Environmental surface sampling of SARS-CoV-2 in selected hospitals in Malaysia.

COVID-19 has spread rapidly worldwide. The role of fomites in facilitating onward transmission is plausible. This study aimed to determine the presence of viable virus and its persistence on the surfaces of fomites in wards treating COVID-19 patients in Malaysia. This study was conducted in two stages. First, environmental sampling was performed on random days in the intensive care unit (ICU) and general wards. Then, in the second stage, samples were collected serially on alternate days for 7 days in two selected general wards. In Stage 1, a total of 104 samples were collected from the surfaces of highly touched and used areas by patients and healthcare workers. Only three samples were tested positive for SARS-COV-2. In Stage 2, three surface samples were detected positive, but no persistence of the virus was observed. However, none of the SARS-CoV-2 RNA was viable through tissue culture. Overall, the environmental contamination of SARS-CoV-2 was low in this hospital setting. Hospitals' strict infection control and the compliance of patients with wearing masks may have played a role in these findings, suggesting adherence to those measures to reduce occupational exposure of COVID-19 in hospital settings.

Phylogenomic analysis of SARS-CoV-2 from third wave clusters in Malaysia reveals dominant local lineage B.1.524 and persistent spike mutation A701V.

The emergence of a third wave of COVID-19 infection in Malaysia since September 2020 has led to imminent changes in public health prevention and control measures. As high as 96.2% of registered COVID-19 cases and 88.5% of confirmed deaths in Malaysia occurred during this third wave of infection. A phylogenomic study on 258 SARS-CoV-2 full genomes from February 2020-February 2021 has led to the discovery of a novel Malaysian lineage B.1.524. This lineage contains another spike mutation A701V that co-exists with the D614G spike mutation that was predominant in most of the third-wave clusters. The study provides vital genomic insights on the rapid spread of the SARS-CoV-2 variants in Malaysia in conjunction with the presence of a dominant SARS-CoV-2 lineage during the third wave of COVID-19 infection.

Environmental surface sampling of SARS-CoV-2 in selected hospitals in Malaysia

@#COVID-19 has spread rapidly worldwide. The role of fomites in facilitating onward transmission is plausible. This study aimed to determine the presence of viable virus and its persistence on the surfaces of fomites in wards treating COVID-19 patients in Malaysia. This study was conducted in two stages. First, environmental sampling was performed on random days in the intensive care unit (ICU) and general wards. Then, in the second stage, samples were collected serially on alternate days for 7 days in two selected general wards. In Stage 1, a total of 104 samples were collected from the surfaces of highly touched and used areas by patients and healthcare workers. Only three samples were tested positive for SARS-COV-2. In Stage 2, three surface samples were detected positive, but no persistence of the virus was observed. However, none of the SARS-CoV-2 RNA was viable through tissue culture. Overall, the environmental contamination of SARS-CoV-2 was low in this hospital setting. Hospitals’ strict infection control and the compliance of patients with wearing masks may have played a role in these findings, suggesting adherence to those measures to reduce occupational exposure of COVID-19 in hospital settings.

Phylogenomic analysis of SARS-CoV-2 from third wave clusters in Malaysia reveals dominant local lineage B.1.524 and persistent spike mutation A701V

@#The emergence of a third wave of COVID-19 infection in Malaysia since September 2020 has led to imminent changes in public health prevention and control measures. As high as 96.2% of registered COVID-19 cases and 88.5% of confirmed deaths in Malaysia occurred during this third wave of infection. A phylogenomic study on 258 SARS-CoV-2 full genomes from February 2020-February 2021 has led to the discovery of a novel Malaysian lineage B.1.524. This lineage contains another spike mutation A701V that co-exists with the D614G spike mutation that was predominant in most of the third-wave clusters. The study provides vital genomic insights on the rapid spread of the SARS-CoV-2 variants in Malaysia in conjunction with the presence of a dominant SARS-CoV-2 lineage during the third wave of COVID-19 infection.

Viability of dengue virus in culture stocks is efficiently preserved by storage in diluted forms.

Storage of dengue virus (DENV) culture stocks in -80°C is a common laboratory practice to maintain the viability of the virus for long-term usage. However, the efficiency of this method could still be hindered by multiple factors. In our laboratory, we observed a constant and substantial deterioration in the titer of DENV in Vero culture supernatant stored in -80°C. Such incident had badly hampered the laboratory work and prompted an investigation to determine the cause. DENV isolates representing all four serotypes were propagated and the culture supernatants were harvested and stored in aliquots of original stock and 10 fold dilutions (10-1 -10-4). DENV titer in these stocks was determined prior to storage and reassessed on the third and sixth month of storage by focus forming unit assay (FFUA). The result demonstrated a constant preservation of titer ranging from 104 ffu/ml to 105 ffu/ml in the diluted DENV virus culture stocks of 10-1, and 10-2 of DENV1-4, a minor reduction of titer from 103 ffu/ml to 102 ffu/ml at dilution 10-3 for DENV4 only and complete deterioration in undiluted culture stock and lower dilution (10-4) within 6 months of storage in -80°C for all serotypes. It is recommended that propagated DENV in Vero cells are stored in 10 fold dilutions as compared to the original form to preserve the titer for long-term usage.

Viability of dengue virus in culture stocks is efficiently preserved by storage in diluted forms

@#Storage of dengue virus (DENV) culture stocks in -80°C is a common laboratory practice to maintain the viability of the virus for long-term usage. However, the efficiency of this method could still be hindered by multiple factors. In our laboratory, we observed a constant and substantial deterioration in the titer of DENV in Vero culture supernatant stored in -80°C. Such incident had badly hampered the laboratory work and prompted an investigation to determine the cause. DENV isolates representing all four serotypes were propagated and the culture supernatants were harvested and stored in aliquots of original stock and 10 fold dilutions (10-1 -10-4). DENV titer in these stocks was determined prior to storage and reassessed on the third and sixth month of storage by focus forming unit assay (FFUA). The result demonstrated a constant preservation of titer ranging from 104 ffu/ml to 105 ffu/ml in the diluted DENV virus culture stocks of 10-1, and 10-2 of DENV1-4, a minor reduction of titer from 103 ffu/ml to 102 ffu/ml at dilution 10-3 for DENV4 only and complete deterioration in undiluted culture stock and lower dilution (10-4) within 6 months of storage in -80°C for all serotypes. It is recommended that propagated DENV in Vero cells are stored in 10 fold dilutions as compared to the original form to preserve the titer for long-term usage.

Drug resistance mutations among virological failure HIV-1 infected patients in Malaysia.

The determination of HIV drug resistance mutations (DRMs) towards antiretroviral (ARV) drugs among HIV-1 treated patients with virological failure is crucial for further management of the patient. This study aimed to assess the most common genomic mutation and to analyse subtypes among the HIV-1 patients with viral load level > 1,000 copies/mL. A total of 101 virological failure HIV-1 patients from four different regions of Peninsular Malaysia with a viral load measurement facility were included in the study. Majority of patients (89.1%) have at least 1 mutation associated with clinical resistance to either protease inhibitors (PIs), nucleoside reverse transcriptase inhibitors (NRTIs) or nonnucleoside reverse transcriptase inhibitors (NNRTIs). Major resistance mutations among the patients towards NRTIs and NNRTIs were 70.3% and 18.8%, respectively. The most common mutation for NRTIs was M184V while K103N mutation was detected in the majority of patients who were treated with NNRTIs. The most commonly observed mutations for major PI and minor PI seen among the study population were V82A/T and L10V, respectively. In HIV-1 subtype analysis, CRF33_01B was the most predominant HIV-1 subtype in this study group. The vast detection of DRMs in this study emphasized the importance of genotypic resistance test in the management of HIV patients as DRMs can alter patient's susceptibility towards ARV drugs. Further study on larger number of samples is essential for the development of a database on HIV-1 DRMs among patients that experience virological failure in Malaysia.

Drug resistance mutations among virological failure HIV-1 infected patients in Malaysia

The determination of HIV drug resistance mutations (DRMs) towards antiretroviral (ARV) drugs among HIV-1 treated patients with virological failure is crucial for further management of the patient. This study aimed to assess the most common genomic mutation and to analyse subtypes among the HIV-1 patients with viral load level > 1,000 copies/mL. A total of 101 virological failure HIV-1 patients from four different regions of Peninsular Malaysia with a viral load measurement facility were included in the study. Majority of patients (89.1%) have at least 1 mutation associated with clinical resistance to either protease inhibitors (PIs), nucleoside reverse transcriptase inhibitors (NRTIs) or nonnucleoside reverse transcriptase inhibitors (NNRTIs). Major resistance mutations among the patients towards NRTIs and NNRTIs were 70.3% and 18.8%, respectively. The most common mutation for NRTIs was M184V while K103N mutation was detected in the majority of patients who were treated with NNRTIs. The most commonly observed mutations for major PI and minor PI seen among the study population were V82A/T and L10V, respectively. In HIV-1 subtype analysis, CRF33_01B was the most predominant HIV-1 subtype in this study group. The vast detection of DRMs in this study emphasized the importance of genotypic resistance test in the management of HIV patients as DRMs can alter patient’s susceptibility towards ARV drugs. Further study on larger number of samples is essential for the development of a database on HIV-1 DRMs among patients that experience virological failure in Malaysia.