in this population. This was a retrospective crosssectional study of 100 Malays who underwent computed
tomography (CT) scan for brain assessment. To measure the
occipital bone thickness of Malay ethnicity at the area of
common screw placement for occipitocervical fusion. The
subject’s data was obtained from the institutional database
with consent from the administrations and the patients. None
of the patients had any head and neck pathology.
Materials and methods: The subject’s data was obtained
from the institutional database with consent from the
administrations and the patients. None of the patients had
any head and neck pathology. Computed tomography (CT)
of 100 Malay patients who underwent head and neck CT
were analysed, based on our inclusion and exclusion criteria.
Measurements were taken using a specialised viewer
software where 55 points were measured, followed a grid
with 10mm distance using external occipital protuberance
(EOP) as the reference point.
Results: There were 57 males and 43 females of Malay
ethnicity with a mean age of 36.7 years analysed in this
study. The EOP was the thickest bone of the occiput which
measured 16.15mm. There was an area of at least 8mm
thickness up to 20mm on either side of the EOP, and at level
10mm inferior to the EOP. There is thickness of at least
8mm, up to 30mm inferior to the EOP at the midline. The
males have significantly thicker bone especially along the
midline compared to females.
Conclusion: Screws of at least 8mm can be safely inserted
in the Malay population at 20mm on either side of the EOP
at the level 10mm inferior to the EOP and up to 30mm
inferior to the EOP at the midline.
3.Multiplex sequencing of SARS-Cov-2 genome directly from clinical samples using the Ion Personal Genome Machine (PGM)
Tan, K.K. ; Tiong, V. ; Tan, J.Y. ; Wong, J.E. ; Teoh, B.T. ; Abd-Jamil, J. ; Johari, J. ; Nor&rsquo ; e, S.S. ; Khor, C.S. ; Yaacob, C.N. ; Zulkifli, M.M.S. ; CheMatSeri, A. ; Mahfodz, N.H. ; Azizan, N.S. ; AbuBakar, S.
Tropical Biomedicine 2021;38(No.3):283-288
Various methods have been developed for rapid and high throughput full genome sequencing of SARS-CoV-2. Here, we described a protocol for targeted multiplex full genome sequencing of SARS-CoV-2 genomic RNA directly extracted from human nasopharyngeal swabs using the Ion Personal Genome Machine (PGM). This protocol involves concomitant amplification of 237 gene fragments encompassing the SARS-CoV-2 genome to increase the abundance and yield of viral specific sequencing reads. Five complete and one near-complete genome sequences of SARS-CoV-2 were generated with a single Ion PGM sequencing run. The sequence coverage analysis revealed two amplicons (positions 13 751-13 965 and 23 941-24 106), which consistently gave low sequencing read coverage in all isolates except 4Apr20-64Hu. We analyzed the potential primer binding sites within these low covered regions and noted that the 4Apr20-64-Hu possess C at positions 13 730 and 23 929, whereas the other isolates possess T at these positions. The genome nucleotide variations observed suggest that the naturally occurring variations present in the actively circulating SARS-CoV-2 strains affected the performance of the target enrichment panel of the Ion AmpliSeq™ SARS CoV 2 Research Panel. The possible impact of other genome nucleotide variations warrants further investigation, and an improved version of the Ion AmpliSeq™ SARS CoV 2 Research Panel, hence, should be considered.
4.Isolation and Identification of an Emerging Pathogen, Kocuria marina, from Rattus rattus diardii
Loong, S.K. ; Johari, J. ; Che Mat Seri, N.A.A. ; AbuBakar, S.
Tropical Biomedicine 2016;33(3):589-593
Members of the genus Kocuria are commonly found in the environment and they
are also commensals of the mammalian skin and oropharynx mucosa. Human infections,
although rare, are increasingly being reported recently suggesting that this genus has mostly
been overlooked or misidentified. Its transmission route however, is still not known. We
report here the isolation and identification of a Kocuria marina isolate from the lung of a
wild urban rat (Rattus rattus diardii) caught at a wet market. The isolate was susceptible to
most of the commonly used antibiotics. The finding suggests a possibility that rats could be
a vector for K. marina.


Result Analysis
Print
Save
E-mail