Raymond Yung - Academia.edu (original) (raw)
Papers by Raymond Yung
Journal of clinical microbiology, 1999
The relationship between the phenotypic and genotypic characteristics of 105 penicillin-intermedi... more The relationship between the phenotypic and genotypic characteristics of 105 penicillin-intermediate or -resistant Streptococcus pneumoniae isolates saved during 1994 to 1997 at the Prince of Wales Hospital and Pamela Youde Nethersole Eastern Hospital, Hong Kong, was studied. The pbp genes for penicillin-binding proteins 1a, 2b, and 2x for each isolate were amplified by PCR, and the products were digested with restriction enzymes HinfI and AluI. A combination of the pulsed-field gel electrophoresis (PFGE) profiles, pbp fingerprints, and phenotypic characteristics of capsular types and antibiograms enabled these isolates to be divided into four major groups. Seventy-four percent (78 of 105) of the strains, belonging to serotypes 23F, 19F, and 14, showed indistinguishable pbp fingerprint patterns (group A1, 1-1-1, 1-1-1), with PFGE patterns belonging to group A and its subtypes, suggesting that these strains were closely related. Eighty-three percent (65 of 78) of these isolates were ...
PLoS ONE, 2008
Background: There are sparse data on whether non-pharmaceutical interventions can reduce the spre... more Background: There are sparse data on whether non-pharmaceutical interventions can reduce the spread of influenza. We implemented a study of the feasibility and efficacy of face masks and hand hygiene to reduce influenza transmission among Hong Kong household members.
BMC infectious diseases, 2006
Cytokines play important roles in antiviral action. We examined whether polymorphisms of IFN-gamm... more Cytokines play important roles in antiviral action. We examined whether polymorphisms of IFN-gamma,TNF-alpha and IL-10 affect the susceptibility to and outcome of severe acute respiratory syndrome (SARS). A case-control study was carried out in 476 Chinese SARS patients and 449 healthy controls. We tested the polymorphisms of IFN-gamma,TNF-alpha and IL-10 for their associations with SARS. IFN-gamma +874A allele was associated with susceptibility to SARS in a dose-dependent manner (P < 0.001). Individuals with IFN-gamma +874 AA and AT genotype had a 5.19-fold (95% Confidence Interval [CI], 2.78-9.68) and 2.57-fold (95% CI, 1.35-4.88) increased risk of developing SARS respectively. The polymorphisms of IL-10 and TNF-alpha were not associated with SARS susceptibility. IFN-gamma +874A allele was shown to be a risk factor in SARS susceptibility.
Journal of Clinical Microbiology, 2003
A new selective medium, cefoperazone MacConkey agar (CMA), was developed for primary isolation of... more A new selective medium, cefoperazone MacConkey agar (CMA), was developed for primary isolation of Laribacter hongkongensis from stool. Its performance in quantitative recovery and in a clinical evaluation of 4,741 human diarrheal stool specimens was superior to that of charcoal cefoperazone deoxycholate agar. In addition, with CMA, Arcobacter butzleri was unexpectedly isolated from the stools of six patients.
Asia Pacific Family Medicine, 2009
To determine the use of antibiotics by primary care doctors.
Few data are available about the effectiveness of nonpharmaceutical interventions for preventing ... more Few data are available about the effectiveness of nonpharmaceutical interventions for preventing influenza virus transmission. To investigate whether hand hygiene and use of facemasks prevents household transmission of influenza. Cluster randomized, controlled trial. Randomization was computer generated; allocation was concealed from treating physicians and clinics and implemented by study nurses at the time of the initial household visit. Participants and personnel administering the interventions were not blinded to group assignment. (ClinicalTrials.gov registration number: NCT00425893) Households in Hong Kong. 407 people presenting to outpatient clinics with influenza-like illness who were positive for influenza A or B virus by rapid testing (index patients) and 794 household members (contacts) in 259 households. Lifestyle education (control) (134 households), hand hygiene (136 households), or surgical facemasks plus hand hygiene (137 households) for all household members. Influenza virus infection in contacts, as confirmed by reverse-transcription polymerase chain reaction (RT-PCR) or diagnosed clinically after 7 days. Sixty (8%) contacts in the 259 households had RT-PCR-confirmed influenza virus infection in the 7 days after intervention. Hand hygiene with or without facemasks seemed to reduce influenza transmission, but the differences compared with the control group were not significant. In 154 households in which interventions were implemented within 36 hours of symptom onset in the index patient, transmission of RT-PCR-confirmed infection seemed reduced, an effect attributable to fewer infections among participants using facemasks plus hand hygiene (adjusted odds ratio, 0.33 [95% CI, 0.13 to 0.87]). Adherence to interventions varied. The delay from index patient symptom onset to intervention and variable adherence may have mitigated intervention effectiveness. Hand hygiene and facemasks seemed to prevent household transmission of influenza virus when implemented within 36 hours of index patient symptom onset. These findings suggest that nonpharmaceutical interventions are important for mitigation of pandemic and interpandemic influenza. Centers for Disease Control and Prevention.
Respirology, 2004
There is so far no consensus on the optimal treatment strategy for the coronavirus-associated sev... more There is so far no consensus on the optimal treatment strategy for the coronavirus-associated severe acute respiratory syndrome (SARS). We aimed to analyse the outcomes of a standard treatment strategy comprising antibiotics, a combination of ribavirin, a 3-week step-down course of corticosteroids, and the possibility of pulsed methylprednisolone rescue in the event of deterioration. This was a prospective cohort study performed at a major public-funded hospital in Hong Kong. Eighty-eight World Health Organisation/Centers for Disease Control and Prevention probable cases of SARS (97% laboratory-confirmed) were treated with a standard protocol previously reported. Seventy-one patients treated de novo were analysed in detail with regard to time to clinical stabilization after combination treatment, requirement of additional therapy (pulsed methylprednisolone; assisted ventilation); and final outcomes (recovery, mortality). The mean age was 42. Twenty-one patients (24%) had comorbidities. Three of 71 treated de novo recovered with antibiotics alone. The remaining 68 received combination treatment at a mean of 5.8 days after symptom onset, of whom 30 subsequently required pulsed methylprednisolone rescue (independent predictors: older age and higher LDH) and 18 required assisted ventilation (independent predictors: older age, higher oxygen requirement and creatinine level). Their median time to clinical stabilization was 8.0 days after combination treatment (independent predictor for longer time to stabilization: median age of 41 or above). Common complications were hyperglycaemia (58%), pneumo-mediastinum/thoraces (13%), psychiatric manifestations (7%) and ventilator-associated pneumonia (2%). One patient (1%) died of SARS-related respiratory failure. All-cause mortality was 3.4%, occurring in patients aged &amp;amp;amp;amp;amp;gt; 65 years only. None of the discharged survivors required continuation of oxygen therapy. This standard treatment protocol resulted in overall satisfactory outcomes. Randomized controlled trial is suggested to confirm its efficacy.
The Lancet, 2004
Laribacter hongkongensis has been recovered from several patients with gastroenteritis. However, ... more Laribacter hongkongensis has been recovered from several patients with gastroenteritis. However, the causative role of this organism in human gastroenteritis is still unproven, and sources of the bacterium are unknown. We undertook a multicentre case-control study to investigate the association of L hongkongensis with gastroenteritis. Faecal samples from patients with community-acquired gastroenteritis and controls were cultured for L hongkongensis. Targeted food surveillance was done to identify potential sources of this bacterium. All isolates of this organism from patients and food items were characterised by pulsed-field gel electrophoresis and ribotyping. During a 4-month period, L hongkongensis was recovered from 17 of 3788 patients with community-acquired gastroenteritis, but was absent in 1894 controls (p=0.001). Those who were culture-positive for this bacterium had a recent history of travel (ten [59%] patients vs two [6%] of 34 matched controls, p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001), of fish consumption (16 [94%] vs 19 [56%], p=0.009), and of eating minced freshwater fish meat (five [29%] vs one [3%], p=0.012). We recovered 25 L hongkongensis isolates from intestinal samples of freshwater fish and two from minced freshwater fish meat. Bacteria with the same pulsed-field gel electrophoretic pattern and ribotype were recovered from one patient and a sample of minced freshwater fish meat, which was from the same retail market recently visited by the patient. We did not see this particular combination of electrophoretic pattern and ribotype in any other isolates. L hongkongensis is associated with community-acquired gastroenteritis and traveller&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s diarrhoea. However, its causative role has not been shown. Freshwater fish is one source of this bacterium.
Journal of Medical Microbiology, 2003
Traditionally, the identification, epidemiology and spectrum of clinical diseases caused by Granu... more Traditionally, the identification, epidemiology and spectrum of clinical diseases caused by Granulicatella adiacens and Abiotrophia defectiva are dependent upon their phenotypic characterization. During a 6-year period (July 1995-June 2001), seven and two AE-haemolytic streptococci were identified as G. adiacens and A. defectiva, respectively, by 16S rRNA gene sequencing. Three patients with haematological malignancies and neutropenic fever had primary bacteraemia. Three patients with valvular problems or congenital heart disease had infective endocarditis. A patient with ischemic heart disease and cerebrovascular accident had infected aortic atheroma with dissection. A patient with recurrent pyogenic cholangitis had acute cholangitis and a patient with polypoid cystitis and benign prostatic hypertrophy had acute prostatitis. Four of the nine patients died, including all three with G. adiacens infective endocarditis or infected atheroma. For the seven G. adiacens isolates, the API 20 STREP system successfully identified one and five isolates as G. adiacens with .95 % and 80-90 % confidence, respectively, whereas the Vitek System (GPI) and ATB Expression system (ID32 STREP) successfully identified none and one isolate as G. adiacens. Of the two A. defectiva isolates, none of the three systems successfully identified either of them as A. defectiva. 16S rRNA gene sequencing is the technique of choice for identifying G. adiacens and A. defectiva, and early surgical intervention should be considered when G. adiacens endocarditis is diagnosed.
Journal of Hospital Infection, 2008
Norovirus outbreaks occur worldwide every year and have become more frequent over the last few ye... more Norovirus outbreaks occur worldwide every year and have become more frequent over the last few years. There were extensive outbreaks in Hong Kong from May to July 2006 and our aim was to describe nosocomial outbreaks from 1 May 2006 to 31 July 2006 in this retrospective observational study. A total of 38 confirmed norovirus outbreaks involving 218 patients were identified. Most of these patients were elderly with a mean age of 74.5 years (range: 3 months to 97 years); 62% of them were either totally or partially dependent for help with daily activities, 83.9% had underlying chronic medical problems and 56% had limited mobility. In all, 97.2% of individuals presented with diarrhoea and only 46.3% of them had vomiting. The median duration for diarrhoea was 3 days and the longest 24 days. The median duration of vomiting was one day and the longest 15 days. Fever occurred in one-third of all cases. Reverse transcriptase-polymerase chain reaction was positive for norovirus in 72.6% cases. We conclude that nosocomial norovirus infection often involves frail elderly patients with limited mobility and that these patients may have more prolonged symptoms.
Journal of Clinical Microbiology, 2005
tein sequences showed that HPIV-4 isolates among the cases were genetically similar, whereas the ... more tein sequences showed that HPIV-4 isolates among the cases were genetically similar, whereas the community controls were more genetically distant, supporting nosocomial transmission of a single HPIV-4 genotype during the outbreak. Moreover, the HPIV-4 causing the outbreak is more closely related to HPIV-4A than HPIV-4B. HPIV-4 may be an important cause of more severe respiratory illness in children. The present RT-PCR assay is a sensitive, specific, and rapid method for the diagnosing HPIV-4 infection. To better define the epidemiology and clinical spectrum of disease of HPIV-4 infections, HPIV-4 should be included in the routine panels of respiratory virus detection on respiratory specimens.
Journal of Clinical Microbiology, 2005
Two hundred nonduplicate methicillin-resistant Staphylococcus aureus (MRSA) isolates causing bact... more Two hundred nonduplicate methicillin-resistant Staphylococcus aureus (MRSA) isolates causing bacteremia in patients in four major Hong Kong hospitals during the period 2000 to 2001 were characterized by antibiogram, pulsed-field gel electrophoresis (PFGE) using SmaI restriction enzymes, and determination of staphylococcal cassette chromosome mec (SCCmec) types. Nine PFGE types, A to I, were obtained. PFGE type A constituted 50% (99/200) of all isolates and was present in isolates from all four hospitals. PFGE types A to E, had previously been identified as the major types at one of the hospitals from 1988 to 2000. The majority had a resistance profile to tetracycline (T), erythromycin (E), clindamycin (D), gentamicin (G), tobramycin (To), and ciprofloxacin (Ci), and belonged to SCCmec type III; and representatives belonged to clonal complex 239 (CC239) (MRSA with SCCmec type III and sequence type 239, designated ST239-MRSA-III).
International Journal of Radiation Oncology*Biology*Physics, 2005
To determine the feasibility of and patient outcomes using customized high-dose-rate (HDR) brachy... more To determine the feasibility of and patient outcomes using customized high-dose-rate (HDR) brachytherapy to boost the nasopharynx after external beam radiation therapy (EBRT) in patients with carcinoma of the nasopharynx. Patients with nonmetastatic squamous cell carcinoma of the nasopharynx were treated using EBRT followed by a HDR brachytherapy boost delivered via customized catheters in a noninvasive, accurate, and reproducible method under direct fiber-optic visualization. Local control (LC), disease-free survival (DFS), and overall survival (OS) were analyzed. We also measured the change in maximum oral aperture as an indication of temporomandibular joint dysfunction. Between March 1996 and July 2003, we treated 38 patients with this customized brachytherapy method. The procedure was well tolerated without any incidents of soft-tissue or bone necrosis and with minimal decrease of oral aperture. Median follow-up time was 47 months (range, 2-84 months); 35 patients had at least 1 year of follow-up. The 5-year actuarial rate of LC, DFS, and OS were 96.0%, 81.4%, and 92.7%, respectively. The treatment has been well tolerated by all patients. The combination of conformal EBRT with our customized HDR brachytherapy boost has resulted in excellent local control to date, while minimizing temporomandibular joint dysfunction.
International Journal of Cancer, 2005
Nasopharyngeal carcinoma (NPC) is well known for its peculiarly skewed distribution with highest ... more Nasopharyngeal carcinoma (NPC) is well known for its peculiarly skewed distribution with highest incidence in Southern Chinese population. Familial aggregation is evident, hence screening for early detection is offered by oncology centers in Hong Kong to first-degree relatives of patients with NPC. During the period 1994-2001, 929 family members were screened in our center. The screenees were advised to attend an annual examination that includes serological test against Epstein Barr Virus (EBV), physical examination to exclude cervical lymphadenopathy and cranial nerve palsy, and endoscopic examination of the nasopharyngeal region. Two different methods were used for the serology test: indirect immuno-fluorescent (IF) test for IgA against viral capsid antigen; and starting in 1997 enzyme-linked immunosorbent assay (ELIZA) against nuclear antigen and viral capsid antigen. Twelve cases of nasopharyngeal carcinoma were diagnosed, giving a detection rate of 5/1,155 (433/100,000) person-year for male and 7/1,404 (499/100,000) person-year for female participants observed. The corresponding average annual incidence in Hong Kong during this period was 24.1 and 9.6 per 100,000, respectively. Forty-one percent of these detected cases had Stage I disease, whereas only 2% of patients referred to the department for primary treatment presented with such early disease. Six cases were detected at first visit, and all were EBV-positive. Another 78 screenees with positive serology at first visit were followed up for 204 person years, and thus far NPC was detected in 3 after an interval of 6-32 months. Of the 845 initially EBV-negative screenees followed up for 2,337 person-years, NPC was detected in 3 after an interval of 12-45 months. One showed sero-conversion at the time of diagnosis. We conclude that family members of known patients do show a substantially higher risk of developing NPC, and regular screening by current method improves the chance of early detection.
Gut, 1996
Background-A study was conducted to evaluate the prevalence of metronidazole resistant Helicobact... more Background-A study was conducted to evaluate the prevalence of metronidazole resistant Helicobacter pyloni strains
Diagnostic Microbiology and Infectious Disease, 2009
Rapid diagnosis of influenza can facilitate timely clinical management. We evaluated the performa... more Rapid diagnosis of influenza can facilitate timely clinical management. We evaluated the performance of the QuickVue Influenza A + B test (Quidel, San Diego, CA) in a community setting and investigated the factors affecting test sensitivity. We recruited 1008 subjects from 30 outpatient clinics in Hong Kong between February and September 2007. Each subject provided 2 pooled pairs of nose and throat swabs; 1 pair was tested by the QuickVue rapid test on site, and the other pair was sent to a laboratory for reference tests. Among 998 enrolled subjects with valid results, the rapid test had overall sensitivity of 0.68 and specificity of 0.96 compared with viral culture. Sensitivity for both influenza A and B was significantly higher for specimens with viral loads greater than 5 log(10) copies/mL. The QuickVue Influenza A + B test has similar sensitivity in point-of-care community settings to more controlled conditions.
Diagnostic Microbiology and Infectious Disease, 2008
This prospective study assessed the epidemiology of community-associated methicillin-resistant St... more This prospective study assessed the epidemiology of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) among patients with purulent skin and soft tissue infections (SSTIs) in Hong Kong. Among 298 patients with SSTIs, 10.4% (13/125) of all S. aureus isolates and 5% (12/241) of all abscesses were attributed to pvl-positive CA-MRSA. Overall, 77% and 69.9% of CA-MRSA and methicillin-sensitive S. aureus (MSSA) were susceptible to erythromycin, 77% and 74.8% to clindamycin, 100% and 97.1% to minocycline, and 100% and 98.1% to rifampin, respectively. Filipino ethnicity was the only clinical and epidemiologic factor significantly associated with CA-MRSA infection (odds ratio, 14.8; 95% confidence interval, 3.3-70.0; P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). Pulsed-field gel electrophoresis analysis showed that 6 CA-MRSA isolates belonged to the ST30-HKU100 clone, 5 belonged to the ST59-HKU200 clone, and 1 was singleton. Features of HKU100 isolates include SCCmec type IV, agr3, spa t019, and pan-susceptibility to non-beta-lactam antibiotics. In contrast, HKU200 isolates are characterized by having SCCmec type IV or V, agr4, spa t437, and variable non-beta-lactam susceptibility profiles. The major CA-MRSA spa types were shared by a minority of the MSSA.
Clinical Infectious Diseases, 2001
Limited data are available about the impact of antimicrobial resistance on clinical outcomes in c... more Limited data are available about the impact of antimicrobial resistance on clinical outcomes in cases of pneumococcal pneumonia. This was studied in 146 persons hospitalized with invasive pneumonia due to Streptococcus pneumoniae (minimum inhibitory concentration of cefotaxime, > or = .25 microg/mL) who were identified through population-based active surveillance for the period of November 1994 through April 1996. Compared with matched control subjects who had infection with more-susceptible S. pneumoniae, the proportion of subjects who died or who were admitted to an intensive care unit did not differ significantly. Multivariable analysis showed no significant contribution of antimicrobial resistance to mortality or the requirement for care in an intensive care unit. The ability to detect an effect of antimicrobial resistance on these important outcome measures may have been influenced by aggressive multidrug empirical therapy in this group of hospitalized patients. Factors other than resistance, such as severity of illness at presentation and advance directive status ("do not resuscitate" orders), appear to have a stronger influence on pneumococcal pneumonia outcomes.
European Journal of …, 2003
The aim of this study was to assess the clinical spectrum of peripartum tuberculosis from the per... more The aim of this study was to assess the clinical spectrum of peripartum tuberculosis from the perspective of immunorestitution disease. Of 29 patients with peripartum tuberculosis, 27 (93.1%) had extrapulmonary tuberculosis, 20 (69%) of whom were affected in the central ...
Journal of clinical microbiology, 1999
The relationship between the phenotypic and genotypic characteristics of 105 penicillin-intermedi... more The relationship between the phenotypic and genotypic characteristics of 105 penicillin-intermediate or -resistant Streptococcus pneumoniae isolates saved during 1994 to 1997 at the Prince of Wales Hospital and Pamela Youde Nethersole Eastern Hospital, Hong Kong, was studied. The pbp genes for penicillin-binding proteins 1a, 2b, and 2x for each isolate were amplified by PCR, and the products were digested with restriction enzymes HinfI and AluI. A combination of the pulsed-field gel electrophoresis (PFGE) profiles, pbp fingerprints, and phenotypic characteristics of capsular types and antibiograms enabled these isolates to be divided into four major groups. Seventy-four percent (78 of 105) of the strains, belonging to serotypes 23F, 19F, and 14, showed indistinguishable pbp fingerprint patterns (group A1, 1-1-1, 1-1-1), with PFGE patterns belonging to group A and its subtypes, suggesting that these strains were closely related. Eighty-three percent (65 of 78) of these isolates were ...
PLoS ONE, 2008
Background: There are sparse data on whether non-pharmaceutical interventions can reduce the spre... more Background: There are sparse data on whether non-pharmaceutical interventions can reduce the spread of influenza. We implemented a study of the feasibility and efficacy of face masks and hand hygiene to reduce influenza transmission among Hong Kong household members.
BMC infectious diseases, 2006
Cytokines play important roles in antiviral action. We examined whether polymorphisms of IFN-gamm... more Cytokines play important roles in antiviral action. We examined whether polymorphisms of IFN-gamma,TNF-alpha and IL-10 affect the susceptibility to and outcome of severe acute respiratory syndrome (SARS). A case-control study was carried out in 476 Chinese SARS patients and 449 healthy controls. We tested the polymorphisms of IFN-gamma,TNF-alpha and IL-10 for their associations with SARS. IFN-gamma +874A allele was associated with susceptibility to SARS in a dose-dependent manner (P < 0.001). Individuals with IFN-gamma +874 AA and AT genotype had a 5.19-fold (95% Confidence Interval [CI], 2.78-9.68) and 2.57-fold (95% CI, 1.35-4.88) increased risk of developing SARS respectively. The polymorphisms of IL-10 and TNF-alpha were not associated with SARS susceptibility. IFN-gamma +874A allele was shown to be a risk factor in SARS susceptibility.
Journal of Clinical Microbiology, 2003
A new selective medium, cefoperazone MacConkey agar (CMA), was developed for primary isolation of... more A new selective medium, cefoperazone MacConkey agar (CMA), was developed for primary isolation of Laribacter hongkongensis from stool. Its performance in quantitative recovery and in a clinical evaluation of 4,741 human diarrheal stool specimens was superior to that of charcoal cefoperazone deoxycholate agar. In addition, with CMA, Arcobacter butzleri was unexpectedly isolated from the stools of six patients.
Asia Pacific Family Medicine, 2009
To determine the use of antibiotics by primary care doctors.
Few data are available about the effectiveness of nonpharmaceutical interventions for preventing ... more Few data are available about the effectiveness of nonpharmaceutical interventions for preventing influenza virus transmission. To investigate whether hand hygiene and use of facemasks prevents household transmission of influenza. Cluster randomized, controlled trial. Randomization was computer generated; allocation was concealed from treating physicians and clinics and implemented by study nurses at the time of the initial household visit. Participants and personnel administering the interventions were not blinded to group assignment. (ClinicalTrials.gov registration number: NCT00425893) Households in Hong Kong. 407 people presenting to outpatient clinics with influenza-like illness who were positive for influenza A or B virus by rapid testing (index patients) and 794 household members (contacts) in 259 households. Lifestyle education (control) (134 households), hand hygiene (136 households), or surgical facemasks plus hand hygiene (137 households) for all household members. Influenza virus infection in contacts, as confirmed by reverse-transcription polymerase chain reaction (RT-PCR) or diagnosed clinically after 7 days. Sixty (8%) contacts in the 259 households had RT-PCR-confirmed influenza virus infection in the 7 days after intervention. Hand hygiene with or without facemasks seemed to reduce influenza transmission, but the differences compared with the control group were not significant. In 154 households in which interventions were implemented within 36 hours of symptom onset in the index patient, transmission of RT-PCR-confirmed infection seemed reduced, an effect attributable to fewer infections among participants using facemasks plus hand hygiene (adjusted odds ratio, 0.33 [95% CI, 0.13 to 0.87]). Adherence to interventions varied. The delay from index patient symptom onset to intervention and variable adherence may have mitigated intervention effectiveness. Hand hygiene and facemasks seemed to prevent household transmission of influenza virus when implemented within 36 hours of index patient symptom onset. These findings suggest that nonpharmaceutical interventions are important for mitigation of pandemic and interpandemic influenza. Centers for Disease Control and Prevention.
Respirology, 2004
There is so far no consensus on the optimal treatment strategy for the coronavirus-associated sev... more There is so far no consensus on the optimal treatment strategy for the coronavirus-associated severe acute respiratory syndrome (SARS). We aimed to analyse the outcomes of a standard treatment strategy comprising antibiotics, a combination of ribavirin, a 3-week step-down course of corticosteroids, and the possibility of pulsed methylprednisolone rescue in the event of deterioration. This was a prospective cohort study performed at a major public-funded hospital in Hong Kong. Eighty-eight World Health Organisation/Centers for Disease Control and Prevention probable cases of SARS (97% laboratory-confirmed) were treated with a standard protocol previously reported. Seventy-one patients treated de novo were analysed in detail with regard to time to clinical stabilization after combination treatment, requirement of additional therapy (pulsed methylprednisolone; assisted ventilation); and final outcomes (recovery, mortality). The mean age was 42. Twenty-one patients (24%) had comorbidities. Three of 71 treated de novo recovered with antibiotics alone. The remaining 68 received combination treatment at a mean of 5.8 days after symptom onset, of whom 30 subsequently required pulsed methylprednisolone rescue (independent predictors: older age and higher LDH) and 18 required assisted ventilation (independent predictors: older age, higher oxygen requirement and creatinine level). Their median time to clinical stabilization was 8.0 days after combination treatment (independent predictor for longer time to stabilization: median age of 41 or above). Common complications were hyperglycaemia (58%), pneumo-mediastinum/thoraces (13%), psychiatric manifestations (7%) and ventilator-associated pneumonia (2%). One patient (1%) died of SARS-related respiratory failure. All-cause mortality was 3.4%, occurring in patients aged &amp;amp;amp;amp;amp;gt; 65 years only. None of the discharged survivors required continuation of oxygen therapy. This standard treatment protocol resulted in overall satisfactory outcomes. Randomized controlled trial is suggested to confirm its efficacy.
The Lancet, 2004
Laribacter hongkongensis has been recovered from several patients with gastroenteritis. However, ... more Laribacter hongkongensis has been recovered from several patients with gastroenteritis. However, the causative role of this organism in human gastroenteritis is still unproven, and sources of the bacterium are unknown. We undertook a multicentre case-control study to investigate the association of L hongkongensis with gastroenteritis. Faecal samples from patients with community-acquired gastroenteritis and controls were cultured for L hongkongensis. Targeted food surveillance was done to identify potential sources of this bacterium. All isolates of this organism from patients and food items were characterised by pulsed-field gel electrophoresis and ribotyping. During a 4-month period, L hongkongensis was recovered from 17 of 3788 patients with community-acquired gastroenteritis, but was absent in 1894 controls (p=0.001). Those who were culture-positive for this bacterium had a recent history of travel (ten [59%] patients vs two [6%] of 34 matched controls, p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001), of fish consumption (16 [94%] vs 19 [56%], p=0.009), and of eating minced freshwater fish meat (five [29%] vs one [3%], p=0.012). We recovered 25 L hongkongensis isolates from intestinal samples of freshwater fish and two from minced freshwater fish meat. Bacteria with the same pulsed-field gel electrophoretic pattern and ribotype were recovered from one patient and a sample of minced freshwater fish meat, which was from the same retail market recently visited by the patient. We did not see this particular combination of electrophoretic pattern and ribotype in any other isolates. L hongkongensis is associated with community-acquired gastroenteritis and traveller&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s diarrhoea. However, its causative role has not been shown. Freshwater fish is one source of this bacterium.
Journal of Medical Microbiology, 2003
Traditionally, the identification, epidemiology and spectrum of clinical diseases caused by Granu... more Traditionally, the identification, epidemiology and spectrum of clinical diseases caused by Granulicatella adiacens and Abiotrophia defectiva are dependent upon their phenotypic characterization. During a 6-year period (July 1995-June 2001), seven and two AE-haemolytic streptococci were identified as G. adiacens and A. defectiva, respectively, by 16S rRNA gene sequencing. Three patients with haematological malignancies and neutropenic fever had primary bacteraemia. Three patients with valvular problems or congenital heart disease had infective endocarditis. A patient with ischemic heart disease and cerebrovascular accident had infected aortic atheroma with dissection. A patient with recurrent pyogenic cholangitis had acute cholangitis and a patient with polypoid cystitis and benign prostatic hypertrophy had acute prostatitis. Four of the nine patients died, including all three with G. adiacens infective endocarditis or infected atheroma. For the seven G. adiacens isolates, the API 20 STREP system successfully identified one and five isolates as G. adiacens with .95 % and 80-90 % confidence, respectively, whereas the Vitek System (GPI) and ATB Expression system (ID32 STREP) successfully identified none and one isolate as G. adiacens. Of the two A. defectiva isolates, none of the three systems successfully identified either of them as A. defectiva. 16S rRNA gene sequencing is the technique of choice for identifying G. adiacens and A. defectiva, and early surgical intervention should be considered when G. adiacens endocarditis is diagnosed.
Journal of Hospital Infection, 2008
Norovirus outbreaks occur worldwide every year and have become more frequent over the last few ye... more Norovirus outbreaks occur worldwide every year and have become more frequent over the last few years. There were extensive outbreaks in Hong Kong from May to July 2006 and our aim was to describe nosocomial outbreaks from 1 May 2006 to 31 July 2006 in this retrospective observational study. A total of 38 confirmed norovirus outbreaks involving 218 patients were identified. Most of these patients were elderly with a mean age of 74.5 years (range: 3 months to 97 years); 62% of them were either totally or partially dependent for help with daily activities, 83.9% had underlying chronic medical problems and 56% had limited mobility. In all, 97.2% of individuals presented with diarrhoea and only 46.3% of them had vomiting. The median duration for diarrhoea was 3 days and the longest 24 days. The median duration of vomiting was one day and the longest 15 days. Fever occurred in one-third of all cases. Reverse transcriptase-polymerase chain reaction was positive for norovirus in 72.6% cases. We conclude that nosocomial norovirus infection often involves frail elderly patients with limited mobility and that these patients may have more prolonged symptoms.
Journal of Clinical Microbiology, 2005
tein sequences showed that HPIV-4 isolates among the cases were genetically similar, whereas the ... more tein sequences showed that HPIV-4 isolates among the cases were genetically similar, whereas the community controls were more genetically distant, supporting nosocomial transmission of a single HPIV-4 genotype during the outbreak. Moreover, the HPIV-4 causing the outbreak is more closely related to HPIV-4A than HPIV-4B. HPIV-4 may be an important cause of more severe respiratory illness in children. The present RT-PCR assay is a sensitive, specific, and rapid method for the diagnosing HPIV-4 infection. To better define the epidemiology and clinical spectrum of disease of HPIV-4 infections, HPIV-4 should be included in the routine panels of respiratory virus detection on respiratory specimens.
Journal of Clinical Microbiology, 2005
Two hundred nonduplicate methicillin-resistant Staphylococcus aureus (MRSA) isolates causing bact... more Two hundred nonduplicate methicillin-resistant Staphylococcus aureus (MRSA) isolates causing bacteremia in patients in four major Hong Kong hospitals during the period 2000 to 2001 were characterized by antibiogram, pulsed-field gel electrophoresis (PFGE) using SmaI restriction enzymes, and determination of staphylococcal cassette chromosome mec (SCCmec) types. Nine PFGE types, A to I, were obtained. PFGE type A constituted 50% (99/200) of all isolates and was present in isolates from all four hospitals. PFGE types A to E, had previously been identified as the major types at one of the hospitals from 1988 to 2000. The majority had a resistance profile to tetracycline (T), erythromycin (E), clindamycin (D), gentamicin (G), tobramycin (To), and ciprofloxacin (Ci), and belonged to SCCmec type III; and representatives belonged to clonal complex 239 (CC239) (MRSA with SCCmec type III and sequence type 239, designated ST239-MRSA-III).
International Journal of Radiation Oncology*Biology*Physics, 2005
To determine the feasibility of and patient outcomes using customized high-dose-rate (HDR) brachy... more To determine the feasibility of and patient outcomes using customized high-dose-rate (HDR) brachytherapy to boost the nasopharynx after external beam radiation therapy (EBRT) in patients with carcinoma of the nasopharynx. Patients with nonmetastatic squamous cell carcinoma of the nasopharynx were treated using EBRT followed by a HDR brachytherapy boost delivered via customized catheters in a noninvasive, accurate, and reproducible method under direct fiber-optic visualization. Local control (LC), disease-free survival (DFS), and overall survival (OS) were analyzed. We also measured the change in maximum oral aperture as an indication of temporomandibular joint dysfunction. Between March 1996 and July 2003, we treated 38 patients with this customized brachytherapy method. The procedure was well tolerated without any incidents of soft-tissue or bone necrosis and with minimal decrease of oral aperture. Median follow-up time was 47 months (range, 2-84 months); 35 patients had at least 1 year of follow-up. The 5-year actuarial rate of LC, DFS, and OS were 96.0%, 81.4%, and 92.7%, respectively. The treatment has been well tolerated by all patients. The combination of conformal EBRT with our customized HDR brachytherapy boost has resulted in excellent local control to date, while minimizing temporomandibular joint dysfunction.
International Journal of Cancer, 2005
Nasopharyngeal carcinoma (NPC) is well known for its peculiarly skewed distribution with highest ... more Nasopharyngeal carcinoma (NPC) is well known for its peculiarly skewed distribution with highest incidence in Southern Chinese population. Familial aggregation is evident, hence screening for early detection is offered by oncology centers in Hong Kong to first-degree relatives of patients with NPC. During the period 1994-2001, 929 family members were screened in our center. The screenees were advised to attend an annual examination that includes serological test against Epstein Barr Virus (EBV), physical examination to exclude cervical lymphadenopathy and cranial nerve palsy, and endoscopic examination of the nasopharyngeal region. Two different methods were used for the serology test: indirect immuno-fluorescent (IF) test for IgA against viral capsid antigen; and starting in 1997 enzyme-linked immunosorbent assay (ELIZA) against nuclear antigen and viral capsid antigen. Twelve cases of nasopharyngeal carcinoma were diagnosed, giving a detection rate of 5/1,155 (433/100,000) person-year for male and 7/1,404 (499/100,000) person-year for female participants observed. The corresponding average annual incidence in Hong Kong during this period was 24.1 and 9.6 per 100,000, respectively. Forty-one percent of these detected cases had Stage I disease, whereas only 2% of patients referred to the department for primary treatment presented with such early disease. Six cases were detected at first visit, and all were EBV-positive. Another 78 screenees with positive serology at first visit were followed up for 204 person years, and thus far NPC was detected in 3 after an interval of 6-32 months. Of the 845 initially EBV-negative screenees followed up for 2,337 person-years, NPC was detected in 3 after an interval of 12-45 months. One showed sero-conversion at the time of diagnosis. We conclude that family members of known patients do show a substantially higher risk of developing NPC, and regular screening by current method improves the chance of early detection.
Gut, 1996
Background-A study was conducted to evaluate the prevalence of metronidazole resistant Helicobact... more Background-A study was conducted to evaluate the prevalence of metronidazole resistant Helicobacter pyloni strains
Diagnostic Microbiology and Infectious Disease, 2009
Rapid diagnosis of influenza can facilitate timely clinical management. We evaluated the performa... more Rapid diagnosis of influenza can facilitate timely clinical management. We evaluated the performance of the QuickVue Influenza A + B test (Quidel, San Diego, CA) in a community setting and investigated the factors affecting test sensitivity. We recruited 1008 subjects from 30 outpatient clinics in Hong Kong between February and September 2007. Each subject provided 2 pooled pairs of nose and throat swabs; 1 pair was tested by the QuickVue rapid test on site, and the other pair was sent to a laboratory for reference tests. Among 998 enrolled subjects with valid results, the rapid test had overall sensitivity of 0.68 and specificity of 0.96 compared with viral culture. Sensitivity for both influenza A and B was significantly higher for specimens with viral loads greater than 5 log(10) copies/mL. The QuickVue Influenza A + B test has similar sensitivity in point-of-care community settings to more controlled conditions.
Diagnostic Microbiology and Infectious Disease, 2008
This prospective study assessed the epidemiology of community-associated methicillin-resistant St... more This prospective study assessed the epidemiology of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) among patients with purulent skin and soft tissue infections (SSTIs) in Hong Kong. Among 298 patients with SSTIs, 10.4% (13/125) of all S. aureus isolates and 5% (12/241) of all abscesses were attributed to pvl-positive CA-MRSA. Overall, 77% and 69.9% of CA-MRSA and methicillin-sensitive S. aureus (MSSA) were susceptible to erythromycin, 77% and 74.8% to clindamycin, 100% and 97.1% to minocycline, and 100% and 98.1% to rifampin, respectively. Filipino ethnicity was the only clinical and epidemiologic factor significantly associated with CA-MRSA infection (odds ratio, 14.8; 95% confidence interval, 3.3-70.0; P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). Pulsed-field gel electrophoresis analysis showed that 6 CA-MRSA isolates belonged to the ST30-HKU100 clone, 5 belonged to the ST59-HKU200 clone, and 1 was singleton. Features of HKU100 isolates include SCCmec type IV, agr3, spa t019, and pan-susceptibility to non-beta-lactam antibiotics. In contrast, HKU200 isolates are characterized by having SCCmec type IV or V, agr4, spa t437, and variable non-beta-lactam susceptibility profiles. The major CA-MRSA spa types were shared by a minority of the MSSA.
Clinical Infectious Diseases, 2001
Limited data are available about the impact of antimicrobial resistance on clinical outcomes in c... more Limited data are available about the impact of antimicrobial resistance on clinical outcomes in cases of pneumococcal pneumonia. This was studied in 146 persons hospitalized with invasive pneumonia due to Streptococcus pneumoniae (minimum inhibitory concentration of cefotaxime, > or = .25 microg/mL) who were identified through population-based active surveillance for the period of November 1994 through April 1996. Compared with matched control subjects who had infection with more-susceptible S. pneumoniae, the proportion of subjects who died or who were admitted to an intensive care unit did not differ significantly. Multivariable analysis showed no significant contribution of antimicrobial resistance to mortality or the requirement for care in an intensive care unit. The ability to detect an effect of antimicrobial resistance on these important outcome measures may have been influenced by aggressive multidrug empirical therapy in this group of hospitalized patients. Factors other than resistance, such as severity of illness at presentation and advance directive status ("do not resuscitate" orders), appear to have a stronger influence on pneumococcal pneumonia outcomes.
European Journal of …, 2003
The aim of this study was to assess the clinical spectrum of peripartum tuberculosis from the per... more The aim of this study was to assess the clinical spectrum of peripartum tuberculosis from the perspective of immunorestitution disease. Of 29 patients with peripartum tuberculosis, 27 (93.1%) had extrapulmonary tuberculosis, 20 (69%) of whom were affected in the central ...