Genetic diversity on the tropical rare wood species of Dalbergia in Vietnam revealed by inter-simple sequence repeat (ISSR) markers

Genetic diversities of three rare hardwood species of Dalbergia (D. assamica, D. nigrescens and D. tonkinensis) were evaluated for conservation based on inter-simple sequence repeat (ISSR) markers. A total of 47 ISSR primers were used for the analysis, but only 31 ISSR primers were successfully amplified for 25 samples from each species. There were 166 fragments across the 75 samples produced, in which 153 were polymorphic with an average of 4.94 polymorphic fragments per primer. The number of amplified fragments ranged from 1 (ISSR13, ISSR54 and ISSR59) to 11 (ISSR14) and their size varied from 200 to 1700 bp. The similarity coefficient ranged from 67.0 to 98.9% in D. assamica; from 71.2 to 98.5% in D. nigrescens and from 68.5 to 95.2% in D. tonkinensis. The estimated value of molecular diversity parameters within species such as the effective number of alleles, Shannon's information index, intralocus gene diversity and Nei’s gene diversity were low among the individuals of the different Dalbergia species (1.227, 0.195, 0.662 and 0.146, respectively in D. assamica; 1.135, 0.111, 0.425 and 0.109, respectively in D. nigrescens; 1.198, 0.166, 0.526 and 0.123, respectively in D. tonkinensis). The analysis of molecular variance (AMOVA) of ISSR data indicated that the greater proportion of total genetic variation existed among species rather than within species. The correlation between genetic and geographic distance was also found in the three Dalbergia species.Key words: Dalbergia, endemic species, genetic similarity, ISSR markers

Risk factors for the development of severe typhoid fever in Vietnam

Background Typhoid fever is a systemic infection caused by the bacterium Salmonella enterica serovar Typhi. Age, sex, prolonged duration of illness, and infection with an antimicrobial resistant organism have been proposed risk factors for the development of severe disease or fatality in typhoid fever. Methods We analysed clinical data from 581 patients consecutively admitted with culture confirmed typhoid fever to two hospitals in Vietnam during two periods in 1993–1995 and 1997–1999. These periods spanned a change in the antimicrobial resistance phenotypes of the infecting organisms i.e. fully susceptible to standard antimicrobials, resistance to chloramphenicol, ampicillin and trimethoprim-sulphamethoxazole (multidrug resistant, MDR), and intermediate susceptibility to ciprofloxacin (nalidixic acid resistant). Age, sex, duration of illness prior to admission, hospital location and the presence of MDR or intermediate ciprofloxacin susceptibility in the infecting organism were examined by logistic regression analysis to identify factors independently associated with severe typhoid at the time of hospital admission. Results The prevalence of severe typhoid was 15.5% (90/581) and included: gastrointestinal bleeding (43; 7.4%); hepatitis (29; 5.0%); encephalopathy (16; 2.8%); myocarditis (12; 2.1%); intestinal perforation (6; 1.0%); haemodynamic shock (5; 0.9%), and death (3; 0.5%). Severe disease was more common with increasing age, in those with a longer duration of illness and in patients infected with an organism exhibiting intermediate susceptibility to ciprofloxacin. Notably an MDR phenotype was not associated with severe disease. Severe disease was independently associated with infection with an organism with an intermediate susceptibility to ciprofloxacin (AOR 1.90; 95% CI 1.18-3.07; p = 0.009) and male sex (AOR 1.61 (1.00-2.57; p = 0.035). Conclusions In this group of patients hospitalised with typhoid fever infection with an organism with intermediate susceptibility to ciprofloxacin was independently associated with disease severity. During this period many patients were being treated with fluoroquinolones prior to hospital admission. Ciprofloxacin and ofloxacin should be used with caution in patients infected with S. Typhi that have intermediate susceptibility to ciprofloxacin

Clinical features of human influenza A (H5N1) infection in Vietnam: 2004-2006.

BACKGROUND: The first cases of avian influenza A (H5N1) in humans in Vietnam were detected in early 2004, and Vietnam has reported the second highest number of cases globally. METHODS: We obtained retrospective clinical data through review of medical records for laboratory confirmed cases of influenza A (H5N1) infection diagnosed in Vietnam from January 2004 through December 2006. Standard data was abstracted regarding clinical and laboratory features, treatment, and outcome. RESULTS: Data were obtained for 67 (72%) of 93 cases diagnosed in Vietnam over the study period. Patients presented to the hospital after a median duration of illness of 6 days with fever (75%), cough (89%), and dyspnea (81%). Diarrhea and mucosal bleeding at presentation were more common in fatal than in nonfatal cases. Common findings were bilateral pulmonary infiltrates on chest radiograph (72%), lymphopenia (73%), and increased serum transaminase levels (aspartate aminotransferase, 69%; alanine aminotransferase, 61%). Twenty-six patients died (case fatality rate, 39%; 95% confidence interval, 27%-51%) and the most reliable predictor of a fatal outcome was the presence of both neutropenia and raised alanine aminotransferase level at admission, which correctly predicted 91% of deaths and 82% of survivals. The risk of death was higher among persons aged < or =16 years, compared with older persons (P < .001), and the risk of death was higher among patients who did not receive oseltamivir treatment (P = .048). The benefit of oseltamivir treatment remained after controlling for potential confounding by 1 measure of severity (odds ratio, 0.15; 95% confidence interval, 0.026-0.893; P = .034). CONCLUSION: In cases of infection with Influenza A (H5N1), the presence of both neutropenia and raised serum transaminase levels predicts a poor outcome. Oseltamivir treatment shows benefit, but treatment with corticosteroids is associated with an increased risk of death

Effect of antituberculosis drug resistance on response to treatment and outcome in adults with tuberculous meningitis.

BACKGROUND: Tuberculous meningitis (TBM) caused by Mycobacterium tuberculosis resistant to 1 or more antituberculosis drugs is an increasingly common clinical problem, although the impact on outcome is uncertain. METHODS: We performed a prospective study of 180 Vietnamese adults admitted consecutively for TBM. M. tuberculosis was cultured from the cerebrospinal fluid (CSF) of all patients and was tested for susceptibility to first-line antituberculosis drugs. Presenting clinical features, time to CSF bacterial clearance, clinical response to treatment, and 9-month morbidity and mortality were compared between adults infected with susceptible and those infected with drug-resistant organisms. RESULTS: Of 180 isolates, 72 (40.0%) were resistant to at least 1 antituberculosis drug, and 10 (5.6%) were resistant to at least isoniazid and rifampicin. Isoniazid and/or streptomycin resistance was associated with slower CSF bacterial clearance but not with any differences in clinical response or outcome. Combined isoniazid and rifampicin resistance was strongly predictive of death (relative risk of death, 11.63 [95% confidence interval, 5.21-26.32]) and was independently associated with human immunodeficiency virus infection. CONCLUSIONS: Isoniazid and/or streptomycin resistance probably has no detrimental effect on the outcome of TBM when patients are treated with first-line antituberculosis drugs, but combined isoniazid and rifampicin resistance is strongly predictive of death

The influence of HIV infection on clinical presentation, response to treatment, and outcome in adults with tuberculous meningitis

BACKGROUND: Tuberculous meningitis occurs more commonly in human immunodeficiency virus (HIV)-infected individuals than in HIV-uninfected individuals, but whether HIV infection alters the presentation and outcome of tuberculous meningitis is unknown. METHODS: We performed a prospective comparison of the presenting clinical features and response to treatment in 528 adults treated consecutively for tuberculous meningitis (96 were infected with HIV and 432 were uninfected with HIV) in 2 tertiary-care referral hospitals in Ho Chi Minh City, Vietnam. Logistic regression was used to model variables associated independently with HIV infection, 9-month survival, and the likelihood of having a relapse or an adverse drug event. Kaplan-Meier estimates were used to compare survival rates and times to fever clearance, coma clearance, relapse, and adverse events. RESULTS: HIV infection did not alter the neurological presentation of tuberculous meningitis, although additional extrapulmonary tuberculosis was more likely to occur in HIV-infected patients. The 9-month survival rate was significantly decreased in HIV-infected patients (relative risk of death from any cause, 2.91 [95% confidence interval, 2.14-3.96]; P < .001), although the times to fever clearance and coma clearance and the number or timing of relapses or adverse drug events were not significantly different between the groups. CONCLUSIONS: HIV infection does not alter the neurological features of tuberculous meningitis but significantly reduces the survival rate

Large scale screening for haemoglobin disorders in southern Vietnam: implications for avoidance and management.

In order to obtain an approximate assessment of the public health burden that will be posed by the inherited disorders of haemoglobin in southern Vietnam, several thousand individuals were screened for these conditions. A smaller sample was screened for glucose-6-phosphate dehydrogenase (G6PD) deficiency. The important haemoglobin disorders identified were beta thalassaemia, haemoglobin E and a variety of different forms of alpha thalassaemia. There were sufficient G6PD-deficient individuals to materially affect malaria control programme design. The most remarkable finding was wide variation in the gene frequencies of these conditions among the ethnic groups sampled. The approximate number of babies expected to be born with clinically significant haemoglobin disorders in Vietnam was estimated from the gene-frequency data. This study emphasizes the importance of wide-scale population screening, including ethnic subgroups, to establish the requirements for inherited haemoglobin disorder programmes in resource-limited settings

Intensified antituberculosis therapy in adults with tuberculous meningitis

BACKGROUND: Tuberculous meningitis is often lethal. Early antituberculosis treatment and adjunctive treatment with glucocorticoids improve survival, but nearly one third of patients with the condition still die. We hypothesized that intensified antituberculosis treatment would enhance the killing of intracerebral Mycobacterium tuberculosis organisms and decrease the rate of death among patients. METHODS: We performed a randomized, double-blind, placebo-controlled trial involving human immunodeficiency virus (HIV)–infected adults and HIV-uninfected adults with a clinical diagnosis of tuberculous meningitis who were admitted to one of two Vietnamese hospitals. We compared a standard, 9-month antituberculosis regimen (which included 10 mg of rifampin per kilogram of body weight per day) with an intensified regimen that included higher-dose rifampin (15 mg per kilogram per day) and levofloxacin (20 mg per kilogram per day) for the first 8 weeks of treatment. The primary outcome was death by 9 months after randomization. RESULTS: A total of 817 patients (349 of whom were HIV-infected) were enrolled; 409 were randomly assigned to receive the standard regimen, and 408 were assigned to receive intensified treatment. During the 9 months of follow-up, 113 patients in the intensified-treatment group and 114 patients in the standard-treatment group died (hazard ratio, 0.94; 95% confidence interval, 0.73 to 1.22; P=0.66). There was no evidence of a significant differential effect of intensified treatment in the overall population or in any of the subgroups, with the possible exception of patients infected with isoniazid-resistant M. tuberculosis. There were also no significant differences in secondary outcomes between the treatment groups. The overall number of adverse events leading to treatment interruption did not differ significantly between the treatment groups (64 events in the standard-treatment group and 95 events in the intensified-treatment group, P=0.08). CONCLUSIONS: Intensified antituberculosis treatment was not associated with a higher rate of survival among patients with tuberculous meningitis than standard treatment. (Funded by the Wellcome Trust and the Li Ka Shing Foundation; Current Controlled Trials number, ISRCTN61649292. opens in new tab.)</p

Timing of initiation of antiretroviral therapy in human immunodeficiency virus (HIV)--associated tuberculous meningitis.

BACKGROUND: The optimal time to initiate antiretroviral therapy (ART) in human immunodeficiency virus (HIV)-associated tuberculous meningitis is unknown. METHODS: We conducted a randomized, double-blind, placebo-controlled trial of immediate versus deferred ART in patients with HIV-associated tuberculous meningitis to determine whether immediate ART reduced the risk of death. Antiretroviral drugs (zidovudine, lamivudine, and efavirenz) were started either at study entry or 2 months after randomization. All patients were treated with standard antituberculosis treatment, adjunctive dexamethasone, and prophylactic co-trimoxazole and were followed up for 12 months. We conducted intention-to-treat, per-protocol, and prespecified subgroup analyses. RESULTS: A total of 253 patients were randomized, 127 in the immediate ART group and 126 in the deferred ART group; 76 and 70 patients died within 9 months in the immediate and deferred ART groups, respectively. Immediate ART was not significantly associated with 9-month mortality (hazard ratio [HR], 1.12; 95% confidence interval [CI], .81-1.55; P = .50) or the time to new AIDS events or death (HR, 1.16; 95% CI, .87-1.55; P = .31). The percentage of patients with severe (grade 3 or 4) adverse events was high in both arms (90% in the immediate ART group and 89% in the deferred ART group; P = .84), but there were significantly more grade 4 adverse events in the immediate ART arm (102 in the immediate ART group vs 87 in the deferred ART group; P = .04). CONCLUSIONS: Immediate ART initiation does not improve outcome in patients presenting with HIV-associated tuberculous meningitis. There were significantly more grade 4 adverse events in the immediate ART arm, supporting delayed initiation of ART in HIV-associated tuberculous meningitis. Clinical Trials Registration. ISRCTN63659091