Staphylococcus aureus nasopharyngeal carriage in rural and urban northern Vietnam

BACKGROUND: Staphylococcus aureus is a common human pathogen that can colonise the respiratory tract and cause infection. Here we investigate the risk factors associated with nasopharyngeal carriage of S. aureus (including methicillin-resistant S. aureus [MRSA]) in Vietnam. METHODS: Between February and June 2012, nasal and pharyngeal swabs for S. aureus culture, and demographic and socioeconomic data were taken from 1016 participants in urban and rural northern Vietnam, who were randomly selected from pre-specified age strata. RESULTS: Overall S. aureus prevalence was 303/1016 (29.8%; adjusted for age: 33.8%). Carriage in the main cohort was found to be associated with younger age (≤5 years [OR 3.13, CI 1.62-6.03]; 6-12 [OR 6.87, CI 3.95-11.94]; 13-19 [OR 6.47, CI 3.56-11.74]; 20-29 [OR 4.73, CI 2.40-9.31]; 30-59 [OR 1.74, CI 1.04-2.92); with ≥60 as reference), living in an urban area (OR 1.36, CI 1.01-1.83) and antibiotics use (OR 0.69, CI 0.49-0.96). MRSA was detected in 80/1016 (7.9%). Being aged ≤5 years (OR 4.84, CI 1.47-15.97); 6-12 (OR 10.21, CI 3.54-29.50); 20-29 (OR 4.01, CI 1.09-14.77) and wealth (>3/5 wealth index, OR 1.63 CI 1.01-2.62) were significant risk factors for MRSA carriage. CONCLUSIONS: Nasopharyngeal carriage of S. aureus is present in one-third of the Vietnamese population, and is more prevalent among children. Pharyngeal carriage is more common than nasal carriage. Risk factors for S. aureus (including MRSA) carriage are identified in the community

Strongyloides stercoralis seroprevalence in Vietnam

Strongyloidiasis is a neglected tropical disease caused by the roundworm Strongyloides stercoralis affecting 30-100 million people worldwide. Many Southeast-Asian countries report a high prevalence of S. stercoralis infection but there is little data from Vietnam. Here, we evaluated the seroprevalence of S. stercoralis related to geography, sex and age in Vietnam through serological testing of anonymized sera. Sera (n = 1710, 1340 adults and 270 children) from an anonymized age stratified serum bank from 4 regions in Vietnam between 2012 and 2013 were tested using a commercial Strongyloides ratti IgG ELISA. Seroreactivity was found in 29.1% (390/1340) of adults and 5.5% (15/270) of children. Male adults were more frequently seroreactive than females (33.3% vs 24.9%, p=0.001). The rural central highlands had the highest seroprevalence (42.4% of adults). Seroreactivity in the other regions was 29.9% (Hue) and 26.0% and 18.2% in the large urban centres of Hanoi and Ho Chi Minh City, respectively. We conclude that seroprevalence of S. stercoralis was high in the Vietnamese adult population, especially in rural areas

Strongyloides stercoralis seroprevalence in Vietnam

Strongyloidiasis is a neglected tropical disease caused by the roundworm Strongyloides stercoralis affecting 30-100 million people worldwide. Many Southeast-Asian countries report a high prevalence of S. stercoralis infection but there is little data from Vietnam. Here, we evaluated the seroprevalence of S. stercoralis related to geography, sex and age in Vietnam through serological testing of anonymized sera. Sera (n = 1710, 1340 adults and 270 children) from an anonymized age stratified serum bank from 4 regions in Vietnam between 2012 and 2013 were tested using a commercial Strongyloides ratti IgG ELISA. Seroreactivity was found in 29.1% (390/1340) of adults and 5.5% (15/270) of children. Male adults were more frequently seroreactive than females (33.3% vs 24.9%, p=0.001). The rural central highlands had the highest seroprevalence (42.4% of adults). Seroreactivity in the other regions was 29.9% (Hue) and 26.0% and 18.2% in the large urban centres of Hanoi and Ho Chi Minh City, respectively. We conclude that seroprevalence of S. stercoralis was high in the Vietnamese adult population, especially in rural areas

Klebsiella pneumoniae Oropharyngeal Carriage in Rural and Urban Vietnam and the Effect of Alcohol Consumption

INTRODUCTION: Community acquired K. pneumoniae pneumonia is still common in Asia and is reportedly associated with alcohol use. Oropharyngeal carriage of K. pneumoniae could potentially play a role in the pathogenesis of K. pneumoniae pneumonia. However, little is known regarding K. pneumoniae oropharyngeal carriage rates and risk factors. This population-based cross-sectional study explores the association of a variety of demographic and socioeconomic factors, as well as alcohol consumption with oropharyngeal carriage of K. pneumoniae in Vietnam. METHODS AND FINDINGS: 1029 subjects were selected randomly from age, sex, and urban and rural strata. An additional 613 adult men from a rural environment were recruited and analyzed separately to determine the effects of alcohol consumption. Demographic, socioeconomic, and oropharyngeal carriage data was acquired for each subject. The overall carriage rate of K. pneumoniae was 14.1% (145/1029, 95% CI 12.0%-16.2%). By stepwise logistic regression, K. pneumoniae carriage was found to be independently associated with age (OR 1.03, 95% CI 1.02-1.04), smoking (OR 1.9, 95% CI 1.3-2.9), rural living location (OR 1.6, 95% CI 1.1-2.4), and level of weekly alcohol consumption (OR 1.7, 95% CI 1.04-2.8). CONCLUSION: Moderate to heavy weekly alcohol consumption, old age, smoking, and living in a rural location are all found to be associated with an increased risk of K. pneumoniae carriage in Vietnamese communities. Whether K. pneumoniae carriage is a risk factor for pneumonia needs to be elucidated

Epidemiology and etiology of influenza-like-illness in households in Vietnam; it's not all about the kids!

BACKGROUND: Household studies provide opportunities to understand influenza-like-illness (ILI) transmission, but data from (sub)tropical developing countries are scarce. OBJECTIVE: To determine the viral etiology and epidemiology of ILI in households. STUDY DESIGN: ILI was detected by active case finding amongst a cohort of 263 northern Vietnam households between 2008 and 2013. Health workers collected nose and throat swabs for virus detection by multiplex real-time RT-PCR. RESULTS: ILI was detected at least once in 219 (23.7%) of 945 household members. 271 (62.3%) of 435 nose/throat swabs were positive for at least one of the 15 viruses tested. Six viruses predominated amongst positive swabs: Rhinovirus (28%), Influenza virus (17%), Coronavirus (8%), Enterovirus (5%), Respiratory syncytial virus (3%), Metapneumovirus virus (2.5%) and Parainfluenza virus 3 (1.8%). There was no clear seasonality, but 78% of episodes occurred in Winter/Spring for Influenza compared to 32% for Rhinovirus. Participants, on average, suffered 0.49 ILI, and 0.29 virus-positive ILI episodes, with no significant effects of gender, age, or household size. In contrast to US and Australian community studies, the frequency of ILI decreased as the number of household members aged below 5 years increased (p=0.006). CONCLUSION: The findings indicate the need for tailored ILI control strategies, and for better understanding of how local childcare practices and seasonality may influence transmission and the role of children

Evaluation of the Luminex xTAG Respiratory Viral Panel FAST v2 assay for detection of multiple respiratory viral pathogens in nasal and throat swabs in Vietnam [version 1; referees: 2 approved]

Background: Acute respiratory infections (ARI) are among the leading causes of hospitalization in children ≤5 years old. Rapid diagnostics of viral pathogens is essential to avoid unnecessary antibiotic treatment, thereby slowing down antibiotic-resistance. We evaluated the diagnostic performance of the Luminex xTAG Respiratory Viral Panel FAST v2 against viral specific PCR as reference assays for ARI in Vietnam. Methods: Four hundred and forty two nose and throat swabs were collected in viral transport medium, and were tested with Luminex xTAG Respiratory Viral Panel FAST v2. Multiplex RT-PCR and single RT-PCR were used as references. Results: Overall, viral pathogens were detected in a total count of 270/294 (91.8%, 95% CI 88.1-94.7) by the Luminex among reference assays, whilst 112/6336 (1.8%, 95% CI, 1.4-2.1) of pathogens were detected by the Luminex, but not by reference assays. Frequency of pathogens detected by Luminex and reference assays was 379 and 292, respectively. The diagnostic yield was 66.7% (295/442, 95%CI 62.1-71.1%) for the Luminex assay and 54.1% (239/442, 95% CI, 49.3-58.8%) for reference assays. The Luminex kit had higher yields for all viruses except influenza B virus, respiratory syncytial virus, and human bocavirus. High agreements between both methods [mean (range): 0.91 (0.83-1.00)] were found for 10/15 viral agents. Conclusions: The Luminex assay is a high throughput multiplex platform for rapid detection of common viral pathogens causing ARI. Although the current high cost may prevent Luminex assays from being widely used, especially in limited resource settings where ARI are felt most, its introduction in clinical diagnostics may help reduce unnecessary use of antibiotic prescription