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Abstract Background Vibrio furnissii is an emerging human pathogen closely related to V. fluvialis that causes acute gastroenteritis. V. furnissii infection has been reported to be rarer than V. fluvialis, but a multi-drug resistance plasmid has recently been discovered in V. furnissii. Methods During daily monitoring at a general hospital in Beijing, China, seven V. furnissii strains were collected from patients aged over 14 years who presented with acute diarrhoea between April and October 2018. Genome analysis and comparison were performed for virulence and antimicrobial resistance genes, plasmids and transposon islands, together with phylogenetic analysis. Antimicrobial resistance to 19 antibiotics was investigated using the microbroth dilution method. Virulence phenotypes were investigated based on type VI secretion system (T6SS) expression and using a bacterial killing assay and a haemolysin assay. Results Phylogenetic analysis based on single-nucleotide polymorphisms revealed a closer relationship between V. furnissii and V. fluvialis than between other Vibrio spp. The seven V. furnissii isolates were in different monophyletic clades in the phylogenetic tree, suggesting that the seven cases of gastroenteritis were independent. High resistance to cefazolin, tetracycline and streptomycin was found in the V. furnissii isolates at respective rates of 100.0%, 57.1% and 42.9%, and intermediate resistance to ampicillin/sulbactam and imipenem was observed at respective rates of 85.7% and 85.7%. Of the tested strains, VFBJ02 was resistant to both imipenem and meropenem, while VFBJ01, VFBJ02, VFBJ05 and VFBJ07 were multi-drug resistant. Transposon islands containing antibiotic resistance genes were found on the multi-drug resistance plasmid in VFBJ05. Such transposon islands also occurred in VFBJ07 but were located on the chromosome. The virulence-related genes T6SS, vfh, hupO, vfp and ilpA were widespread in V. furnissii. The results of the virulence phenotype assays demonstrated that our isolated V. furnissii strains encoded an activated T6SS and grew in large colonies with strong beta-haemolysis on blood agar. Conclusion This study showed that diarrhoea associated with V. furnissii occurred sporadically and was more common than expected in the summer in Beijing, China. The antibiotic resistance of V. furnissii has unique characteristics compared with that of V. fluvialis. Fluoroquinolones and third-generation cephalosporins, such as ceftazidime and doxycycline, were effective at treating V. furnissii infection. Continua laboratory-based surveillance is needed for the prevention and control of V. furnissii infection, especially the dissemination of the antibiotic resistance genes in this pathogen.

Background Transmitted drug resistance (TDR) is an important public health issue, because TDRassociated mutation may affect the outcome of antiretroviral treatment potentially or directly. Men who have sex with men (MSM) constitute a major risk group for HIV transmission. However, current reports are scarce on HIV TDR-associated mutations and their co-variation among MSM. Methods Blood samples from 262 newly diagnosed HIV-positive, antiretroviral therapy (ART)-naïve MSM, were collected from January 2011 and December 2013 in Beijing. The polymerase viral genes were sequenced to explore TDR-associated mutations and mutation co-variation. Results A total of 223 samples were sequenced and analyzed. Among them, HIV-1 CRF01_AE are accounted for 60.5%, followed by CRF07_BC (27.8%), subtype B (9.9%), and others. Fiftyseven samples had at least one TDR-associated mutation, mainly including L10I/V (6.3%), A71L/T/V (6.3%), V179D/E (5.4%), and V106I (2.7%), with different distributions of TDRassociated mutations by different HIV-1 subtypes and by each year. Moreover, eight significant co-variation pairs were found between TDR-associated mutations (V179D/E) and seven overlapping polymorphisms in subtype CRF01_AE. Conclusions To date, this work consists the most comprehensive genetic characterization of HIV-1 TDRassociated mutations prevalent among MSM. It provides important information for understanding TDR and viral evolution among Chinese MSM, a population currently at particularly high risk of HIV transmission. [ABSTRACT FROM AUTHOR]