MyMedR

Fulltext Utility of 16S rDNA Sequencing for Identification of Rare Pathogenic Bacteria

Loong SK, Khor CS, Jafar FL, AbuBakar S

J Clin Lab Anal, 2016 Nov;30(6):1056-1060.

PMID: 27184222 DOI: 10.1002/jcla.21980

BACKGROUND: Phenotypic identification systems are established methods for laboratory identification of bacteria causing human infections. Here, the utility of phenotypic identification systems was compared against 16S rDNA identification method on clinical isolates obtained during a 5-year study period, with special emphasis on isolates that gave unsatisfactory identification.

METHODS: One hundred and eighty-seven clinical bacteria isolates were tested with commercial phenotypic identification systems and 16S rDNA sequencing. Isolate identities determined using phenotypic identification systems and 16S rDNA sequencing were compared for similarity at genus and species level, with 16S rDNA sequencing as the reference method.

RESULTS: Phenotypic identification systems identified ~46% (86/187) of the isolates with identity similar to that identified using 16S rDNA sequencing. Approximately 39% (73/187) and ~15% (28/187) of the isolates showed different genus identity and could not be identified using the phenotypic identification systems, respectively. Both methods succeeded in determining the species identities of 55 isolates; however, only ~69% (38/55) of the isolates matched at species level. 16S rDNA sequencing could not determine the species of ~20% (37/187) of the isolates.

CONCLUSION: The 16S rDNA sequencing is a useful method over the phenotypic identification systems for the identification of rare and difficult to identify bacteria species. The 16S rDNA sequencing method, however, does have limitation for species-level identification of some bacteria highlighting the need for better bacterial pathogen identification tools.

Isolation of Aggregatibacter aphrophilus from a patient with acute appendicitis

Aye AM, Law CW, Sabet NS, Karunakaran R, Hanifah YA, Jafar FL, et al.

Eur Rev Med Pharmacol Sci, 2011 Jul;15(7):845-7.

PMID: 21780555

Acute appendicitis is a common surgical emergency. The etiology and pathophysiology of appendicitis have been well investigated. Aggregatibacter aphrophilus is a fastidious gram-negative coccobacilli. Detection of this organism in clinical samples and its differentiation from Haemophilus aphrophilus or from Aggregatibacter actinomycetemcomitans in routine microbiology settings could be difficult.

Fulltext Comparative Genetic Analyses of Human Rhinovirus C (HRV-C) Complete Genome from Malaysia

Khaw YS, Chan YF, Jafar FL, Othman N, Chee HY

Front Microbiol, 2016;7:543.

PMID: 27199901 DOI: 10.3389/fmicb.2016.00543

Human rhinovirus-C (HRV-C) has been implicated in more severe illnesses than HRV-A and HRV-B, however, the limited number of HRV-C complete genomes (complete 5' and 3' non-coding region and open reading frame sequences) has hindered the in-depth genetic study of this virus. This study aimed to sequence seven complete HRV-C genomes from Malaysia and compare their genetic characteristics with the 18 published HRV-Cs. Seven Malaysian HRV-C complete genomes were obtained with newly redesigned primers. The seven genomes were classified as HRV-C6, C12, C22, C23, C26, C42, and pat16 based on the VP4/VP2 and VP1 pairwise distance threshold classification. Five of the seven Malaysian isolates, namely, 3430-MY-10/C22, 8713-MY-10/C23, 8097-MY-11/C26, 1570-MY-10/C42, and 7383-MY-10/pat16 are the first newly sequenced complete HRV-C genomes. All seven Malaysian isolates genomes displayed nucleotide similarity of 63-81% among themselves and 63-96% with other HRV-Cs. Malaysian HRV-Cs had similar putative immunogenic sites, putative receptor utilization and potential antiviral sites as other HRV-Cs. The genomic features of Malaysian isolates were similar to those of other HRV-Cs. Negative selections were frequently detected in HRV-Cs complete coding sequences indicating that these sequences were under functional constraint. The present study showed that HRV-Cs from Malaysia have diverse genetic sequences but share conserved genomic features with other HRV-Cs. This genetic information could provide further aid in the understanding of HRV-C infection.

Diverse human rhinoviruses A and C from children with respiratory infections in Kuala Lumpur, Malaysia

Chan YF, Jafar FL, Nathan AM, de Bruyne JA, Hassan A, Nor'e SS, et al.

J Infect, 2012 Jun;64(6):633-6.

PMID: 22425558 DOI: 10.1016/j.jinf.2012.03.011

Fulltext Providing a laboratory diagnostic service for pandemic SARS-CoV-2 in a developing country

Sam IC, Chong J, Kamarudin R, Jafar FL, Lee LM, Bador MK, et al.

Trans R Soc Trop Med Hyg, 2020 08 01;114(8):553-555.

PMID: 32497211 DOI: 10.1093/trstmh/traa037

Seasonal influenza activity based on laboratory surveillance in Malaysia, 2011-2016

Sam IC, Noraini W, Sandhu SS, Norizah I, Selvanesan S, Thayan R, et al.

J Med Virol, 2019 03;91(3):498-502.

PMID: 30199092 DOI: 10.1002/jmv.25313

Influenza seasonality in equatorial countries is little understood. Seasonal and alert influenza thresholds were determined for Malaysia, using laboratory-based data obtained from the Malaysia Influenza Surveillance System and a major teaching hospital, from 2011 to 2016. Influenza was present year-round, with no clear annual seasons. Variable periods of higher transmission occurred inconsistently, in November to December, January to March, July to September, or a combination of these. These coincide with seasons in the nearby southeast Asian countries or winter seasons of the northern and southern hemispheres. Changes in the predominant circulating influenza type were only sometimes associated with increased transmission. The data can provide public health interventions such as vaccines.

A large exposure to Brucella melitensis in a diagnostic laboratory

Sam IC, Karunakaran R, Kamarulzaman A, Ponnampalavanar S, Syed Omar SF, Ng KP, et al.

J Hosp Infect, 2012 Apr;80(4):321-5.

PMID: 22237130 DOI: 10.1016/j.jhin.2011.12.004

Brucella species are easily transmitted by aerosols and can be acquired in the laboratory.

Fulltext Full genome SNP-based phylogenetic analysis reveals the origin and global spread of Brucella melitensis

Tan KK, Tan YC, Chang LY, Lee KW, Nore SS, Yee WY, et al.

BMC Genomics, 2015;16:93.

PMID: 25888205 DOI: 10.1186/s12864-015-1294-x

Brucellosis is an important zoonotic disease that affects both humans and animals. We sequenced the full genome and characterised the genetic diversity of two Brucella melitensis isolates from Malaysia and the Philippines. In addition, we performed a comparative whole-genome single nucleotide polymorphism (SNP) analysis of B. melitensis strains collected from around the world, to investigate the potential origin and the history of the global spread of B. melitensis.

Fulltext Evolution of Influenza B Virus in Kuala Lumpur, Malaysia, between 1995 and 2008

Sam IC, Su YC, Chan YF, Nor'E SS, Hassan A, Jafar FL, et al.

J Virol, 2015 Sep;89(18):9689-92.

PMID: 26136576 DOI: 10.1128/JVI.00708-15

Influenza B virus causes significant disease but remains understudied in tropical regions. We sequenced 72 influenza B viruses collected in Kuala Lumpur, Malaysia, from 1995 to 2008. The predominant circulating lineage (Victoria or Yamagata) changed every 1 to 3 years, and these shifts were associated with increased incidence of influenza B. We also found poor lineage matches with recommended influenza virus vaccine strains. While most influenza B virus lineages in Malaysia were short-lived, one circulated for 3 to 4 years.

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