Comparing mortality between positive and negative blood culture results: an inverse probability of treatment weighting analysis of a multicenter cohort.

BACKGROUND: The association between blood culture status and mortality among sepsis patients remains controversial hence we conducted a tri-center retrospective cohort study to compare the early and late mortality of culture-negative versus culture-positive sepsis using the inverse probability of treatment weighting (IPTW) method. METHODS: Adult patients with suspected sepsis who completed the blood culture and procalcitonin tests in the emergency department or hospital floor were eligible for inclusion. Early mortality was defined as 30-day mortality, and late mortality was defined as 30- to 90-day mortality. IPTW was calculated from propensity score and was employed to create two equal-sized hypothetical cohorts with similar covariates for outcome comparison. RESULTS: A total of 1405 patients met the inclusion criteria, of which 216 (15.4%) yielded positive culture results and 46 (21.3%) died before hospital discharge. The propensity score model showed that diabetes mellitus, urinary tract infection, and hepatobiliary infection were independently associated with positive blood culture results. There was no significant difference in early mortality between patients with positive or negative blood culture results. However, culture-positive patients had increased late mortality as compared with culture-negative patients in the full cohort (IPTW-OR, 1.95, 95%CI: 1.14-3.32) and in patients with severe sepsis or septic shock (IPTW-OR, 1.92, 95%CI: 1.10-3.33). After excluding Staphylococcal bacteremia patients, late mortality difference became nonsignificant (IPTW-OR, 1.78, 95%CI: 0.87-3.62). CONCLUSIONS: Culture-positive sepsis patients had comparable early mortality but worse late mortality than culture-negative sepsis patients in this cohort. Persistent Staphylococcal bacteremia may have contributed to the increased late mortality.

Establishment of portable Pseudomonas aeruginosa detection platform based on one-tube CRISPR/Cas12a combined with recombinase polymerase amplification technology.

Pseudomonas aeruginosa, a common Gram-negative bacterium, is associated with diverse diseases. Its increasing resistance to antibiotics presents challenges in clinical treatment. The predominant diagnostic approach involves conventional biochemical cultures, known for their time and labor intensiveness. Despite progress in isothermal amplification studies, limitations persist, including reliance on specialized equipment, intricate primer design, and aerosol contamination. Therefore, there is a demand for enhanced clinical assays. This study successfully combined RPA and CRISPR/Cas12a techniques. Through a series of experiments involving the design and screening of lasB crRNA, the creation of lasB RPA primers, and the establishment of a streamlined RPA-CRISPR/Cas12a assay, the study developed a one-tube detection method targeting P. aeruginosa's lasB gene. The assay demonstrated inclusive behavior across standard and 21 isolates, while specifically discerning P. aeruginosa from diverse strains. Sensitivity reached 15.9 CFU/reaction. Clinical validation revealed a 97.62% concordance with traditional methods. The one-tube assay's protocol mitigated aerosol contamination. Offering precision, specificity, and sensitivity, this method shows promise for field applications in resource-scarce regions, enabling early detection and improved management of P. aeruginosa infections.

Application of gold nanoparticles in biomedical researches and diagnosis.

Gold nanoparticles have been widely used in biomedical research and diagnosis for their good biocompatibility, high surface areas, nontoxic and unique physicochemical properties. This article reviews the applications of gold nanoparticles in the detection of pathogens, proteins, toxic substances, and drug analyses, and in the preparation of biosensors, treatment of disease, and etiological analysis. The application of gold nanoparticles will have broader applications in biomedical research and diagnosis along with a deeper research into AuNPs and more findings in its novel special properties.

The destructive effects of high-intensity focused ultrasound on hydatid cysts enhanced by ultrasound contrast agent and superabsorbent polymer alone or in combination.

Cystic echinococcosis, caused by the metacestode stage of Echincoccus granulosus, remains endemic in many regions around the world. The present work evaluated whether or not a superabsorbent polymer (SAP) and ultrasound contrast agent (UCA) alone or in combination could enhance damage efficacy of high-intensity focused ultrasound (HIFU) on hydatid cysts in vitro. HIFU of 100 W acoustic power, with the aid of 0.1 ml UCA and 0.1 g SAP alone or in combination, was used to ablate hydatid cysts in vitro. The comparison of ultrasound image for each layer of hydatid cyst before and after HIFU ablation was made immediately, and the protoscolices of the cysts were stained by eosin exclusion assay, and the structures of protoscolices were observed by light microscopy. To understand the destructive effects of HIFU, the pathological changes in cyst walls of hydatid cyst ablated with HIFU were examined. The results demonstrated that HIFU had some lethal effect on hydatid cysts: echo enhancement of ultrasound image, increase of mortality rate of protoscolices, serious structural damage of protoscolices, and complete destruction or even disappearance of laminated layer and germinal layer was observed in the group of HIFU combined with UCA and SAP alone or in combination. It was found that the destructive effect of HIFU aided with a combination of UCA and SAP to hydatid cysts was more effective than that of HIFU just aided with UCA or SAP alone. These results suggested that UCA and SAP might be used as a HIFU enhancing agent to improve the efficacy of HIFU ablation to hydatid cysts, which could be a possible therapeutic option for cystic echinococcosis.

The damages of high intensity focused ultrasound to transplanted hydatid cysts in abdominal cavities of rabbits with aids of ultrasound contrast agent and superabsorbent polymer.

The present study investigates the damages of high intensity focused ultrasound (HIFU) to transplanted hydatid cysts in abdominal cavities of rabbits with aids of ultrasound contrast agent (UCA) and superabsorbent polymer (SAP) alone or in combination. A rabbit model with transplanted hydatid cyst was established by implanting hydatid cyst isolated from infected sheep liver, and HIFU was used to ablate the transplanted cysts with the aid of UCA and SAP alone or in combination. The hydatid cyst with thin wall, good elasticity, approximately spherical, and a diameter of approximately 30 mm was selected for the following experiments. According to our previous studies, a mixture of 0.1 g SAP and 0.5 ml anhydrous ethanol, and the solution of 0.1 ml UCA SonoVue, or both materials were injected into different cyst before HIFU ablation, respectively. The cyst inoculated with the SAP and UCA alone or in combination was immediately implanted into the abdominal cavity of rabbit for HIFU ablation at a dosage of 100 W acoustic powers. The ablation mode was spot scanning at the speed of 3 mm/s. Every target point was scanned three times; every ablating time lasted 3 s. The distance of each ablated layer was 5 mm. The total ablation time depended on the volume of cyst. The comparison of ultrasound image for each layer of hydatid cyst was made before and after HIFU ablation. The protoscolices in ablated cysts were stained by trypan blue exclusion assay, and their structures were observed by light microscopy. To estimate ablation effects of HIFU to the walls of hydatid cysts, the ultrastructure changes of cyst walls were examined by electron microscopy. The pathological changes of rabbits' skins through which ultrasound penetrated were observed to investigate the side effects of HIFU ablation. The results demonstrated that HIFU had some lethal effects to hydatid cysts in vivo, namely, echo enhancements of ultrasound images of cysts, increases in mortality rate of protoscolices from 15.19 % (HIFU alone) to 48.66 % (HIFU + SAP), 38.67 % (HIFU + UCA), and 67.75 % (HIFU + SAP + UCA), respectively, serious structural damages of protoscolices, and destructions or even disappearance of laminated layers and germinal layers in the walls of hydatid cysts ablated by HIFU aided with UCA and SAP alone or in combination. This study demonstrated that destructive effects of HIFU to transplanted hydatid cyst could be enhanced by UCA and SAP alone, but the destruction of HIFU aided with a combination of UCA and SAP to hydatid cysts was more effective than those aided with UCA or SAP alone. The enhanced thermal and cavitation effects of HIFU induced by UCA and SAP might be involved in the enhanced destructive effects of HIFU on hydatid cysts. There were no evidences of pathological changes on rabbits' skins overlying the hydatid cysts after HIFU ablation. The results suggested that the rabbit model with transplanted hydatid cyst may serve as an optional animal model for the experiments of HIFU ablation to hydatid cyst in vivo, and the materials of UCA and SAP were proved as enhancing agents of HIFU ablation to hydatid cysts, and HIFU at a dosage of 100 W acoustic powers was a safe and feasible parameter to ablate the hydatid cysts in this special animal model. These results laid a theoretical foundation for improving HIFU therapy for cystic echinococcosis by inoculation of UCA and SAP into hydatid cysts.

[Enhancement of in vitro protoscolicidal effects of high-intensity focused ultrasound by a superabsorbent polymer and ultrasound contrast agent].

This study evaluated whether or not a superabsorbent polymer (SAP) combined with ultrasound contrast agent (UCA) could enhance damage efficacy of high intensity focused ultrasound (HIFU) on Echinococcus granulosus protoscoleces in vitro. Thirty test tubes each with 6 000-7 500 protoscolices were divided into 5 groups: group A (blank control) without HIFU treatment, group B treated with HIFU (50 W) only, group C treated with 10 microl UCA and HIFU, group D treated with 0.01 g SAP and HIFU, group E treated with 10 microl UCA, 0.01 g SAP, and HIFU. In group B, echo enhancement of ultrasound image, suspension temperature (26.0 degrees C +/- 0.2 degrees C) and protoscoleces mortality (30.4%) were higher than that of group A (18.0 degrees C +/- 0.1 degrees C, 1.9%) (P < 0.01). Compared with group B, the echo enhancement of ultrasound image, suspension temperature (27.0 degrees C +/- 0.2 degrees C, 28.2 degrees C +/- 0.2 degrees C) and protoscoleces mortality (50.0%, 53.7%) of groups C and D increased significantly (P < 0.01). In group E, more protoscoleces were stained in red and their internal structures were indistinct. By chi-square test, the protoscoleces mortality of group E (69.7%) was higher than that of groups C and D (P < 0.01). There was no significant difference in suspension temperature among the 3 groups.

Establishment and Clinical Application of a RPA-LFS Assay for Detection of Capsulated and Non-Capsulated Haemophilus influenzae.

A recombinase polymerase amplification-lateral flow strip assay was established for detection of the outer membrane protein P6 (omp6) and the capsule encoding gene bexA of Haemophilus influenzae and the detection limit, sensitivity, and specificity were determined. Specific primers and probes were designed based on the published nucleotide sequences of omp6 and bexA. The minimum detection limit was determined with standard strains and the practical applicability of the RPA-LFS assay was assessed by detection of 209 clinical samples. The results confirmed that the RPA-LFS assay was both specific and sensitive for the detection of capsulated and non-capsulated H. influenzae with a detection limit of 1 CFU/µL. The detection rate of the 209 clinical samples was 97.1%, while the detection rate of capsulated H. influenzae was 63.2%. The detection results were consistent with the traditional culture method and dual polymerase chain reaction (PCR), confirming the applicability of the RPA-LFS assay.

In vitro dynamic bladder models for studying urinary tract infections: a narrative review.

Experimental models of the bladder are key to studying the pathogenic mechanism of catheter-related bacterial biofilm infection. Although numerous studies have reported multiple models, these model designs were heterogeneous. This study aimed to review the status quo and explore the problems associated with in vitro dynamic bladder models for studying urinary tract infections (UTIs). The PubMed and SinoMed databases were searched from their inception to February 2020. Studies regarding in vitro bladder models related to UTIs were reviewed based on a bibliometric evaluation of their basic characteristics and model analysis. A total of 74 papers and 44 bladder models were included in this study. The results were as follows: (I) urine transmission devices: 10 studies applied the gravity effect of culture media, while the others used peristaltic pumps, and 11 of them combined stirring or rotating forces. The flow rates in all studies ranged from 15 µL/min to 50 mL/min. (II) Bladder model: two studies reported on simulating the bladder using plastic bags, while the others reported on glass cylinders or fermenters with a capacity of 200 to 700 mL. E. coli and P. mirabilis were the main bacterial strains. (III) Infection carrier: six studies reported planktonic bacteria as their infection carrier, while 45 studies reported silica gel, rubber, polyurethane, silicone, polytetrafluoroethylene, or perfusion bag. (IV) Infection medium: 25 studies reported the culture medium. Thirty-two studies reported artificial urine, while 17 studies reported human urine. (V) Research analysis: 45 studies investigated the bacterial biofilm formation in the bladder model. Thirty-six studies compared the effects of various drug coatings, diverse material surfaces, or different materials. Only five studies compared distinct bladder models. The included studies' main defects were the single simulation of bladder urodynamics, divers parameter settings, and non-standard experimental modeling. Our analysis showed for the first time that in vitro dynamic bladder models could provide new ideas for exploring the mechanism and prevention of bacterial biofilm infection in urinary implanted biomaterials. Due to the limitations of the included studies, more high-quality studies are needed to verify the conclusions above further.

[Clinical oberservation on rotator cuff suture threader and strapping suture in meniscus tear under arthroscopy].

OBJECTIVE: To explore clinical effect of arthroscopic meniscus tear strapping suture by rotator cuff suture threader. METHODS: Forty patients with meniscus tear injury admitted from July 2015 to May 2019, including 27 males and 13 females, aged from 20 to 55 years old with an average of (36.0±1.4) years old. Menisci laceration was sutured with rotator cuff suture thread under arthroscopy. Postoperative complication was observed, Lysholm knee joint score before and after operation at 12 months were used to evaluate clinical effects, visual analogue scale (VAS) and range of knee flexion and extension were applied to evaluate recovery of pain and function. RESULTS: All patients were followed up from 12 to 15 months with an average of (12.6±0.7) months.No complication such as joint effusion, suture failure occurred. Two patients occurred mild pain after activity without clinical physical abnormality, and 1 patient manifested moderate pain with joint space tenderness, the other rest without abnormal. Lysholm knee joint score was increased from (49.55±1.21) preoperatively to (98.95±0.42) at 12 months after operation, VAS score decreased from (5.18±0.78)preoperatively to (1.03±0.77) at 12 months after operation, and range of knee joint flexion and extension activity increased from (50.63±9.20)°preoperatively to (130.38±4.99)°after operation, and there were statistical differences in Lysholm knee joint score, VAS and range of knee joint flexion and extension activity (P< 0.05). CONCLUSION: Arthroscopic strapping suture by rotator cuff suture threading device applies to most meniscus injuries, including medial meniscus posterior horn tears, lateral meniscus body tears and lateral meniscus posterior horn tears. This technique meets the need of full-internal meniscus suture without specialmeniscus suture, and has advantages of convenient operation, less complications and good postoperative function.

Combining procalcitonin with the qSOFA and sepsis mortality prediction.

To investigate whether procalcitonin (PCT) can improve the performance of quick sequential organ failure assessment (SOFA) score in predicting sepsis mortality, we conducted a retrospective multicenter cohort study with independent validation in a prospectively collected cohort in 3 tertiary medical centers. Patients with presumed sepsis were included. Serum PCT levels were measured at admission. Quick SOFA score and systemic inflammatory response syndrome (SIRS) criteria were calculated for each patient. PCT levels were assigned into 0, 1, and 2 points for a serum level of <0.25, 0.25 to 2, and >2 ng/mL, and added to the quick sepsis-related organ failure assessment (qSOFA) score. The incremental value of PCT to qSOFA was then evaluated by logistic regression, receiver-operating characteristic (ROC) curve, and reclassification analysis.In all, 1318 patients with presumed severe infection were enrolled with a 30-day mortality of 13.5%. Serum level of PCT showed a high correlation with qSOFA score and 30-day inhospital mortality. The area under the ROC curve was 0.56 for SIRS criteria, 0.67 for qSOFA score, and 0.73 for qSOFA_PCT in predicting 30-day mortality. The risk prediction improvement was reflected by a net reclassification improvement of 35% (17%-52%). Incorporation of PCT into the qSOFA model could raise the sensitivity to 86.5% (95% confidence interval 80.6%-91.2%). In the validation cohort, qSOFA_PCT greatly improved the sensitivity to 90.9%.A simple modification of qSOFA score by adding the ordinal scale of PCT value to qSOFA could greatly improve the suboptimal sensitivity problem of qSOFA and may serve as a quick screening tool for early identification of sepsis.

In vitro damage of Candida albicans biofilms by chitosan.

With the increasing usage of indwelling medical devices in clinical practice, the frequency of fungal infections has increased, such as that of Candida albicans (C. albicans). Biofilms, a protected niche for microorganisms, are resistant to a range of current antifungal agents. Chitosan is a polyatomic biopolymer with advantageous biocompatibility, biodegradation, nontoxicity and antibacterial properties. To investigate the inhibitory effect of chitosan on biofilms formed by C. albicans, cell viability, 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-caboxanilide reduction, and morphological assays, including fluorescence microscopy and scanning electron microscopy (SEM), were employed. As assessed by cell viability assay, chitosan showed significant inhibitory effects on the planktonic cells and the biofilm of C. albicans in a dose-dependent manner. Fluorescence microscopy and SEM assays confirmed that the chitosan-treated group showed delayed C. albicans biofilm formation with defect morphological features, due to the inhibitory effects of the vast majority of fungal cell growth. In conclusion, C. albicans biofilms were compromised by the treatment with chitosan, providing an alternative therapeutic strategy against the fungal biofilms in the medical devices.