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Magnetic reconnection is a rapid process that releases magnetic free energy stored in current sheets (CSs), driving various explosive phenomena throughout the Universe. In planets within the solar system, reconnection is controlled by both the solar wind and the planet’s magnetic field and rotation. In this study, we perform a statistical analysis of the characteristics of CSs and reconnection events in the Martian magnetotail, considering varying solar wind conditions and local crustal field variations. The results show that higher solar wind dynamic pressure leads to a significantly increased probability of reconnection, primarily due to the enhanced cross-tail current density. In contrast, the orientation of interplanetary magnetic fields and local crustal anomalies predominantly affect the spatial distribution of CSs and reconnection events. Moreover, high solar wind dynamic pressure significantly enhances the average tailward flux of hydrogen and oxygen ions, likely attributable to the enhanced pickup of planetary ions.

Tigecycline is one of the few therapeutic options for treating infections caused by some multi-drug resistant pathogens, such as Klebsiella pneumoniae. However, tigecycline-resistant K. pneumoniae has been discovered recently in China. From 2009 to 2013, nine tigecycline-resistant K. pneumoniae isolates were identified in our hospital. Six of nine strains were identified before using tigecycline. To investigate the efflux-mediated resistance mechanisms of K. pneumoniae, the expression of efflux pump genes (acrA, acrB, tolC, oqxA and oqxB) and pump regulators (acrR, marA, soxS, rarA, rob and ramA) were examined by real-time RT-PCR. Molecular typing of the tigecycline resistant strains was performed. ST11 was the predominant clone of K. pneumoniae strains, while ST1414 and ST1415 were novel STs. Efflux pump inhibitor (EPI)-carbonyl cyanide chlorophenylhydrazone (CCCP) was able to reverse the resistance patterns of 5 resistant K. pneumoniae strains. In comparison with strain A111, a tigecycline-susceptible strain (negative control), we found that the expression levels of efflux pump genes and pump regulators were higher in a majority of resistant strains. Higher expression levels of regulators rarA (2.41-fold, 9.55-fold, 28.44-fold and 18.31-fold, respectively) and pump gene oqxB (3.87-fold, 31.96-fold, 50.61-fold and 29.45-fold, respectively) were observed in four tigecycline resistant strains (A363, A361, A368, A373, respectively). Increased expression of acrB was associated with ramA and marA expression. To our knowledge, studies on tigecycline resistance mechanism in K. pneumoniae are limited especially in China. In our study, we found that both efflux pump AcrAB-TolC and OqxAB contributed to tigecycline resistance in K. pneumoniae isolates.

The Martian dynamo evolution is critical for understanding Mars’s interior structure, thermal evolution, and climate change. It has been inferred to shut down at ∼4.1–4.0 Ga based on the magnetic signatures of large impact craters, but be present at ∼3.9 Ga and ∼3.7 Ga from the paleomagnetic studies and magnetic fields above volcanic units. Here, we investigate the magnetic signatures of the Iota crater, located inside the CT3-G area with a centrally strong magnetic anomaly. The Iota crater shows a weak central magnetic field with an inside-outside strength ratio of 0.39. Forward modeling is established to explore the relationship between the magnetic field signatures of craters and the magnetization caused by impact. The results show that the average magnetization of the retained materials beneath the Iota crater is about 20% of the maximum of the surroundings, indicating that the dynamo strength at that time became weak. The magnetic signatures of Iota and CT3-G reveal that the Martian dynamo decayed at ∼4.1 Ga, but did not stop completely.

Background Morbidity and mortality in transplant patients is increased by infection caused mainly by rare opportunistic pathogens. The present study reports a case where Hongkongmyces snookiorum caused subcutaneous phaeohyphomycosis in a kidney transplant patient. Case presentation A 47-year old Chinese woman with chronic kidney disease 5 underwent kidney transplantation 3 years ago. Her regular medications included Tacrolimus (1 mg, two times daily), Mycophenolate Mofetil (two times 250 mg, twice daily) and Prednisone acetate tablets (5 mg daily). Eighteen months ago, her proximal right index finger was red, painful and swollen. After admission, a hard and fluctuating 1 cm × 1 cm abscess was found on the dorsal side of the right index finger. Gram and fluorescence staining of a direct smear of a syringe extraction from the abscess revealed presence of filamentous fungi. White velvet colonies (2–3 mm) were found on blood plate and Sabouraud glucose agar (SGA) after 1 week, and grey aerial hyphae were observed. After 15 days, a 26 mm gray colony was also observed on SGA. The homology between this filamentous fungus and Hongkongmyces snookiorum ILLS00125755 (Genbank Sequence ID: MH161189.1) was 99.66%. An in vitro antifungal susceptibility test showed that this filamentous fungus was sensitive to azoles such as itraconazole and voriconazole. Conclusions We report an opportunistic fungus infection caused by Hongkongmyces snookiorum in a transplant patient. Our finding shows that prevention of subcutaneous fungal infection is necessary for kidney transplantation patients.

Background Pulmonary infections caused by non-diphtheriae corynebacteria are increasing. However, rapid identification of Corynebacterium species poses a challenge due to the low genetic variation within the genus. Methods Three reference strains and 99 clinical isolates were used in this study. A qPCR followed by high-resolution melting (HRM) targeting ssrA was performed to simultaneously identify C. striatum , C. propinquum and C. simulans . To further evaluate this assay’s performance, 88 clinical sputum samples were tested by HRM and the detection results were compared with those of the traditional culture method and multiple cross-displacement amplification (MCDA) assay. Results The melting curve produced by a pair of universal primers generated species-specific HRM curve profiles and could distinguish the three target species from other related bacteria. The limit of detection of HRM assay for DNA from the three purified Corynebacterium species was 100 fg. Compared with the culture method, HRM detected 22 additional positive specimens, representing a 23.9% relative increase in detection rate. The HRM assay had 98.4% (95% confidence interval [CI], 90.5–99.9%) sensitivity and 100% (95% CI, 82.8–100%) specificity. Additionally, 95.5% concordance between HRM and MCDA (κ = 0.89 [95% CI, 0.79–0.99]) was noted. Conclusions The HRM assay was a simple, rapid, sensitive, and specific diagnostic tool for detecting C. striatum , C. propinquum, and C. simulans , with the potential to contribute to early diagnosis, epidemiological surveillance, and rapid response to outbreak.

From June, 2012 to November, 2013 five linezolid-resistant Staphylococcus cohnii isolates were identified in our hospital in Beijing, China. The investigation of the resistance mechanisms confirmed that the cfr -carrying plasmids were the main cause of linezolid resistance in those clinical isolates. Moreover, all the five isolates had ribosomal protein L3 mutations, which had different coordinate effect on cfr -mediated linezolid resistance directly through the substitution of serine 158 by phenylalanine or tyrosine in L3 protein. In this study, two types of plasmids (p432, p438) (Accession No. KM114207) were found, which share high sequence identity with previously reported cfr -carrying pRM01 and pMHZ plasmids originated from northern and southern China, showing wide regional dissemination in China. The stability of linezolid resistance was studied by passaging single colonies serially on antibiotic-free blood medium, which showed that the susceptible derivatives emerged until the passages 39–42 with the elimination of cfr -carrying plasmid. Thus the high stability of this plasmid may pose a risk for the transmission among patients or even cause an outbreak in clinical settings.

Tigecycline is one of the few therapeutic options for treating infections caused by some multi-drug resistant pathogens, such as Klebsiella pneumoniae. However, tigecycline-resistant K. pneumoniae has been discovered recently in China. From 2009 to 2013, nine tigecycline-resistant K. pneumoniae isolates were identified in our hospital. Six of nine strains were identified before using tigecycline. To investigate the efflux-mediated resistance mechanisms of K. pneumoniae, the expression of efflux pump genes (acrA, acrB, tolC, oqxA and oqxB) and pump regulators (acrR, marA, soxS, rarA, rob and ramA) were examined by real-time RT-PCR. Molecular typing of the tigecycline resistant strains was performed. ST11 was the predominant clone of K. pneumoniae strains, while ST1414 and ST1415 were novel STs. Efflux pump inhibitor (EPI)-carbonyl cyanide chlorophenylhydrazone (CCCP) was able to reverse the resistance patterns of 5 resistant K. pneumoniae strains. In comparison with strain A111, a tigecycline-susceptible strain (negative control), we found that the expression levels of efflux pump genes and pump regulators were higher in a majority of resistant strains. Higher expression levels of regulators rarA (2.41-fold, 9.55-fold, 28.44-fold and 18.31-fold, respectively) and pump gene oqxB (3.87-fold, 31.96-fold, 50.61-fold and 29.45-fold, respectively) were observed in four tigecycline resistant strains (A363, A361, A368, A373, respectively). Increased expression of acrB was associated with ramA and marA expression. To our knowledge, studies on tigecycline resistance mechanism in K. pneumoniae are limited especially in China. In our study, we found that both efflux pump AcrAB-TolC and OqxAB contributed to tigecycline resistance in K. pneumoniae isolates.

Staphylococcus epidermidis is the most commonly isolated species from human skin and the second leading cause of bloodstream infections. Here, we performed a large-scale comparative study without any pre-assigned reference to identify genomic determinants associated with their diversity and adaptation as a “double-side spy”, a skin dominant colonization, and a successful pathogen. The pan-genome of S. epidermidis is open with 435 core proteins and a pan-genome size of 8034 proteins. Genome-wide phylogenetic tree shows that whole genome sequence is a powerful tool to analyze the complex evolutionary process of S. epidermidis and investigate the source of infection. Comparative genome analyses demonstrate the high diversity of antimicrobial resistances, especially mobile genetic elements. The complicated relationships of host-bacterium and bacterium-bacterium help S. epidermidis to play a vital role in balancing the epithelial microflora. The highly variable and dynamic nature of the S. epidermidis genome may be the result of its success in adapting to broad habitats, which is necessary to deal with complex environments. This study gives the general landscape of S. epidermidis pan-genome and provides valuable insights into mechanisms for genome evolution and lifestyle adaptation of this ecologically flexible species.

PurposeThis study was conducted to evaluate the status of depression and anxiety of healthcare workers and to explore the risk factors during the outbreak of COVID-19 in China.MethodsA cross-sectional study was designed using convenience sampling to obtain a sample of healthcare workers. A structured questionnaire was designed to collect the information of the basic characteristics, workload, and the health condition. Burnout, coping style, anxiety, and depression were measured by specific scales. Multiple logistic regression model was performed to explore the risk factors of anxiety or depression.ResultsThere were 902 questionnaires received between February 9, 2020 and February 11, 2020. The proportion of healthcare workers with symptoms of moderate/severe anxiety and moderate/severe depression were 16.63% and 18.29%, respectively. There were 24.50% healthcare workers experiencing moderate/severe anxiety and depression at the same time. The increased workload, respiratory symptoms, digestive symptoms, having done specific test(s) related to COVID-19, having family member needs to be taken care of, negative coping style, and job burnout were the independent risk factors of anxiety. Furthermore, the increased workload, respiratory symptoms, digestive symptoms, having done specific test(s) related to COVID-19, negative coping style, and job burnout were the independent risk factors of depression.ConclusionMore attention should be paid to the mental health of frontline healthcare workers at the outbreak of COVID-19 in China. Taking steps to reduce the intensity of the work and burnout will be effective to stabilize the mental state of them.