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Enterococcus faecium has become a globally disseminated nosocomial pathogen mainly because of acquisition and diffusion of virulence factors and multidrug resistance determinants, including glycopeptides, which are some of the last resort antimicrobials used to treat more serious infections common in high-risk patients. In this study we investigated and characterized hospital-associated (HA) E. faecium isolates collected at Hue Central Hospital, Vietnam. Our results highlighted the spread among hospital wards of a surprisingly heterogeneous multidrug-resistant E. faecium population comprising five different CC17-related sequence types (STs), of which 46% VREf carry the vanB gene. Whole genome sequencing of selected E. faecium isolates showed that VREf from different STs carried the same chromosomal integrated Tn1549-like transposon, with a highly mutated vanB2-operon, showing an increased level of vancomycin resistance (VanB phenotype) and able, in one isolate, to confer resistance to teicoplanin (VanA incongruent phenotype). Two unusual vanA/vanB 2 -type strains were detected within the vanB 2 -type ST17 population, harbouring a Tn1546-vanA-like transposon in pJEG40-like plasmids. Wg-SNPs-based analysis showed the genetic relatedness of VSEf/VREf of the same STs and indicated lateral exchange of the Tn1549-like element among isolates followed by clonal expansion. Microevolution among ST17 isolates, including the vanA/vanB 2 -type strains, and inter-wards VREf transmission, were highlighted. The use of teicoplanin is strongly discouraged in the study hospital because of the spreading of Tn1549-vanB 2 associated to teicoplanin resistance. A rational use of glycopeptides and effective surveillance measures are required to reduce nosocomial VSEF/VREf spread and to avoid the rise of unusual and misleading VREf genotypes., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

In Vietnam, the high prevalence of Helicobacter pylori infection represents a serious health problem. Virulence genes of H. pylori have been associated to increased risk of severe gastrointestinal diseases and the genetic background differs in geographical areas. We investigated cagA and vacA genotypes of H. pylori from dyspeptic patients from central Vietnam and the correlation with clinical outcomes; we also performed sequencing analysis of partial cagA gene. Overall, 84% of strains were cagA-positive, 75% were East-Asian type with a prevalence of vacAs1i1m1 and vacAs1i1m2 genotypes (66.7% and 33.3%, respectively) and 9% were Western type vacAs1i1m1 (n=4) and vacAs1i1m2 (n=4); vacAs1i2m2 (n=4) and vacAs2i2m2 (n=2) genotypes were associated to cagA-negative. Strains from gastric ulcer and cancer were of East-Asian type, while cagA-negative or Western strains were from gastritis and duodenal ulcer. H. pylori strains from gastric ulcer patients were predominantly vacAs1i1m1 compared to other vacA genotypes (p<0.05). East-Asian type strains vacAs1i1m1 or vacAs1i1m2 were found in gastric cancer patients and also in less severe disease. Phylogenetic tree analysis of CagA sequences showed the co-circulation of H. pylori of different geographical origins with Western sequences closer related to Cambodia, one of the entry of Western strains in Southeast-Asia through human migrations. Sequence analysis revealed in two Western type strains a chimeric CagA-3' region with identity with East-Asian CagA suggesting recombination event in the process of evolution among East-Asian and Western H. pylori strains. Moreover, polymorphism in CagA multimerization (CM) motif was observed including new East-Asian CM motifs. In conclusion, we have found in central Vietnam a geographically dependent diversity of cagA genotype, with higher rates of cagA-negative and Western-type strains compared with other nation's parts that can partly explain the lower risk of gastric cancer. The polymorphism of CM motifs may explain the variability of disease manifestations of vacAs1i1m1 and s1i1m2 East-Asian isolates., (Copyright © 2017. Published by Elsevier B.V.)

Increasing antimicrobial resistance to key antibiotics in Helicobacter pylori has become a main cause of treatment failures in many countries, including Vietnam. For this reason it is advisable to perform antimicrobial sensitivity tests to provide more focused regimens for H. pylori eradication. However, this approach is generally unavailable for H. pylori in Vietnam and the selection of treatment regimens is mainly based on the trend of antibiotic use in the population, resistance development in the region, and history of H. pylori eradication of patients. The aim of this review is to examine the current situation of antimicrobial resistance in Vietnam and suggest management strategies for treatment selection.

Antimicrobial resistance in Helicobacter pylori has increased worldwide and has become a major cause of treatment failure in many countries, including Vietnam. It is advisable to perform an antibiogram to provide optimal regimens for H. pylori eradication. This study evaluated the rate of antibiotic resistance to the four commonly used antibiotics against H. pylori at a tertiary care hospital in Central Vietnam and analysed point mutations in genes related to clarithromycin (CLA) and levofloxacin (LFX) resistance. A total of 92 H. pylori strains from gastric biopsy specimens were tested; 42.4% were resistant to CLA (primary, 34.2%; secondary, 73.7%), 41.3% to LFX (primary, 35.6%; secondary, 63.2%), 76.1% to metronidazole (MTZ) and 1.1% to amoxicillin. Multidrug resistance was observed in 56.5% (primary, 50.7%; secondary, 78.9%) of isolates (P<0.05). The rate of resistance to LFX was significantly higher in females than males (P<0.05). Most of the CLA- and LFX-resistant strains harboured resistance-associated mutations, with common positions at A2143G and T2182C in the 23S rRNA gene and at Asn-87 or Asp-91 in GyrA. Minimum inhibitory concentrations (MICs) increased in strains carrying quadruple mutations in their 23S rRNA gene and in strains with Asn-87 GyrA mutation (P<0.05). One high-level LFX-resistant strain (MIC=32mg/L) had new mutations with a combination of N87A, A88N and V65I. High resistance rates to CLA, MTZ and LFX discourage standard and LFX-based triple therapies as first-line treatment in Vietnam., (Copyright © 2014 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.)