Evaluation of Different Blood Culture Bottles for the Diagnosis of Bloodstream Infections in Patients with HIV.

INTRODUCTION: Bloodstream infection (BSI) is a significant factor contributing to hospitalization and high mortality rates among human immunodeficiency virus(HIV)-positive patients. Therefore, the timely detection of this condition is of utmost importance. Blood culture is considered the gold standard for diagnosing BSIs. Currently, BD BACTEC™ Plus Aerobic/F culture bottles and the BD BACTEC™ Myco/F Lytic culture bottles can be used for blood culture. This study aimed to evaluate the efficacy of two different types of culture bottles in diagnosing BSIs in patients with HIV. METHODS: A retrospective analysis was conducted on HIV-positive patients hospitalized in the Infection Department of Wenzhou Central Hospital between July 2019 and October 2021. A total of 246 pairs of blood samples were included, consisting of an aerobic culture vial and a Myco/F culture vial. Blood culture results and clinical diagnosis were utilized to identify the presence of BSI. RESULTS: Out of 246 cases, 84 cases had positive blood cultures. Fungal BSIs, particularly Talaromyces marneffei BSIs, were the most prevalent among patients with HIV. The positive rate of Myco/F culture bottles (89.29%) was significantly higher compared with aerobic culture bottles (69.05%; P = 0.001). In the diagnosis of fungal BSIs, the positive rate of Myco/F culture bottles was 88.57%, which was significantly higher than that of aerobic culture bottles (72.86%; P = 0.018). The Myco/F culture bottle has more advantages in diagnosing Talaromyces marneffei BSIs (P=0.028). In addition, mycobacteria were exclusively detected in Myco/F culture bottles. CONCLUSIONS: Fungal BSIs are the predominant type of infections in HIV-positive patients. Myco/F culture bottles exhibit noteworthy attributes of high positive rate in diagnosing HIV combined with BSI. These advantages are conducive to obtaining accurate culture results and minimizing missed diagnoses.

Polarity inversion of bioanode for biocathodic reduction of aromatic pollutants.

The enrichment of specific pollutant-reducing consortium is usually required prior to the startup of biocathode bioelectrochemical system (BES) and the whole process is time consuming. To rapidly establish a non-specific functional biocathode, direct polar inversion from bioanode to biocathode is proposed in this study. Based on the diverse reductases and electron transfer related proteins of anode-respiring bacteria (ARB), the acclimated electrochemically active biofilm (EAB) may catalyze reduction of different aromatic pollutants. Within approximately 12 d, the acclimated bioanodes were directly employed as biocathodes for nitroaromatic nitrobenzene (NB) and azo dye acid orange 7 (AO7) reduction. Our results indicated that the established biocathode significantly accelerated the reduction of NB to aniline (AN) and AO7 to discolored products compared with the abiotic cathode and open circuit controls. Several microbes possessing capabilities of nitroaromatic/azo dye reduction and bidirectional electron transfer were maintained or enriched in the biocathode communities. Cyclic voltammetry highlighted the decreased over-potentials and enhanced electron transfer of biocathode as well as demonstrated the ARB Geobacter containing cytochrome c involved in the backward electron transfer from electrode to NB. This study offers new insights into the rapid establishment and modularization of functional biocathodes for the potential treatment of complicated electron acceptors-coexisting wastewaters.

[Bioanode and Inversion of Bioanode to Biocathode for the Degradation of Antibiotic Chloramphenicol].

In order to investigate the possibility of the normal bioanode and bioanode switched to biocathode for the bio-electrochemical degradation of the antibiotic chloramphenicol (CAP), both the bioanode acclimated with CAP and the biocathode inversed from bioanode were monitored for CAP degradation in the bio-electrochemical system. The results demonstrated that the normal enriched bioanode could simultaneously generate current and degrade CAP (k = 0.098 5, 35 mg x L(-1) of CAP) after a long-term acclimation by gradually increasing the concentration of CAP from 5 mg x L(-1) to 80 mg x L(-1). After switching bioanode to biocathode, the cathode biofilm was still capable of catalyzing CAP degradation, although it was influenced to some extent due to changed electrode potential from -0.20 V to -0.40 V vs. standard hydrogen electrode (SHE). The k of biocathode was 0.264 3, significantly higher than that of abiotic cathode (k = 0.160 9). This mode of biocathode, which was switched from bioanode, not only had the ability of reducing nitro group in CAP but also catalyzed the complete dechloridation and carbanyl group reduction of the side chain of aromatic amine product.

Accelerated azo dye removal by biocathode formation in single-chamber biocatalyzed electrolysis systems.

Biocatalyzed electrolysis systems (BES) have been the topic of a great deal of research. However, the biocathodes formed in single-chamber BES without extra inocula have not previously been researched. Along with the formation of biocathodes, the polarization current increased to 1.76 mA from 0.35 mA of abio-cathodes at -1.2 V (vs. SCE). Electrochemical impedance spectroscopy (EIS) results also indicated that the charge transfer resistance (Rct) was decreased to 148.9 Ω, less than 1978 Ω of the abio-cathodes cleared. The performance of the biocathodes was tested for azo dye decolorization, and the dye removal efficiency was 13.3±3.2% higher than abio-cathodes with a 0.5 V direct current (DC) power supply. These aspects demonstrate that biocathode accelerates the rate of electrode reaction in BES and comparing with noble metal catalysts, biocathodes have low toxicity or non-toxic and reproducible properties, which can be widely applied in bioelectrochemical field in the future.

Accelerated reduction of chlorinated nitroaromatic antibiotic chloramphenicol by biocathode.

Chlorinated nitroaromatic antibiotic chloramphenicol (CAP) is a priority pollutant in wastewaters. A fed-batch bioelectrochemical system (BES) with biocathode with applied voltage of 0.5 V (served as extracellular electron donor) and glucose as intracellular electron donor was applied to reduce CAP to amine product (AMCl2). The biocathode BES converted 87.1 ± 4.2% of 32 mg/L CAP in 4 h, and the removal efficiency reached 96.0 ± 0.9% within 24 h. Conversely, the removal efficiency of CAP in BES with an abiotic cathode was only 73.0 ± 3.2% after 24 h. When the biocathode was disconnected (no electrochemical reaction but in the presence of microbial activities), the CAP removal rate was dropped to 62.0% of that with biocathode BES. Acetylation of one hydroxyl of CAP was noted exclusive in the biocatalyzed process, while toxic intermediates, hydroxylamino (HOAM), and nitroso (NO), from CAP reduction were observed only in the abiotic cathode BES. Electrochemical hydrodechlorination and dehalogenase were responsible for dechlorination of AMCl2 to AMCl in abiotic and microbial cathode BES, respectively. The cyclic voltammetry (CV) highlighted higher peak currents and lower overpotentials for CAP reduction at the biocathode compared with abiotic cathode. With the biocathode BES, antibacterial activity of CAP was completely removed and nitro group reduction combined with dechlorination reaction enhanced detoxication efficiency of CAP. The CAP cathodic transformation pathway was proposed based on intermediates analysis. Bacterial community analysis indicated that the dominate bacteria on the biocathode were belonging to α, ß, and γ-Proteobacteria. The biocathode BES could serve as a potential treatment process for CAP-containing wastewater.