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Staphylococci are mainly found on the skin or in the nose. These bacteria are typically friendly, causing no harm to healthy individuals or resulting in only minor issues that can go away on their own. However, under certain circumstances, staphylococcal bacteria could invade the bloodstream, affect the entire body, and lead to life-threatening problems like septic shock. In addition, antibiotic-resistant Staphylococcus is another issue because of its difficulty in the treatment of infections, such as the notorious methicillin-resistant Staphylococcus aureus (MRSA) which is resistant to most of the currently known antibiotics. Therefore, rapid and accurate diagnosis of Staphylococcus and characterization of the antibiotic resistance profiles are essential in clinical settings for efficient prevention, control, and treatment of the bacteria. This chapter highlights recent advances in the diagnosis of Staphylococci in clinical settings with a focus on the advanced technique of surface-enhanced Raman spectroscopy (SERS), which will provide a framework for the real-world applications of novel diagnostic techniques in medical laboratories via bench-top instruments and at the bedside through point-of-care devices.

Background Surgical site infection (SSI) after colorectal surgery (CRS) remains a significant problem for its negative clinical outcomes. However, it is poorly understood in China. This study aims to investigate the incidence, risk factors and microbiology of SSI after CRS. Methods A nationwide prospective multicenter design was applied. Patients in 19 Chinese hospitals from 2015 to 2018 were prospectively monitored for SSI after CRS. Demographic data, hospital characteristics, and potential perioperative risk factors were collected and analyzed, using univariate and multivariate logistic regression models. Results Among 3,663 study participants, 134(3.66%) episodes of SSI were identified. The incidence rate of SSI decreased from 5.9 infections per 100 procedures in 2015 to 3.1 infections per 100 procedures in 2018 (incidence rate ratio, 0.52; 95% CI, 0.28–0.94). The SSI rates were 1.88, 4.15, 6.27 and 11.58 per 100 operations for the National Nosocomial Infections Surveillance system (NNIS) risk index categories of 0, 1, and 2 or 3, respectively. Escherichia coli (54/134, 40.3%) and Klebsiella pneumoniae (10/134, 7.5%) were the most frequently isolated microorganisms. A high prevalence of antibiotic resistance were observed in our study, with rates of extended spectrum beta-lactamase-producing or carbapenem-resistant Escherichia coli and Klebsiella pneumonia of 50.0%(27/54) and 30.0%(3/10) respectively. Preoperative hospital stay ≥ 48 h (OR = 2.28, 95% CI: 1.03-5.02, P = 0.042) and contaminated or dirty wound (OR = 3.38, 95% CI: 1.88-6.06, P = 4.50 × 10−5) were significantly associated with increasing risk of SSI after CRS. Conclusion A statistically significant but modest decrease in the incidence rate of CRS SSI over the 4-year study period was observed in this study. Noticeably, the relatively high rates of multidrug-resistant pathogens causing SSI after CRS should be alert, while more studies with large population are needed due to the small number of isolates identified in our survey.

Objective. The mechanism of enhanced radiosensitivity induced by mitochondrial uncoupling protein UCP2 was investigated in HeLa cells to provide a theoretical basis as a novel target for cervical cancer treatment. Methods. HeLa cells were irradiated with 4 Gy X-radiation at 1.0 Gy/min. The expression of UCP2 mRNA and protein was assayed by real-time quantitative polymerase chain reaction and western blotting. UCP2 siRNA and negative control siRNA fragments were constructed and transfected into HeLa cells 24 h after irradiation. The effect of UCP2 silencing and irradiation on HeLa cells was determined by colony formation, CCK-8 cell viability, γH2AX immunofluorescence assay of DNA damage, Annexin V-FITC/PI apoptosis assay, and propidium iodide cell cycle assay. The effects on mitochondrial structure and function were investigated with fluorescent probes including dichlorodihydrofluorescein diacetate (DCFH-DA) assay of reactive oxygen species (ROS), rhodamine 123, and MitoTracker Green assay of mitochondrial structure and function. Results. Irradiation upregulated UCP2 expression, and UCP2 knockdown decreased the survival of irradiated HeLa cells. UCP2 silencing sensitized HeLa cells to irradiation-induced DNA damage and led to increased apoptosis, cell cycle arrest in G2/M, and increased mitochondrial ROS. Increased radiosensitivity was associated with an activation of P53, decreased Bcl-2, Bcl-xl, cyclin B, CDC2, Ku70, and Rad51 expression, and increased Apaf-1, cytochrome c, caspase-3, and caspase-9 expression. Conclusions. UCP2 inhibition augmented the radiosensitivity of cervical cancer cells, and it may be a potential target of radiotherapy of advanced cervical cancer.

Background: Surgical site infection (SSI) after colorectal surgery (CRS) remains a significant problem for its negative clinical outcomes. However, it is poorly understood in China . This study aims to investigate the prevalence, risk factors and microbiology of SSI after CRS. Methods: A nationwide prospective multicenter design was applied. Patients in 19 Chinese hospitals from 2015 to 2018 were prospectively monitored for SSI after CRS. Demographic data, hospital characteristics, and potential perioperative risk factors were collected and analyzed, using univariate and multivariate logistic regression models. Results: Among 3,663 study participants, 134(3.66%) episodes of SSI were identified. The prevalence rate of SSI decreased from 5.9 infections per 100 procedures in 2014 to 3.1 infections per 100 procedures in 2017 (prevalence rate ratio [PRR], 0.52; 95% CI, 0.28–0.94). The SSI rates were 1.88, 4.15, 6.27 and 11.58 per 100 operations for the National Nosocomial Infections Surveillance system (NNIS) risk index categories of 0, 1, and 2 or 3, respectively. Escherichia coli (54/134, 40.3%) and Klebsiella pneumoniae (10/134, 7.5%) were the most frequently isolated microorganisms. A high prevalence of antibiotic resistance were observed in our study, with rates of extended spectrum beta-lactamase-producing or carbapenem-resistant Escherichia coli and Klebsiella pneumonia of 50.0%(27/54) and 30.0%(3/10) respectively. Preoperative hospital stay ≥ 48h (OR=2.28, 95% CI: 1.03–5.02) and contaminated or dirty wound (OR=3.38, 95% CI: 1.88–6.06) were significantly associated with increasing risk of SSI after CRS. Conclusion: A statistically significant but modest decrease in the prevalence rate of CRS SSI over the 4-year study period was observed in this study. Noticeably, the relatively high rates of multidrug-resistant pathogens causing SSI after CRS should be alert despite of the small number of isolates identified in our survey.

Entrapped and pooled dense non-aqueous phase liquid (DNAPL) often persists in aquifers and serves as a long-term source of groundwater contamination. Despite vigorous research efforts over the last two decades, all current DNAPL pool remediation strategies suffer from a combination of inefficiency, enhanced risk of contaminant spreading due to uncontrolled mobilization, and or high treatment costs. In the present contribution, we report a novel strategy that makes the density of the representative DNAPL of trichloroethene (TCE) reduction utilizing colloidal liquid aphrons (CLAs) in the remediation process. The effects of the electrolyte (AlCl3) concentrations, the volume fraction of the dispersed oil phase (n-octane) and temperature on the demulsification behavior of CLA dispersion were discussed. Steady-state flow and dynamic viscoelasticity were measured by using a controlled stress rheometer HAAKE RS 6000 with cone-plate geometry in an attempt to reveal the rheological properties of CLAs. A series of batch experiments was conducted to evaluate the recovery efficiency of DNAPL from sand pack under different volumes, flow rates of CLAs and surfactant (Tergitol 15-S-9) flushing solutions. Experimental results suggest that CLAs can be destabilized by a low concentration of Al3+ in the continuous phase. The flow behavior of CLAs presents the typical non-Newtonian liquids with strong shear thinning properties and it could be well described by the Hershel–Bulkley model. Above the phase volume ratio (PVR = Vorg/Vaq) of 8, the systems display viscoelastic behavior. Relative to water, the density reversal of TCE occurs at an electrolyte concentration of 0.05 M, which effectively prevents TCE downward migration during surfactant flushing. As much as 94% of the TCE entrapped in the sand column is removed under the conditions of amounts of 1 PV (pore volume) for CLAs, 4 PV and 1.5 mL/min for Tergitol solution. This approach holds great promise for manipulating DNAPL densities prior to or during remediation processes.

Hot simulation tests at different deformation technology parameters were carried out for a microalloyed high strength steel produced by CSP hot rolling and the stress-strain curves during deformation were measured. Based on the experimental results and the discussions of present flow stress models, a new flow stress model incorporating interactional effect of deformation temperature, strain and strain rate on flow stress was developed in the paper. Excellent agreement between measured and predicted flow stress values is obtained for new flow stress model of a microalloyed high strength steel rolled by CSP. In addition, the comparisons of flow stress prediction errors between several models and one given in the paper reveal that the prediction accuracy of new flow stress model presented in the paper is higher than other models.

With the rise of international oil prices and the increasingly scarce of oil energy, the fuel consumption of cars has received more and more attention of the community. In recent years, the number of cars has sharply soared, and its resulting resource consumption and environment are more and more problems, the most direct solution is the production of pure electric vehicles or oil electric hybrid cars, due to pure electric vehicles technology is not yet mature, hybrid cars have become the best choice to solve the energy and environmental problems. This paper first expatiates the characteristics of three kinds of hybrid power system, and introduces the working principle and way of working of the hybrid electric vehicle system; the second part establishes the mathematical model of automobile hybrid, to give the expression form of resistance coefficient, air resistance, rolling resistance and acceleration resistance under the hybrid driven; for the three forms of separate control power system, the third uses MATLAB/ADVISOR control software to carry out simulation, to provide a theoretical reference for the design and application of automobile hybrid power control system.

To study the molecular types of Staphylococcus aureus isolated from a severe food-poisoning and to trace the possible strains.Real-time PCR was applied to detect nuc gene as a specific marker for S. aureus, mecA gene encoding methicillin resistance and 5 other genes encoding staphylococcal enterotoxins (sea, seb, see, sed, see). Isolates were also performed with 16S rRNA oligonucleotide sequence analyzing by DNAStar MegAlign 5.0 software and pulse-field gel electrophoresis (PFGE) by BioNumerics Version 4.0 software.The nuc gene was detected from the 10 isolated strains, sea and seb genes were detected from 7 strains. There were 4 16 S rRNA types and 5 PFGE types found from all the strains.Three relative S. aureus strains were involved in the severe food-poisoning at least. Molecular subtyping might give a molecular epidemiological evidence and support the source tracing of an outbreak.

To apply pulse-field gel electrophoresis analysis(PFGE) in analysing a case of food poisoning caused by Vibrio parahaemolyticus.PFGE using restriction enzyme Not I was employed in molecular subtyping of thirty strains of V. parahaemolyticus isolated from a case of food poisoning in Guangzhou city and PFGE patterns were analyzed by using BioNumerics Version 4.0 software to perform cluster analysis. Pattern profiles were compared by using the Dice coefficient and unweighted pair group method with arithmetic averages (UPGMA).Thirty strains were of the same type of pulsotype.Molecular subtyping by PFGE might disclose the epidemiological relationships of the strains from humans, food and the environment, giving a strong molecular epidemiological evidence and a support for the source-tracking of outbreak events.

To apply multiplex polymerase chain reaction (MPCR) assay and sequencing in study of the carrying status of four pathogenicity-related genes of Vibrio cholerae (V.cholerae) and the variation of ctxA.Primers targeting cholera toxin sub-unit A gene (ctxA), toxin-coregulated pilus gene (tcpA), accessory cholera enterotoxin gene (ace), zonula occludens toxin gene (zot) were designed and the MPCR method was applied to detect the pathogenicity-related genes of 276 strains of V.cholerae isolates. The amplified fragments of ctxA gene were sequenced and the genetic homology of the amplified fragments of ctxA was analyzed.Of the 276 strains of V.cholerae, 93.9% strains from human sources belong to the pathogenicity-related genes type A (ctxA(+)tcpA(+)ace(+)zot(+) type) and 6.1% belong to pathogenicity-related genes type C (ctxA(-)tcpA(-)ace(-)zot(-) type). Type A strains from clinical sources were isolated from patients with mild to severe symptom and carriers, among which 68.5% were isolated from patients with mild symptom and 21.9% from carriers. All 63.6% of type C strains from clinical sources were isolated from patients with mild symptom and 36.4% from carriers. The proportion of type C strains that caused mild symptom was higher than that of type A strains. Of the 78 strains isolated from the environment, 9.0% strains belong to pathogenicity-related type A and 35.9% belong to the pathogenicity-related genes type B (ctxA(-)tcpA(-)ace(+)zot(+) type), while 55.1% belong to pathogenicity-related genes type C. The sequencing results showed little genetic variation among the amplified fragments for ctxA.MPCR disclosed the polymorphic status of pathogenicity-related gene patterns in V.cholerae isolates of Guangzhou, providing effective means for further study on evolution of pathogenicity-related genes among V.cholerae isolates from human and environmental sources. This study also offers significant guidance for effective prevention, control and warning against cholera epidemic in local area.