INTRODUCTION

Needlestick injury is a major healthcare hazard. The burden of the problem is difficult to estimate due to underreporting by healthcare workers.

To gain insight into the level of knowledge and perception, attitude and practices of obstetrician-gynecologist (OB-GYN) residents and subspecialty fellows-in-training in a tertiary hospital on blood-borne diseases from needle stick injuries and postexposure prophylaxis.

A cross-sectional study among all residents and fellows in training of the Department of Obstetrics and Gynecology of a tertiary hospital was conducted in December 2017. The explanatory sequential mixed method approach of data collection was utilized using a self-administered original pilot-tested questionnaire and focused group discussion.

Eighty-four OB-GYN s in training took part in the study. The prevalence of needle stick injury was 80.95%, but only about half of the incidents were reported. There was no statistically significant difference in the knowledge and attitudes toward management and policies on needlestick injuries between fellows and residents. The fellows appeared to be more frequently compliant with practices to prevent and manage needle stick injuries compared to the residents. There is weak but statistically significant positive relationship between the respondents’ knowledge and practice scores.

Although the respondents have very good knowledge, adherence to the practices to prevent and manage needlestick injuries is low.

The CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR associated proteins) system is an adaptive immune system of bacteria and archaea against phages, plasmids and other exogenous genetic materials. The system uses a special RNA (CRISPR RNA, crRNA) guided endonuclease to cut the exogenous genetic materials complementary to crRNA, thus blocking the infection of exogenous nucleic acid. According to the composition of the effector complex, CRISPR-Cas system can be divided into two categories: class 1 (including type Ⅰ, Ⅳ, and Ⅲ) and class 2 (including type Ⅱ, Ⅴ, and Ⅵ). Several CRISPR-Cas systems have been found to have very strong ability to specifically target RNA editing, such as type Ⅵ CRISPR-Cas13 system and type Ⅲ CRISPR-Cas7-11 system. Recently, several systems have been widely used in the field of RNA editing, making them a powerful tool for gene editing. Understanding the composition, structure, molecular mechanism and potential application of RNA-targeting CRISPR-Cas systems will facilitate the mechanistic research of this system and provide new ideas for developing gene editing tools.
CRISPR-Cas Systems/genetics* ; RNA/genetics* ; Bacteria/genetics* ; Gene Editing ; Archaea

The CRISPR/Cas systems comprising the clustered regularly interspaced short palindromic repeats (CRISPR) and its associated Cas protein is an acquired immune system unique to archaea or bacteria. Since its development as a gene editing tool, it has rapidly become a popular research direction in the field of synthetic biology due to its advantages of high efficiency, precision, and versatility. This technique has since revolutionized the research of many fields including life sciences, bioengineering technology, food science, and crop breeding. Currently, the single gene editing and regulation techniques based on CRISPR/Cas systems have been increasingly improved, but challenges still exist in the multiplex gene editing and regulation. This review focuses on the development and application of multiplex gene editing and regulation techniques based on the CRISPR/Cas systems, and summarizes the techniques for multiplex gene editing or regulation within a single cell or within a cell population. This includes the multiplex gene editing techniques developed based on the CRISPR/Cas systems with double-strand breaks; or with single-strand breaks; or with multiple gene regulation techniques, etc. These works have enriched the tools for the multiplex gene editing and regulation and contributed to the application of CRISPR/Cas systems in the multiple fields.
Gene Editing ; CRISPR-Cas Systems/genetics* ; Bacteria/genetics* ; Archaea ; Bioengineering

CRISPR/Cas(the clustered regularly interspaced short palindromic repeats-CRISPR associated)system exists in most bacteria and all archaea. It is an important strategy for bacteria and archaea to resist foreign nucleic acid invasion and use for self-defense. The CRISPR/Cas system is a simple, fast, and specific diagnostic tool, which is widely used in agriculture, industry, animal husbandry, and medicine. This article mainly introduces and discusses recently advantages and limitations of biosensors combining CRISPR/Cas system with fluorescence, visualization and surface enhanced raman related technologies, as well as future research directions.
Animals ; CRISPR-Cas Systems ; Bacteria/genetics* ; Archaea

Objective: To explore the reentry rate of reactive blood donors in the bloodborne pathogen infection screening in Hangzhou City, and analyze the donation behavior of those who successfully returned. Methods: A retrospective analysis of the return data of blood donors with reactive bloodborne pathogen screening markers was conducted at Zhejiang Provincial Blood Center from June 2017 to May 2022. The reentry process for blood donors with reactive bloodborne pathogen screening markers in Hangzhou City is as follows: after the initial screening period of 6 months, donors can voluntarily apply for return to the blood center. Samples are collected and subjected to routine enzyme-linked immunosorbent assay (ELISA) screening for HBsAg, anti-HCV, HIV Ab/Ag, and anti-TP, as well as a single nucleic acid (HIV/HCV/HBV) test. For samples that show non-reactivity in both ELISA and nucleic acid tests, serum biomarker testing for the reasons of exclusion is performed using chemiluminescence immunoassay (CLIA), and those with non-reactivity are allowed to return. Results: A total of 4 583 reactive blood donors who met the criteria for re-entry applied for reentry, out of which 475 applications were received from donors in the Hangzhou area. Among these, 279 donors were successfully readmitted, resulting in a success rate of 58.74% (279/475). By the end of December 2021, out of the 174 donors who successfully returned, 114 donors chose to donate again. They collectively donated 39 530 ml of whole blood and 1 147.2 therapeutic doses of platelets. Among these, 21 donors once again showed reactivity for pathogen infection biomarkers, accounting for 18.42% (21/114). Conclusion: The reentry strategy has somewhat mitigated the attrition of blood donors. Nevertheless, there are instances where donors who were successfully readmitted show reactivity once more in the screening for pathogen infection biomarkers.
Humans ; Blood Donors ; Blood-Borne Pathogens ; Retrospective Studies ; Mass Screening/methods* ; Biomarkers ; HIV Infections ; Nucleic Acids ; Hepatitis B virus

Objective: To explore the reentry rate of reactive blood donors in the bloodborne pathogen infection screening in Hangzhou City, and analyze the donation behavior of those who successfully returned. Methods: A retrospective analysis of the return data of blood donors with reactive bloodborne pathogen screening markers was conducted at Zhejiang Provincial Blood Center from June 2017 to May 2022. The reentry process for blood donors with reactive bloodborne pathogen screening markers in Hangzhou City is as follows: after the initial screening period of 6 months, donors can voluntarily apply for return to the blood center. Samples are collected and subjected to routine enzyme-linked immunosorbent assay (ELISA) screening for HBsAg, anti-HCV, HIV Ab/Ag, and anti-TP, as well as a single nucleic acid (HIV/HCV/HBV) test. For samples that show non-reactivity in both ELISA and nucleic acid tests, serum biomarker testing for the reasons of exclusion is performed using chemiluminescence immunoassay (CLIA), and those with non-reactivity are allowed to return. Results: A total of 4 583 reactive blood donors who met the criteria for re-entry applied for reentry, out of which 475 applications were received from donors in the Hangzhou area. Among these, 279 donors were successfully readmitted, resulting in a success rate of 58.74% (279/475). By the end of December 2021, out of the 174 donors who successfully returned, 114 donors chose to donate again. They collectively donated 39 530 ml of whole blood and 1 147.2 therapeutic doses of platelets. Among these, 21 donors once again showed reactivity for pathogen infection biomarkers, accounting for 18.42% (21/114). Conclusion: The reentry strategy has somewhat mitigated the attrition of blood donors. Nevertheless, there are instances where donors who were successfully readmitted show reactivity once more in the screening for pathogen infection biomarkers.
Humans ; Blood Donors ; Blood-Borne Pathogens ; Retrospective Studies ; Mass Screening/methods* ; Biomarkers ; HIV Infections ; Nucleic Acids ; Hepatitis B virus

Cytochrome c is a type of heme proteins that are widely distributed in living organisms. It consists of heme and apocytochrome c, and has potential applications in bioelectronics, biomedicine and pollutant degradation. However, heterologous overexpression of cytochrome c is still challenging. To date, expression of the cytochrome c from uncultured anaerobic methanotrophic archaea has not been reported, and nothing is known about the function of this cytochrome c. A his tagged cytochrome c was successfully expressed in E. coli by introducing a thrombin at the N-terminus of CytC4 and co-expressing CcmABCDEFGH, which is responsible for the maturation of cytochrome c. Shewanella oneidensis, which naturally has enzymes for cytochrome c maturation, was then used as a host to further increase the expression of CytC4. Indeed, a significantly higher expression of CytC4 was achieved in S. oneidensis when compared with in E. coli. The successful heterologous overexpression of CytC4 will facilitate the exploitation of its physiological functions and biotechnological applications.
Anaerobiosis ; Archaea/metabolism* ; Cytochromes c/metabolism* ; Escherichia coli/metabolism* ; Heme/metabolism*

DNA polymerases are widely used in PCR and play important roles in life science research and related fields. Development of high-performance DNA polymerases is of great commercial interest as the current commercial DNA polymerases could not fully satisfy the requirements of scientific research. In this study, we cloned and expressed a family B DNA polymerase (NCBI accession number TEU_RS04875) from Thermococcus eurythermalis A501, characterized its enzymatic property and evaluated its application in PCR. The recombinant Teu-PolB was expressed in E. coli and purified with affinity chromatography and ion-exchange chromatography. The enzymatic properties of Teu-PolB were characterized using fluorescence-labeled oligonucleotides as substrates. The application potential of Teu-PolB in PCR was evaluated using the phage λ genomic DNA as a template. Teu-PolB has DNA polymerase and 3'→5' exonuclease activities, and is highly thermostable with a half-life of 2 h at 98 ℃. The most suitable PCR buffer is consisted of 50 mmol/L Tris-HCl pH 8.0, 2.5 mmol/L MgCl₂, 60 mmol/L KCl, 10 mmol/L (NH₄)₂SO₄, 0.015% Triton X-100 and 0.01% BSA, and the optimal extension temperature is 68 ℃. Under the optimized conditions, a 4 kb target fragment was successfully amplified with an extension rate of 2 kb/min. The yield of the Teu-PolB amplified-DNA was lower than that of Taq DNA polymerase, but its extension rate and fidelity was higher than that of Taq and Pfu DNA polymerases. The biochemical properties of Teu-PolB demonstrate that this enzyme can be used in PCR amplification with high thermostability, good salt tolerance, high extension rate and high fidelity.
DNA-Directed DNA Polymerase/genetics* ; Escherichia coli/genetics* ; Polymerase Chain Reaction/methods* ; Temperature ; Thermococcus/genetics*

Objective: To analyze the risk factors of blood-borne occupational exposure among medical staff and explore the relevant intervention measures. Methods: In June 2020, the data of blood-borne occupational exposure and related factors reported by medical staff in a grade Ⅲ, Grade A general hospital from 2011 to 2019 were analyzed by retrospective investigation. Results: Among 431 cases of blood-borne occupational exposure, 69.37% were nurses. It mainly occurred in medical staff with 0-4 years of service, accounting for 63.57%; The main place of occupational exposure was in the ward 47.56%; Sharp instrument injury was the main occupational exposure route 91.65%. Occupational exposure department was mainly surgery department 17.87%; The main source of exposure was hepatitis B virus (HBV) 37.12%, followed by treponema pallidum 20.19%. Statistical analysis results show that: Exposure sites (χ(2)=43.585, P<0.01) , exposure sources (χ(2)=22.693, P<0.01) , treatment methods after exposure (χ(2)=18.866, P<0.01) , Flushing (χ(2)=31.963, P<0.01) and disinfection (χ(2)=14.216, P<0.01) were significantly different. Conclusion: The effective measures to reduce blood-borne occupational exposure are to strengthen occupational protection training of medical staff, standardize operation procedures, strengthen supervision of key groups and departments, improve reporting, monitoring and follow-up systems to realize informatization, and do a good job in risk control.
Blood-Borne Pathogens ; Humans ; Medical Staff ; Needlestick Injuries ; Occupational Exposure/prevention & control* ; Retrospective Studies ; Risk Factors

β-glucosidase has important applications in food, medicine, biomass conversion and other fields. Therefore, exploring β-glucosidase with strong stability and excellent properties is a research hotspot. In this study, a GH3 family β-glucosidase gene named Iubgl3 was successfully cloned from Infirmifilum uzonense. Sequence analysis showed that the full length of Iubgl3 was 2 106 bp, encoding 702 amino acids, with a theoretical molecular weight of 77.0 kDa. The gene was cloned and expressed in E. coli and the enzymatic properties of purified IuBgl3 were studied. The results showed that the optimal pH and temperature for pNPG hydrolysis were 5.0 and 85 ℃, respectively. The enzyme has good thermal stability, and more than 85% of enzyme activity can be retained after being treated at 80 ℃ for2 h. This enzyme has good pH stability and more than 85% of its activity can be retained after being treated at pH 4.0-11.0 for 1 h. It was found that the enzyme had high hydrolysis ability to p-nitrophenyl β-d-glucoside (pNPG) and p-nitrophenyl β-d-xylopyranoside (pNPX). When pNPG was used as the substrate, the kinetic parameters K_m and V_max were 0.38 mmol and 248.55 μmol/(mg·min), respectively, and the catalytic efficiency k_cat/K_m was 6 149.20 s^-1mmol^-1. Most metal ions had no significant effect on the enzyme activity of IuBgl3. SDS completely inactivated the enzyme, while EDTA increased the enzyme activity by 30%. This study expanded the β-glucosidase gene diversity of the thermophilic archaea GH3 family and obtained a thermostable acid bifunctional enzyme with good industrial application potential.
beta-Glucosidase/chemistry* ; Archaea/metabolism* ; Escherichia coli/metabolism* ; Hydrogen-Ion Concentration ; Temperature ; Glucosides ; Enzyme Stability ; Substrate Specificity ; Kinetics