Gene–diet interactions on metabolic disease-related outcomes in Southeast Asian populations: a systematic review

Diabetes and obesity are chronic diseases that are a burden to low- and middle-income countries. We conducted this systematic review to understand gene–diet interactions affecting the Southeast Asian population’s risk of obesity and diabetes. The literature search was performed on Google Scholar and MEDLINE (PubMed) search engines independently by four reviewers who evaluated the eligibility of articles based on inclusion criteria. Out of 19,031 articles, 20 articles examining gene–diet interactions on obesity and/or diabetes-related traits met the inclusion criteria. Three (Malaysia, Indonesia, and Singapore) out of eleven Association of Southeast Asian Nations (ASEAN) countries have conducted studies on gene–diet interactions on obesity and diabetes. From the 20 selected articles, the most common interactions were observed between macronutrients and genetic risk score (GRS) on metabolic disease-related traits in the Malay, Chinese, and Indian ethnicities. Overall, we identified 29 significant gene–diet interactions in the Southeast Asian population. The results of this systematic review demonstrate ethnic-specific gene–nutrient interactions on metabolic-disease-related traits in the Southeast Asian population. This is the first systematic review to explore gene–diet interactions on obesity and diabetes in the Southeast Asian population and further research using larger sample sizes is required for better understanding and framing nutrigenetic approaches for personalized nutrition

Pneumococcal conjugate vaccine implementation in middle-income countries

Since 2000, the widespread adoption of pneumococcal conjugate vaccines (PCVs) has had a major impact in the prevention of pneumonia. Limited access to international financial support means some middle-income countries (MICs) are trailing in the widespread use of PCVs. We review the status of PCV implementation, and discuss any needs and gaps related to low levels of PCV implementation in MICs, with analysis of possible solutions to strengthen the PCV implementation process in MICs

Development and Evaluation of a Rapid Molecular Assay and a Mask Sampling Method Enabling the Study of Tuberculosis Transmission

Mycobacterium tuberculosis (Mtb) is transmitted in small aerosol droplets expectorated by individuals with active pulmonary tuberculosis (TB). There is still no established method for sampling these infectious aerosols and measuring the bacterial concentration in them. Little is known about the relationship between tuberculous aerosol output and infectiousness of TB cases; medical practice currently relies on the acid-fast smear status to gauge this and determine when it is safe to discharge TB patients. This study involved the development and evaluation of a rapid molecular assay and a mask sampling approach to increase our knowledge relating to TB transmission. A molecular assay targeting the mycobacterial 16S rDNA and differentiating Mtb complex from non-tuberculous mycobacteria was developed to facilitate recruitment of TB patients for the mask sampling study. Although the assay did not achieve this outcome during the study, we demonstrated its clinical utility on mycobacterial isolates. A second molecular assay targeting the Mtb global lineagedefining and locally prevalent RD750 polymorphism was also developed for preliminary genotyping of Mtb strains to assess for potential recent transmission events. Both the 16S and RD assays were performed in single thermocycler runs but in separate reaction tubes and utilised a combination of TaqMan and SYBR Green technologies to simultaneously differentiate two products. The 16S-RD assay shows promising potential for direct specimen analysis and detection of mixed infections. A novel method of mask aerosol sampling coupled to a mycobacteriophage amplification assay developed in this study was able to detect and to some extent quantify the amount of respiratory-borne Mtb. This approach could potentially be more reliable than smear microscopy in assessing TB infectivity. With further optimisation and improvement, both the 16S-RD assay and the mask sampling method have potential to facilitate better understanding of TB transmission and subsequently contribute to public and clinical management of this disease

Investigation of Upper Respiratory Carriage of Bacterial Pathogens among University Students in Kampar, Malaysia

The carriage of bacterial pathogens in the human upper respiratory tract (URT) is associated with a risk of invasive respiratory tract infections, but the related epidemiological information on this at the population level is scarce in Malaysia. This study aimed to investigate the URT carriage of Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa among 100 university students by nasal and oropharyngeal swabbing. The presence of S. aureus, K. pneumoniae and P. aeruginosa was assessed via swab culture on selective media and PCR on the resulting isolates. For S. pneumoniae, H. influenzae and N. meningitidis, their presence was assessed via multiplex PCR on the total DNA extracts from chocolate agar cultures. The carriage prevalence of H. influenzae, S. aureus, S. pneumoniae, K. pneumoniae, N. meningitidis and P. aeruginosa among the subjects was 36%, 27%, 15%, 11%, 5% and 1%, respectively, by these approaches. Their carriage was significantly higher in males compared to females overall. The S. aureus, K. pneumoniae and P. aeruginosa isolates were also screened by the Kirby-Bauer assay, in which 51.6% of S. aureus were penicillin-resistant. The outcomes from carriage studies are expected to contribute to informing infectious disease control policies and guidelines

Serotype distribution of invasive, noninvasive and carried Streptococcus pneumoniae in Malaysia: a meta-analysis

Background: Pneumococcal pneumonia is the leading cause of under-five mortality globally. The surveillance of pneumococcal serotypes is therefore vital for informing pneumococcal vaccination policy and programmes. Pneumococcal conjugate vaccines (PCVs) have been available as an option in the private healthcare setting and beginning December 2020, PCV10 was incorporated as part of routine national immunisation programme (NIP) in Malaysia. We searched existing literature on pneumococcal serotype distribution across Malaysia to provide an overall view of this distribution before the implementation of PCV10. Methods: Online databases (PubMed, Ovid MEDLINE and Scopus), reference lists of articles identified, and grey literature (Malaysian Ministry of Health website, WHO website) were systematically searched for relevant literature on pneumococcal serotype distribution across Malaysia up to 10th November 2020. No lower date limit was set to maximise the number of target reports returned. Results of serotypes were split by age categories, including ≤5 years, > 5 years and unreported for those that did not specify. Results: The search returned 18 relevant results, with a total of 2040 isolates. The most common serotypes across all disease types were 19F (n = 313, 15.3% [95%CI: 13.8–17.0]), 23F (n = 166, 8.1% [95%CI: 7.0–9.4]), 14 (n = 166, 8.1% [95%CI: 7.0–9.4]), 6B (n = 163, 8.0% [95%CI: 6.9–9.2]) and 19A (n = 138, 6.8% [95%CI: 5.8–7.9]). Conclusion: Four of the most common serotypes across all isolate sources in Malaysia are covered by PCV10, while PCV13 provides greater serotype coverage in comparison to PCV10. There is still a need for surveillance studies, particularly those investigating serotypes in children under 5 years of age, to monitor vaccine effectiveness and pneumococcal population dynamic following implementation of PCV10 into routine immunisation

Serotype distribution of invasive, non-invasive and carried Streptococcus pneumoniae in Malaysia: a meta-analysis

Background: pneumococcal pneumonia is the leading cause of under-five mortality globally. The surveillance of pneumococcal serotypes is therefore vital for informing pneumococcal vaccination policy and programmes. Pneumococcal conjugate vaccines (PCVs) have been available as an option in the private healthcare setting and beginning December 2020, PCV10 was incorporated as part of routine national immunisation programme (NIP) in Malaysia. We searched existing literature on pneumococcal serotype distribution across Malaysia to provide an overall view of this distribution before the implementation of PCV10.Methods: online databases (PubMed, Ovid MEDLINE and Scopus), reference lists of articles identified, and grey literature (Malaysian Ministry of Health website, WHO website) were systematically searched for relevant literature on pneumococcal serotype distribution across Malaysia up to 10th November 2020. No lower date limit was set to maximise the number of target reports returned. Results of serotypes were split by age categories, including ≤5 years, &gt; 5 years and unreported for those that did not specify.Results: the search returned 18 relevant results, with a total of 2040 isolates. The most common serotypes across all disease types were 19F (n = 313, 15.3% [95%CI: 13.8-17.0]), 23F (n = 166, 8.1% [95%CI: 7.0-9.4]), 14 (n = 166, 8.1% [95%CI: 7.0-9.4]), 6B (n = 163, 8.0% [95%CI: 6.9-9.2]) and 19A (n = 138, 6.8% [95%CI: 5.8-7.9]).Conclusion: four of the most common serotypes across all isolate sources in Malaysia are covered by PCV10, while PCV13 provides greater serotype coverage in comparison to PCV10. There is still a need for surveillance studies, particularly those investigating serotypes in children under 5 years of age, to monitor vaccine effectiveness and pneumococcal population dynamic following implementation of PCV10 into routine immunisation.</p

Investigation of carriage and antibiotic susceptibility of pathogenic bacteria in the nose and oropharynx among students of Universiti Tunku Abdul Rahman Kampar Campus

Some members of the normal microbiota of the human upper respiratory tract can be potentially pathogenic when they overgrow or translocate to other body sites; the latter could lead to pneumonia and meningitis. The presence of these pathogens can be investigated via respiratory carriage studies, which have been recognised as a pragmatic solution to gaining large real-time epidemiological data on their carriage at the population level. This study aimed to investigate the upper respiratory carriage of Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa among the students of UTAR Kampar Campus. Nasal and oropharyngeal swabs from 100 students aged 18-28 years were collected and cultured onto various media, which include the chocolate agar, Columbia blood agar, MacConkey agar, mannitol salt agar, and King’s A medium. Identification of the S. aureus, K. pneumoniae, and P. aeruginosa isolates obtained was done through assessment of their growth characteristics, Gram stain, biochemical tests, and 16S rDNA sequencing. They were isolated from 39%, 12%, and 1% of subjects in this study, respectively. In the Kirby-Bauer assay, 19 S. aureus isolates were resistant to penicillin while 11 were intermediately resistant to quinupristin-dalfopristin. All the K. pneumoniae isolates were resistant to ampicillin as expected. Two S. aureus isolates were mecA-positive but only one showed methicillin resistance and was determined to be methicillin-resistant S. aureus (MRSA). Nine and two K. pneumoniae isolates were blaSHV- and blaTEM-positive in the multiplex extended-spectrum beta-lactamase (ESBL) PCR, respectively; however, these did not correspond to the findings of the combination disc test. In this study, the presence of S. pneumoniae, H. influenzae, and N. meningitidis was assessed via multiplex PCR on total DNA extracts from the chocolate agar sweeps. Among the 44 subjects screened, 9.1%, 20.5%, and 2.3% were positive for these target bacteria, respectively. All these were from the oropharyngeal swabs except for the sole N. meningitidis-positive sample, which was of nasal origin. The outcomes of this study contributed to better understanding of the respiratory carriage of bacterial pathogens, which will be of value to help inform the immunisation and antibiotic prescription policies