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Fulltext Prevalence and antibiotic susceptibility of Ureaplasma urealyticum in Malaysian neonates with respiratory distress

Tay ST, Boo NY, Khoo TB, Koay AS, Rohani MY

Med J Malaysia, 1997 Dec;52(4):409-11.
PMID: 10968119

Ureaplasma urealyticum was isolated from the endotracheal aspirates of 39 (21.4%) of 182 neonates with respiratory distress requiring ventilatory support. Mycoplasma hominis was isolated from one (0.5%) neonate. Bacterial cultures were negative in 123 (67.6%) neonates. Antibiotic susceptibility test carried out on ten isolates of U. urealyticum showed that all the organisms were sensitive to erythromycin but resistant to lincomycin and sulfamethoxazole trimethoprim. All, except one, U. urealyticum were sensitive to tetracycline and minocycline. Two isolates were resistant to ciprofloxacin. This study showed that U.urealyticum was a common organism isolated from the endotracheal aspirates of neonates with respiratory distress.
Francisella spp. detected in Dermacentor ticks in Malaysian forest reserve areas

Koh FX, Nurhidayah MN, Tan PE, Kho KL, Tay ST

Vet Parasitol Reg Stud Reports, 2019 08;17:100315.
PMID: 31303231 DOI: 10.1016/j.vprsr.2019.100315

Limited information is available on tropical ticks and tick-borne bacteria affecting the health of humans and animals in the Southeast Asia region. Francisella tularensis is a tick-borne bacterium which causes a potentially life-threatening disease known as tularemia. This study was conducted to determine the occurrence of Francisella spp. in questing ticks collected from Malaysian forest reserve areas. A total of 106 ticks (mainly Dermacentor and Haemaphysalis spp.) were examined for Francisella DNA using a Polymerase chain reaction (PCR) assay targeting the bacterial 16S rDNA. Francisella DNA was detected from 12 Dermacentor ticks. Sequence analysis of the amplified 16S rDNA sequences (1035 bp) show >99% identity with that of Francisella endosymbiont reported in a tick from Thailand. A dendrogram constructed based on the bacterial 16S rDNA shows that the Francisella spp. were distantly related to the pathogenic strains of F. tularensis. Three Francisella-positive ticks were identified as Dermacentor atrosignatus, based on sequence analysis of the tick mitochondrial 16S rRNA gene. Further screening of cattle and sheep ticks (Haemaphysalis bispinosa and Rhipicephalus microplus) and animal samples (cattle, sheep, and goats) did not yield any positive findings. Our findings provide the first molecular data on the occurrence of a Francisella strain with unknown pathogenicity in Dermacentor questing ticks in Malaysia.
Molecular analysis of ciprofloxacin resistance among non-typhoidal Salmonella with reduced susceptibility to ciprofloxacin isolated from patients at a tertiary care hospital in Kuala Lumpur, Malaysia

Karunakaran R, Tay ST, Rahim FF, Lim BB, Puthucheary SD

Jpn J Infect Dis, 2014;67(3):157-62.
PMID: 24858603

We investigated the prevalence of non-typhoidal Salmonella (NTS) with "reduced susceptibility to ciprofloxacin" (RS-Cip) (minimum inhibitory concentration [MIC], 0.12-1.0 μg/mL) as well as their resistance genes in 75 NTS isolates (53 from stool, 21 from blood, and 1 from urine) from patients at a tertiary care Malaysian hospital between January and December 2009. RS-Cip was detected in 24/75 (32.0%) isolates. Using the ciprofloxacin MIC interpretive criteria for Salmonella in the Clinical and Laboratory Standards Institute 2013 guidelines, 51/75 (68.0%) isolates were found to be sensitive, 22/75 (29.3%) were intermediate, and 2/75 (2.7%) were resistant to ciprofloxacin. The 24 isolates that were intermediate or resistant to ciprofloxacin were the same isolates categorized as having RS-Cip. Among the 23 tested isolates with RS-Cip, the qnrS gene was detected in 17/23 (73.9%) and single gyrA mutations were detected in 6/23 (26.1%) (Asp87Tyr [n = 3], Asp87Asn [n = 2], and Ser83Phe [n = 1]). A parC (Thr57Ser) mutation was detected in 13/23 (56.5%) isolates, coexisting with either a qnrS gene or a gyrA mutation. The high incidence of the qnrS gene among isolates with RS-Cip needs to be monitored because qnr genes can spread via plasmids and aid in the emergence of increased resistance levels.
Transcriptome analysis of Burkholderia pseudomallei SCV reveals an association with virulence, stress resistance and intracellular persistence

Al-Maleki AR, Vellasamy KM, Mariappan V, Venkatraman G, Tay ST, Vadivelu J

Genomics, 2020 01;112(1):501-512.
PMID: 30980902 DOI: 10.1016/j.ygeno.2019.04.002

Differences in expression of potential virulence and survival genes were associated with B. pseudomallei colony morphology variants. Microarray was used to investigate B. pseudomallei transcriptome alterations among the wild type and small colony variant (SCV) pre- and post-exposed to A549 cells. SCV pre- and post-exposed have lower metabolic requirements and consume lesser energy than the wild type pre- and post-exposed to A549. However, both the wild type and SCV limit their metabolic activities post- infection of A549 cells and this is indicated by the down-regulation of genes implicated in the metabolism of amino acids, carbohydrate, lipid, and other amino acids. Many well-known virulence and survival factors, including T3SS, fimbriae, capsular polysaccharides and stress response were up-regulated in both the wild type and SCV pre- and post-exposed to A549 cells. Microarray analysis demonstrated essential differences in bacterial response associated with virulence and survival pre- and post-exposed to A549 cells.
The first molecular survey of theileriosis in Malaysian cattle, sheep and goats

Kho KL, Amarajothi ADG, Koh FX, Panchadcharam C, Hassan Nizam QN, Tay ST

Vet Parasitol Reg Stud Reports, 2017 12;10:149-153.
PMID: 31014589 DOI: 10.1016/j.vprsr.2017.08.003

This study reports the molecular detection of Theileria spp. from six cattle farms, a sheep farm and a goat farm located at different states in Peninsular Malaysia. Animal blood samples were screened for the presence of Theileria DNA using a conventional polymerase chain reaction (PCR) assay. A total of 155 (69.2%) of 224 cattle investigated were PCR-positive for Theileria DNA. The occurrences of Theileria spp. ranged from 17.5% to 100.0% across six cattle farms. Theileria DNA was detected from 90.0% of 40 sheep but none of 40 goats examined in this study. Sequence analyses of amplified 18S rRNA partial fragments (335-338bp) confirmed the identification of Theileria buffeli, Theileria sergenti, and Theileria sinensis in representative samples of cattle and ticks. T. luwenshuni was identified in the infected sheep. The high occurrences of Theileria spp. in our farm animals highlight the needs for appropriate control and preventive measures for theileriosis.
Determination of molecular types and genetic heterogeneity of Cryptococcus neoformans and C. gattii in Malaysia

Tay ST, Lim HC, Tajuddin TH, Rohani MY, Hamimah H, Thong KL

Med Mycol, 2006 Nov;44(7):617-22.
PMID: 17071555

The molecular types and genetic heterogeneity of Cryptococcus neoformans and C. gattii clinical isolates in Malaysia were determined in this study. Of 44 C. neoformans collected between 1980 and 2003, 42 (95.5%) were molecular type VNI, 2 (4.5%) were molecular type VNII. Of 17 C.gattii isolates, 13 (76.5%) were molecular type VGI, and 4 (23.5%) were molecular type VGII. A difference was noted when comparing the molecular types of cryptococcal isolates in the earlier and recent cases of cryptococcosis. While both molecular types VNI and VGI were equally predominant in the earlier cases of cryptococcosis, VNI was the most predominant molecular type isolated from the recent cases. VNII was a new molecular type, isolated from 5.1% of the recent cases. All the bird dropping isolates were molecular type VNI. The genetic heterogeneity of the two predominant molecular types, i.e., VNI, VGI clinical isolates and bird dropping isolates of C. neoformans were further determined by polymerase chain reaction (PCR) fingerprinting method, using (GTG)5 as single primer. Two clusters of cryptococcal isolates were distinguished at 68.5% of similarity, with cluster I consisting of VNI isolates and cluster II consisting of VGI isolates. Each cluster was further subdivided into three subtypes at >/=80% of similarity. Fourteen bird dropping isolates were grouped into a subtype within VN1, sharing 82.7% of similarity with the clinical isolates. A higher degree of similarities, ranging from 93.4-97.6% was noted between 3 bird dropping isolates with the clinical isolates in another subtype. This study demonstrated the existence of various molecular types of C. neoformans isolates in Malaysia and the genetic heterogeneity within the predominant molecular types. The study also provides evidence for genetic relatedness of clinical isolates with bird dropping isolates in the environment.
High Seroprevalence Against Typhus Group and Spotted Fever Group Rickettsiae in Rural Indigenous Populations of Peninsular Malaysia

Tappe D, Gross Y, Ngui R, Rauch J, Tay ST, Lim YAL

Vector Borne Zoonotic Dis, 2019 05;19(5):323-327.
PMID: 30540546 DOI: 10.1089/vbz.2018.2391

Rickettsioses of the typhus group (TG) and spotted fever group (SFG) are emerging bacterial infections worldwide, especially in the tropics. Only a few studies on these pathogens and their respective clinical diseases have been conducted in Malaysia. Here, we performed a seroprevalence study among 544 healthy, afebrile indigenous people (Orang Asli) from peninsular Malaysia for TG and SFG rickettsioses in nine rural and peri-urban settlements. The study population encompassed children, adolescents, and adults. The overall seroprevalence of rickettsiosis in the Orang Asli was 48.5%, with 27.9% seroprevalence against TG rickettsiae and 20.6% seroprevalence against SFG rickettsiae. In 7.9% of the study participants, antibodies against both rickettsial groups were found. The highest seropositivity rates against TG and SRG rickettsiae were detected in young children and adults. Overall, there were no gender differences. Seroprevalences were similar among inhabitants of different settlements, except for two localities. More studies are needed to shed more light on the ecology and risk factors for TG and SFG rickettsioses in Malaysia.
Fulltext Nocardia kroppenstedtii: a rare pathogen isolated from the spinal vertebral abscess of a patient on long-term immunosuppressive therapy

Tay ST, Wong PL, Chiu CK, Tang SN, Lee JL, Hamdan NW, et al.

Eur Rev Med Pharmacol Sci, 2021 01;25(2):605-608.
PMID: 33577013 DOI: 10.26355/eurrev_202101_24618

OBJECTIVE: Nocardia kroppenstedtii was isolated from the spinal vertebral abscess of a 78-year-old patient presenting with mid-thoracic pain and bilateral lower limb weakness and numbness. The patient was on long-term immunosuppressive therapy with steroids for underlying autoimmune hemolytic anemia. Investigations showed a T5 pathological fracture and vertebra plana with the erosion of the superior and inferior endplates. There was evidence of paraspinal collection from the T4-T6 vertebrae with an extension into the spinal canal. Analysis of Nocardia 16S rRNA (99.9%, 1395/1396 nt) and secA1 gene (99.5%, 429/431 nt) fragments showed the highest sequence similarity with Nocardia kroppenstedtii type strain (DQ157924), and next with Nocardia farcinica (Z36936). The patient was treated with intravenous carbapenem and oral trimethoprim-sulfamethoxazole for four weeks, followed by another six months of oral trimethoprim-sulfamethoxazole. Despite the improvement of neurological deficits, the patient required assistive devices to ambulate at discharge. This study reports the first isolation of N. kroppenstedtii from the spinal vertebral abscess of a patient from Asia. Infections caused by N. kroppenstedtii may be underdiagnosed as the bacterium can be misidentified as N. farcinica in the absence of molecular tests in the clinical laboratory.
Genetic diversity, antifungal susceptibility and enzymatic characterisation of Malaysian clinical isolates of Candida glabrata

Lotfalikhani A, Khosravi Y, Sabet NS, Na SL, Ng KP, Tay ST

Trop Biomed, 2018 Dec 01;35(4):1123-1130.
PMID: 33601859

Candida glabrata has been reported as the second or third most common yeast species isolated from patients with vaginitis and invasive candidiasis. This study was aimed to determine the genetic diversity, antifungal susceptibility and enzymatic profiles of C. glabrata isolated from vaginal and blood samples in the Medical Microbiology Diagnostic Laboratory, University Malaya Medical Centre. A random amplified polymorphic DNA (RAPD) analysis method, using M13 and (GTG)5 primers, was used for strain differentiation of C. glabrata isolates. Antifungal susceptibility testing of C. glabrata isolates was determined using E-test against amphotericin B, caspofungin, fluconazole and voriconazole and microbroth dilution method against clotrimazole. The enzymic profiles of C. glabrata were determined using APIZYM semi-quantitation kit and egg-yolk agar method. A total of 14 RAPD patterns were identified amongst C. glabrata isolates investigated this study. Susceptibility to amphotericin B, caspofungin, fluconazole and voriconazole was noted. Approximately one third of the isolates demonstrated resistance to clotrimazole (MIC>=1 µg/ml). A single isolate of C. glabrata was resistant to caspofungin (MIC:1.5 µg/ml). Enzymatic activities of acid and alkaline phosphatase, aminopeptidases, esterase and lipase and phospholipase were detected in the C. glabrata isolates. The genetic diversity and antifungal susceptibility profiles of C. glabrata isolates were presented in this study. Continued surveillance and monitoring of the incidence and antifungal resistance in C. glabrata isolates is necessary.
Molecular detection of Anaplasma spp. in pangolins (Manis javanica) and wild boars (Sus scrofa) in Peninsular Malaysia

Koh FX, Kho KL, Panchadcharam C, Sitam FT, Tay ST

Vet Parasitol, 2016 Aug 30;227:73-6.
PMID: 27523941 DOI: 10.1016/j.vetpar.2016.05.025

Anaplasma spp. infects a wide variety of wildlife and domestic animals. This study describes the identification of a novel species of Anaplasma (Candidatus Anaplasma pangolinii) from pangolins (Manis javanica) and Anaplasma bovis from wild boars (Sus scrofa) in Malaysia. Based on 16S rRNA gene sequences, Candidatus Anaplasma pangolinii is identified in a distinct branch within the family Anaplasmataceae, exhibiting the closest sequence similarity with the type strains of Anaplasma bovis (97.7%) and Anaplasma phagocytophilum (97.6%). The sequence also aligned closely (99.9%) with that of an Anaplasma spp. (strain AnAj360) detected from Amblyomma javanense ticks. The nearly full length sequence of the 16S rRNA gene derived from two wild boars in this study demonstrated the highest sequence similarity (99.7%) to the A. bovis type strain. Partial 16S rRNA gene fragments of A. bovis were also detected from a small population of Haemaphysalis bispinosa cattle ticks in this study. Our finding suggests a possible spread of two Anaplasma species in the Malaysian wildlife and ticks. The zoonotic potential of the Anaplasma species identified in this study is yet to be determined.
Fulltext A qualitative study to explore farmworkers' knowledge, beliefs and preventive practices toward ticks and tick-borne diseases

Ghane Kisomi M, Wong LP, Tay ST, Bulgiba A, Nizam QNH

J Infect Dev Ctries, 2019 12 31;13(12):1117-1126.
PMID: 32088699 DOI: 10.3855/jidc.11668

INTRODUCTION: Farmworkers are considered a high-risk group for tick-borne diseases (TBDs). This qualitative study aimed to gain an in-depth understanding of the farmworkers' experience, knowledge, health beliefs, information needs, and preventive practices of tick bites and TBDs.
METHODOLOGY: A total of nine focus group discussions with 56 farmworkers across eight animal farms in Peninsular Malaysia were conducted between August and October 2013.
RESULTS: Farmworkers explained their experience of tick bites, but no one reported TBDs. Many farmworkers indicated that they did not seek any medical treatment. There was a misconception that ticks are solely pathogenic to farm animals. Farmworkers perceived low severity and susceptibility of tick bites, and low self-efficacy of tick bite prevention, however, a group also perceived susceptibility to getting tick bites due to the characteristics of their job. Barriers for prevention were related to the perception and knowledge towards ticks. Farmworkers requested information about TBDs.
CONCLUSIONS: This study of farmworkers identified gaps in the knowledge of TBDs, barriers of the tick bite preventive measures and information needs. These findings suggest a need for education programs to improve the knowledge of ticks and TBDs, change health beliefs and address the barriers of tick bite preventive measures.
Review: antimicrobial properties of allicin used alone or in combination with other medications

Choo S, Chin VK, Wong EH, Madhavan P, Tay ST, Yong PVC, et al.

Folia Microbiol (Praha), 2020 Jun;65(3):451-465.
PMID: 32207097 DOI: 10.1007/s12223-020-00786-5

Garlic (Allium sativum L.) is a well-known spice widely utilised for its medicinal properties. There is an extensive record of the many beneficial health effects of garlic which can be traced back to as early as the ancient Egyptian era. One of the most studied properties of garlic is its ability to cure certain ailments caused by infections. In the 1940s, the antimicrobial activities exhibited by garlic were first reported to be due to allicin, a volatile compound extracted from raw garlic. Since then, allicin has been widely investigated for its putative inhibitory activities against a wide range of microorganisms. Allicin has demonstrated a preference for targeting the thiol-containing proteins and/or enzymes in microorganisms. It has also demonstrated the ability to regulate several genes essential for the virulence of microorganisms. Recently, it was reported that allicin may function better in combination with other antimicrobials compared to when used alone. When used in combination with antibiotics or antifungals, allicin enhanced the antimicrobial activities of these substances and improved the antimicrobial efficacy. Hence, it is likely that combination therapy of allicin with additional antimicrobial drug(s) could serve as a viable alternative for combating rising antimicrobial resistance. This review focuses on the antimicrobial activities exhibited by allicin alone as well as in combination with other substances. The mechanisms of action of allicin elucidated by some of the studies are also highlighted in the present review in order to provide a comprehensive overview of this versatile bioactive compound and the mechanistic evidence supporting its potential use in antimicrobial therapy.
Fulltext Profiling Bartonella infection and its associated risk factors in shelter cats in Malaysia

Alias NNA, Omar S, Ahmad NI, Watanabe M, Tay ST, Aziz NA, et al.

J Vet Sci, 2023 May;24(3):e38.
PMID: 37271506 DOI: 10.4142/jvs.22277

BACKGROUND: Poor disease management and irregular vector control could predispose sheltered animals to disease such as feline Bartonella infection, a vector-borne zoonotic disease primarily caused by Bartonella henselae.
OBJECTIVES: This study investigated the status of Bartonella infection in cats from eight (n = 8) shelters by molecular and serological approaches, profiling the CD4:CD8 ratio and the risk factors associated with Bartonella infection in shelter cats.
METHODS: Bartonella deoxyribonucleic acid (DNA) was detected through polymerase chain reaction (PCR) targeting 16S-23S rRNA internal transcribed spacer gene, followed by DNA sequencing. Bartonella IgM and IgG antibody titre, CD4 and CD8 profiles were detected using indirect immunofluorescence assay and flow cytometric analysis, respectively.
RESULTS: B. henselae was detected through PCR and sequencing in 1.0% (1/101) oral swab and 2.0% (1/50) cat fleas, while another 3/50 cat fleas carried B. clarridgeiae. Only 18/101 cats were seronegative against B. henselae, whereas 30.7% (31/101) cats were positive for both IgM and IgG, 8% (18/101) cats had IgM, and 33.7% (34/101) cats had IgG antibody only. None of the eight shelters sampled had Bartonella antibody-free cats. Although abnormal CD4:CD8 ratio was observed in 48/83 seropositive cats, flea infestation was the only significant risk factor observed in this study.
CONCLUSIONS: The present study provides the first comparison on the Bartonella spp. antigen, antibody status and CD4:CD8 ratio among shelter cats. The high B. henselae seropositivity among shelter cats presumably due to significant flea infestation triggers an alarm of whether the infection could go undetectable and its potential transmission to humans.
Identification of rickettsiae from wild rats and cat fleas in Malaysia

Tay ST, Mokhtar AS, Low KC, Mohd Zain SN, Jeffery J, Abdul Aziz N, et al.

Med Vet Entomol, 2014 Aug;28 Suppl 1:104-8.
PMID: 25171613 DOI: 10.1111/mve.12075

Rickettsioses are emerging zoonotic diseases reported worldwide. In spite of the serological evidence of spotted fever group rickettsioses in febrile patients in Malaysia, limited studies have been conducted to identify the animal reservoirs and vectors of rickettsioses. This study investigated the presence of rickettsiae in the tissue homogenates of 95 wild rats and 589 animal ectoparasites. Using PCR assays targeting the citrate synthase gene (gltA), rickettsial DNA was detected in the tissue homogenates of 13 (13.7%) wild rats. Sequence analysis of the gltA amplicons showed 98.6-100% similarity with those of Rickettsia honei/R. conorii/R. raoultii (Rickettsiales: Rickettsiaceae). Sequence analysis of outer membrane protein A gene (ompA) identified Rickettsia sp. TCM1 strain from two rats. No rickettsia was detected from Laelaps mites, Rhipicephalus sanguineus and Haemaphysalis bispinosa ticks, and Felicola subrostratus lice in this study. R. felis was identified from 32.2% of 177 Ctenocephalides felis fleas. Sequence analysis of the gltA amplicons revealed two genotypes of R. felis (Rf31 and RF2125) in the fleas. As wild rats and cat fleas play an important role in the enzoonotic maintenance of rickettsiae, control of rodent and flea populations may be able to reduce transmission of rickettsioses in the local setting.
Exploring naphthoquinone and anthraquinone derivatives as antibiotic adjuvants against Staphylococcus aureus biofilms: Synergistic effects of menadione

Chan YL, Tang SN, Osman CP, Chee CF, Tay ST

Microb Pathog, 2024 Aug 31;195:106886.
PMID: 39182855 DOI: 10.1016/j.micpath.2024.106886

Given the ability of Staphylococcus aureus to form biofilms and produce persister cells, making infections difficult to treat with antibiotics alone, there is a pressing need for an effective antibiotic adjuvant to address this public health threat. In this study, a series of quinone derivatives were evaluated for their antimicrobial and antibiofilm activities against methicillin-susceptible and methicillin-resistant S. aureus reference strains. Following analyses using broth microdilution, growth curve analysis, checkerboard assay, time-kill experiments, and confocal laser scanning microscopy, menadione was identified as a hit compound. Menadione exhibited a notable antibacterial profile (minimum inhibitory concentration, MIC = 4-16 μg/ml; minimum bactericidal concentration, MBC = 256 μg/ml) against planktonic S. aureus and its biofilms (minimum biofilm inhibitory concentration, MBIC50 = 0.0625-0.25 μg/ml). When combined with oxacillin, erythromycin, and vancomycin, menadione exhibited a synergistic or additive effect against planktonic cells and biofilms of two S. aureus reference strains and six clinical isolates, highlighting its potential as a suitable adjuvant for further development against S. aureus biofilm-associated infections.
Fulltext Physician's Perspectives on Factors Influencing Antibiotic Resistance: A Qualitative Study in Vietnam

Di KN, Tay ST, Sri La Sri Ponnampalavanar S, Pham DT, Wong LP

Healthcare (Basel), 2022 Dec 31;11(1).
PMID: 36611587 DOI: 10.3390/healthcare11010126

(1) Background: The antibiotic resistance (ABR) rates are escalating to seriously high levels worldwide. This study was conducted to determine physicians' perspectives on factors influencing ABR in Vietnam. (2) Methods: Focus group discussion (FGD) was conducted through in-depth interviews on ABR perspectives with 5-6 physicians from different geographical locations and hospitals in Vietnam between March and June 2020. The research questions were focused on three main themes of (a) knowledge deficiency on ABR and hospital-acquired infection, (b) antibiotic prescribing practice among clinicians in the healthcare setting, and (c) regulations and hospital policies on antibiotic use. The descriptive analysis was performed using QRS NVivo software. (3) Results: A total of six FGDs were conducted among 34 physicians (18 males, 16 females) aged 26-53 years old from six public and six private hospitals in Vietnam. Most of the participants were attending physicians (85.3%) and had 5-10 years of experience in surgical wards (55.9%). For theme (a), a majority of participants agreed that they had adequate information updates on how ABR develops in their clinical setting; and were well aware of hospital-acquired infections. For theme (b), the participants agreed that WHO guidelines and Vietnam national guidelines were two important reference documents in guiding physicians in antibiotic use. For theme (c), the FGD study revealed awareness of ABR, hospital antibiotic policies, and procedures for administrators on antibiotic use that were updated and complied with. (4) Conclusions: While different levels of control measures against ABR are ongoing in Vietnam, several weaknesses in the current antibiotic prescribing strategies in the hospital and clinical setting management policies have been identified in the healthcare system. The research findings will be helpful for policymakers to have better plans of action against ABR in Vietnam.
Fulltext Altered Proteome of Burkholderia pseudomallei Colony Variants Induced by Exposure to Human Lung Epithelial Cells

Al-Maleki AR, Mariappan V, Vellasamy KM, Tay ST, Vadivelu J

PLoS One, 2015;10(5):e0127398.
PMID: 25996927 DOI: 10.1371/journal.pone.0127398

Burkholderia pseudomallei primary diagnostic cultures demonstrate colony morphology variation associated with expression of virulence and adaptation proteins. This study aims to examine the ability of B. pseudomallei colony variants (wild type [WT] and small colony variant [SCV]) to survive and replicate intracellularly in A549 cells and to identify the alterations in the protein expression of these variants, post-exposure to the A549 cells. Intracellular survival and cytotoxicity assays were performed followed by proteomics analysis using two-dimensional gel electrophoresis. B. pseudomallei SCV survive longer than the WT. During post-exposure, among 259 and 260 protein spots of SCV and WT, respectively, 19 were differentially expressed. Among SCV post-exposure up-regulated proteins, glyceraldehyde 3-phosphate dehydrogenase, fructose-bisphosphate aldolase (CbbA) and betaine aldehyde dehydrogenase were associated with adhesion and virulence. Among the down-regulated proteins, enolase (Eno) is implicated in adhesion and virulence. Additionally, post-exposure expression profiles of both variants were compared with pre-exposure. In WT pre- vs post-exposure, 36 proteins were differentially expressed. Of the up-regulated proteins, translocator protein, Eno, nucleoside diphosphate kinase (Ndk), ferritin Dps-family DNA binding protein and peptidyl-prolyl cis-trans isomerase B were implicated in invasion and virulence. In SCV pre- vs post-exposure, 27 proteins were differentially expressed. Among the up-regulated proteins, flagellin, Eno, CbbA, Ndk and phenylacetate-coenzyme A ligase have similarly been implicated in adhesion, invasion. Protein profiles differences post-exposure provide insights into association between morphotypic and phenotypic characteristics of colony variants, strengthening the role of B. pseudomallei morphotypes in pathogenesis of melioidosis.
Spotted Fever Group Rickettsioses and Murine Typhus in a Malaysian Teaching Hospital

Kho KL, Koh FX, Singh HK, Zan HA, Kukreja A, Ponnampalavanar S, et al.

Am J Trop Med Hyg, 2016 10 05;95(4):765-768.
PMID: 27402519

Limited information is available on the etiological agents of rickettsioses in southeast Asia. Herein, we report the molecular investigation of rickettsioses in four patients attending a teaching hospital in Malaysia. DNA of Rickettsia sp. RF2125, Rickettsia typhi, and a rickettsia closely related to Rickettsia raoultii was detected in the blood samples of the patients. Spotted fever group rickettsioses and murine typhus should be considered in the diagnosis of patients with nonspecific febrile illness in this region.
Fulltext Short report: Predictors of severe disease in melioidosis patients in Kuala Lumpur, Malaysia

Mohd Roslani AD, Tay ST, Puthucheary SD, Rukumani DV, Sam IC

Am J Trop Med Hyg, 2014 Dec;91(6):1176-8.
PMID: 25246695 DOI: 10.4269/ajtmh.14-0354

The predictors of severe disease or death were determined for 85 melioidosis patients in Kuala Lumpur, Malaysia. Most of the patients were male, > 40 years old, and diabetic. Severe disease or death occurred in 28 (32.9%) cases. Lower lymphocyte counts and positive blood cultures were significant independent predictors of severe disease, but age, presentations with pneumonia, inappropriate empirical antibiotics, or flagellin types of the infecting isolates were not. Knowledge of local predictors of severe disease is useful for clinical management.
Fulltext Outbreak preparedness and response strategies in ASEAN member states: a scoping review

Mphande-Nyasulu FA, Yap NJ, Teo CH, Chang LY, Tay ST

IJID Reg, 2024 Sep;12:100430.
PMID: 39290689 DOI: 10.1016/j.ijregi.2024.100430

OBJECTIVES: The 21st century has witnessed significant disease outbreaks with severe impact in Association of Southeast Asian Nations (ASEAN) countries, including SARS, H1N1, H5N1, and COVID-19. This review aimed to compile and analyze outbreak preparedness and response strategies, highlighting the success of coordinated multi-sectoral approaches and policy responses within the ASEAN region.
METHODS: The protocol for this review was registered on the Open Science Framework and PROSPERO. A systematic analysis of publications from the 2002-2022 period was conducted following PRISMA guidelines on 4522 records retrieved from PubMed, CINAHL, Web of Science, and Scopus. The titles and abstracts were screened, and 229 articles were selected for full-text screening. Finally, 34 articles were included in this review.
RESULTS: Four preparedness pillars were identified: governance and stewardship, disease detection, disease prevention, and health care management. The pillars were crucial in preparing for and responding to the COVID-19 pandemic. Coordinated responses among the ASEAN countries and local and international stakeholders were reported.
CONCLUSIONS: The findings emphasize that understanding the transmission dynamics of infectious diseases is paramount for effective disease prevention, surveillance, and timely response efforts to prevent the next pandemic. A well-coordinated multi-country and multi-agency policy response and understanding the different disease management models are crucial in addressing future outbreaks in the region. Future post-pandemic publications will shed more light on lessons learned and preparedness and response plans for future pandemics.

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