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The multidrug resistance and biofilm formation of Gram-negative bacteria (GNB) may lead to incurable “superbug” infections. Drug combinations, with the potential to augment the original treatment ranges of drugs, are alternative treatment strategies against GNB.

Cooccurrence of multidrug resistant (MDR) and hypervirulence phenotypes in liver abscess-causing Klebsiella pneumoniae (LAKp) would pose a major threat to public health. However, relatively little information is available on the genomic and phenotypic characteristics of this pathogen. This study aimed to investigate the virulence and resistance phenotype and genotype of MDR LAKp strains from 2016 to 2020. We collected 18 MDR LAKp strains from 395 liver abscess samples and characterized these strains using antimicrobial susceptibility test, string test, mucoviscosity assay, biofilm formation assay, Galleria mellonella killing assay, and whole-genome sequencing. Besides, phylogenetic and comparative genomic analyses were performed on these MDR LAKp, along with 94 LAKp genomes from global sources. Most of these MDR LAKp strains exhibited resistance to cephalosporins, quinolones, and chloramphenicol. Virulence assays revealed that only half of MDR LAKp strains exhibited higher virulence than classical MDR strain K. pneumoniae MGH78578. Importantly, we identified three ST11 KL64 hypervirulence carbapenem-resistant strains carrying

Background Pseudomonas aeruginosa (P. aeruginosa) has been majorly implicated in the infection of burns, wounds, skin, and respiratory tract. Colistin is considered the last line of defense against P. aeruginosa infections. However, colistin is becoming increasingly invalid in treating patients infected with colistin-resistant (COL-R) P. aeruginosa. As one of the disinfectants used for wound infections, acetic acid (AA) offers good antibacterial and antibiofilm activities against P. aeruginosa. This study investigated the effects of AA on COL-R P. aeruginosa in terms of its antibacterial, antibiofilm, and anti-virulence properties and the corresponding underlying mechanisms. Results The antimicrobial susceptibility and growth curve data revealed that 0.078% (v/v) AA exhibited good antibacterial activity against COL-R P. aeruginosa. Subinhibitory concentrations of AA were ineffective in inhibiting biofilm formation, but 4 × and 8 × of the minimum inhibitory concentration (MIC) was effective in removing the preformed biofilms in biofilm-eradication assays. The virulence results illustrated that AA inhibited COL-R P. aeruginosa swimming, swarming, twitching, and pyocyanin and elastase production. The analysis of the potential antibacterial mechanisms of AA on COL-R P. aeruginosa revealed that AA acted by increasing the outer and inner membrane permeability, polarizing the membrane potential, and decreasing the reduction potential in a concentration-dependent manner. The qRT-PCR results revealed that AA may inhibit the virulence of COL-R P. aeruginosa by inhibiting the expression of T3SS-related and QS-related genes. Conclusions AA possesses antibacterial, antibiofilm, and anti-virulence properties that ultimately lead to the alteration of the bacterial membrane permeability, membrane potential, and reduction potential. Our findings indicated that AA is presently one of the effective treatment options for infections. A high concentration of AA (> 0.156% v/v) can be used to sterilize biofilm-prone surgical instruments, for hospital disinfection, and for treating the external wound, whereas a low concentration of AA (0.00975–0.039% v/v) may be used as an anti-virulence agent for adjuvant treatment of COL-R P. aeruginosa, thereby further improving the application value of AA in the treatment of infections.

Lingbo Wang,1,* Ying Zhang,2,* Shixing Liu,1 Na Huang,1 Weiliang Zeng,1 Wenya Xu,1 Tieli Zhou,1 Mo Shen1 1Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People’s Republic of China; 2School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, People’s Republic of China*These authors contributed equally to this workCorrespondence: Mo Shen; Tieli ZhouDepartment of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, People’s Republic of ChinaTel +86-577-8668-9885Email shenmo601@163.com; wyztli@163.comBackground: The emergence and spread of linezolid-resistant Enterococcus faecalis (E. faecalis) have emerged as a serious threat to human health globally. Therefore, this study aims to compare the anti-microbic as well as the anti-biofilm activity of linezolid, tedizolid, and radezolid against linezolid-resistant E. faecalis.Methods: A total of 2128 E. faecalis isolates were assessed from the First Affiliated Hospital of Wenzhou Medical University from 2011 to 2019. Antibiotic sensitivity was evaluated using the micro broth dilution method. Oxazolidinone-resistant chromosomal and plasmid-borne genes such as cfr, cfr(A), cfr(B), cfr(C), cfr(D), optrA, and poxtA were detected by PCR and then sequenced to detect the presence of mutations in the domain V of the 23S rRNA and the ribosomal proteins L3, L4, and L22. Conjugation experiments were conducted using the broth method. The inhibition and eradication of biofilm were evaluated through crystal violet staining, whereas the efflux pump activities were detected by agar dilution.Results: Out of 2128 isolated E. faecalis, 71 (3.34%) were linezolid-resistant isolates in which the MICs of tedizolid and radezolid ranged from 1 to 4 μg/mL and 0.5– 1 μg/mL, respectively. The MIC50/MIC90 of tedizolid and radezolid were 4 and 8-fold lower than the linezolid, respectively. Out of 71 resistant isolates, 57 (80.28%) carried optrA, 1 (1.41%) carried cfr, 4 (5.63%) carried optrA and cfr, and 6 (8.45%) carried optrA and cfr(D), with no mutations of 23S rRNA gene and ribosomal proteins L3, L4, and L22. Besides, the transfer rate of the optrA, cfr, and cfr(D) was 17.91%, 0% and 0%, respectively. Radezolid showed more effectiveness in eradicating biofilm (8 × MIC). However, tedizolid was more effective than radezolid and linezolid in inhibiting the biofilm formation (1/4 MIC, 1/8MIC, and 1/16MIC). Additionally, in combination with CCCP, the MICs of radezolid in all linezolid-resistant isolates decreased ≥ 4-fold.Conclusion: Radezolid showed greater antimicrobial activity than tedizolid and linezolid against linezolid-resistant E. faecalis. However, both tedizolid and radezolid showed differential activity on biofilm inhibition, eradication, and efflux pump compared to linezolid. Thus, our study might bring important clinical value in the application of these drugs for resistant pathogenic strains.Keywords: Enterococcus faecalis, linezolid, tedizolid, radezolid, in vitro activity, anti-biofilm activity

Huaiyu Jia,1 Ying Zhang,2 Jianzhong Ye,1 Wenya Xu,1 Ye Xu,1 Weiliang Zeng,2 Wenli Liao,1 Tao Chen,1 Jianming Cao,2 Qing Wu,1 Tieli Zhou1 1Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People’s Republic of China; 2Department of Medical Laboratory Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, People’s Republic of ChinaCorrespondence: Tieli Zhou; Qing WuDepartment of Clinical Laboratory, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou, People’s Republic of ChinaTel/Fax +86-0577-8668-9885Email wyztli@163.com; wuqing830@163.comBackground: OXA-232-producing carbapenem-resistant Klebsiella pneumoniae (CRKP) has the potential to become the “third epidemic” of carbapenem-resistant Klebsiella strain after KPC-2 and NDM in China. We investigated the first outbreak of CRKP in the First Affiliated Hospital of Wenzhou Medical University.Methods: We collected 610 clinical isolates of CRKP from the First Affiliated Hospital of Wenzhou Medical University between January 2019 and September 2020 and screened them by Polymerase Chain Reaction (PCR). The multilocus sequence typing and pulsed-field gel electrophoresis were used to determine the genetic relatedness of the strains. The antimicrobial susceptibility test was performed to determine the drug resistance of the clinical isolates. The molecular mechanism underlying carbapenem resistance was elucidated by performing PCR and conjugation experiments. The virulence potential of the strains was determined by the string test, detection of virulence-associated genes and capsular serotypes, and Galleria mellonella larval infection model.Results: Between September 2019 and May 2020, 26 OXA-232-producing CRKP were obtained from 12 patients in our hospital. Ten patients were hospitalized in the intensive care units (ICU) and the overall mortality of the inpatients involved in the outbreak was 50% (6/12). Epidemiological investigations reported that all the OXA-232-producing CRKP strains belonged to the sequence type ST15 and can be clonally transmitted among the inpatients in the ICU. All the strains had low virulence and were resistant to commonly used clinical antibiotics except for ceftazidime/avibactam, colistin, and tigecycline. The OXA-232-producing CRKP was sensitive to triclosan and chlorhexidine, and its eradication from our hospital can be achieved by the use of disinfectants in the ICU.Conclusion: In our study, OXA-232-producing CRKP isolates appeared to be clonally transmitted and the sequence type ST15 was responsible for the outbreak. Therefore, effective measurements for the infection control of CRKP are urgently needed to prevent its epidemic in the nearby region in the future.Keywords: Klebsiella pneumoniae, carbapenem-resistance, virulence, OXA-232, outbreak

In this study, we investigated the in vitro activity and resistance mechanisms of the new generation tetracycline agents, namely eravacycline, omadacycline, and tigecycline, against Staphylococcus aureus isolates. A total of 1,017 non-duplicate S. aureus isolates were collected and subjected to susceptibility testing against eravacycline, omadacycline, and tigecycline using the broth microdilution method. Tetracyclines-resistant (eravacycline/omadacycline/tigecycline-resistant) isolates were selected to elucidate the resistance mechanisms using polymerase chain reaction (PCR), cloning experiment, efflux pump inhibition, and quantitative real-time PCR. The results of the antibacterial susceptibility testing showed that compared with omadacycline, eravacycline and tigecycline had superior antibacterial activity against S. aureus isolates. Among 1,017 S. aureus, 41 tetracyclines-resistant isolates were identified. These resistant isolates possessed at least one tetracycline resistance gene and genetic mutation in the MepRAB efflux pump and 30S ribosome units. A frameshift mutation in mepB was detected in most tetracyclines-resistant strains (except for JP3349) compared with tetracyclines-susceptible (eravacycline/omadacycline/tigecycline-susceptible) strains. This was first shown to decrease susceptibility to omadacycline, but not to eravacycline and tigecycline. After treatment with eravacycline, omadacycline or tigecycline, overexpression of mepA, tet38, tet(K) and tet(L) was detected. Moreover, multi-locus sequence typing showed a major clonal dissemination type, ST5, and its variant ST764 were seen in most tetracyclines-resistant strains. To conclude, eravacycline and tigecycline exhibited better activity against S. aureus including tetracycline-resistant isolates than omadacycline. The resistance to these new generation tetracyclines due to an accumulation of many resistance mechanisms.

Alar retraction is considered a challenge in rhinoplasty. The classification of alar retraction remains poorly defined, especially in Asia. Patients with alar retraction are associated with excessive exposure to the nostrils in Asia. This study aimed to introduce a classification method of alar retraction based on nostril exposure.Medical records of patients who had undergone rhinoplasty with alar retraction based on nostril exposure between January 2015 and December 2020 were retrospectively reviewed. The corrections of alar retraction were categorized into three groups according to a classification method of alar retraction based on nostril exposure: mild alar retraction, moderate alar retraction, and severe alar retraction. The visual analog scale (VAS) and rhinoplasty outcomes evaluation (ROE) were used to evaluate the satisfaction rate.Within a median period of 13.3 months, 45 patients (51.14%) with mild alar retraction were corrected by alar contour graft. 23 patients (26.14%) with moderate alar retraction were treated with the alar contour graft(n=10), the lateral crural strut graft (n = 6), and the alar projection graft (n = 7). 20 patients (22.73%) with severe alar retraction were corrected by lateral crural strut graft combined with composite graft (n = 6), lateral crural strut graft (n = 10), and composite graft (n = 4). The severe alar retraction group had a higher satisfaction rate in ROE(P0.05) and VAS (P0.05) than moderate alar retraction and mild alar retraction at a follow-up of 12 months after surgery.The classification of alar retraction based on nostril exposure is more practical for rhinoplasty in Asia.

Ceftazidime/avibactam (CZA) is an alternative antibiotic used for the treatment of infections caused by carbapenem-resistant Enterobacterales (CRE). However, the CZA-resistant CRE strains have been detected worldwide. Therefore, it is critical to screen CZA-resistant CRE strains in colonized patients or a specific population so as to rapidly implement infection control measures to limit their transmission. In this study, we developed a Salmonella-Shigella (SS) CZA-selective medium and assessed its performance to screen for clinical CZA-resistant CRE isolates in both pure-strain specimens and stool samples. A total of 150 non-duplicated isolates, including 75 CZA-susceptible and 75 CZA-resistant CRE pathogens, were tested by using the broth microdilution method and the SS CZA medium, respectively. The bacterial suspensions were serially diluted in the SS CZA medium, which showed excellent screening performance in both pure CZA-resistant CRE strain and the stool samples with the lowest detection limit of 101-102 and 101-103 CFU/ml, respectively. Notably, none of the susceptible isolates showed growth even at the highest dilution concentration of 108 CFU/ml. Most importantly, the SS CZA medium demonstrated excellent performance in screening simulated clinical polymicrobial specimens. Moreover, its screening performance was unaffected by the different resistance determinants for tested isolates. Cumulatively, our data suggest that the SS CZA medium can be used as a promising selective medium to screen CZA-resistant CRE, irrespective of their resistance mechanisms.

Aims: Colistin became the critical treatment option for multidrug-resistant Gram-negative bacteria (GNB); however, resistance to colistin is increasingly being reported among clinical isolates. New...

Ceftazidime/avibactam (CZA) is an alternative antibiotic used for the treatment of infections caused by carbapenem-resistant

Background Vancomycin and linezolid resistance among enterococci is an increasing problem due to a lack of alternative antibiotics. Early identification of vancomycin-resistant and linezolid-resistant strains can help prevent the spread of resistance to these antibiotics. Hence, early, rapid and accurate detection of vancomycin and linezolid resistance is critical. Objectives The resazurin microplate method (RMM) was developed for detecting vancomycin and linezolid susceptibility among Enterococcus faecalis (E. faecalis) and Enterococcus faecium (E. faecium) clinical isolates, and its performance was further evaluated. Methods A total of 209 non-duplicate clinical isolates and three strains from the faeces of domestic animals, including 142 E. faecalis (71 linezolid non-susceptible and 71 linezolid susceptible) and 70 E. faecium (23 vancomycin non-susceptible, 23 vancomycin susceptible, 12 linezolid non-susceptible and 12 linezolid susceptible), were tested using RMM. Results The susceptibility of E. faecium to vancomycin was detected within 5 h, with high susceptibility (23/23) and specificity (23/23). The susceptibility of E. faecalis and E. faecium to linezolid was detected within 4 h, with specificities of 98.59% and 100% and susceptibilities of 94.37% and 58.33% for E. faecalis and E. faecium, respectively. Conclusions RMM had a good positive predictive value for the detection of vancomycin-non-susceptible E. faecium and linezolid-non-susceptible E. faecalis. It thus has the potential to become an alternative method for the rapid screening of these resistant pathogens in clinical practice.

Due to the lack of research on the characteristics of different clusters of Enterobacter cloacae complex (ECC), this study aimed to characterize and explore the differences among species of the ECC. An analysis based on hsp60 showed that Enterobacter hormaechei was predominant in ECC. Interestingly, the antibiotic resistance rates of clusters were different, among which E. hormaechei subsp. steigerwaltii (cluster VIII) and Enterobacter cloacae IX (cluster IX) possessed high resistant rates to ciprofloxacin and levofloxacin, but cluster II (Enterobacter kobei) had low resistant rates. Cluster II exhibited a strong biofilm formation ability. Different motility and protease production ability were shown for distinct clusters. A PCR analysis showed that clusters I, III, VI, VIII, and IX carried more virulence genes, while cluster II had fewer. Clusters I, VIII, and IX with high pathogenicity were evaluated using the Galleria mellonella infection model. Thus, the characteristics of resistance, biofilm-forming ability, mobility, and virulence differed among the clusters. The strains were divided into 12 subgroups based on hsp60. The main clusters of ECC clinical strains were I, II, III, VI, VIII, and IX, among which IX, VIII, and I were predominant with high resistance and pathogenicity, and cluster II (E. kobei) was a special taxon with a strong biofilm formation ability under nutrient deficiency, but was associated with low resistance, virulence, and pathogenicity. Hence, clinical classification methods to identify ECC subgroups are an urgent requirement to guide the treatment of clinical infections.

It is a challenge to apply the precoder design maximizing the mutual information with finite-alphabet inputs to practical multiple-input multiple-output (MIMO) systems, because it needs to iteratively solve an optimization problem, which is difficult to satisfy the requirement of real time. This letter develops a deep learning based precoding scheme, which employs the property of deep neural network (DNN) as approximator of functions. Simulation results show that a DNN can accurately learn the input-output relationship of a nearly optimal precoder achieved by the traditional interior-point method (IPM); moreover, in different MIMO scenarios, a trained DNN of small size offers almost the same performance as the nearly optimal precoder, but with huge improvement in efficiency, especially in cases of higher modulation and more antennas. The improved efficiency makes it possible to be applied to practical communication systems.

A real-time responsive customised bus (RTRCB) provides demand-oriented and shared-ride service for passengers with random travel demands. Unlike other works in the literature, the authors developed a hierarchical methodology to optimise the RTRCB schedule. It involves a trade-off between the interests of the transporter and those of the passengers. After minimising the initial travel distance while maintaining a wide service range, the bus routes are planned holistically based on the main travel locations. Based on the initial routes, the buses are dispatched to satisfy the real-time travel demands. The procedure for solving the proposed problem is developed by modifying the genetic algorithm (GA) and non-dominated sorting GA with elite strategy. The proposed method is applied to a real-life problem in the city of Shenzhen, and certain extensional analyses are performed to demonstrate their feasibility. The computational results show that: (i) the travel distance limitation and tortuosity ratio of the bus route play the most important roles in planning bus routes; (ii) the designation of all the initial bus stops as the control stops results in comparatively stable service for more passengers; and (iii) a better service performance can be achieved by introducing the soft time window strategy with an acceptable delivery delay.

The fine shape control of metal oxides nanocrystal and component are the key for the preparation of high-performance metal oxides/graphene nanocomposites. Herein, a simpler and practicable in situ one-pot approach was used to synthetize α-Fe2O3@reduced graphene oxide (rGO) core–shell nanocomposites. By controlling the amount of hydrazine hydrate and GO in reaction system, the shape of α-Fe2O3 nanocrystals can be tailored from spindle gradually to ellipsoid and quasi-sphere, and the thickness of enwrapped rGO can also be finely controlled. The as-prepared α-Fe2O3@rGO core–shell composites showed much better lithium storage performance than bare α-Fe2O3 nanocrystals. Owing to the core–shell structure and the high conductivity and stability of rGO nanosheet, the quasi-sphere-α-Fe2O3@rGO composites delivered a high reversible specific capacity up to 971 mAh g−1 at the current density of 0.2 A g−1, retaining 530 mA h g−1 at 2 A g−1 and 361 mA h g−1 at 5 A g−1 after 800 cycles with only 0.05% decay per-cycle. Moreover, the facile approach can provide a new strategy for the fabrication of other shape-size dependent, functional, and multicomponent graphene-based composites.

The application of ridesharing strategy to autonomous taxi system holds great promise for improving the efficiency in the future on-demand ride-hailing services. Prior to the implementation of dispatching strategies to the autonomous taxi system, it is necessary to gain insight into the performance of the dispatching strategies. This study aims to solve the dynamic ridesharing problem and conduct a comprehensive quantity analysis of the ridesharing efficiency for various demand levels and carrying capacities in a metropolitan area. We quantify the success rate of serviced requests, the trip travel time, the discount rate of taxi fare, and total energy consumption for different carrying capacities and demand levels in the road network of Shenzhen city. The simulation results show that the ride-matching success rate within 3 minutes enables to increase by more than 13% in the ridesharing mode, and over 80% of the passengers can be served within 6 minutes if the carrying capacity is set to four. The trip travel time and energy consumption also show a significant downward trend as the capacity of the taxi increases in the ridesharing mode.

Carbapenem-resistant Klebsiella pneumonia (CRKP) infections has become a concerning threat. However, knowledge regarding the characteristics of intestinal CRKP isolates is limited. This study aimed to investigate and compare the clinical, virulence and molecular epidemiological characteristics of intestinal colonization and extraintestinal infections CRKP strains. The clinical characteristics were investigated retrospectively. Polymerase chain reaction was used to investigate the capsular serotype, virulence genes and carbapenemase genes. Capsular polysaccharide quantification assay, serum resistance assay, biofilm formation assay, and infection model of Galleria mellonella larvae were performed to compare the virulence and pathogenicity. Besides, multilocus-sequence-typing (MLST) and pulsed-field-gel-electrophoresis (PFGE) were conducted to explore the homology of intestinal CRKP isolates. A total of 54 intestinal CRKP isolates were included. The main capsular serotypes were K14, K64, and K19. C-reactive protein and the proportion of ICU isolation of the infection group were significantly higher than that of the colonization group (P < 0.05). The carrier rates of various virulence genes of CRKP in the infection group were mostly higher than those in the colonization group, wherein the carrier rates of peg-344 and rmpA were significantly different (P < 0.05). There was no significant difference in capsular polysaccharides, antiserum ability, biofilm formation ability between the two group (P > 0.05), but the lethality of the infection group to Galleria mellonella was significantly higher than that of the colonization group (P < 0.05). The MLST categorized the 54 isolates into 13 different sequence types. PFGE revealed that homology among the 54 CRKP strains was

Colistin is being considered as “the last ditch” treatment in many infections caused by Gram-negative stains. However, colistin is becoming increasingly invalid in treating patients who are infected with colistin-resistant Escherichia coli (E. coli) and Klebsiella Pneumoniae (K. pneumoniae). To cope with the continuous emergence of colistin resistance, the development of new drugs and therapies is highly imminent. Herein, in this work, we surprisingly found that the combination of quercetin with colistin could efficiently and synergistically eradicate the colistin-resistant E. coli and K. pneumoniae, as confirmed by the synergy checkboard and time-kill assay. Mechanismly, the treatment of quercetin combined with colistin could significantly downregulate the expression of mcr-1 and mgrB that are responsible for colistin-resistance, synergistically enhancing the bacterial cell membrane damage efficacy of colistin. The colistin/quercetin combination was notably efficient in eradicating the colistin-resistant E. coli and K. pneumoniae both in vitro and in vivo. Therefore, our results may provide an efficient alternative pathway against colistin-resistant E. coli and K. pneumoniae infections.

Daptomycin is a last-line antibiotic used in the treatment of multidrug-resistant

Due to the lack of research on the characteristics of different clusters of

Colistin is being considered as “the last ditch” treatment in many infections caused by Gram-negative stains. However, colistin is becoming increasingly invalid in treating patients who are infected with colistin-resistant Escherichia coli (E. coli) and Klebsiella Pneumoniae (K. pneumoniae). To cope with the continuous emergence of colistin resistance, the development of new drugs and therapies is highly imminent. Herein, in this work, we surprisingly found that the combination of quercetin with colistin could efficiently and synergistically eradicate the colistin-resistant E. coli and K. pneumoniae, as confirmed by the synergy checkboard and time-kill assay. Mechanismly, the treatment of quercetin combined with colistin could significantly downregulate the expression of mcr-1 and mgrB that are responsible for colistin-resistance, synergistically enhancing the bacterial cell membrane damage efficacy of colistin. The colistin/quercetin combination was notably efficient in eradicating the colistin-resistant E. coli and K. pneumoniae both in vitro and in vivo. Therefore, our results may provide an efficient alternative pathway against colistin-resistant E. coli and K. pneumoniae infections.

Cardiovascular disease (CVD) is a kind of chronic disease involving the heart and blood vessels. In the early 21st century, cardiovascular diseases accounted for nearly 50% of the mortality in developed countries and about 25% in developing countries, and cardiovascular diseases have gradually become common diseases. Accurate prediction of survival events of patients with cardiovascular disease can provide more meaningful reference for subsequent treatment, and strive for the best treatment opportunity for patients to achieve the purpose of prolonging life. The data set collected by Kaggle was used in this study, which included variables such as high blood pressure, creatinine phosphokinase, ejection fraction, serum creatinine, and smoking. Based on Akaike information criterion (AIC), stepwise regression analysis was used to select the strongly correlated variables of cardiovascular disease, and then an artificial neural network (ANN) based survival prediction model of cardiovascular disease was constructed. In this paper, support vector machine (SVM) and naive Bayes are used to compare with the artificial neural network. The results show that the performance of artificial neural network is better than other algorithms regardless of the use of strongly correlated variables. After using strongly correlated variables, the performance of each algorithm is improved. After training the artificial neural network with strong correlation variables, it has the highest accuracy, accuracy, recall rate, F1-score and AUC, which can reach 0.81, 0.83, 0.85, 0.84 and 0.84 respectively.

Aims Quorum sensing (QS) is the intercellular communication used by bacteria to regulate collective behavior. QS regulates the production of virulence factors in many bacterial species and is considered to be an attractive target for reducing bacterial pathogenicity. Chlorogenic acid (CA) is abundant in vegetables, fruits, and traditional Chinese medicine, and has multiple activities. This study, aimed to investigated the QS quenching activity of CA against clinically isolated multidrug-resistant Pseudomonas aeruginosa. Methods and results The results showed that CA inhibited the mobility of bacteria, reduced the production of pyocyanin, and inhibited the activity of elastase. Furthermore, crystal violet staining and scanning electron microscope experiments showed that CA inhibited the formation of multidrug-resistant P. aeruginosa biofilm. CA at or below the concentration of 2560 µg/mL exerted negligible cytotoxicity to RAW264.7 cells. The study also examined the expression of QS-related genes, including lasI, lasR, rhlI, rhlR, pqsA, and pqsR in P. aeruginosa and found that the expression of these genes was down-regulated under CA treatment. Conclusions The study showed that CA could be used as an anti-virulence factor for treating clinical P. aeruginosa infection. Significance and impact of study For the first time, this study took clinically isolated multi-drug resistant P. aeruginosa as the experimental object, and suggested that CA might be an effective antimicrobial compound targeting QS in treating P. aeruginosa infection, thus providing a new therapeutic direction for treating bacterial infection and effectively alleviating bacterial resistance.

Background OXA-232-producing carbapenem-resistant Klebsiella pneumoniae (CRKP) has the potential to become the “third epidemic” of carbapenem-resistant Klebsiella strain after KPC-2 and NDM in China. We investigated the first outbreak of CRKP in the First Affiliated Hospital of Wenzhou Medical University. Methods We collected 610 clinical isolates of CRKP from the First Affiliated Hospital of Wenzhou Medical University between January 2019 and September 2020 and screened them by Polymerase Chain Reaction (PCR). The multilocus sequence typing and pulsed-field gel electrophoresis were used to determine the genetic relatedness of the strains. The antimicrobial susceptibility test was performed to determine the drug resistance of the clinical isolates. The molecular mechanism underlying carbapenem resistance was elucidated by performing PCR and conjugation experiments. The virulence potential of the strains was determined by the string test, detection of virulence-associated genes and capsular serotypes, and Galleria mellonella larval infection model. Results Between September 2019 and May 2020, 26 OXA-232-producing CRKP were obtained from 12 patients in our hospital. Ten patients were hospitalized in the intensive care units (ICU) and the overall mortality of the inpatients involved in the outbreak was 50% (6/12). Epidemiological investigations reported that all the OXA-232-producing CRKP strains belonged to the sequence type ST15 and can be clonally transmitted among the inpatients in the ICU. All the strains had low virulence and were resistant to commonly used clinical antibiotics except for ceftazidime/avibactam, colistin, and tigecycline. The OXA-232-producing CRKP was sensitive to triclosan and chlorhexidine, and its eradication from our hospital can be achieved by the use of disinfectants in the ICU. Conclusion In our study, OXA-232-producing CRKP isolates appeared to be clonally transmitted and the sequence type ST15 was responsible for the outbreak. Therefore, effective measurements for the infection control of CRKP are urgently needed to prevent its epidemic in the nearby region in the future.

BackgroundN6-methyladenosine (m6A) RNA modification is vital for cancers because methylation can alter gene expression and even affect some functional modification. Our study aimed to analyze m6A RNA methylation regulators and m6A-related genes to understand the prognosis of early lung adenocarcinoma.MethodsThe relevant datasets were utilized to analyze 21 m6A RNA methylation regulators and 5,486 m6A-related genes in m6Avar. Univariate Cox regression analysis, random survival forest analysis, Kaplan–Meier analysis, Chi-square analysis, and multivariate cox analysis were carried out on the datasets, and a risk prognostic model based on three feature genes was constructed.ResultsRespectively, we treated GSE31210 (n = 226) as the training set, GSE50081 (n = 128) and TCGA data (n = 400) as the test set. By performing univariable cox regression analysis and random survival forest algorithm in the training group, 218 genes were significant and three prognosis-related genes (ZCRB1, ADH1C, and YTHDC2) were screened out, which could divide LUAD patients into low and high-risk group (P < 0.0001). The predictive efficacy of the model was confirmed in the test group GSE50081 (P = 0.0018) and the TCGA datasets (P = 0.014). Multivariable cox manifested that the three-gene signature was an independent risk factor in LUAD. Furthermore, genes in the signature were also externally validated using the online database. Moreover, YTHDC2 was the important gene in the risk score model and played a vital role in readers of m6A methylation.ConclusionThe findings of this study suggested that associated with m6A RNA methylation regulators and m6A-related genes, the three-gene signature was a reliable prognostic indicator for LUAD patients, indicating a clinical application prospect to serve as a potential therapeutic target.

Chinese dragon’s blood (CDB), a characteristic red resin, is an important traditional Chinese medicine (TCM), and empiric therapy of infected wounds with CDB is performed in clinical settings. For the first time, we herein report the antibacterial and anti-biofilm efficacy of CDB against Staphylococcus aureus (S. aureus). Antimicrobial susceptibility testing, growth curve assay, time-kill curve assay, crystal violet biofilm assay, scanning electron microscope (SEM) analysis, cell membrane tests, and quantitative real-time polymerase chain reaction (qRT-PCR) were used for this purpose. The results suggested that the minimum inhibitory concentration (MIC) values of CDB against S. aureus ranged from 32 to 128 μg/mL. Growth curves and time-kill curves confirmed that CDB could inhibit the growth of S. aureus. The biofilm formation ability and the expression levels of saeR, saeS, and hla of S. aureus in the presence and absence of CDB were statistically significant (P < 0.01). The results of SEM analysis and cell membrane tests revealed that exposure to CDB had some destructive effects on S. aureus cells. In conclusion, CDB exhibits positive antibacterial activity against S. aureus. Moreover, CDB could reduce the biofilm formation and the virulence factors of S. aureus by downregulating the expression levels of saeR, saeS, and hla genes. These findings indicated that CDB has immense potential to serve as a viable alternative for the treatment of infected wounds caused by S. aureus in clinical settings.

Due to the lack of explicit expression of instantaneous mutual information (IMI), online throughput optimization for energy harvesting (EH) MIMO systems with finite alphabet inputs suffers from heavy computation burden and large feedback overhead. We propose a two-layer predictive strategy with the aid of context information, by constructing a precoding codebook offline at both the transmitter and receiver, to relax the time pressure for the online strategy. Two schemes were provided to accelerate the codebook construction. One is to estimate IMI during optimization by using a reference function. The other is by starting the optimization of each precoder from an adjacent precoder. With the channel distribution information (CDI), the feedback overhead is reduced by minimizing the codebook size. By the methods above, the building speed of the precoding codebook can be up to two orders of magnitude faster than no accelerating strategies. Meanwhile, through topology analysis, we propose a higher layer predictive strategy, which determines the index of allocated energy at each slot within a frame. The higher layer strategy takes full advantage of the constructed precoding codebook and context information when estimating the future throughput. Simulation results demonstrate the effectiveness and practicality of the proposed two-layer strategy.

Dynamic shared autonomous taxi (SAT) systems are regarded as a promising means of improving travel flexibility. With no human drivers, SATs urgently require precise traffic information in order to plan accurate paths independently; in addition, on-time arrival is an essential service quality in SAT systems. In this study, taxis are assumed to be replaced with ride-sharing autonomous vehicles. To improve the probability of on-time arrival, the reliable path concept and collected travel time information are used to facilitate path finding for SATs, and the potential benefits are examined. Two simulation scenarios—one based on historical traffic information and the other based on real-time traffic information—are executed to evaluate the information’s usefulness in reliable path finding. In simulation results, reliable path scenarios showed a higher on-time arrival ratio than shortest path scenarios, in which the shortest path algorithm is used in path finding for SATs, and the historical information-based scenarios showed a higher on-time arrival ratio than the real-time information-based scenarios. A system-beneficial path finding method is proposed and is verified to be effective for mitigating road network congestion.

This paper investigates the performance of linear precoders in massive multiple-input multiple-output (MIMO) systems. Different from the existing research, in this paper, we consider a more realistic scenario, where the input signals are taken from finite-alphabet constellation sets, such as phase shift keying (PSK) or quadrature amplitude modulation (QAM), instead of Gaussian signals. The expressions are derived for the achievable mutual information with two commonly known linear precoders, i.e., zero forcing (ZF) and matched filter (MF), in the scenarios were perfect and imperfect channel state information (CSI) is known at the base station (BS). Also, the performance upper bound of mutual information with precoding techniques is analyzed. Both the theoretical analysis and simulation results show that ZF and MF precoders are near optimal when the number of antennas equipped at the BS is much larger than the number of users, which is similar to the case of Gaussian inputs. However, different from the Gaussian inputs, for the case of finite-alphabet inputs, the increase in the number of antennas does not always mean the improvement of performance; specifically, after the number of antennas at the BS, reaches a certain value, more antennas actually almost have no help for the performance improvement of mutual information, which is true whether the CSI is perfect or imperfect.

This paper considers the transmit linear precoding problem for a multiple-input-multiple-output system with simultaneous wireless information and power transfer (SWIPT), where we assume that the transmitter only has statistical channel state information. The optimal precoder is designed based on maximizing the lower bound of average mutual information under the constraints of transmitting power and harvested energy level. Different from previous works on SWIPT, this paper formulates the design from the standpoint of realistic communication systems with finite-alphabet input signals instead of Gaussian input signals. The formulated problem is NP-hard, so a globally optimal solution cannot be found with polynomial-time complexity. However, by exploiting the structure of the problem, we develop two algorithms to obtain a near optimal solution, among which one is based on a semidefinite relaxation (SDR) technique and the other is based on power allocation. The SDR-based algorithm has more extensive applicability, while the power-allocation-based algorithm offers higher efficiency. The simulation results show the efficacy of the proposed algorithms.

Background Cutis verticis gyrate (CVG) is a rare morphologic syndrome that presents with hypertrophy and folding of the scalp. CVG can be classified into three forms: primary essential, primary non-essential, and secondary. Cerebriform intradermal nevus (CIN) is a rare cause of secondary CVG. We are here to report a rare case of CVG with an underlying CIN and discuss the clinical course, treatment options, and critical screening guidelines for these patients. Case presentation A 25 year-old male patient presented with a chief complaint of generalized hair loss in the scalp parietaloccipital region for a duration of 1 year and the hair loss area was occasionally accompanied by mild itching. The hair loss started gradually and worsened over time. In addition, he had scalp skin folds resembling the ridge and furrow of the cerebral cortex in the parietaloccipital region since birth. Physical examination revealed hypertrophy and formation of folds in the parietal-occipital area, forming 5 to 6 furrows and ridges. The size of the cerebriform mass was about 12.0 cm × 8.5 cm, without other skin lesions. Diffuse non-scarring hair loss was distributed on the posterior-parietal scalp, mid-parietal scalp and superior-occipital scalp. The diseased tissue of the patient's parietaloccipital area was excised under general anesthesia. The postoperative pathological examination of the tissue excised showed that there were dense intradermal melanocytic nevus, so the patient was diagnosed with secondary CVG caused by CIN. At the 2 year follow-up, there were no obvious changes in the lesions. Conclusions CIN must be differentiated from other conditions that manifest as CVG, including primary essential or non-essential CVG and secondary CVG caused by other reasons. Each CIN patient requires a specific decision of whether to excise the lesion surgically or follow a wait-and-see policy, depending on the patient's will and specific condition. Surgical treatment may be performed when there is an aesthetic demand. However, clinical observation and close follow-up is also a good treatment choice for patients with stable disease or mild symptoms.

Ying Zhang,1 Lingbo Wang,2 Cui Zhou,2 Yishuai Lin,1 Shixing Liu,2 Weiliang Zeng,1 Kaihang Yu,1 Tieli Zhou,2 Jianming Cao1 1Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, 325035, People’s Republic of China; 2Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, 325035, People’s Republic of ChinaCorrespondence: Jianming CaoDepartment of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, People’s Republic of ChinaTel +86-0577-88069595Email wzcjming@163.comTieli ZhouDepartment of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People’s Republic of ChinaTel +86-0577-86689885Email wyztli@163.comPurpose: Multidrug-resistant (MDR) Enterococcus faecium is an important nosocomial pathogen causing urinary tract infection, and the reapplication of nitrofurantoin (NIT) in the clinic has attracted great attention. This study aims to explore the NIT resistance mechanisms and epidemiological characteristics of E. faecium clinical isolates.Patients and Methods: A total of 633 E. faecium clinical isolates was obtained from urine samples in a clinical teaching hospital during 2017– 2018. Among them, 40 NIT-resistant strains, and a similar number of -intermediate and -susceptible strains were isolated. The minimum inhibitory concentrations (MICs) of NIT were detected by agar dilution method. The prevalence and mutations of nitroreductase-encoding genes ef0404 and ef0648 were explored by polymerase chain reaction (PCR), followed by efflux pump inhibition test and quantitative real-time PCR (qRT-PCR) to investigate the resistance mechanisms of NIT. Furthermore, the epidemiological characteristics were detected by multilocus sequence typing (MLST).Results: The carrying rates of nitroreductase in NIT-susceptible, -intermediate, and -resistant isolates were 100%, 50%, and 20%, respectively. After exposure to the efflux pump inhibitor, the MIC of 12 E. faecium decreased by ≥ 4-fold. However, the efflux pump genes efrAB, emeA, and oqxAB were not overexpressed in NIT-resistant E. faecium isolates. Moreover, MLST analysis revealed that all the NIT-resistant isolates belonged to CC17, of which 30 (75%) were associated with ST78.Conclusion: This study has established for the first time that the absence of EF0404 and EF0648 is the main mechanism of NIT resistance in E. faecium. Our findings are likely to fill the knowledge gap pertaining to the NIT resistance mechanism in E. faecium and provide important insights for molecular epidemiological characteristics analysis.Keywords: Enterococcus faecium, nitrofurantoin, nitroreductase, resistance mechanism, epidemiology

Xiangkuo Zheng,1,* Renchi Fang,2,* Chong Wang,3 Xuebin Tian,4 Jie Lin,1 Weiliang Zeng,4 Tieli Zhou,1 Chunquan Xu1 1Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325035, People’s Republic of China; 2Department of Laboratory Medicine, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, 310003, People’s Republic of China; 3Department of Laboratory Medicine, Qingdao Municipal Hospital, Qingdao, 266000, People’s Republic of China; 4School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, 325035, People’s Republic of China*These authors contributed equally to this workCorrespondence: Chunquan Xu; Tieli ZhouDepartment of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, People’s Republic of ChinaTel +86-577-5557-9725; +86-577-8668-9885Email 417242374@qq.com; wyztli@163.comBackground: Staphylococcus aureus (S. aureus) is a major contributor to nosocomial and community-acquired infections. S. aureus small colony variants (SCVs) which changed in relevant phenotype have made more limited and difficult for therapeutic options against S. aureus infections increasingly. Rifampicin is considered as the “last-resort” antibiotic against S. aureus. Our study investigated resistance profiles and biological characteristics of rifampicin-resistant S. aureus SCVs.Methods: We collected S. aureus SCVs that were selected from 41 rifampicin-resistant clinical isolates. Then, biological characteristics, resistance spectrum, and rifampicin resistance mechanisms of tested S. aureus SCVs and corresponding parental strains were investigated by classic microbiological methods, agar dilution method, polymerase chain reaction (PCR). Moreover, the fitness cost of S. aureus SCVs, including growth, biofilm formation ability, and virulence profile, was also determined by bacterial growth curve assay, biofilm formation assay, and Galleria mellonella infection model.Results: There were three S. aureus SCVs (JP310 SCVs, JP1450 SCVs, JP1486 SCVs) that were selected from 41 rifampicin-resistant S. aureus. S. aureus SCVs colonies were tiny, with decreased pigmentation, and the hemolysis circle was not obvious compared with corresponding parental strains. And SCVs could not be restored to normal-colony phenotype after hemin, menaquinone, or thymidine supplementation. Different rpoB mutations occurred in JP1486 SCVs. Antimicrobial susceptibility testing revealed MICs of SCVs were higher than corresponding parental strains. Besides, the growth ability and virulence of SCVs were lower, and biofilm formation ability of which increased compared with parental strains.Conclusion: S. aureus SCVs share the rifampicin resistance mechanisms with parental strains, although there were some differences in the position of rpoB mutations. Moreover, we found that the biological characteristics of SCVs were significantly different from corresponding parental strains. In contrast, decreased susceptibility to other antibiotics of SCVs was observed during phenotype switch. Furthermore, SCVs incur the fitness cost.Keywords: Staphylococcus aureus, small-colony variant, rifampicin resistance, resistance profile, biological characteristic

Chlorhexidine is used widely to prevent the spread of bacteria in the hospital environment. However, bacteria are increasingly becoming tolerant to chlorhexidine. Here we investigated clinical characteristics, tolerance mechanisms, and molecular epidemiology of chlorhexidine-tolerant Pseudomonas aeruginosa. According to the proposed epidemiological cut-off value to determine chlorhexidine tolerance (50 µg/mL) in P. aeruginosa, 32 chlorhexidine-tolerant isolates were detected from 294 P. aeruginosa isolates, which accounted for 10.9%. Our results indicated MICs of chlorhexidine-tolerant strains were 64 µg/mL. Patient's data showed chlorhexidine tolerance was associated with following factors: hospital length of stay, ICU admission, length of stay in ICU, invasive procedure, duration of mechanical ventilation, chlorhexidine usage, and occurrence of nosocomial pneumonia. Tolerance mechanisms were analyzed by efflux pump inhibition test, qRT-PCR, and serial passage experiment. Increased expression of efflux pump genes mexA, mexC, mexE and mexX, and decreased expression of oprD were observed in chlorhexidine-tolerant and chlorhexidine-induced strains, which suggested that hyperexpression of Mex-Opr efflux pump was the main mechanism. Moreover, serial passage experiment found chlorhexidine-induced strains showed decreased susceptibility to tested antibiotics, which illustrated that long-term exposure of P. aeruginosa to chlorhexidine could result in multidrug-resistant (MDR) or cross-resistance phenotypes. MLST and PFGE analysis demonstrated the homology of 32 chlorhexidine-tolerant strains was low and no obvious clonal transmission was observed. We comprehensively investigated the development and molecular mechanisms of chlorhexidine-tolerant P. aeruginosa, which revealed that the control and surveillance of chlorhexidine tolerance should be more strict. Moreover, it seems to make sense to avoid the continuous or unreasonable application of chlorhexidine in hospital settings.

After more than 40 years’ opening-up and reform, China’s urbanization has entered a new type of urbanization. In order to reveal the rule of different infrastructure investments and urbanization relationships, this paper uses Shanghai as a case by applying econometric methods to study the detailed relationship between different indicators from 1990 to 2019. Firstly, we quantify that each variable has a long-term co-integration relationship with urbanization by co-integration test. And we found that the real estate is a main driving force of urbanization while the construction project investment plays an important role in promoting the urbanization rate in the studied period. Secondly, according to the Granger test, our study illustrates that each variable has a bilateral Granger relationship with urbanization while the urbanization rate has more Granger causality impact on the studied variables. Thirdly, based on impulse response test and variance decomposition analysis, we found that urbanization rate with other variables accounts for the majority of the percentage of impacts while the total investment in fixed assets and its three categories contribute a small amount to the urbanization rate. Finally, we propose policy suggestions to strengthen healthy urbanization development in Shanghai.

Background Staphylococcus aureus (S. aureus) is a major contributor to nosocomial and community-acquired infections. S. aureus small colony variants (SCVs) which changed in relevant phenotype have made more limited and difficult for therapeutic options against S. aureus infections increasingly. Rifampicin is considered as the “last-resort” antibiotic against S. aureus. Our study investigated resistance profiles and biological characteristics of rifampicin-resistant S. aureus SCVs. Methods We collected S. aureus SCVs that were selected from 41 rifampicin-resistant clinical isolates. Then, biological characteristics, resistance spectrum, and rifampicin resistance mechanisms of tested S. aureus SCVs and corresponding parental strains were investigated by classic microbiological methods, agar dilution method, polymerase chain reaction (PCR). Moreover, the fitness cost of S. aureus SCVs, including growth, biofilm formation ability, and virulence profile, was also determined by bacterial growth curve assay, biofilm formation assay, and Galleria mellonella infection model. Results There were three S. aureus SCVs (JP310 SCVs, JP1450 SCVs, JP1486 SCVs) that were selected from 41 rifampicin-resistant S. aureus. S. aureus SCVs colonies were tiny, with decreased pigmentation, and the hemolysis circle was not obvious compared with corresponding parental strains. And SCVs could not be restored to normal-colony phenotype after hemin, menaquinone, or thymidine supplementation. Different rpoB mutations occurred in JP1486 SCVs. Antimicrobial susceptibility testing revealed MICs of SCVs were higher than corresponding parental strains. Besides, the growth ability and virulence of SCVs were lower, and biofilm formation ability of which increased compared with parental strains. Conclusion S. aureus SCVs share the rifampicin resistance mechanisms with parental strains, although there were some differences in the position of rpoB mutations. Moreover, we found that the biological characteristics of SCVs were significantly different from corresponding parental strains. In contrast, decreased susceptibility to other antibiotics of SCVs was observed during phenotype switch. Furthermore, SCVs incur the fitness cost.

The agricultural and forestry waste walnut shell and copolyester hot-melt adhesives (Co-PES) powder were selected as feedstock. A kind of low-cost, low-power consumption, and environmentally friendly walnut shell/Co-PES powder composites (WSPC) was used for selective laser sintering (SLS). Though analyzing the size and morphology of walnut shell particle (&le, 550 &mu, m) as well as performing an analysis of surface roughness, density, and mechanical test of WSPC parts with different particle sizes, results showed that the optimal mechanical performance (tensile strength of 2.011 MPa, bending strength of 3.5 MPa, impact strength of 0.718 KJ/m2) as walnut shell powder particle size was 80 to 120 &mu, m. When walnut shell powder particle diameter was 120 to 180 &mu, m, the minimum value of surface roughness of WSPC parts was 15.711 &mu, m and density was approximately the maximum (0.926 g/cm3).

Background Bloodstream infection (BSI) caused by multidrug-resistant Acinetobacter baumannii (MDR-AB) has been increasingly observed among hospitalized patients. The following study analyzed the epidemiology and microbiological characteristics of MDR-AB, as well as the clinical features, antimicrobial treatments, and outcomes in patients over a six years period in China. Methods This retrospective study was conducted in a large tertiary hospital in China between January 2013 and December 2018. The clinical and microbiological data of all consecutive hospitalized patients with MDR-AB induced bloodstream infection were included and analyzed. Results A total of 108 BSI episodes were analyzed. All MDR isolates belonged to ST2, a sequence type that has spread all over the world. Overall, ST2 strains showed strong biofilm formation ability, high serum resistance, and high pathogenicity. As for the clinical characteristics of the patient, 30-day mortality was 69.4% (75/108). The three main risk factors included mechanical ventilation, intensive care unit (ICU) stay, and thrombocytopenia; three protective factors included a change of antimicrobial regimen within 48 h after positive blood culture, use of the antibacterial agent combination, and more inpatient days. The most effective antibacterial regimen was the combination of cefoperazone/sulbactam and tigecycline. Conclusions BSI caused by ST2 A.baumannii represents a difficult challenge for physicians, considering the high mortality associated with this infection. The combination of cefoperazone/sulbactam and tigecycline may be an effective treatment option.