BackgroundThe aim of this study was to elucidate the molecular epidemiology of carbapenem non-susceptible Enterobacteriaceae(CNSE) isolated in the Eastern region of Heilongjiang Province, China, and the mechanism of carbapenem resistance.MethodsA total of 53 CNSE isolates were collected in a grade-3 hospital in Heilongjiang province. Sensitivity to antibiotics was determined using the VITEK-2 Compact automatic system. The modified Hodge test (MHT) and modified carbapenem inactivation test (mCIM) were performed for phenotypic identification. Beta-lactamases gene were detected by Polymerase chain reaction(PCR) and DNA sequencing. The transfer of blaNDM and blaKPC was investigated through conjugation experiment. The clinical data of patients were retrospectively reviewed. Homology of Carbapenem-resistant Klebsiella pneumoniae(CRKP) was conducted by multilocus sequence typing (MLST).ResultsCNSE were highly resistant to the majority of antimicrobial agents. The resistance rate was 100% for first, third, fourth generation cephalosporins and enzyme inhibitor compounds. Gentamicin and tobramycin recorded a resistance rate higher than 80%. Less than 30% resistance was detected for amikacin and levofloxacin. Among CNSE 52(98.1%) and 48(90.6%) of CNSE were positive for mCIM and MHT respectively. There were 42 positive blaKPC genes, three blaNDM-1 genes, three blaNDM-5 genes, one blaNDM-7 gene, and six blaIMP-4 genes. Most isolates harbored multiple drug resistance gene, especially as related to extended-spectrum-β-lactamases, blaSHV, blaTEM and blaCTX-M-15 genes.The resistant gene was transferred into recipient Escherichia coli J53 through conjugation in 21.3% (10/47) of the strains. MLST revealed that ST76 (n = 36) was the most predominant clone, followed by ST896, ST323 and ST11. A new one ST 2946 was identity by this study.ConclusionThe carbapenem resistance phenomenon is alarming and blaKPC-2 is the main resistant gene of CNSE in our hospital. This is the first report of an outbreak caused by blaKPC-2 positive K. pneumoniae ST76 in the Eastern region of Heilongjiang Province, China. Relevant departments should implement infection control and prevention measures to avoid further dissemination of the multi drug-resistant bacteria (MDR).

BackgroundToll-like receptors (TLR) 7 and 8 are important in single-stranded viral RNA recognition and may play a role in HIV infection and disease progression. We analyzed TLR7/8 expression and signaling in monocytes from HIV-infected and uninfected subjects to investigate a pathway with new potential for the suppression of HIV replication.MethodsEighty-one HIV-infected and uninfected subjects from Liaoning and Henan provinces in China participated in this study. Monocytes were isolated from subjects' peripheral blood mononuclear cells by magnetic bead selection. TLR7 and TLR8 mRNA was measured using quantitative real-time reverse transcriptase PCR. R-848 (resiquimod) was used as a ligand for TLR7 and TLR8 in order to 1) assess TLR7/8-mediated monocyte responsiveness as indicated by IL-12 p40 and TNF-α secretion and 2) to examine HIV replication in cultured monocytes in the presence of R-848.ResultsWe found that expression of TLR7/8 mRNA in peripheral blood monocytes decreased with disease progression. TLR7 expression was decreased with stimulation with the TLR7/8 agonist, R-848, in vitro, whereas TLR8 expression was unaffected. Following R-848 stimulation, monocytes from HIV-infected subjects produced significantly less TNF-α than those from uninfected subjects, but trended towards greater production of IL-12 than stimulated monocytes from uninfected subjects. R-848 stimulation also suppressed HIV replication in cultured monocytes.ConclusionsOur study provides evidence that the TLR7 and TLR8 triggering can suppress HIV replication in monocytes and lead to postpone HIV disease progression, thereby offering novel targets for immunomodulatory therapy.

Background: Carbapenem-resistant hypervirulent Klebsiella pneumoniae strains have recently come into existence worldwide; however, researchers in northeast China are not aware of their clinical features and molecular characteristics. Methods: Here, the molecular and virulent characteristics of 44 carbapenem-resistant K. pneumoniae (CRKP) isolates collected from January 2015 to December 2017 were studied. Multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) were carried out to define the clonal relatedness among the isolates. PCR and capsular serotyping of the virulence-associated genes, as well as biofilm formation and serum complement-mediated killing assays, were employed to determine the virulent potential. The genomic features and associated mobile genetic elements of JmsCRE57 were detected by whole genome sequencing. Results: The only positive isolate was JmsCRE57, which belonged to the ST375 serotype K2 that expressed uge, mrkD, fimH, kpn, aerobactin and rmpA virulence-associated genes and showed strong biofilm formation and serum sensitivity. Sequencing results showed that the JmsCRE57 genome mainly consisted of a circular chromosome, three antimicrobial resistant plasmids and a virulent plasmid. The antimicrobial resistant plasmid expressing bla KPC-2 , bla CTX-M-15 , aph(3″)-Ib, aph(6)-Id, qnrB1, aac(3)-IIa, aac(6′)-Ib-cr, bla OXA-1 , bla TEM-1B , catB4, sul2, dfrA14 and bla SHV-99. The virulent plasmid belonged to the IncHI1B group, which is mainly composed of mucoid phenotype genes and siderophore-associated genes. The remaining CRKP strains that expressed uge, fimH, mrkD and kpn virulenceassociated genes were not successfully typed.

ABSTRACT. We examined whether polymorphisms in the methylenetetrahydrofolate dehydrogenase (MTHFD) and transcobalamin (TC) genes, which are involved in folate metabolism, affect maternal risk for Down syndrome. We investigated 76 Down syndrome mothers and 115 control mothers from Bengbu, China. Genomic DNA was isolated from the peripheral lymphocytes. Polymerase chain reaction and restriction fragment length polymorphism were used to examine the polymorphisms of MTHFD G1958A and TC C776G. The frequencies of the polymorphic alleles were 24.3 and 19.1% for MTHFD 1958A, 53.9 and 54.2% for TC 776G, in the case and control groups, respectively. No significant differences were found between two groups in relation to either the allele or the genotype frequency for both polymorphisms. However, when gene-gene interactions between these two polymorphisms together with previous studied C677T and A1298C polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) 1765©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 13 (1): 1764-1773 (2014) Folate gene polymorphisms and the risk of Down syndrome gene were analyzed, the combined MTHFR 677CT/TT and MTHFD 1958AA/GA genotype was found to be significantly associated with the risk of having a Down syndrome child [odds ratio (OR) = 3.11; 95% confidence interval (95%CI) = 1.07-9.02]. In addition, the combined TC 776CG and MTHFR 677TT genotype increased the risk of having a child with Down syndrome 3.64-fold (OR = 3.64; 95%CI = 1.28-10.31).In conclusion, neither MTHFD G1958A nor TC C776G polymorphisms are an independent risk factor for Down syndrome. However, the combined MTHFD/MTHFR, TC/MTHFR genotypes play a role in the risk of bearing a Down syndrome child in the Chinese population.

Higher expression levels of hA3G and hA3B mRNA in the peripheral blood mononuclear cells of Chinese HIV-infected individuals were found to be associated with slower HIV disease progression, suggesting their potential roles in antiviral innate immunity.