Burkholderia cepacia complex (Bcc) is an emerging nosocomial pathogen, with violet-pigmented strains representing a rare and possibly neglected but clinically important subset. We report a case of a 62-year-old man with end-stage renal disease on dialysis who presented with fever and cough. Blood cultures from central and peripheral lines grew violet-pigmented, non-lactose fermenting colonies on MacConkey agar, later identified as Burkholderia contaminans sequence type 922 (ST922) via a multimodal approach. Initial phenotypic methods (VITEK-2, API20NE and MALDI-ToF) and 16S rDNA sequencing were inconclusive; however, multilocus sequence typing confirmed ST922, a strain previously reported in India and associated with nosocomial outbreaks. The isolate was susceptible to ceftazidime, trimethoprim/sulfamethoxazole, minocycline, and meropenem. The patient responded well to intravenous ceftazidime, with subsequent blood cultures yielding no growth. Notably, antimicrobial susceptibility varied geographically, with some ST922 isolates resistant to third-generation cephalosporins. This case illustrates the diagnostic challenges in Bcc speciation and highlights the value of molecular tools such as MLST. The detection of this strain in Malaysia raises concerns about global dissemination, potentially via contaminated medical devices or water systems. Early recognition of violet-pigmented Bcc in resource-limited settings can facilitate prompt, targeted treatment. This report underscores the need for environmental surveillance and antimicrobial stewardship to prevent spread, while reinforcing Bcc’s ecological adaptability and clinical significance, especially in immunocompromised individuals.

Nipah virus (NiV), a pathogen with pandemic potential, lacks approved treatments or vaccines, highlighting the urgent need for research on immune-targeted antigenic determinants. A significant gap persists in NiV research, as studies on the fusion (F) protein critical for viral entry as well as the B cells epitopes, have primarily focused on computational prediction rather than experimental validation of immunogenic epitopes obtained through immunoinformatics approach. This study focused on the conserved F protein across NiV human isolates and employed an immunoinformatics approach to predict linear B-cell epitopes capable of direct immune activation. Predicted epitopes were screened for antigenicity, toxicity, and allergenicity. Molecular docking analysis was performed to evaluate its binding affinity with B-cell receptors (BCRs). To validate its immunogenicity, the LF6 peptide was synthesized and used in an indirect ELISA to test sera from cohort previously infected with NiV as well as with negative cohort. Epitope LF6 (LISNIEIGFCL) was identified as a strong candidate based on its immunogenic properties. Molecular docking showed favorable binding of LF6 with BCR. ELISA results revealed that one sera from the survival cohort showed positive response which is an IgG antibody response 2-fold higher (0.343) than the cut-off value (0.0171). This study provides the first reported evidence linking computational predictions with functional immune reactivity for a B-cell epitope of NiV. The findings suggest that LF6 has the potential to elicit specific immune responses. However, given the small sample size, further validation in larger cohorts is essential to confirm LF6’s vaccine relevance.

Mosquito-borne arboviral diseases such as dengue and chikungunya have continuously been a major global public health concern. Introducing the intracellular bacterial endosymbiont Wolbachia into mosquito populations has been proven to reduce dengue virus transmission, and its broader efficacy against other arboviruses has also been investigated. Several Wolbachia strains have been successfully propagated in insect cell lines, highlighting the utility of in vitro systems for studying microbial-host interactions under controlled conditions. This study investigated the initial establishment and replication kinetics of a flea-derived Wolbachia strain (wCfe), which was originally isolated from Malaysian Ctenocephalides felis and maintained in the Ixodes scapularis tick-derived cell line (IDE8), and then transferred into an Aedes albopictus-derived cell line (C6/36). The wCfe strain was semi-purified from IDE8 cultures and inoculated into C6/36 cells in 24-well plates. Replication dynamics were monitored by quantitative real-time PCR targeting the Wolbachia pipientis 16S rRNA gene. Following infection, a lag phase was observed at day 0 to 5 days post-infection (d.p.i.), followed by exponential growth from 6 d.p.i. after which Wolbachia levels remained relatively stable until the end of the observation period at 12 d.p.i. Overall, a 25.30-fold increase in Wolbachia density was detected relative to 0 d.p.i. Across replicates, the estimated generation time of wCfe in C6/36 cells ranged from 1.7 to 2.5 days. These results demonstrate successful initial establishment and replication of the flea-derived Wolbachia strain in the Aedes mosquito cell line. However, longer-term in vivo studies will be necessary to determine the persistence of wCfe infection in C6/36 cells and within the mosquito host.

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.

The present study aimed at exploring whether sunlight exposure might account for the relative difference in COVID-19-related morbidity and mortality between tropical and non-tropical countries. A retrospective observational study was designed and data from the World Health Organization weekly COVID-19 epidemiological update was compiled. We examined the total number of confirmed COVID-19 cases per 100 000 population, as well as the total number of COVID-19-related mortalities per 100 000 population. Solar variables data were obtained from the Global Solar Atlas website (https://globalsolaratlas.info/). These data were analyzed to determine the association of sunlight exposure to COVID-19-related morbidity and mortality in tropical and non-tropical countries. Results revealed a statistically significant decrease in the number of confirmed COVID-19 cases per 100 000 population (P<0.001), as well as the number of COVID-19-related mortalities per 100 000 population (P<0.001) between tropical and non-tropical countries. Analyses of sunlight exposure data found that specific photovoltaic power output, global horizontal irradiation, diffuse horizontal irradiation and global tilted irradiation at optimum angle were significantly inversely correlated to COVID-19-related morbidity and mortality. This suggests that stronger sunlight exposure potentially leads to lower COVID-19-related morbidity and mortality. Findings from this study suggest that the relatively low COVID-19-related morbidity and mortality in tropical countries were possibly due to better sunlight exposure that translates into adequate vitamin D status.

Dengue is a mosquito-transmitted infection endemic in tropical and subtropical locations of the world where nearly half of the world’s population resides. The disease may present as mild febrile illness to severe and can even be fatal if untreated. There are four genetically related but antigenically distinct dengue virus (DENV) serotypes. Immune responses to DENV infection are in general protective but under certain conditions, they can also aggravate the disease. The importance of the cellular immune responses and the antibody responses involving IgG and IgM has been well-studied. In contrast, not much has been described on the potential role of hypersensitivity reactions involving IgE in dengue. Several studies have shown elevated levels of IgE in patients with dengue fever, but its involvement in the immune response against the virus and disease is unknown. Activation of mast cells (MCs) and basophils mediated through dengue-specific IgE could result in the release of mediators affecting dengue virus infection. The present review explores the relationships between the induction of IgE in dengue virus infection, and the potential role of MCs and basophils, exploring both protective and pathogenic aspects, including antibody-dependent enhancement (ADE) of infection in dengue.

Nipah virus (NiV), a highly pathogenic henipavirus of the family Paramyxoviridae, which causes fatal encephalitis in 40-70% of affected patients, was first reported in Malaysia over 20 years ago. Pteropid bats are the natural hosts of henipaviruses, and ticks have been proposed as a possible link between bats and mammalian hosts. To investigate this hypothesis, infection of the tick cell line IDE8 with NiV was examined. Presence of viral RNA and antigen in the NiV-infected tick cells was confirmed. Infectious virions were recovered from NiV-infected tick cells and ultrastructural features of NiV were observed by electron microscopy. These results suggest that ticks could support NiV infection, potentially playing a role in transmission.

Introduction: Prematurity-related respiratory disorders are an important public health concern that should be treated efficiently and effectively. Antenatal corticosteroid (ACS) therapy has been recommended to hasten fetal lung maturation in pregnancies at risk but has not been delivered adequately in low to middle-income countries. This study aimed to estimate the treatment effects associated with the use of a single-dose antenatal corticosteroid on the incidence of respiratory-associated morbidity among prematurely delivered neonates. Methods: This was a retrospective cohort study of neonates delivered at 24 to 33 weeks gestation at a tertiary hospital comparing outcomes in those given single-dose ACS with those given no ACS. Association was estimated using logistic and propensity score (PS) analyses, as well as average treatment effect (ATE) and among those treated (ATET). Results: Most neonates (78.11%) received a single dose before delivery (single-dose ACS group) and only a few (21.89%) did not receive any dose (no ACS dose group). The odds ratio of respiratory morbidity in the single-dose ACS group was 0.44 (0.23-0.84) from an adjusted logistic regression model and 0.33 (0.17-0.80) from the PS matching model. The latter model was used to estimate that the average treatment effect from a single-ACS dose on the entire sample was -0.09 (-0.03 to -0.15), while its effect among the actual recipients was -0.08 (-0.02 to -0.15). Conclusion There is a small benefit attributed to the single-dose ACS, reinforcing the need for dose administration and completion. Future studies are recommended to clarify the estimated association and improve on the methodological constraints encountered.
Morbidity ; Propensity Score

Introduction: Despite the growing popularity of utilizing observational studies for determining associations with public health implications, there is limited literature using them for examining and quantifying the effects of exposures or treatments: The study compared traditional regression with scoring approaches in estimating treatment effects considering the noted limitations in the dataset. Methods: We conducted a secondary analysis of previously collected retrospective cohort data derived from maternal-neonatal dyads delivered prematurely in a tertiary hospital. Propensity scores (PS) were estimated using logistic and boosting regression. These scores were implemented into matching, stratification, and weighting models. The estimated measures of effect from traditional regression and PS-adjusted models were compared using certain metrics (i.e., the width of CI, SE, AIC, BIC). Sensitivity analysis was also performed. Results: We included data from 562 patients (123 untreated and 439 treated). Both the estimated scores demonstrated satisfactory fit and reduction in the standardized differences between the groups. However, the logit-estimated scores had better prediction (AUC: 0.71 vs 0.66) and forecasting properties (Brier: 0.15 vs 0.17) than the boosting-estimated scores. All generated statistical models demonstrated a reduction in the occurrence of respiratory morbidity among preterm neonates exposed to a single-dose antenatal corticosteroid (ACS) (ORs ranged from 0.37 to 0.59). The estimated average treatment effects (ATE) and effect among those treated (ATET) from various models suggested a small benefit attributed to the single-dose ACS (ATEs range from -0.09 to -0.41; ATETs range from -0.07 to -0.17). Conclusion PS estimated using logistic regression performed better than those estimated using machine learning strategies. The matching model using the said scores demonstrated better fit and parsimony over conventional and propensity-adjusted models. Future studies are recommended to improve the application of these analytic techniques in real-world data.
Propensity Score ; Machine Learning ; Logistic Models

The Plasmodium knowlesi secreted protein with an altered thrombospondin repeat (PkSPATR) is an important protein that helps in the parasite’s invasion into the host cell. This protein has been regarded as one of the potential vaccine candidates against P. knowlesi infection. This study investigates the genetic diversity and natural selection of PkSPATR gene of P. knowlesi clinical isolates from Malaysia. PCR amplification of the full length PkSPATR gene was performed on 60 blood samples of infected P. knowlesi patients from Peninsular Malaysia and Malaysian Borneo. The amplified PCR products were cloned and sequenced. Sequence analysis of PkSPATR from Malaysia showed higher nucleotide diversity (CDS p: 0.01462) than previously reported Plasmodium vivax PvSPATR (p = 0.0003). PkSPATR from Peninsular Malaysia was observed to have slightly higher diversity (CDS p: 0.01307) than those from Malaysian Borneo (CDS p: 0.01212). Natural selection analysis on PkSPATR indicated significant purifying selection. Multiple amino acid sequence alignment revealed 69 polymorphic sites. The phylogenetic tree and haplotype network did not show any distinct clustering of PkSPATR. The low genetic diversity level, natural selection and absence of clustering implied functional constrains of the PkSPATR protein.