A high death rate among red hybrid tilapias was observed in a farm in Selangor, Malaysia, in January 2020. The affected fish appeared lethargic, isolated from schooling group, showed loss of ...appetite, red and haemorrhagic skin, exophthalmia and enlarged gall bladders. Histopathological assessment revealed deformation of kidney tubules, and severe congestion with infiltrations of inflammatory cells in the brains and kidneys. Syncytial cells and intracytoplasmic inclusion bodies were occasionally observed in the liver and brain sections. Tilapia Lake Virus (TiLV),
and
were identified in the affected fish, either through isolation or through PCR and sequencing analysis. The phylogenetic tree analysis revealed that the TiLV strain in this study was closely related to the previously reported Malaysian strain that was isolated in 2019. On the other hand,
and
were closer to Algerian and Brazilian strains, respectively. The multiple antibiotic resistance index for
and
was 0.50 and 0.25, respectively. Co-infections of virus and bacteria in cultured tilapia is a new threat for the tilapia industry.
Global tuberculosis (TB) control is hampered by cost and slow or insensitive diagnostic methods to be used for TB diagnosis in clinic. Thus, TB still remains a major global health problem. The ...failure to rapidly and accurately diagnose of TB has posed significant challenges with consequent secondary resistance and ongoing transmission. We developed a rapid Mycobacterium tuberculosis (MTB) amplification/detection method, called MTB isothermal solid-phase amplification/detection (MTB-ISAD), that couples isothermal solid-phase amplification and a silicon biophotonics-based detection sensor to allow the simultaneous amplification and detection of MTB in a label-free and real-time manner. We validated the clinical utility of the MTB-ISAD assay by detecting MTB nucleic acid in sputum samples from 42 patients. We showed the ability of the MTB-ISAD assay to detect MTB in 42 clinical specimens, confirming that the MTB-ISAD assay is fast (<20 min), highly sensitive, accurate (>90%, 38/42), and cost-effective because it is a label-free method and does not involve thermal cycling. The MTB-ISAD assay has improved time-efficiency, affordability, and sensitivity compared with many existing methods. Therefore, it is potentially adaptable for better diagnosis across various clinical applications.
Mycoplasma genitalium is an emerging sexually transmitted infection, with increasing rates of resistance to fluroquinolones and macrolides, the recommended treatments. Despite this, M. genitalium is ...not part of routine screening for Sexually Transmitted Infections (STIs) in many countries and the prevalence of infection and patterns of disease remain to be determined in many populations. Such data is of particular importance in light of the reported rise in antibiotic resistance in M. genitalium isolates.
Urine and urethral swab samples were collected from the primary public sexual health clinic in Singapore and tested for C. trachomatis (CT) or N. gonorrhoeae (NG) infection and for the presence of M. genitalium. Antibiotic resistance in M. genitalium strains detected was determined by screening for genomic mutations associated with macrolide and fluroquinolone resistance.
We report the results of a study into M. genitalium prevalence at the national sexual health clinic in Singapore. M. genitalium was heavily associated with CT infection (8.1% of cases), but present in only of 2.4% in CT negative cases and not independently linked to NG infection. Furthermore, we found high rates of resistance mutations to both macrolides (25%) and fluoroquinolones (37.5%) with a majority of resistant strains being dual-resistant. Resistance mutations were only found in strains from patients with CT co-infection.
Our results support targeted screening of CT positive patients for M. genitalium as a cost-effective strategy to reduce the incidence of M. genitalium in the absence of comprehensive routine screening. The high rate of dual resistance also highlights the need to ensure the availability of alternative antibiotics for the treatment of multi-drug resistant M. genitalium isolates.
In Singapore, after a major outbreak of dengue in 2005, another outbreak occurred in 2007. Laboratory-based surveillance detected a switch from dengue virus serotype 1 (DENV-1) to DENV-2. ...Phylogenetic analysis showed a clade replacement within DENV-2 cosmopolitan genotype, which accompanied the predominant serotype switch, and cocirculation of multiple genotypes of DENV-3.
ObjectivesWHO recommends that low burden countries consider systematic screening and treatment of latent tuberculosis infection (LTBI) in migrants from high incidence countries. We aimed to determine ...LTBI prevalence and risk factors and evaluate cost-effectiveness of screening and treating LTBI in migrants to Singapore from a government payer perspective.DesignCross-sectional study and cost-effectiveness analysis.SettingMigrants in Singapore.Participants3618 migrants who were between 20 and 50 years old, have not worked in Singapore previously and stayed in Singapore for less than a year were recruited.Primary and secondary outcome measuresCosts, quality-adjusted life-years (QALYs), threshold length of stay, incremental cost-effectiveness ratios (ICERs), cost per active TB case averted.ResultsOf 3584 migrants surveyed, 20.4% had positive interferon-gamma release assay (IGRA) results, with the highest positivity in Filipinos (33.2%). Higher LTBI prevalence was significantly associated with age, marital status and past TB exposure. The cost-effectiveness model projected an ICER of S$57 116 per QALY and S$12 422 per active TB case averted for screening and treating LTBI with 3 months once weekly isoniazid and rifapentine combination regimen treatment compared with no screening over a 50-year time horizon. ICER was most sensitive to the cohort’s length of stay in Singapore, yearly disease progression rates from LTBI to active TB, followed by the cost of IGRA testing.ConclusionsFor LTBI screening and treatment of migrants to be cost-effective, migrants from high burden countries would have to stay in Singapore for ~50 years. Risk-stratified approaches based on projected length of stay and country of origin and/or age group can be considered.
We assessed microbial safety and quality of raw fish sold in Singapore during 2015-2016 to complement epidemiologic findings for an outbreak of infection with group B Streptococcus serotype III ...sequence type (ST) 283 associated with raw fish consumption. Fish-associated group B Streptococcus ST283 strains included strains nearly identical (0-2 single-nucleotide polymorphisms) with the human outbreak strain, as well as strains in another distinct ST283 clade (57-71 single-nucleotide polymorphisms). Our investigations highlight the risk for contamination of freshwater fish (which are handled and distributed separately from saltwater fish sold as sashimi) and the need for improved hygienic handling of all fish for raw consumption. These results have led to updated policy and guidelines regarding the sale of ready-to-eat raw fish dishes in Singapore.
Wastewater discharged from clinical isolation and general wards at two hospitals in Singapore was examined to determine the emerging trends of antibiotic resistance (AR). We quantified the ...concentrations of 12 antibiotic compounds by analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS), antibiotic-resistant bacteria (ARB), the class 1 integrase gene (intI1), and 16 antibiotic resistance genes (ARGs) that confer resistance to 10 different clinically relevant antibiotics. A subset of 119 antibiotic-resistant isolates were phylogenetically classified and tested for the presence of ARGs encoding resistance to β-lactam antibiotics (bla
, bla
, bla
, bla
), amikacin aac(6')-Ib, co-trimoxazole (sul1, sul2, dfrA), ciprofloxacin (qnrA, qnrB), and the intI1 gene. Among these resistant isolates, 80.7% were detected with intI1 and 66.4% were found to carry at least 1 of the tested ARGs. Among 3 sampled locations, the clinical isolation ward had the highest concentrations of ARB and the highest levels of ARGs linked to resistance to β-lactam (bla
), co-trimoxazole (sul1, sul2, dfrA), amikacin aac(6')-Ib, ciprofloxacin (qnrA), and intI1 We found strong positive correlations (P < 0.05) between concentrations of bacteria resistant to meropenem, ceftazidime, amikacin, co-trimoxazole, and ciprofloxacin and abundances of bla
, aac(6')-Ib, sul1, sul2, dfrA, qnrA, and intI1 genes.
The frequency of epidemics caused by Dengue viruses 1-4, Zika virus and Chikungunya viruses have been on an upward trend in recent years driven primarily by uncontrolled urbanization, mobility of ...human populations and geographical spread of their shared vectors, Aedes aegypti and Aedes albopictus. Infections by these viruses present with similar clinical manifestations making them challenging to diagnose; this is especially difficult in regions of the world hyperendemic for these viruses. In this study, we present a targeted-enrichment methodology to simultaneously sequence the complete viral genomes for each of these viruses directly from clinical samples. Additionally, we have also developed a customized computational tool (BaitMaker) to design these enrichment baits. This methodology is robust in its ability to capture diverse sequences and is amenable to large-scale epidemiological studies. We have applied this methodology to two large cohorts: a febrile study based in Colombo, Sri Lanka taken during the 2009-2015 dengue epidemic (n = 170) and another taken during the 2016 outbreak of Zika virus in Singapore (n = 162). Results from these studies indicate that we were able to cover an average of 97.04% ± 0.67% of the full viral genome from samples in these cohorts. We also show detection of one DENV3/ZIKV co-infected patient where we recovered full genomes for both viruses.
Summary Sixty-six animal workers received primary rabies vaccination with purified Vero cell vaccine (PVRV, Verorab™). One year later, 26 (39%) demonstrated antibody titers below the recommended ...minimum of 0.5 IU/ml, and required a booster. All 15 of a separate group reporting primary vaccination with at least one booster had titers above 0.5 IU/ml 1 year later, demonstrating long-term boostable immunity. Rabies antibody titers should be checked 1 year after primary rabies vaccination in persons at high risk of frequent rabies exposure. If access to serological surveillance is unavailable, such high-risk individuals should receive booster vaccination.
The purpose of this study was to characterize the presentations, long-term outcomes, and visual prognostic factors in dengue-related maculopathy of 41 patients with dengue fever and impaired vision ...from dengue-related maculopathy in a retrospective noninterventional and observational series.
The medical records of patients with dengue-related maculopathy diagnosed over 18 months between July 2004 and December 2005 at The Eye Institute, Tan Tock Seng Hospital and Communicable Disease Center, Singapore, were reviewed and followed up for 24 months. Visual acuity and symptoms (presence of scotoma on automated visual fields and Amsler grid) were correlated with optical coherence tomography evaluation.
Mean age was 28.7 years and there were more men (53.7%). The most common visual complaints were blurring of vision (51.2%) and central scotoma (34.1%). Most patients recovered best-corrected visual acuity >20/40. Optical coherence tomography showed 3 patterns of maculopathy: 1) diffuse retinal thickening; 2) cystoid macular edema; and 3) foveolitis. The visual outcome was independent of the extent of edema, but scotomata persisted longest in patients with foveolitis and shortest with those with diffuse retinal thickening.
Dengue-associated ocular inflammation is an emerging ophthalmic condition and often involves the posterior segment. Prognosis is variable. Patients usually regain good vision but may retain persistent scotomata even at 2 years despite clinical resolution of the disease. Optical coherence tomography patterns in dengue maculopathy are useful for characterization, monitoring, and prognostication of the visual defect.
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