Effects of Ti3C2Tx MXene Addition to a Co Complex/Ionic Liquid-Based Electrolyte on the Photovoltaic Performance of Solar Cells.

Redox mediators comprising I-, Co3+, and Ti3C2Tx MXene were applied to dye-sensitized solar cells (DSCs). In the as-prepared DSCs (I-DSCs), wherein hole conduction occurred via the redox reaction of I-/I3- ions, the power conversion efficiency (PCE) was not altered by the addition of Ti3C2Tx MXene. The I-DSCs were exposed to light to produce Co2+/Co3+-based cells (Co-DSCs), wherein the holes were transferred via the redox reaction of Co2+/Co3+ ions. A PCE of 9.01% was achieved in a Co-DSC with Ti3C2Tx MXene (Ti3C2Tx-Co-DSC), which indicated an improvement from the PCE of a bare Co-DSC without Ti3C2Tx MXene (7.27%). It was also found that the presence of Ti3C2Tx MXene in the redox mediator increased the hole collection, dye regeneration, and electron injection efficiencies of the Ti3C2Tx-Co-DSC, leading to an improvement in both the short-circuit current and the PCE when compared with those of the bare Co-DSC without MXene.

Evaluating Salmonella pullorum dissemination and shedding patterns and antibody production in infected chickens.

BACKGROUND: Pullorum disease caused by Salmonella pullorum is one of the most important infectious diseases in the poultry industry, responsible for causing substantial economic losses globally. On farms, the traditional method to detect S. pullorum infection mainly involves the collection of feces and sera to test for antigens and antibodies, respectively, but the regularity of Salmonella pullorum dissemination in internal organs and shedding patterns and antibody production in infected chickens remains unclear. Herein we aimed to investigate the dissemination of S. pullorum to different organs and bacterial shedding patterns in the faeces as well as serum antibody production post-infection in chickens of different ages. RESULT: In this study, the liver and heart of 2-day-old chickens showed the highest copy numbers of S. pullorum at 6.4 × 106 and 1.9 × 106 copies of DNA target sequences/30 mg, respectively. In case of 10-day-old chickens, the percentage of S. pullorum fecal shedding (0%-40%) and antibody production (0%-56.6%) markedly fluctuated during the entire experiment; furthermore, in case of 42-week-old chickens, the percentage of birds showing S. pullorum shedding in the faeces showed a downward trend (from 63.33% to 6.6% in the oral inoculation group and from 43.3% to 10% in the intraperitoneal injection group), while that of birds showing serum antibody production remained at a high level (38.3% and 80% in the oral inoculation and intraperitoneal injection groups, respectively). We also performed cohabitation experiments, showed that 15% 10-day-old and 3.33% 42-week-old chickens were infected via the horizontal transmission in cohabitation with S. pullorum infected chickens, and revealed a high risk of horizontal transmission of S. pullorum. CONCLUSION: This study systematically evaluated the dissemination of S. pullorum in internal organs and bacterial fecal shedding patterns, and antibody production in infected chickens. Collectively, our findings indicate how to effectively screen S. pullorum-negative chickens on livestock farms and should also help in the development of measures to control and eradicate S. pullorum.

First report of Chaetomium pseudocochliodes causing flower rot disease of Camellia reticulata in Yunnan, China.

Camellia reticulata is the world-famous ornamental flower (Wang et al. 2021). In February 2021, the infected flowers of C. reticulata 'Shizitou' were collected in Zixi Mountain, Chuxiong city, Yunnan province, China (24°9'95″ N, 101°42'53″ E). Flower rot disease incidence ranged from 40% to 75% in the garden. The infected flowers showed symptoms of varying degrees of yellow-browning, dry or wet rot to the whole flower wilted and even dropped (Figure 1A, B, C). Three symptomatic flowers were randomly collected in the garden. Tissues from the infected flowers (cut to 5×5 mm size) were surface-disinfected by 75% ethyl alcohol for 30s, rinsed in sterile water for 3 times to air dry, and cultured in Potato Dextrose Agar medium (PDA) at 25℃±2 in the normal light for 5-7 days (Fang, 1998). Similar fungal colonies were isolated from 50%-75% of the infected flowers. Three isolates from different flowers showed similar colony morphology. After sub-culturing of hyphal tips on PDA for 5-7 days, the initially yellow colored colonies showed abundant white aerial mycelium, with sporulation (Figure 1E, F). The asci (Figure 1G) sporulation site is 24(-37) ×7(-14) µm, and the stalk length is 17-42 µm, with 8 biseriate acuminate ascospores. The mature ascospores (Figure 1H) are olive-brown or brown, lemon-like, double-pointed, with slightly umbilical protrusions at both ends, flat on both sides, 9(-11.5) × 7(-9) × 5.5(-7) µm in size, with germ holes on the top (Wang et al. 2016). These morphological features are consistent with Chaetomium pseudocochliodes. The genomic DNA was extracted from the isolated strains. To identified this fungal pathogen genetically, sequence analyses were conducted using the ITS1/ITS4 (Henson et al. 1993), NL1/NL4 (Liu et al. 2011), EF1-938F /EF1-2218R (Tan et al. 2016) primers for the internal transcribed spacer (ITS), large ribosomal subunit (LSU), and elongation factor 1-α (EF1-α) genes. The obtained sequences were deposited in GenBank with accession numbers MZ817067 (ITS), MZ817072 (LSU), MZ820167 (EF1-α). The phylogenetic trees (Figure 2) were constructed to determine the phylogenetic relationships based on MEGA 6.0 maximum likelihood method. In order to confirm the pathogenicity, the tests were conducted with fungus plug (5 mm) from a 7-day-old colony placed onto the surface of healthy petals. The sterile water-absorbent cottons place onto healthy petal surface near fungus plug and plastic wraps cover in petri dish were used for moisturizing. A total of 3 replicates in each of 3 groups were included (3 healthy petals for a group, 1 for wounded inoculation, 1 for unwounded inoculation, and 1 for sterile PDA plug). A sterile PDA plug was placed onto the surface of healthy petals as a control. After incubation at room temperature for 5 days (Ren. 2019), 3 replicates in each of 2 groups of treated healthy petals for wounded inoculation showed obvious symptoms (Figure 1D), and no symptoms appeared in the control, and healthy petals unwounded showed symptoms for 7-10 days. The fungus was re-isolated from the lesions of inoculated tissues. The re-isolated fungal colonies showed identical morphology and high sequence similarity with ITS, LSU and EF-1α of the initial isolate. No fungus was isolated from the controls. The first extraction of C. pseudocochliodes was also obtained from the roots of the Panax notoginseng in Wenshan, Yunnan (Wang et al. 2016). To our knowledge, this is the first report of flower rot caused by C. pseudocochliodes on C. reticulata in China.

Rapid and label free detection of aflatoxin B1 in alcoholic beverages with a microfluid fiber device.

A rapid and label free aflatoxin B1 (AFB1) microfluid sensor was proposed and tested. The device was fabricated with hollow-core photonics crystal fiber infiltrated with the AFB1 solution. The autofluorescence emitting from the AFB1 molecules was detected. The sensor length was optimized. The AFB1 concentration was tested with a 4 cm long sensor. The best limit of detection was achieved as low as 1.34 ng/ml, which meets the test requirement of the national standards for AFB1 in food. The effectiveness of this sensor being applied in beer solution was also verified to be a little more sensitive than in aqueous solution. Compared with traditional AFB1 detection methods, the proposed single-ended device perfectly satisfies the demand of process control in alcoholic beverages manufacture.

Characterization and whole-genome sequencing of broad-host-range Salmonella-specific bacteriophages for bio-control.

Salmonella Enteritidis (S. Enteritidis), which could cause human disease and death by consuming the contaminated food, is an important zoonotic pathogen. With the rapid increase of antibiotic resistance all over the world, bacteriophage-based bio-control has gradually attracted public attention widely. In order to find a suitable phage treating S. Enteritidis infection, four phages infecting S. Enteritidis were isolated from poultry fecal samples. Host range showed that four phages had a broad-host-range to Salmonella isolates. The morphological analysis illustrated that all of those phages were classified as the Myoviridae family. The one-step growth curve indicated that bacteriophage BPSELC-1 has a short latent period of about 10 min and a large burst size of 500 pfu/cell in comparison to the other three phages. Then phage BPSELC-1 was sequenced and conducted in vitro experiment. The genome of phage BPSELC-1 is 86,996 bp in size and has 140 putative genes containing structure proteins-encoding genes, tRNA genes and DNA replication or nucleotide metabolism genes. Importantly, no known virulence-associated, antibiotic and lysogeny-related genes were identified in the genome of BPSELC-1. In vitro experiment of phage treatment pointed out that the number of viable S. Enteritidis ATCC 13076 was reduced by 5.9×log10 at MOI of 102 after 4 h. To the best of our knowledge, the phage BPSELC-1 exhibited higher efficiency in S. Enteritidis treatment compared to previous studies. Moreover, it is promising to be used as a broad-spectrum candidate against Salmonella infections in commercial owing to its broad-host-range.

MAN3 gene regulates cadmium tolerance through the glutathione-dependent pathway in Arabidopsis thaliana.

Pollution of soil by the heavy metal cadmium (Cd) is a global environmental problem. The glutathione (GSH)-dependent phytochelatin (PC) synthesis pathway is one of the most important mechanisms contributing to Cd accumulation and tolerance. However, the regulation of this pathway is poorly understood. Here, we identified an Arabidopsis thaliana cadmium-tolerant dominant mutant xcd1-D (XVE system-induced cadmium-tolerance 1) and cloned XCD1 gene (previously called MAN3), which encodes an endo-ß-mannanase. Overexpression of MAN3 led to enhanced Cd accumulation and tolerance, whereas loss-of-function of MAN3 resulted in decreased Cd accumulation and tolerance. In the presence of estradiol, enhanced Cd accumulation and tolerance in xcd1-D was associated with GSH-dependent, Cd-activated synthesis of PCs, which was correlated with coordinated activation of gene expression. Cd stress-induced expression of MAN3 and the consequently increased mannanase activity, led to increased mannose content in cell walls. Moreover, mannose treatment not only rescued the Cd-sensitive phenotype of the xcd1-2 mutant, but also improved the Cd tolerance of wild-type plants. Significantly, this mannose-mediated Cd accumulation and tolerance is dependent on GSH-dependent PC concentrations via coordinated control of expression of genes involved in PC synthesis. Our results suggest that MAN3 regulates the GSH-dependent PC synthesis pathway that contributes to Cd accumulation and tolerance in A. thaliana by coordinated control of gene expression.

Arthroscopic Linear Chain Fixation for the Treatment of Medial Meniscus Posterior Root Tear: A Case Study.

BACKGROUND: The repair and reconstruction of medial meniscus posterior root tears (MMPRTs) is an important issue in the field of orthopedic sports medicine. This study reports the first application of arthroscopic linear chain fixation for the treatment of MMPRTs. CASE PRESENTATION: A 78-year-old female patient presented with a 1.5-month history of right knee pain accompanied by a locked facet joint. The patient underwent surgery with the new linear chain fixation method. In this method, the suture and the loop part of the buckle-strap titanium plate were combined into a linear chain mechanical complex, and the tension of the posterior root stump was gradually increased by pulling on the two attachment lines at the external mouth of the tibial tunnel. The postoperative Lysholm score was 89, and the visual analogue scale score was 0.9, indicating a significant improvement in knee joint function. At the 7-month and 1-year post-surgery follow-up, physical and MRI examinations confirmed satisfactory healing of the MMPRTs. CONCLUSION: This surgical approach offers several benefits, including a simplified instrumentation setup, preservation of natural anatomical structures, and reliable residual stump fixation. It has the potential for clinical implementation.

Invasive fungal infections secondary to acute-on-chronic liver failure: a retrospective study.

Although the consequences of invasive fungal infections (IFIs) secondary to chronic hepatitis B infections secondary IFIs are serious, the incidence and main pathogenic factors of IFIs in acute-on-chronic liver failure (ACLF) patients remain unclear. This study included 1200 hepatitis B patients who were treated in the Department of Infectious Diseases, Shanghai Changzheng Hospital from January 2006 to January 2009. Patients with ACLF were screened according to the diagnostic guidelines for liver failure. Patients with ACLF and secondary IFI were the disease group, and patients with ACLF without secondary IFI were the controls. The incidence of IFI, mortality, and possible IFI causes in two groups were evaluated retrospectively. Sixty patients with ACLF had secondary IFI, of which 14 were confirmed cases and 46 were suspected cases. The incidence of IFI was 47.62% for ACLF patients. Logistic regression analysis showed that the level of hepatitis B viral (HBV) DNA was an important risk factor for secondary IFI in ACLF patients. Receiver operating characteristic curve analysis suggested that when the number of HBV DNA copies was higher than 3.16 × 10(3) copies ml(-1) , the possibility of secondary IFI in ACLF patients increased significantly, while white blood cell levels showed protective effects for these patients. The incidence of IFI is high in ACLF patients and high hepatitis B virus DNA levels may be an independent risk factor of secondary IFI in these patients.

Characterization of antibiotic-resistance genes in antibiotic resistance Escherichia coli isolates from a lake.

The spread of antibiotic-resistance bacteria and antibiotic-resistance genes (ARGs) has been of concern worldwide. In this study, 114 Escherichia coli isolates were isolated from surface water samples of a lake to identify their susceptibility to antibiotics, including tetracycline (TC), gentamicin (GN), ampicillin (AMP), streptomycin (ST), oxytetracycline (OC), levofloxacin (LEV), nalidixic acid (NA), and sulfamethoxazole/trimethoprim (SFT). Isolates showing resistance to TC, GN, AMP, ST, OC, LEV, NA, and SFT occurred in 50, 76, 68, 71, 55, 32, 82, and 85 % of the total isolates, respectively. Thirty-seven different resistance patterns were identified, and the most abundant resistance profile (28 of 104) was TC/GN/AMP/ST/OC/LEV/NA/SFT. The occurrence of 29 ARGs were detected in their corresponding resistance clones, and 88 % of TC-resistance, 94 % of SFT-resistance, 90 % of AMP-resistance, 78 % of ST-resistance, and 72 % of quinolone-resistance clones can be described by their corresponding ARGs. It should be noted that most of these antibiotic-resistance clones harbored at least two corresponding ARGs, indicating that high frequencies of combined ARGs occurred in these isolates. In addition, 9 new types of DNA sequence of qnr(B) gene were obtained and were clustered into the same group as showed by phylogenetic trees analysis. These results suggest that the development of antibiotic resistance can be ascribed to the high frequency in the recombination of ARGs through horizontal gene transfer.

Research on the isolation and identification of black spot disease of Rosa chinensis in Kunming, China.

Through a survey of rose diseases in the South Tropical Garden in Kunming, China, it was found that black spot was the most common and serious disease of rose cultivated in the open air there, with an incidence of more than 90%. In this study, fungus isolation was performed on leaf samples of five black spot susceptible varieties of rose from the South Tropical Garden by tissue isolation. 18 strains of fungus were initially obtained, and seven of them were finally identified to cause black spot symptoms on healthy leaves of rose after verification by Koch's rule. By observing the morphology of colonies and spores, and constructing a phylogenetic tree by combining molecular biology and multiple genes, two pathogenic fungus were identified, namely, Alternaria alternata and Gnomoniopsis rosae. G. rosae was the first pathogenic fungi of rose black spot isolated and identified in this study. The results of this study can provide a reference base for further research and control of the black spot disease of rose in Kunming.

A dual-process of targeted and unbiased Nanopore sequencing enables accurate and rapid diagnosis of lower respiratory infections.

BACKGROUND: Nanopore metagenomics has been used for infectious disease diagnosis for bacterial pathogens. However, this technology currently lacks comprehensive performance studies in clinical settings for simultaneous detection of bacteria, fungi, and viruses. METHODS: We developed a dual-process of Nanopore sequencing for one sample, with unbiased metagenomics in Meta process and target enrichment in Panel process (Nanopore Meta-Panel process, NanoMP) and prospectively enrolled 450 respiratory specimens from multiple centers. The filter system of pathogen detection was established with machine learning and receiver operator characteristic (ROC) curve to optimize the detection accuracy based on orthogonal test of 21 species. Antimicrobial resistance (AMR) genes were identified based on the Comprehensive Antibiotic Resistance Database (CARD) and single-nucleotide polymorphism matrix. FINDINGS: Our approach showed high sensitivity in Meta process, with 82.9%, 88.7%, and 75.0% for bacteria, fungi (except Aspergillus), and Mycobacterium tuberculosis groups, respectively. Moreover, target amplification improved the sensitivity of virus (>80.0% vs. 39.4%) and Aspergillus (81.8% vs. 42.3%) groups in Panel process compared with Meta process. Overall, NanoMP achieved 80.2% sensitivity and 98.8% specificity compared with the composite reference standard, and we were able to accurately detect AMR genes including blaKPC-2, blaOXA-23 and mecA and distinguish their parent organisms in patients with mixed infections. INTERPRETATION: We combined metagenomic and enriched Nanopore sequencing for one sample in parallel. Our NanoMP approach simultaneously covered bacteria, viruses and fungi in respiratory specimens and demonstrated good diagnostic performance in real clinical settings. FUNDING: National Key Research and Development Program of China and National Natural Science Foundation of China.

Cryptococcus neoformans Csn1201 Is Associated With Pulmonary Immune Responses and Disseminated Infection.

Cryptococcus neoformans is a major etiological agent of fungal meningoencephalitis. The outcome of cryptococcosis depends on the complex interactions between the pathogenic fungus and host immunity. The understanding of how C. neoformans manipulates the host immune response through its pathogenic factors remains incomplete. In this study, we defined the roles of a previously uncharacterized protein, Csn1201, in cryptococcal fitness and host immunity. Use of both inhalational and intravenous mouse models demonstrated that the CSN1201 deletion significantly blocked the pulmonary infection and extrapulmonary dissemination of C. neoformans. The in vivo hypovirulent phenotype of the csn1201Δ mutant was attributed to a combination of multiple factors, including preferential dendritic cell accumulation, enhanced Th1 and Th17 immune responses, decreased intracellular survival inside macrophages, and attenuated blood-brain barrier transcytosis rather than exclusively to pathogenic fitness. The csn1201Δ mutant exhibited decreased tolerance to various stressors in vitro, along with reduced capsule production and enhanced cell wall thickness under host-relevant conditions, indicating that the CSN1201 deletion might promote the exposure of cell wall components and thus induce a protective immune response. Taken together, our results strongly support the importance of cryptococcal Csn1201 in pulmonary immune responses and disseminated infection.

Withdrawal of Colistin Reduces Incidence of mcr-1-Harboring IncX4-Type Plasmids but Has Limited Effects on Unrelated Antibiotic Resistance.

The global dissemination of plasmid-mediated colistin resistance gene mcr and its variants have posed a great threat to public health. Therefore, the Chinese government banned the use of colistin as a feed additive in livestock in April 2017. To explore the dynamic changes of overall antibiotic resistance genes (ARGs) and phylogenetic relationship of bacteria from a single pig farm before and after the withdrawal of colistin, fecal swab samples were collected from a large-scale pig farm before (n = 32; 2 months pre-withdrawal of colistin) and after withdrawal of colistin (n = 30; 13 months post-withdrawal of colistin). Escherichia coli and Klebsiella pneumoniae were isolated. Whole-genome sequencing (Illumina, MiSeq) was performed to examine ARGs, plasmids and the genetic relationship of the isolates. The overall SNP results indicated all isolates had high genetic diversity, and the evolutionary relationship across isolates was not influenced by the ban of colistin. However, the prevalence of mcr-1.1 (5.6%, p < 0.01) was significantly lower than before the ban (86.4%). Plasmid profiling analysis showed that 17 of 20 (85.0%) observed mcr-1.1 genes reside on IncX4-type plasmids, 16 of which (94.1%) were from isolates before the ban. On the contrary, the presence of blaCTX-M gene was significantly increased (p = 0.0215) post-withdrawal of colistin. Our results showed that withdrawal of colistin reduced the incidence of mcr-1-harboring IncX4-type plasmids, but had limited influences on unrelated ARGs.

Exploring the profile of antimicrobial resistance genes harboring by bacteriophage in chicken feces.

Bacteriophage may play an important role in antimicrobial resistance genes (ARGs) transmission. However, the contribution of bacteriophage to the spread of ARGs in environment, especially in poultry farm environment, is rarely known. In this study, the prevalence of ARGs in bacteriophage DNA was investigated in chicken feces from 30 different poultry farms in China. Then the abundance of the aac(6')-Ib-cr, blaCTX-M, ermB, floR, mcr-1, sul1, tetM and intI1 genes was determined by qPCR in bacteriophage and compared with certain representative plasmid DNA samples. The results showed that 12 ARGs (aac(6')-Ib-cr, aph(3')-IIIa, blaCTX-M, ermB, ermF, floR, mcr-1, qnrS, sul1, sul2, vanA, tetM genes) and class 1 integron gene intI1 were detected in bacteriophage DNA fraction. The sul1, tetM and aac(6')-Ib-cr genes were most prevalent with high detection rates of 77%, 61% and 55%, respectively. To our best knowledge, this study firstly reported the presence of the mcr-1 gene in bacteriophage DNA derived from farms environments. We found that the gene copy (GC) numbers of the aac(6')-Ib-cr, ermB and sul1 genes were as high as 5.47, 5.22 and 5.54 log10 GC/g, respectively. Both the prevalence and abundance of ARGs in broiler fecal wastes were also generally higher than in laying hens. In addition, although the GC numbers of the aac(6')-Ib-cr, floR and tetM genes in plasmid DNA was higher than that in phage DNA fraction by 4.68, 3.59 and 3.9 orders of magnitude, respectively, the absolute abundances of the blaCTX-M and mcr-1 genes in phage DNA were close to or even higher than that in plasmid DNA at farm SIL2, SIL4 and SIB1. As potential vessels for ARGs, bacteriophage could not be ignored due to their unique extracellular persistence in environments. Overall, this is the first comprehensive survey about bacteriophage carried ARGs from farms in different regions in China.

Genome sequence of multidrug-resistant Erysipelothrix rhusiopathiae ZJ carrying several acquired antimicrobial resistance genes.

OBJECTIVES: This study aimed to determine the genetic environment of antimicrobial resistance genes (ARGs) in Erysipelothrix rhusiopathiae strain ZJ isolated from a pig with symptoms of swine erysipelas in China. METHODS: Illumina MiSeq (200× coverage) and PacBio RS II (100× coverage) platforms were used for genome sequencing. ARGs and prophages were identified using ResFinder 3.0 and PHASTER, respectively. A conjugation experiment, induced prophage infection and long-term passage assay were performed to determine the transferability and stability of ARGs in this strain. RESULTS: The assembled circular genome of E. rhusiopathiae ZJ was 1 945 689 bp with a GC content of 36.48%; no plasmid sequence was detected. Eleven acquired ARGs were identified in the genome. A novel integrative and conjugative element (ICE) encoding a multidrug resistance (MDR) gene cluster [aadE-apt-spw-lsa(E)-lnu(B)-aadE-sat4-aphA3] was identified in strain ZJ. A prophage Φ1605 harbouring mef(A)-msr(D) and tet(M) was also found in this strain, which can take a circular form and can be induced by mitomycin C to infect E. rhusiopathiae G4T10 for ARG transfer. CONCLUSION: To our knowledge, this is the first report of a complete genome sequence of E. rhusiopathiae carrying multiple ARGs obtained from a pig farm. This is the first identification of a novel chimeric ICE carrying a MDR gene cluster and a prophage carrying ARGs in E. rhusiopathiae, which will provide a valuable reference to understand the potential transfer mechanism of MDR gene clusters carried by ICEs and prophages in Gram-positive bacteria.

Prevalence and transmission of antimicrobial-resistant Staphylococci and Enterococci from shared bicycles in Chengdu, China.

Shared bicycles are prevailing in China but the extent to which they contribute to maintaining and transmitting pathogens and antibiotic-resistant bacteria remain largely unknown. To fill the knowledge gap, herein, swab samples (n = 963) were collected from handlebars of shared bicycles in areas of hospital, school, metro station (n = 887) and riders (n = 76) in Chengdu, China. Staphylococci (n = 241) and Enterococci (n = 69) were widely distributed across sampling locations at a frequency of 2.3%-12.9%, and 0.08%-5.5%, respectively. Bicycle or rider-borne Gram-positive bacteria were frequently resistant to clinically important antibiotics including linezolid, fosfomycin, and vancomycin, and a significant portion of these isolates (3.4%-16.6% for Staphylococci and 0.1%-13.8% for Enterococci) indicated multidrug resistance. Nineteen Staphylococcus aureus isolates were identified in this collection and 52.6% of which were considered as methicillin-resistant S. aureus. Whole genome sequencing further characterized 26 antimicrobial resistance genes (ARGs) including fosB, fusB, and lnu(G) in S. aureus and 21 ARGs including optrA in Enterococci. Leveraging a complementary approach with conventional MLST, whole genome SNP and MLST analyses, we present that genetically closely-related bacteria were found in bicycles and riders across geographical-distinct locations suggesting bacterial transmission. Further, five new ST types 5697-5701 were firstly characterized in S. aureus. ST 942 and ST 1640 are new ST types observed in E. faecalis, and E. faecium, respectively. Our results highlighted the risk of shared bicycle system in disseminating pathogens and antibiotic resistance which warrants effective disinfections.

The Yersinia high-pathogenicity island (HPI) carried by a new integrative and conjugative element (ICE) in a multidrug-resistant and hypervirulent Klebsiella pneumoniae strain SCsl1.

Multidrug-resistant and hypervirulent Klebsiella pneumoniae (hvKP) poses a significant risk to public health. To better understand the molecular characteristics of multidrug-resistant and hypervirulent K. pneumoniae of animal origin, fifteen K. pneumoniae strains from the liver, blood of sick pigs and chicken feces were collected. All K. pneumoniae isolates were subjected to antimicrobial susceptibility testing, string test, multi-locus sequence typing and whole genome sequencing. Seven K. pneumoniae isolates were found carrying the mcr-1.1 gene. Among them, a multidrug-resistant and hypervirulent K. pneumoniae strain SCsl1 isolated from the liver of a diseased pig was found to harbor 16 resistance genes (e.g., mcr-1.1) and 16 virulence genes including aerobactin. Moreover, a novel integrative and conjugative element, named ICEKpSL1, was identified in SCsl1, which contains a full Yersinia high-pathogenicity island (HPI). This element could be excised from the chromosome to form a circular intermediate, indicating potential transmission of the Yersinia pathogenicity island. The emergence of multidrug-resistance and hypervirulence in K. pneumoniae from animals warrants further surveillance.

Characterization of Plasmid-Mediated Quinolone Resistance in Gram-Negative Bacterial Strains from Animals and Humans in China.

The aim of this study was to determine the molecular epidemiology of plasmid-mediated quinolone resistance (PMQR) determinants in Escherichia coli, Salmonella enterica (Salmonella spp.), Klebsiella pneumoniae, and Proteus mirabilis. Four hundred seventy-two nonrepetitive isolates were collected from different sources in China and screened for the presence of PMQR genes (PMQRs). Then, 49 PMQR producers were selected to study the coexistence of PMQRs and other resistance genes using whole-genome sequencing (WGS). High rates of resistance to tetracycline (93.4%), nalidixic acid (81.5%), and norfloxacin (65.8%) were observed. The predominant PMQRs were aac(6')-Ib-cr (28.6%) and oqxAB (21.4%). The prevalence of PMQR determinants was significantly higher (p < 0.05) in E. coli from stockmen (55.9%, 19/34), pigs (51.1%, 70/137), and laying hens (43.1%, 28/65) than that from wild animals (21.7%, 5/23) and dairy cattle (20.1%, 5/24). WGS results showed that 89.8% of the PMQR-positive isolates co-harbored ß-lactamase genes, with blaCTX-M being the dominant ß-lactamase gene. In K. pneumoniae, the coexistence rate of oqxAB and qnrB with fosA, blaDHA-1, and blaSHV was significantly higher than that in P. mirabilis and E. coli. In contrast, the coexistence of qnrD and blaOXA-1 was more prominent (p < 0.001) in P. mirabilis than in the other two species. Particularly, oqxAB and mcr-1 had an obvious preference for E. coli than K. pneumonia and P. mirabilis (p < 0.001), which had not been reported in previous studies on the prevalence of PMQRs.

Antimalarial Drug Pyrimethamine Plays a Dual Role in Antitumor Proliferation and Metastasis through Targeting DHFR and TP.

Pyrimethamine (Pyr), an antimalarial drug that targeting plasmodium dihydrofolate reductase (pDHFR), has been proved to have antitumor activity. However, its direct target on cancer cells remains unclear. Methotrexate (MTX) is a widely used anticancer drug that blocks human dihydrofolate reductase (hDHFR). In this work, we examined the anticancer effects of Pyr in vitro and in vivo Our results showed that hDHFR and pDHFR have similar secondary and three-dimensional structures and that Pyr can inhibit the activity of hDHFR in lung cancer cells. Although Pyr and MTX can inhibit the proliferation of lung cancer cells by targeting DHFR, only Pyr can inhibit the epithelial-mesenchymal transition (EMT), metastasis and invasion of lung cancer cells. These results indicated that hDHFR is not the only target of Pyr. We further found that thymidine phosphorylase (TP), an enzyme that is closely associated with the EMT of cancer cells, is also a target protein of Pyr. The data retrieved from the Cancer Genome Atlas (TCGA) database revealed that TP overexpression is associated with poor prognosis of patients with lung cancer. In conclusion, Pyr plays a dual role in antitumor proliferation and metastasis by targeting DHFR and TP. Pyr may have potential clinical applications for the treatment of lung cancer.

The Prevalence of Colistin Resistant Strains and Antibiotic Resistance Gene Profiles in Funan River, China.

Anthropogenic activities near urban rivers may have significantly increased the acquisition and dissemination of antibiotic resistance. In this study, we investigated the prevalence of colistin resistant strains in the Funan River in Chengdu, China. A total of 18 mcr-1-positive isolates (17 Escherichia coli and 1 Enterobacter cloacae) and 6 mcr-3-positive isolates (2 Aeromonas veronii and 4 Aeromonas hydrophila) were detected, while mcr-2, mcr-4 and mcr-5 genes were not detected in any isolates. To further explore the overall antibiotic resistance in the Funan River, water samples were assayed for the presence of 15 antibiotic resistance genes (ARGs) and class 1 integrons gene (intI1). Nine genes, sul1, sul2, intI1, aac(6')-Ib-cr, bla CTX-M, tetM, ermB, qnrS, and aph(3')-IIIa were found at high frequencies (70-100%) of the water samples. It is worth noting that mcr-1, bla KPC, bla NDM and vanA genes were also found in water samples, the genes that have been rarely reported in natural river systems. The absolute abundance of selected antibiotic resistance genes [sul1, aac(6')-Ib-cr, ermB, blaCTX-M, mcr-1, and tetM] ranged from 0 to 6.0 (log10 GC/mL) in water samples, as determined by quantitative polymerase chain reaction (qPCR). The sul1, aac(6')-Ib-cr, and ermB genes exhibited the highest absolute abundances, with 5.8, 5.8, and 6.0 log10 GC/mL, respectively. The absolute abundances of six antibiotic resistance genes were highest near a residential sewage outlet. The findings indicated that the discharge of resident sewage might contribute to the dissemination of antibiotic resistant genes in this urban river. The observed high levels of these genes reflect the serious degree of antibiotic resistant pollution in the Funan River, which might present a threat to public health.