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A new species with primitive characteristics, Ameletus daliensis Tong, sp. nov., is described, based on the morphology of imago, larva and egg with molecular data of the mitochondrial COI from Mount Cangshan, Dali, China. The new species is closely related to one of the most primitive mayflies, Ameletus primitivus Traver, 1939, by sharing persistent mouthparts in the alate stage, but it can be distinguished from the latter by the morphological differences of the mouthpart remains, wings and genitals in the imaginal stage. Both morphological and molecular evidence support that A. daliensis Tong, sp. nov. is a new member of the genus Ameletus. The discovery of the new species could help understand the origin and evolution of the genus Ameletus. [ABSTRACT FROM AUTHOR]

Limited studies have characterized multiple carbapenem-resistant Escherichia coli isolates and compared their genetic characteristics through whole-genome sequencing (WGS) because of the scarcity of these isolates. In this study, we determined the prevalence of carbapenem resistance in 2,993 E. coli isolates collected from three Chinese hospitals. The carbapenem-resistant isolates were further characterized by WGS, and the molecular epidemiological characters and resistance mechanisms were explored through the publicly available platforms from the Center for Genomic Epidemiology. Twenty-four carbapenem-resistant E. coli isolates were screened out from 2,993 E. coli clinical isolates and all carbapenem-resistant isolates showed multiple drug-resistant phenotypes. The main serotypes identified among carbapenem-resistant isolates through WGS included E. coli O8:H21 (n = 6), E. coli O102:H6 (n = 6), and E. coli O25:H4 (n = 3), and the dominant sequence types (ST) were ST410 (n = 8), ST405 (n = 6), and ST131 (n = 3). Carbapenemase encoding genes, including blaIMP-4 (n = 3), blaKPC-2 (n = 2), blaNDM-5 (n = 1), and blaIMP-1 (n = 1) were identified in seven isolates. WGS analysis could provide a vast amount of molecular epidemiological data of the resistant isolates all at once, such as serotypes, multilocus sequence typing (MLST) types, plasmid replicons, and resistant determinants. Since carbapenem is the last resort to treat life-threatening E. coli infections, it is urgent to characterize the transmission routes and develop risk management strategies to block or slow down the transmission of resistance mechanisms and save carbapenems. [ABSTRACT FROM AUTHOR]

Regulatory T cells (Tregs), which could be down-regulated by IL-28B, were reported to suppress T-cell-mediated immunity. The aim of this study was to investigate the role of IL-28B on the immune responses and protective efficacy of a tuberculosis (TB) subunit vaccine. First, a recombinant adenoviral vector expressing mouse IL-28B (rAd-mIL-28B) was constructed; then C57BL/6 mice were immunized with subunit vaccine ESAT6-Ag85B-Mpt64(190-198)-Mtb8.4-HspX (EAMMH) and rAd-mIL-28B together thrice or primed with Mycobacterium bovis bacillus Calmette-Guérin (BCG) and boosted by EAMMH and rAd-mIL-28B twice. At last the immune responses were evaluated, and the mice primed with BCG and boosted by subunit vaccines were challenged with virulent Mycobacterium tuberculosis H37Rv to evaluate the protective efficacy. The results showed that rAd-mIL-28B treatment significantly down-regulated the frequency of Tregs at 4 weeks after the last immunization but did not increase the Th1-type immune responses. Moreover, in the regimen of BCG priming and EAMMH boosting, rAd-mIL-28B treatment did not increase the antigen-specific cellular and humoral immune responses, and consequently did not reduce the bacteria load following H37Rv challenge. Instead, it induced more serious pathology reaction. In conclusion, IL-28B down-regulates Tregs following EAMMH vaccination but does not improve the protective immune responses. [ABSTRACT FROM AUTHOR]

A total of 59 and 74 nonduplicate plasmid-mediated quinolone resistance (PMQR) genes-carrying Klebsiella pneumoniaeand Escherichia coliisolates were collected. All strains were assayed for fluoroquinolone susceptibility and the prevalence of quinolone resistance-determining regions (QRDRs) mutation. The association between PMQR determinants and common β-lactamase genes was also analyzed. Genetic relatedness of the isolates was analyzed by pulsed-field gel electrophoresis (PFGE). The PMQR genes-carrying K. pneumoniaeand E. coliisolates exhibited high fluoroquinolone resistance rates, indicating that PMQR determinants play an essential role in the development of fluoroquinolone resistance. Remarkably, most qnr-carrying strains had only a single or no QRDR mutation in GyrA or ParC, and most exhibited decreased ciprofloxacin (CIP) susceptibility or low-level CIP resistance. However, 71.4% and 98.4% of qnr-negative K. pneumoniaeand E. colicontained double QRDR mutations, and most presented high-level CIP resistance. Additionally, K. pneumoniaepresented a lower CIP resistance rate than E. coli(59.3% vs. 91.9%) and low carriage of double QRDR mutations (38.9% vs. 89.9%). Also, most (88.1%) K. pneumoniaeexamined in this study carried qnrand only 14.9% of E. coliwere qnrpositive. Thus, the high fluoroquinolone susceptibility of K. pneumoniaeisolates is primarily due to fewer QRDR substitutions as a result of high prevalence of qnralleles in the host. Our findings support the hypothesis that chromosomal resistance mutations could be affected by the presence of Qnr, in other words, Qnr may protect the QRDR domains in the gyrase and topoisomerase IV from mutations under the inhibition of fluoroquinolones. Another remarkable finding was that the PMQR genes-carrying K. pneumoniaeexhibited much higher proportions of extended-spectrum β-lactamases (ESBLs)-positive phenotype than E. coli(73.5% vs. 59.5%). This is due to not only the high prevalence of SHV-type ESBL-conferring enzymes in K. pneumoniaebut also the interference of DHA-producing K. pneumoniaeas a result of the strong association between qnrBand blaDHA. [ABSTRACT FROM AUTHOR]

Recent studies have reported that Escherichia coliin fecal samples of healthy humans could also serve as important reservoirs of drug-resistant bacteria. Limited data are available for E. coli–resistant profiles of healthy food handlers in hospitals who provide food service to inpatients and hospital staffs. E. coliisolates were recovered from hospital healthy food handlers, and one random selected isolate from each food handler was subjected to antimicrobial susceptibility testing, phylogenetic typing, and screening for antimicrobial-resistant mechanisms by polymerase chain reaction amplification. Ciprofloxacin-resistant isolates were further characterized by mutation analysis in the quinolone resistance determining regions (QRDRs) of GyrA and ParC. And extended-spectrum β-lactamase (ESBL) producing isolates were screened for blaCTX-Mby polymerase chain reaction amplification and DNA sequence analysis. In total, more than 50% (47/92) of E. coliisolates from healthy food handlers showed multidrug-resistant profiles and 50% (46/92) isolates carried intI. Resistance prevalence of the B2 phylogenetic group was significantly lower than that of the non-B2 groups for all tested antimicrobials (p< 0.05) except chloramphenicol and tetracycline. Seven isolates of phylogenetic group A (n= 3) and D (n= 4) produced ESBL, and 12 isolates of phylogenetic group A (n= 5), B2 (n= 2), and D (n= 5) were resistant to ciprofloxacin. Transferable quinolone resistance determinants were identified in four isolates. Point mutations in QRDRs of GyrA or ParC were identified among 59 out of 62 E. coliisolates showing decreased susceptibility or resistance to ciprofloxacin. Genes encoding CTX-M enzyme were identified in seven ESBL-producing isolates. The preponderance in hospital food handlers of multidrug-resistant E. colimakes it important to introduce control measures such as improved biosecurity to ensure that they do not pass through the food service and limit inpatient therapeutic options. [ABSTRACT FROM AUTHOR]

Alterations in topoisomerases and plasmid-mediated quinolone-resistant (PMQR) determinants have been identified as main quinolone-resistant mechanisms in Salmonella enterica Typhimurium. But the joint effects of these mechanisms have not been thoroughly characterized in homologous Salmonella Typhimurium strains. In this study, isogenic topoisomerase mutants were constructed using phage λ Red recombinase system and phage transduction. And the joint effects of topoisomerase mutations ( gyrA [S83F], gyrA [S83F, D87N] and parC [S80I]) and PMQR determinants (including qnrB4, qnrS1, aac(6′)-Ib-cr, and qepA) were studied in homologous genetic constitutions. Our data showed that mutations in gyrA played a dominant role in fluoroquinolone resistance in Salmonella Typhimurium and have a synergistic effect with other resistant mechanisms. The mutation (S80I) in parC would have no effect in quinolone resistance without gyrA mutations. The joint effect of aac(6′)-Ib-cr and topoisomerase mutations were only observed for ciprofloxacin among tested quinolones. Different joint effects between topoisomerase mutations and qepA, qnrB4, or qnrS1 were observed for tested quinolones. Importantly, the acquirement of the PMQR determinants could improve 0- to 32-fold of the host mutant prevention concentration to ciprofloxacin. Our data showed that the acquirement of PMQR determinants could not only improve the host minimal inhibitory concentrations to quinolones but also accelerate the generation of high-level fluoroquinolone-resistant mutants. [ABSTRACT FROM AUTHOR]

Background: The categories of recognized transferable quinolone resistance determinants have been increasing sharply. The rapid horizontal transfer of these quinolone resistance genes has caused concern since they bring new dissemination possibilities for quinolone resistance. [ABSTRACT FROM PUBLISHER]

A convenient one-pot synthesis of fused phosphorus-heterocycles with biological activity via the cyclization reactions of Lawesson's reagent with bifunctional substrates is reported. [ABSTRACT FROM AUTHOR]

A letter to the editor about the prevalence of New Delhi metallo-β-lactamase-1(NDM-1)-producing strains from the family Enterobacteriaceae in China is presented.

Melaleuca bracteata possesses antioxidant, antibacterial, and herbicidal activities. However, the agricultural applications of M. bracteata have not been explored yet. The M. bracteata leaves were distilled, and the petroleum ether extract of the essential oils (PEEO) was analysed by GC-MS, where methyl eugenol was found to be the most abundant (66.68%). The total polyphenol content (TPC), the total flavonoids content (TFC) of the PEEO were 6.617 ± 0.535 mg gallic acid equivalents/g and 7.086 ± 0.452 mg rutin equivalents/g, respectively. The IC50 values of the DPPH, ABTS and Fe3+ were 4.180 ± 0.050 mg/ml, 5.400 ± 0.140 mg/ml, and 8.935 ± 0.067 mg/g, respectively. The EC50 value of the PEEO was 33.78 ± 2.35 μg/ml against the Pyricularia oryzae. The minimum inhibitory concentration and minimum bactericidal concentration values were 0.10 mg/ml and 0.45 mg/ml against Bacillus subtilis. The results indicate that M. bracteata PEEO possesses excellent antioxidant activities and bioactivities. [ABSTRACT FROM AUTHOR]

Background: To evaluate in vitro susceptibilities of aerobic and facultative Gram-negative bacterial (GNB) isolates from intra-abdominal infections (IAIs) to 12 selected antimicrobials in Chinese hospitals from 2012 to 2014.Methods: Hospital acquired (HA) and community acquired (CA) IAIs were collected from 21 centers in 16 Chinese cities. Extended spectrum beta-lactamase (ESBL) status and antimicrobial susceptibilities were determined at a central laboratory using CLSI broth microdilution and interpretive standards.Results: From all isolated strains the Enterobacteriaceae (81.1%) Escherichia coli accounted for 45.4% and Klebsiella pneumoniae for 20.1%, followed by Enterobacter cloacae (5.2%), Proteus mirabilis (2.1%), Citrobacter freundii (1.8%), Enterobacter aerogenes (1.8%), Klebsiella oxytoca (1.4%), Morganella morganii (1.2%), Serratia marcescens (0.7%), Citrobacter koseri (0.3%), Proteus vulgaris (0.3%) and others (1.0%). Non- Enterobacteriaceae (18.9%) included Pseudomonas aeruginosa (9.8%), Acinetobacter baumannii (6.7%), Stenotrophomonas maltophilia (0.9%), Aeromonas hydrophila (0.4%) and others (1.1%). ESBL-screen positive Escherichia coli isolates (ESBL+) showed a decreasing trend from 67.5% in 2012 to 58.9% in 2014 of all Escherichia coli isolates and the percentage of ESBL+ Klebsiella pneumoniae isolates also decreased from 2012 through 2014 (40.4% to 26.6%), which was due to reduced percentages of ESBL+ isolates in HA IAIs for both bacteria. The overall susceptibilities of all 5160 IAI isolates were 87.53% to amikacin (AMK), 78.12% to piperacillin-tazobactam (TZP) 81.41% to imipenem (IMP) and 73.12% to ertapenem (ETP). The susceptibility of ESBL-screen positive Escherichia coli strains was 96.77%-98.8% to IPM, 91.26%-93.16% to ETP, 89.48%-92.75% to AMK and 84.86%-89.34% to TZP, while ESBL-screen positive Klebsiella pneumoniae strains were 70.56%-80.15% susceptible to ETP, 80.0%-87.5% to IPM, 83.82%-87.06% to AMK and 63.53%-68.38% to TZP within the three year study. Susceptibilities to all cephalosporins and fluoroquinolones were less than 50% beside 66.5% and 56.07% to cefoxitin (FOX) for ESBL+ Escherichia coli and Klebsiella pneumoniae strains respectively.Conclusions: The total ESBL+ rates decreased in Escherichia coli and Klebsiella pneumoniae IAI isolates due to fewer prevalence in HA infections. IPM, ETP and AMK were the most effective antimicrobials against ESBL+ Escherichia coli and Klebsiella pneumoniae IAI isolates in 2012-2014 and a change of fluoroquinolone regimens for Chinese IAIs is recommended. [ABSTRACT FROM AUTHOR]

Background: The objective of this study was to investigate the distribution and susceptibility of aerobic and facultative Gram-negative bacilli isolated from Chinese patients with UTIs collected within 48 h (community acquired, CA) or after 48 h (hospital acquired, HA) of hospital admission.Methods: From 2010 to 2014, the minimum inhibitory concentrations (MICs) of 12 antibiotics for 4,332 aerobic and facultative Gram-negative bacilli, sampled in 21 hospitals in 16 cities, were determined by the broth microdilution method.Results: Enterobacteriaceae composed 88.5% of the total isolates, with Escherichia coli (E. coli) (63.2%) the most commonly isolated species, followed by Klebsiella pneumoniae (K. pneumoniae) (12.2%). Non-Enterobacteriaceae accounted for only 11.5% of all isolates and included mainly Pseudomonas aeruginosa (P. aeruginosa) (6.9%) and Acinetobacter baumannii (A. baumannii) (3.3%). Among the antimicrobial agents tested, the susceptibility rates of E.coli to the two carbapenems, ertapenem and imipenem as well as amikacin and piperacillin-tazobactam ranged from 92.5 to 98.7%. Against K. pneumonia, the most potent antibiotics were imipenem (92.6% susceptibility), amikacin (89.2% susceptibility) and ertapenem (87.9% susceptibility). Although non-Enterobacteriaceae did not show high susceptibilities to the 12 common antibiotics, amikacin exhibited the highest in vitro activity against P. aeruginosa over the 5-year study period, followed by piperacillin-tazobactam, imipenem, ceftazidime, cefepime, ciprofloxacin, and levofloxacin. The Extended Spectrum Beta-Lactamase (ESBL) rates decreased slowly during the 5 years in E. coli from 68.6% in 2010 to 59.1% in 2014, in K. pneumoniae from 59.7 to 49.2%, and in Proteus mirabilis (P. mirabilis) from 40.0 to 26.1%. However, the ESBL rates were different in 5 regions of China (Northeast, North, East, South and Middle-China).Conclusion: E. coli and K. pneumonia were the major pathogens causing UTIs and carbapenems and amikacin retained the highest susceptibility rates over the 5-year study period, indicating that they are good drug choices for empirical therapies, particularly of CA UTIs in China. [ABSTRACT FROM AUTHOR]

Background: Recently, the emergence of multidrug-resistant organisms such as extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae has raised considerable concern regarding the appropriate treatment of intra-abdominal infections (IAIs). In this study, we investigated the molecular characteristics of ESBL among clinical isolates of Escherichia coli and Klebsiella pneumoniae causing IAIs and their pattern of antimicrobial resistance, which can provide useful information about the epidemiology and risk factors associated with these infections. Materials and methods: One hundred sixty-seven E.coli and 47 K. pneumoniae ESBL-producing strains causing IAIs were collected from 9 hospitals in China, during 2012 and 2013. The antimicrobial susceptibility profile of these strains was determined. Polymerase chain reaction and sequencing were performed to identify genes for β-lactamase (blaTEM, blaSHV, blaOXA-1-like, and blaCTX-M). The isolates were also analyzed by pulsed-field gel electrophoresis (PFGE). Results: In 167 ESBL-producing E. coli strains, 104 strains (62.3%) were positive for CTX-M, and 9 strains (5.39%) were positive for SHV. Among the 47 K. pneumoniae strains, 35 strains (74.5%) were positive for SHV-2a, 12 strains (25.5%) were positive for CTX-M. No TEM-type and OXA-1-like strain was detected among all the ESBL-producing strains. Regarding the CTX-M-positive E. coli and K. pneumoniae strains, CTX-M-15 was the most common genotype in E. coli and K. pneumoniae strains, accounting for 28.7% and 17.0%, respectively, followed by CTX-M-55 accounting for 16.2% and 2.13%, respectively; the remaining genotypes included CTX-M-123 and CTX-M-82. PFGE showed that E.coli and K. pneumoniae ESBL-producing strains causing IAIs were diverse and that emerging resistance may not be due to the dissemination of national clones. [ABSTRACT FROM AUTHOR]

Background: Vancomycin-resistant Enterococcus (VRE) has been identified in China. However, little is known about the spread of VRE isolates. Methods: The genetic relatedness of vancomycin-resistant Enterococcus faecium (VREfm) isolates was analyzed by pulsed-field gel electrophoresis (PFGE), their antimicrobial susceptibilities were analyzed by E-test and the VITEK 2 AST-GP67 test Kit, and their sequence types (STs) were investigated by multilocus sequence typing (MLST). S1-PFGE was used for plasmid profiling, and PCR and subsequent sequencing were performed to identify the virulence genes. Results: A total of 96 nonduplicated VREfm isolates were obtained and categorized into 38 PFGE types (type 1-38). The predominant MLST type was ST78, while ST17, ST341, and ST342 were also sporadically identified. All types of clinical VREfm strains harbored the vanA gene; however, they carried plasmids of different sizes. While 92.1%, 71.1%, and 60.5% of VREfm strains carried hyl, scm, and ecbA genes, respectively, all of them were positive for esp, acm, sgrA, pilA, and pilB genes. Conclusions: Clonal VREfm spread was observed, and nonplasmid-mediated horizontal transfer of vancomycin-resistant gene might have conveyed resistance to some vancomycin-susceptible E. faecium strains. E. faecium ST78 carrying vanA gene was the most prevalent clone in this study. The high prevalence of virulence genes, including esp, hyl, acm, scm, ecbA, sgrA, pilA, and pilB, confirmed their important roles in the emergence of VREfm ST78 in nosocomial infections. [ABSTRACT FROM AUTHOR]

The article focuses on the existence of carbapenemase-producing organisms (CPOs) in single patients posing as a threat to the medical care industry. It talks about the affect of antibiotics like moxifloxacin, piperacillin and ceftazidime on patients with CPOs infection. It tells about pathogens like Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa being under CPOs.

Insulin-secreting ß cells and glucagon-secreting a cells maintain physiological blood glucose levels, and their malfunction drives diabetes development. Using ChIP sequencing and RNA sequencing analysis, we determined the epigenetic and transcriptional landscape of human pancreatic α, ß, and exocrine cells. We found that, com-pared with exocrine and ß cells, differentiated a cells exhibited many more genes bivalently marked by the activating H3K4me3 and repressing H3K27me3 histone modifications. This was particularly true for ß cell sig-nature genes involved in transcriptional regulation. Remarkably, thousands of these genes were in a monovalent state in ß cells, carrying only the activating or repressing mark. Our epigenomic findings suggested that α to ß cell reprogramming could be promoted by manipulating the histone methylation signature of human pancre-atic islets. Indeed, we show that treatment of cultured pancreatic islets with a histone methyltransferase inhibi-tor leads to colocalization of both glucagon and insulin and glucagon and insulin promoter factor 1 (PDX1) in human islets and colocalization of both glucagon and insulin in mouse islets. Thus, mammalian pancreatic islet cells display cell-type-specific epigenomic plasticity, suggesting that epigenomic manipulation could provide a path to cell reprogramming and novel cell replacement-based therapies for diabetes. [ABSTRACT FROM AUTHOR]

A major obstacle to transplantation tolerance is humoral immunity. In this paper, we demonstrate that the intrinsic developmental propensity of the B lymphocyte compartment for acquisition of self-tolerance can be harnessed to induce humoral unresponsiveness to transplanted alloantigens. In the current study, when transitional B cells developed in the presence of donor lymphoid cells, the mature B lymphocyte compartment failed to mount a donor-specific alloantibody response to an organ transplant-despite unrestrained acute T cell-mediated allograft rejection. Specifically, we generated an experimental system wherein a B6 strain B cell compartment developed de novo in the presence of F1 (B6xBALB/c) lymphoid cells and in a T cell-deficient setting. Following establishment of a steady-state B cell compartment, these B6 mice were transplanted with heterotopic cardiac allografts from allogeneic BALB/c donors. The mice were then inoculated with purified syngeneic B6 T cells. As expected, all cardiac allografts were acutely rejected. However, the B lymphocyte compartment of these mice was completely inert in its capacity to form a BALB/c-specific alloantibody response. Using an alloantigen-specific Ig transgenic system, we demonstrated that this profound degree of humoral tolerance was caused by clonal deletion of alloreactive specificities from the primary B cell repertoire. Thus, de novo B cell compartment development at the time of transplantation is of critical importance in recipient repertoire "remodeling" to a humoral tolerant state. [ABSTRACT FROM AUTHOR]