Control of HIV-1 Replication by CD8+ T Cells Specific for Two Novel Pol Protective Epitopes in HIV-1 Subtype A/E Infection.

Although many HIV-1-specific CD8+ T cell epitopes have been identified and used in various HIV-1 studies, most of these epitopes were derived from HIV-1 subtypes B and C. Only 17 well-defined epitopes, none of which were protective, have been identified for subtype A/E infection. The roles of HIV-1-specific T cells have been rarely analyzed for subtype A/E infection. In this study, we identified six novel HLA-B*15:02-restricted optimal HIV-1 subtype A/E epitopes and then analyzed the presentation of these epitopes by HIV-1 subtype A/E virus-infected cells and the T cell responses to these epitopes in treatment-naive HIV-1 subtype A/E-infected HLA-B*15:02+ Vietnamese individuals. Responders to the PolTY9 or PolLF10 epitope had a significantly lower plasma viral load (pVL) than nonresponders among HLA-B*15:02+ individuals, whereas no significant difference in pVL was found between responders to four other epitopes and nonresponders. The breadth of T cell responses to these two Pol epitopes correlated inversely with pVL. These findings suggest that HLA-B*15:02-restricted T cells specific for PolTY9 and PolLF10 contribute to the suppression of HIV-1 replication in HLA-B*15:02+ individuals. The HLA-B*15:02-associated mutation Pol266I reduced the recognition of PolTY9-specific T cells in vitro but did not affect HIV-1 replication by PolTY9-specific T cells in Pol266I mutant virus-infected individuals. These findings indicate that PolTY9-specific T cells suppress replication of the Pol266I mutant virus even though the T cells selected this mutant. This study demonstrates the effective role of T cells specific for these Pol epitopes to control circulating viruses in HIV-1 subtype A/E infection. IMPORTANCE It is expected that HIV-1-specific CD8+ T cells that effectively suppress HIV-1 replication will contribute to HIV-1 vaccine development and therapy to achieve an HIV cure. T cells specific for protective epitopes were identified in HIV-1 subtype B and C infections but not in subtype A/E infection, which is epidemic in Southeast Asia. In the present study, we identified six T cell epitopes derived from the subtype A/E virus and demonstrated that T cells specific for two Pol epitopes effectively suppressed HIV-1 replication in treatment-naive Vietnamese individuals infected with HIV-1 subtype A/E. One of these Pol protective epitopes was conserved among circulating viruses, and one escape mutation was accumulated in the other epitope. This mutation did not critically affect HIV-1 control by specific T cells in HIV-1 subtype A/E-infected individuals. This study identified two protective Pol epitopes and characterized them in cases of HIV-1 subtype A/E infection.

Effect of Difference in Consensus Sequence between HIV-1 Subtype A/E and Subtype B Viruses on Elicitation of Gag-Specific CD8+ T Cells and Accumulation of HLA-Associated Escape Mutations.

The Gag280 mutation is associated with HLA-C*01:02 but not with HLA-B*52:01 in subtype A/E-infected individuals, whereas this mutation is associated with HLA-B*52:01 but not with HLA-C*01:02 in subtype B infections. Although it is known that the Gag280 mutant is selected by HLA-B*52:01-restricted GagRI8 (Gag275-282)-specific T cells in subtype B infections, it remains unknown why this Gag280 mutation is associated with HLA-C*01:02 rather than HLA-B*52:01 in subtype A/E infections. The subtype B and A/E viruses have different consensus sequence, with Thr and Val at Gag280, respectively. To clarify the effect of this difference in Gag280 consensus sequence, we investigated the role of HLA-C*01:02-restricted GagYI9 (Gag277-285)-specific T cells in selection of Gag280 mutations in subtype A/E-infected Vietnamese and subtype B-infected Japanese individuals. GagYI9-4V-specific T cells, which were frequently elicited in Vietnamese individuals infected with the consensus-type A/E virus, failed to recognize GagV280T mutant A/E virus-infected cells. GagYI9-4T mutant epitope-specific T cells, which were weakly elicited in individuals infected with the mutant A/E virus, had weak or no ability to recognize the mutant virus. These results account for the mechanism for selection and accumulation of GagV280T mutants in the case of subtype A/E infections. In contrast, HLA-C*01:02-restricted GagYI9-4T-specific T cells were weakly elicited in Japanese individuals infected with the subtype B virus, explaining why HLA-C*01:02-restricted Gag280 mutations are not accumulated in the case of a subtype B infection. The present study demonstrated that a difference in the Gag280 consensus sequence influenced the elicitation of the GagYI9-specific T cells involved in the accumulation of HLA-C*01:02-associated Gag280 mutations.IMPORTANCE HIV-1 mutations escaped from HIV-specific CD8+ T cells are mostly detected as HLA-associated mutations. A diversity of HLA-associated mutations is somewhat distinct to each race and region, since HLA allele distribution differs among them. A difference in the consensus sequence among HIV-1 subtypes may also influence the diversity of HLA-associated mutations. HLA-C*01:02-associated GagV280T and HLA-B*52:01-associated GagT280A/S mutations were previously identified in HIV-1 subtype A/E-infected and subtype B-infected individuals, respectively, though these subtype viruses have a different consensus sequence at Gag280. We demonstrated that the GagV280T mutant virus was selected by HLA-C*01:02-restricted GagYI9-4V-specific T cells in subtype A/E-infected Vietnamese but that HLA-C*01:02-restricted GagYI9-4T-specific T cells were weakly elicited in subtype B-infected Japanese. Together with our recent study which demonstrated the mechanism for the accumulation of HLA-B*52:01-associated mutations, we clarified the mechanism for the accumulation of different Gag280 mutations and the effect of the difference in the consensus sequence on the accumulation of escape mutations.

Understanding the epidemiology, clinical characteristics, knowledge and barriers to treatment and prevention of malaria among returning international laborers in northern Vietnam: a mixed-methods study.

BACKGROUND: With the decline in local malaria transmission in Vietnam as a result of the National Malaria Control Program (NMCP) elimination activities, a greater focus on the importation and potential reintroduction of transmission are essential to support malaria elimination objectives. METHODS: We conducted a multi-method assessment of the demographics, epidemiology, and clinical characteristics of imported malaria among international laborers returning from African or Southeast Asian countries to Vietnam. Firstly, we conducted a retrospective review of hospital records of patients from January 2014 to December 2016. Secondly, we conducted a mixed-methods prospective study for malaria patients admitted to the study sites from January 2017 to May 2018 using a structured survey with blood sample collection for PCR analysis and in-depth interviews. Data triangulation of the qualitative and quantitative data was used during analysis. RESULTS: International laborers were young (median age 33.0 years IQR 28.0-39.5 years), predominantly male (92%) adults returning mostly from the African continent (84%) who stayed abroad for prolonged periods (median time 13.5 months; IQR 6.0-331.5 months) and were involved in occupations that exposed them to a higher risk of malaria infection. Epidemiological trends were also similar amongst study strands and included the importation of Plasmodium falciparum primarily from African countries and P. vivax from Southeast Asian countries. Of 11 P. malariae and P. ovale infections across two study strands, 10 were imported from the African continent. Participants in the qualitative arm demonstrated limited knowledge about malaria prior to travelling abroad, but reported knowledge transformation through personal or co-worker's experience while abroad. Interestingly, those who had a greater understanding of the severity of malaria presented to the hospital for treatment sooner than those who did not; median of 3 days (IQR 2.0-7.0 days) versus 5 days (IQR 4.0-9.5 days) respectively. CONCLUSION: To address the challenges to malaria elimination raised by a growing Vietnamese international labor force, consideration should be given to appropriately targeted interventions and malaria prevention strategies that cover key stages of migration including pre-departure education and awareness, in-country prevention and prophylaxis, and malaria screening upon return.

Existence of Replication-Competent Minor Variants with Different Coreceptor Usage in Plasma from HIV-1-Infected Individuals.

Cell entry by HIV-1 is mediated by its principal receptor, CD4, and a coreceptor, either CCR5 or CXCR4, with viral envelope glycoprotein gp120. Generally, CCR5-using HIV-1 variants, called R5, predominate over most of the course of infection, while CXCR4-using HIV-1 variants (variants that utilize both CCR5 and CXCR4 [R5X4, or dual] or CXCR4 alone [X4]) emerge at late-stage infection in half of HIV-1-infected individuals and are associated with disease progression. Although X4 variants also appear during acute-phase infection in some cases, these variants apparently fall to undetectable levels thereafter. In this study, replication-competent X4 variants were isolated from plasma of drug treatment-naive individuals infected with HIV-1 strain CRF01_AE, which dominantly carries viral RNA (vRNA) of R5 variants. Next-generation sequencing (NGS) confirmed that sequences of X4 variants were indeed present in plasma vRNA from these individuals as a minor population. On the other hand, in one individual with a mixed infection in which X4 variants were dominant, only R5 replication-competent variants were isolated from plasma. These results indicate the existence of replication-competent variants with different coreceptor usage as minor populations.IMPORTANCE The coreceptor switch of HIV-1 from R5 to CXCR4-using variants (R5X4 or X4) has been observed in about half of HIV-1-infected individuals at late-stage infection with loss of CD4 cell count and disease progression. However, the mechanisms that underlie the emergence of CXCR4-using variants at this stage are unclear. In the present study, CXCR4-using X4 variants were isolated from plasma samples of HIV-1-infected individuals that dominantly carried vRNA of R5 variants. The sequences of the X4 variants were detected as a minor population using next-generation sequencing. Taken together, CXCR4-using variants at late-stage infection are likely to emerge when replication-competent CXCR4-using variants are maintained as a minor population during the course of infection. The present study may support the hypothesis that R5-to-X4 switching is mediated by the expansion of preexisting X4 variants in some cases.

Multi-drug resistance in Streptococcus pneumoniae among children in rural Vietnam more than doubled from 1999 to 2014.

AIM: This study assessed the Streptococcus pneumoniae colonisation rate and susceptibility to antibiotics among preschool children in rural Vietnam. METHOD: Nasopharyngeal samples were collected from 546 preschool children aged 6-59 months living in 460 households in the rural BaVi District of Hanoi and their main caregivers completed questionnaires. The samples were cultured, and the Streptococcus pneumoniae colonisation rate and antibiotic susceptibility were investigated. Resistance data from this 2014 study were compared with studies in 1999 and 2007, to identify 15-year trends, together with clinical isolates from a national surveillance system of 16 Vietnamese hospital laboratories established in 2013. RESULTS: We found that 221/546 (40%) of the cultures were positive for Streptococcus pneumoniae. The susceptibility rates were trimethoprim-sulphamethoxazole (5%), erythromycin (8%), ciprofloxacin (12%), benzyl-penicillin (35%), tetracycline (49%), cefotaxime (55%), moxifloxacin (99%) and vancomycin (99%). All the susceptibility rates were lower in 2014 than 1999 and 2007, except tetracycline. Multi-drug resistance was 80% in 2014, compared to 60% in 2007 and 31% in 1999. Antibiotics was reported used by 191 (35%) within one month, mainly cephalosporins 86 (45%), amoxycillin/ampicillin 69 (36%) and macrolides 30 (16%). CONCLUSION: Streptococcus pneumoniae showed remarkable high resistance to commonly used antibiotics, including cephalosporins. Multi-drug resistance rose from 31% to 80% during the 15-year study period.

Trends in antimicrobial resistance in Neisseria gonorrhoeae in Hanoi, Vietnam, 2017-2019.

BACKGROUND: Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is an emerging global health threat. Surveillance of AMR in N. gonorrhoeae in the Western Pacific Region is important, as resistant strains have typically emerged from this region. There are sparse data regarding antibiotic susceptibility of N. gonorrhoeae from Vietnam. This study aimed to provide updated data on antibiotic susceptibilities in N. gonorrhoeae isolates from Hanoi, Vietnam. METHODS: From 2017 to 2019, 409 N. gonorrhoeae clinical isolates were collected at the National Hospital for Venereology and Dermatology in Hanoi, Vietnam. Antibiotic susceptibility testing was performed by disk diffusion method according to the Clinical and Laboratory Standards Institute (CLSI) protocol. The zone diameters of inhibition were recorded and interpreted according to standard CLSI criteria, except for azithromycin, due to the absence of CLSI interpretation. Categorical variables were analyzed by Chi-square and Fisher's exact tests. Linear regression was used to evaluate zones of inhibition by year. RESULTS: Among the 409 isolates, no isolates were susceptible to penicillin, 98.3% were resistant to ciprofloxacin, and all isolates were susceptible to spectinomycin. There were 122/407 (30.0%) isolates resistant to azithromycin and there was an association between resistance and year (p <  0.01), ranging from 15.3% of isolates in 2017 to 46.7% of the isolates in 2018. Resistance to cefixime was found in 13/406 (3.2%) of isolates and there was no association by year (p = 0.30). Resistance to ceftriaxone occurred in 3/408 (0.7%) of isolates. Linear regression indicated the zone of inhibition diameters decreased by 0.83 mm each year for ceftriaxone (95% CI: - 1.3, - 0.4; p <  0.01) and decreased by 0.83 mm each year (95% CI: - 1.33, - 0.33; p <  0.01) for azithromycin; the association was not significant for cefixime (p = 0.07). CONCLUSIONS: We found decreasing susceptibility of N. gonorrhoeae to ceftriaxone and azithromycin, as well as a high prevalence of resistance to azithromycin, among isolates in Hanoi, Vietnam from 2017 to 2019. The trends of decreasing susceptibility to first-line treatments are concerning and highlight the urgency of addressing antimicrobial resistance in N. gonorrhoeae. Expanded surveillance efforts within the Western Pacific Region are critical to monitoring trends and informing treatment guidelines.

HLA Class I-Mediated HIV-1 Control in Vietnamese Infected with HIV-1 Subtype A/E.

HIV-1-specific cytotoxic T cells (CTLs) play an important role in the control of HIV-1 subtype B or C infection. However, the role of CTLs in HIV-1 subtype A/E infection still remains unclear. Here we investigated the association of HLA class I alleles with clinical outcomes in treatment-naive Vietnamese infected with subtype A/E virus. We found that HLA-C*12:02 was significantly associated with lower plasma viral loads (pVL) and higher CD4 counts and that the HLA-A*29:01-B*07:05-C*15:05 haplotype was significantly associated with higher pVL and lower CD4 counts than those for individuals without these respective genotypes. Nine Pol and three Nef mutations were associated with at least one HLA allele in the HLA-A*29:01-B*07:05-C*15:05 haplotype, with a strong negative correlation between the number of HLA-associated Pol mutations and CD4 count as well as a positive correlation with pVL for individuals with these HLA alleles. The results suggest that the accumulation of mutations selected by CTLs restricted by these HLA alleles affects HIV control.IMPORTANCE Most previous studies on HLA association with disease progression after HIV-1 infection have been performed on cohorts infected with HIV-1 subtypes B and C, whereas few such population-based studies have been reported for cohorts infected with the Asian subtype A/E virus. In this study, we analyzed the association of HLA class I alleles with clinical outcomes for 536 HIV-1 subtype A/E-infected Vietnamese individuals. We found that HLA-C*12:02 is protective, while the HLA haplotype HLA-A*29:01-B*07:05-C*15:05 is deleterious. The individuals with HIV-1 mutations associated with at least one of the HLA alleles in the deleterious HLA haplotype had higher plasma viral loads and lower CD4 counts than those of individuals without the mutations, suggesting that viral adaptation and escape from HLA-mediated immune control occurred. The present study identifies a protective allele and a deleterious haplotype for HIV-1 subtype A/E infection which are different from those identified for cohorts infected with HIV-1 subtypes B and C.

Low concordance of oral and genital HPV infection among male patients with sexually transmitted infections in Vietnam.

BACKGROUND: Human papillomavirus (HPV) causes cancers in men, including penile, anal, and oropharyngeal cancers. This cross-sectional study aimed to investigate the prevalence, the genotypes, and the risk factors of HPV infections in the oral cavity, compared to those in the genitals, among males diagnosed with sexually transmitted infections (STIs) in Vietnam. METHODS: Oral, urinary, penile, and urethral samples were collected from 198 male Vietnamese patients with STIs (median age 31.0 years, range 17-68). HPV DNA was isolated and amplified with PCR, with modified and/or original GP5+/GP6+ primers. Samples were genotyped with a gene array assay and/or population sequencing. RESULTS: HPV DNA was detected in 69 (34.8%) of 198 patients. Of these, 16 patients (8.1%) had infections in the oral cavity and 58 (29.3%) had infections in the genitals (4.5% in the urine, 25.8% in the penis, and 8.1% in the urethra). The concordance of HPV infections between the oral cavity and the genitals was poor (kappa = 0.01). Of the 16 patients with oral HPV DNA, 11 (68.8%) had no HPV DNA in the genitals. In the remaining five patients, HPV DNA was found at both sites, but only one showed similar strains at both sites. In the other four patients, the HPV genotypes were completely discordant between these sites. HPV18 was the most common high-risk HPV genotype in both oral (9/16, 56.3%) and genital (10/58, 17.2%) sites. Multivariable analyses showed that older age (OR 1.05), higher education (OR 2.17), and no knowledge of STIs (OR 4.21) were independent risk factors for genital HPV infections; in contrast, only older age (OR 1.05) was an independent risk factor for oral HPV infections. CONCLUSIONS: The low concordance of HPV genotypes between oral and genital infection sites suggested that the acquisition, persistence, and/or clearance of HPV infections were different between these sites. Although HPV DNA was detected significantly less frequently in oral samples than in genital samples, oral samples should also be used for HPV screening in men.

Genomic analysis of diversity, population structure, virulence, and antimicrobial resistance in Klebsiella pneumoniae, an urgent threat to public health.

Klebsiella pneumoniae is now recognized as an urgent threat to human health because of the emergence of multidrug-resistant strains associated with hospital outbreaks and hypervirulent strains associated with severe community-acquired infections. K. pneumoniae is ubiquitous in the environment and can colonize and infect both plants and animals. However, little is known about the population structure of K. pneumoniae, so it is difficult to recognize or understand the emergence of clinically important clones within this highly genetically diverse species. Here we present a detailed genomic framework for K. pneumoniae based on whole-genome sequencing of more than 300 human and animal isolates spanning four continents. Our data provide genome-wide support for the splitting of K. pneumoniae into three distinct species, KpI (K. pneumoniae), KpII (K. quasipneumoniae), and KpIII (K. variicola). Further, for K. pneumoniae (KpI), the entity most frequently associated with human infection, we show the existence of >150 deeply branching lineages including numerous multidrug-resistant or hypervirulent clones. We show K. pneumoniae has a large accessory genome approaching 30,000 protein-coding genes, including a number of virulence functions that are significantly associated with invasive community-acquired disease in humans. In our dataset, antimicrobial resistance genes were common among human carriage isolates and hospital-acquired infections, which generally lacked the genes associated with invasive disease. The convergence of virulence and resistance genes potentially could lead to the emergence of untreatable invasive K. pneumoniae infections; our data provide the whole-genome framework against which to track the emergence of such threats.

Bacterial bloodstream infections in a tertiary infectious diseases hospital in Northern Vietnam: aetiology, drug resistance, and treatment outcome.

BACKGROUND: Bloodstream infections (BSIs) are associated with high morbidity and mortality worldwide. However their aetiology, antimicrobial susceptibilities and associated outcomes differ between developed and developing countries. Systematic data from Vietnam are scarce. Here we present aetiologic data on BSI in adults admitted to a large tertiary referral hospital for infectious diseases in Hanoi, Vietnam. METHODS: A retrospective study was conducted at the National Hospital for Tropical Diseases between January 2011 and December 2013. Cases of BSI were determined from records in the microbiology department. Case records were obtained where possible and clinical findings, treatment and outcome were recorded. BSI were classified as community acquired if the blood sample was drawn ≤48 h after hospitalization or hospital acquired if >48 h. RESULTS: A total of 738 patients with BSI were included for microbiological analysis. The predominant pathogens were: Klebsiella pneumoniae (17.5%), Escherichia coli (17.3%), Staphylococcus aureus (14.9%), Stenotrophomonas maltophilia (9.6%) and Streptococcus suis (7.6%). The overall proportion of extended spectrum beta-lactamase (ESBL) production among Enterobacteriaceae was 25.1% (67/267 isolates) and of methicillin-resistance in S. aureus (MRSA) 37% (40/108). Clinical data was retrieved for 477 (64.6%) patients; median age was 48 years (IQR 36-60) with 27.7% female. The overall case fatality rate was 28.9% and the highest case fatality was associated with Enterobacteriaceae BSI (34.7%) which accounted for 61.6% of all BSI fatalities. CONCLUSIONS: Enterobacteriaceae (predominantly K. pneumoniae and E. coli) are the most common cause of both community and hospital acquired bloodstream infections in a tertiary referral clinic in northern Vietnam.

Human papillomavirus infection in male patients with STI-related symptoms in Hanoi, Vietnam.

This cross-sectional study investigated the prevalence, genotypes, and risk factors for human papillomavirus (HPV) infection in Hanoi, Vietnam. The study included 192 males (mean age, 32.9 years) with symptoms related to sexually transmitted infections (STI). Urinary, penile, and urethral samples were collected in April and May, 2014. HPV DNA was detected with PCR, performed with modified and/or original GP5(+)/GP6(+) primers. HPV genotypes were determined with a gene array assay. Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) DNA were detected with loop-mediated isothermal amplification. HPV DNA, NG, and CT were detected in 48 (25.0%), 23 (12.0%), and 41 (21.4%) patients, respectively. HPV DNA appeared in penile samples (21.0%, 39/186) more frequently than in urinary (3.1%, 6/191, P < 0.001) and urethral (9.4%, 18/192, P = 0.002) samples. Among patients with HPV, genotype prevalence was: HPV81 (22.9%), HPV52 (18.8%), HPV18 (16.7%), and HPV16 (6.3%). Multiple-type and high risk-type HPV infections were determined in 33.3% and 64.6%, respectively. Multivariate analysis showed a significant association of HPV infection in urethra with younger sexual debut age. HPV52 was the most prevalent high-risk HPV genotype, whereas HPV16 was less common in the male Vietnamese patients with STI-related symptoms. Younger sexual-debut age was a risk factor for HPV infection in urethra.

Characterizing Neisseria meningitidis in Southern Vietnam between 2012 and 2021: A predominance of the chloramphenicol-resistant ST-1576 lineage.

Objectives: Our goal was to describe Invasive Meningococcal Disease (IMD) in Southern Vietnam over the last 10 years. We characterized 109 Neisseria meningitidis strains in Southern Vietnam isolated between 1980s to 2021, that were collected from IMD (n = 44), sexually transmitted infections (n = 2), and healthy carriage (n = 63). Methods: IMD were confirmed by bacterial culture and/or real-time polymerase chain reaction at the national reference laboratory in Pasteur Institute of Ho Chi Minh City (PIHCM). Antimicrobial resistance was determined on 31 IMD and two sexually transmitted infection isolates with E-test for chloramphenicol (CHL), penicillin (PEN), ciprofloxacin (CIP), ceftriaxone (CRO), and rifampicin (RIF). Sequencing was performed for analyzing of multilocus-sequence-typing (MLST), porA, fetA, and antibiotic resistance genes, including gyrA, penA, and rpoB. Results: The incidence rate during this period was 0.02 per 100,000 persons/year. Serogroup B accounted for over 90% of cases (50/54). ST-1576 were mainly responsible for IMD, 27/42 MLST profiles, and associated with CHL resistance. Resistance was prevalent among IMD isolates. Thirteen were resistant to CHL (minimum inhibitory concentration [MIC] ≥16 mg/l), 12 were intermediate to PEN (MIC between 0.19 and 0.5 mg/l), and five were CIP-resistant (MIC between 0.19 and 0.5 mg/l). Particularly, one was non-susceptible to CRO (MIC at 0.125 mg/l), belonging to ST-5571 lineage. The resistance was due to carrying resistant alleles of penA and gyrA genes, and catP gene. Notably, seven isolates were resistant/non-susceptible to two or more antibiotics. Conclusion: Our results suggest the persistence of the circulating ST-1576 in Southern Vietnam, with a spread of antimicrobial resistance across the community.

Antibiotic use and resistance in emerging economies: a situation analysis for Viet Nam.

BACKGROUND: Antimicrobial resistance is a major contemporary public health threat. Strategies to contain antimicrobial resistance have been comprehensively set forth, however in developing countries where the need for effective antimicrobials is greatest implementation has proved problematic. A better understanding of patterns and determinants of antibiotic use and resistance in emerging economies may permit more appropriately targeted interventions.Viet Nam, with a large population, high burden of infectious disease and relatively unrestricted access to medication, is an excellent case study of the difficulties faced by emerging economies in controlling antimicrobial resistance. METHODS: Our working group conducted a situation analysis of the current patterns and determinants of antibiotic use and resistance in Viet Nam. International publications and local reports published between 1-1-1990 and 31-8-2012 were reviewed. All stakeholders analyzed the findings at a policy workshop and feasible recommendations were suggested to improve antibiotic use in Viet Nam.Here we report the results of our situation analysis focusing on: the healthcare system, drug regulation and supply; antibiotic resistance and infection control; and agricultural antibiotic use. RESULTS: Market reforms have improved healthcare access in Viet Nam and contributed to better health outcomes. However, increased accessibility has been accompanied by injudicious antibiotic use in hospitals and the community, with predictable escalation in bacterial resistance. Prescribing practices are poor and self-medication is common - often being the most affordable way to access healthcare. Many policies exist to regulate antibiotic use but enforcement is insufficient or lacking.Pneumococcal penicillin-resistance rates are the highest in Asia and carbapenem-resistant bacteria (notably NDM-1) have recently emerged. Hospital acquired infections, predominantly with multi-drug resistant Gram-negative organisms, place additional strain on limited resources. Widespread agricultural antibiotic use further propagates antimicrobial resistance. CONCLUSIONS: Future legislation regarding antibiotic access must alter incentives for purchasers and providers and ensure effective enforcement. The Ministry of Health recently initiated a national action plan and approved a multicenter health improvement project to strengthen national capacity for antimicrobial stewardship in Viet Nam. This analysis provided important input to these initiatives. Our methodologies and findings may be of use to others across the world tackling the growing threat of antibiotic resistance.

Clinical characteristics and outcome of Penicillium marneffei infection among HIV-infected patients in northern Vietnam.

OBJECTIVE: This study reports the clinical characteristics and outcome of HIV-associated Penicilliummarneffei infection in northern Vietnam. METHODS: We conducted a retrospective chart review of all patients with laboratory confirmed Penicilliummarneffei infection admitted to the National Hospital for Tropical Diseases in Hanoi, Vietnam, between July 2006 and September 2009. RESULTS: 127 patients with P. marneffei infection were identified. All were HIV-infected; median CD4+ T-cell count was 24 cells/µl (IQR:12-48); 76% were men. Common clinical features were fever (92.9%), skin lesions (82.6%), hepatomegaly (61.4%), lymphadenopathy (40.2%), weight loss (59.1%) and cough (49.6%). Concurrent opportunistic infections were present in 22.0%; half of those had tuberculosis. Initial treatment regimens were: itraconazole or ketoconazole capsule (77.2%), amphotericin B (20.5%), and fluconazole (1.6%). In-hospital mortality was 12.6% and showed no significant difference in patients treated with itraconazole (or ketoconazole) and amphotericin B (p = 0.43). Dyspnea, ascites, and increased LDH level were independent predictors of mortality. No seasonality was observed. CONCLUSION: The clinical features, treatments and outcomes of HIV-associated P. marneffei infection in northern Vietnam are similar to those reported in other endemic regions. Dyspnea was an important predictor of mortality. More patients were treated with itraconazole than amphotericin B and no significant difference in treatment outcome was observed. It would be of clinical value to compare the efficacy of oral itraconazole and amphotericin B in a clinical trial.

Prevalence of HBV infection among different HIV-risk groups in Hai Phong, Vietnam.

Hepatitis B virus (HBV) infection in Hai Phong, northern Vietnam, was characterized by analyzing the prevalence and genotype distribution of HBV as well as co-infection with human immunodeficiency virus type 1 (HIV-1) among five different risk groups for HIV infection. Plasma samples were collected from intravenous drug users (n=760, anti-HIV-1 antibody positive rate: 35.9%), female sex workers (FSWs; n=91, 23.1%), seafarers (n=94, 0%), pregnant women (n=200, 0.5%), and blood donors (n=210, 2.9%) in 2007 [Ishizaki et al. (2009): AIDS Res Hum Retroviruses 25:175-182]. Samples were screened for the hepatitis B surface antigen (HBsAg) and anti-HBs antibody and analyzed genetically. The cumulative HBV incidence rate (HBsAg+anti-HBs) was 53.2% (10.7+42.5%) in intravenous drug users, 51.6% (11.0+40.6%) in FSWs, 54.3% (9.6+44.7%) in seafarers, 50.5% (12.5+38.0%) in pregnant women, and 51.0% (18.1+32.9%) in blood donors; there was no significant difference among these groups. Of 163 HBsAg-positive samples, 113 could be analyzed genetically. Phylogenetic analysis, based on the preS1 region, revealed genotype B4 was most prevalent (90/113; 79.6%), followed by C1 (17.7%), I1 (1.8%), and B2 (0.9%). There was no significant difference in HBV genotype distribution among different HIV infection-risk groups. The prevalence of HBsAg was 10.3% (31/301) in HIV-1-infected individuals and 12.5% (132/1,054) in non-HIV-1-infected individuals, which was not significant. In addition, no significant difference in HBV genotype distribution was observed between HBV/HIV-1 coinfected and HBV mono-infected groups. These results suggest that, although HBV and HIV-1 share modes of transmission, major transmission routes of HBV have been different from those of HIV-1 in Hai Phong, Vietnam.

Critical effect of Pol escape mutations associated with detrimental allele HLA-C*15: 05 on clinical outcome in HIV-1 subtype A/E infection.

OBJECTIVE: The mechanism explaining the role of detrimental HLA alleles in HIV-1 infections has been investigated in very few studies. HLA-A*29:01-B*07:05-C*15:05 is a detrimental haplotype in HIV-1 subtype A/E-infected Vietnamese individuals. The accumulation of mutations at Pol 653/657 is associated with a poor clinical outcome in these individuals. However, the detrimental HLA allele and the mechanism responsible for its detrimental effect remains unknown. Therefore, in this current study we identified the detrimental HLA allele and investigated the mechanism responsible for the detrimental effect. DESIGN AND METHODS: A T-cell epitope including Pol 653/657 and its HLA restriction were identified by using overlapping HIV-1 peptides and cell lines expressing a single HLA. The effect of the mutations on the T-cell recognition of HIV-1-infected cells was investigated by using target cells infected with the mutant viruses. The effect of these mutations on the clinical outcome was analyzed in 74 HLA-C*15:05 Vietnamese infected with the subtype A/E virus. RESULTS: We identified HLA-C*15:05-restricted SL9 epitope including Pol 653/657. PolS653A/T/L mutations within this epitope critically impaired the T-cell recognition of HIV-1-infected cells, indicating that these mutations had escaped from the T cells. T-cell responders infected with these mutants showed significantly lower CD4 T-cell counts than those with the wild-type virus or Pol S653K/Q mutants, which are not associated with HLA-C*15:05. CONCLUSION: The accumulation of Pol S653A/T/L escape mutants critically affected the control of HIV-1 by SL9-specific T cells and led to a poor clinical outcome in the subtype A/E-infected individuals having the detrimental HLA-C*15:05 allele.

Complete Genome Sequences, Derived by Next-Generation Sequencing, of JC Polyomavirus Strains Isolated from Vietnamese Renal Transplant Recipients.

JC polyomavirus (JCPyV) may cause clinical syndromes such as progressive multifocal leukoencephalopathy in immunocompromised patients. Here, we report seven complete genome sequences of JCPyV genotype 7A, generated directly from urine samples from Vietnamese renal transplant recipients by using rolling-circle amplification and next-generation sequencing.

Acute febrile myalgia in Vietnam due to trichinellosis following the consumption of raw pork.

Trichinellosis outbreaks occur occasionally in Vietnam following the consumption of undercooked pork. Diagnosing trichinella can be problematic because fever and myalgia are nonspecific, and diagnosis may be delayed. We describe 5 Vietnamese patients in whom trichinellosis was diagnosed after several weeks of illness.

Mutations in the gyrA, parC, and mexR genes provide functional insights into the fluoroquinolone-resistant Pseudomonas aeruginosa isolated in Vietnam.

INTRODUCTION: Pseudomonas aeruginosa has many mechanisms of resistance to fluoroquinolones. The main mechanism is to change the effect of two enzymes that open the DNA helix - the enzyme DNA gyrase (gyrA) and the topoisomerase IV (parC). In addition, mutations that render the MexAB-oprM pump (mexR) dysfunctional, leading to its overexpression, also enhance resistance to fluoroquinolones. In this study, we aim to detect point mutations of gyrA, parC, and mexR genes that are predicted to be associated with fluoroquinolone resistance in 141 fluoroquinolone-resistant clinical isolates of P. aeruginosa isolated in Vietnam during 2013-2016. METHODS: We tested minimum inhibitory concentrations (MICs) of fluoroquinolone antibiotics in 141 clinical isolates of P. aeruginosa using the VITEK 2 Compact System, followed by PCR assay, to detect and clone the fluoroquinolone resistance-determining region (FRDR) of gyrA, parC, and mexR. Point mutations were analyzed through Sanger sequencing, and the correlation between genetic mutations and phenotypic resistance of 141 clinical isolates was undertaken. RESULTS: Fluoroquinolone-resistant substitution mutations such as Ile for Thr83 and Met for Thr133 in gyrA, Leu for Ser87 in parC, and Val for Glu126 in the repressor of mexR were mainly detected. Comparative analytical data indicated that amino acid alterations within the gyrA and parC genes are highly associated with resistance to ciprofloxacin (CIP) and levofloxacin (LEV) in the isolates, whereas alterations in the efflux regulatory mexR gene are not highly consistent with resistance in these isolates. Moreover, fluoroquinolone-resistant clinical isolates of P. aeruginosa were mainly isolated from pus and sputum specimens. CONCLUSION: In clinical isolates of P. aeruginosa, a high correlation was observed between MICs of CIP and LEV and alterations in gyrA and parC genes. However, mutations occurring in mexR did not highly correlate with the antibiotic resistance of the bacterium.