Publications by authors named "Rosana W S Poon"

Objective: Infectious diseases are global health challenge, impacted the communities worldwide particularly in the midst of COVID-19 pandemic. The need of rapid and accurate automated systems for detecting pathogens of concern has always been critical. Ideally, such systems shall detect a large panel of pathogens simultaneously regardless of well-equipped facilities and highly trained operators, thus realizing on-site diagnosis for frontline healthcare providers and in critical locations such as borders and airports.

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Article Synopsis
  • - A previously healthy Chinese boy was diagnosed with cerebral phaeohyphomycosis and found to have a deficiency in CARD9, a gene related to immune response.
  • - Initial scans misidentified the condition as a brain tumor, but further testing confirmed the fungal infection in the brain.
  • - The boy was successfully treated with specific antifungal medications and showed significant recovery after one year.
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Whether Burkholderia cepacia complex should be an objectionable organism in antiseptic solutions with acceptable total bacterial counts is controversial. By using next-generation sequencing, we documented a polyclonal B. cepacia complex outbreak affecting peritoneal dialysis patients in Hong Kong that was caused by contaminated chlorhexidine solutions.

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In 2012, a novel canine Dirofilaria species, D. hongkongensis was identified in Hong Kong that caused human diseases and subsequently reported in an Austrian traveller returning from the Indian subcontinent. Here we present a case of human infection by D.

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has been detected in several species of free-ranging odontocetes, in several geographic areas but it has not been reported in Indo-Pacific finless porpoises () nor in any odontocetes in waters in the South China Sea. Sampling of odontocetes stranded in Hong Kong Special Administrative Region, People's Republic of China, was carried out as part of a stranding monitoring program to evaluate the pathogens harbored by these threatened species. A real-time PCR method targeting the genus-specific 31kDa cell surface salt extractable () gene, gene sequencing, and phylogenetic characterisation produced three PCR products of the expected size and sequence, from two stranded Indo-Pacific finless porpoises.

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Aims: Helminth infections are becoming uncommon in high-income countries and laboratory staff may lose expertise in their morphological identification, especially in histological sections where speciation of helminths is challenging. Commercially available molecular diagnostic panels for faecal specimens only offer tests for protozoa but not helminths. We aim to improve the identification accuracy of helminths using a multiplex PCR assay.

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We report the first case of microabscesses detected by polymerase chain reaction (PCR) amplification of nucleic acid from ultrasound-guided aspirated fluid in a three-year old boy with acute lymphoblastic leukemia and febrile neutropenia during induction chemotherapy. Fever persisted despite effective antifungal treatment. The addition of corticosteroid therapy successfully controlled the suspected immune reconstitution inflammatory syndrome (IRIS).

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Aims: Granulomatous mastitis due to is an increasingly recognised cause of an indolent and distressing mastitis in non-lactating females. This slow-growing lipophilic organism is not reliably isolated using routine culture methods. A novel selective culture medium (CKSM) is designed to optimise the isolation of this organism from clinical specimens.

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The 2017 Hong Kong influenza A(H3N2) summer season was unexpectedly severe. However, antigenic characterization of the 2017 circulating A(H3N2) viruses using ferret antisera did not show significant antigenic drift. We analyzed the hemagglutinin amino acid sequences of A(H3N2) virus circulating in Hong Kong in 2017, and found that viruses with hemagglutinin N121K substitution, which was rare before 2017, emerged rapidly and dominated in 2017 (52.

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Talaromyces marneffei, previously known as Penicillium marneffei, is the most important pathogenic thermally dimorphic fungus causing systemic mycosis in Southeast Asia. Traditionally, T. marneffei infection in human was mainly associated with acquired immunodeficiency syndrome caused by HIV infection.

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Unlike bacteria and fungi, identification of helminths by gene sequencing is not well-standardized. No "pan-cestode" or "pan-nematode" PCR primers are available. In this study, we designed 2 pairs of PCR primers for amplifying the cox1 genes of cestodes and nematodes respectively and validated their usefulness for real-time PCR and sequencing identification using clinical samples with cestodes and nematodes collected from a variety of animals and human in 7 countries in Asia, Europe and Africa.

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This retrospective study of patients with infections revealed a predominance of mastitis and a potential association with psychiatric illnesses. At least one third of our patients with mastitis had psychiatric illness, and >92% received antipsychotic medications. Drug-induced hyperprolactinemia may be an important modifiable risk factor in these patients.

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Human sparganosis is a foodborne zoonosis endemic in Asia. We report a series of 9 histologically confirmed human sparganosis cases in Hong Kong, China. All parasites were retrospectively identified as Spirometra erinaceieuropaei.

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Oncovirus-associated malignancies are potentially preventable diseases with major public health significance. Human polyomaviruses (HPyVs) may be associated with oncogenesis or symptomatic illnesses in immunocompromised patients, but the site of viral shedding of most recently discovered HPyVs remains obscure. Using real-time PCR assay using specific primers targeting the HPyV6 large tumor antigen gene, we detected a phylogenetically distinct HPyV6 which was highly prevalent in the bile samples of patients with malignant biliary obstruction (18.

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Oocysts of a coccidian morphologically matching features of Caryospora megafalconis Klüh, 1994 were found in fecal samples and contents of the large intestines in five wild caught Clamydotis macqueenii (Gray) and 19 captive bred C. undulata (Jaquin). Scrapings of the intestinal mucosa of necropsied birds revealed macrogamonts and unsporulated oocysts.

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Two bacterial strains, HKU50T and HKU46, were isolated in Hong Kong from the blood culture and the peritoneal dialysis effluent of two patients. The strains are Gram-stain-positive, acid-fast, non-motile, non-sporulating bacilli. They grow on Columbia agar with 5 % defibrinated sheep blood and brain-heart infusion agar under aerobic conditions with 5 % CO2 at 37 °C as pink-to-orange, non-haemolytic colonies.

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The most common pathogens associated with peritonitis in patients on continuous ambulatory peritoneal dialysis (CAPD) are gram-positive bacteria, which constitute 60 - 80% of all isolates. With the advancement of molecular technologies for bacterial identification, cases of CAPD-related peritonitis caused by bacteria previously not known to be associated with this clinical condition have been reported. Here we report the first case of CAPD-related peritonitis due to Laribacter hongkongensis.

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Since its emergence in 2012, more than 900 laboratory-confirmed cases of Middle East respiratory syndrome (MERS) have been reported with a fatality rate of more than 30%. However, no antigen detection assay for commercial use is available for diagnosis. In this study, the full-length nucleocapsid protein (NP) gene of MERS coronavirus (MERS-CoV) was cloned and expressed in Escherichia coli.

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Scabies remains the most prevalent, endemic, and neglected ectoparasitic infestation globally and can cause institutional outbreaks. The sensitivity of routine microscopy for demonstration of Sarcoptes scabiei mites or eggs in skin scrapings is only about 50%. Except for three studies using conventional or two-tube nested PCR on a small number of cases, no systematic study has been performed to improve the laboratory diagnosis of this important infection.

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OBJECTIVE To assess the effectiveness of infection control preparedness for human infection with influenza A H7N9 in Hong Kong. DESIGN A descriptive study of responses to the emergence of influenza A H7N9. SETTING A university-affiliated teaching hospital.

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Background: Prolonged asymptomatic carriage of vancomycin-resistant enterococci (VRE) in the gastrointestinal tract and the lack of effective decolonization regimen perpetuate the endemicity of VRE in the healthcare settings.

Case Presentation: We report a regimen for decolonization of gastrointestinal carriage of VRE by a combination of environmental disinfection, patient isolation, bowel preparation to wash-out the fecal bacterial population using polyethylene glycol, a five-day course of oral absorbable linezolid and non-absorbable daptomycin to suppress any remaining VRE, and subsequent oral Lactobacillus rhamnosus GG to maintain the colonization resistance in four patients, including two patients with end-stage liver cirrhosis, one patient with complication post liver transplant, and one patient with complicated infective endocarditis. All patients had clearance of VRE immediately after decolonization, and 3 of them remained VRE-free for 23 to 137 days of hospitalization, despite subsequent use of intravenous broad-spectrum antibiotics without anti-VRE activity.

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Microscopic detection and morphological identification of parasites from clinical specimens are the gold standards for the laboratory diagnosis of parasitic infections. The limitations of such diagnostic assays include insufficient sensitivity and operator dependence. Immunoassays for parasitic antigens are not available for most parasitic infections and have not significantly improved the sensitivity of laboratory detection.

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Quantitative PCR on nasopharyngeal aspirate (NPA) can achieve high sensitivity and specificity in diagnosing Pneumocystis pneumonia (PCP) compared to microscopic examination of bronchoscopic specimens in a population with low HIV prevalence. Since NPA is a minimally invasive procedure, it is ideal as a screening test for PCP.

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Pneumocystis colonization has been associated with airway inflammation and obstruction. We conducted a retrospective cohort study to investigate the clinical significance of Pneumocystis in the airway of patients with active tuberculosis. Of the 108 respiratory specimens tested positive for M.

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