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As strain variation and drug resistance become more pervasive, the prevention and control of infection have been a serious problem in recent years. The detection of pathogen is one of the most important parts of the process of diagnosis. Having a series of advantages, such as rapid response, high sensitivity, ease of use, and low cost, biosensors have received much attention and been studied deeply. Moreover, relying on its characteristics of small size, real time, and multiple analyses, biosensors have developed rapidly and used widely and are expected to be applied for microbiological detection in order to meet higher accuracy required by clinical diagnosis. The main goal of this contribution is not to simply collect and list all papers related to pathogen detection based on biosensors published recently, but to discuss critically the development and application of many kinds of biosensors such as electrochemical (amperometric, impedimetric, potentiometric, and conductometric), optical (fluorescent, fibre optic and surface plasmon resonance), and piezoelectric (quartz crystal microbalances and atomic force microscopy) biosensors in pathogen detection as well as the comparisons with the existing clinical detection methods (traditional culture, enzyme-linked immunosorbent assay, polymerase chain reaction, and mass spectrometry).

Bacterial infection continues to be a growing global health problem with the most widely accepted treatment paradigms restricted to antibiotics. However, antibiotics overuse and misuse have triggered increased multidrug resistance, frustrating the therapeutic outcomes and leading to higher mortalities. Even worse, the tendency of bacteria to form biofilms on living and nonliving surfaces further increases the difficulty in confronting bacteria because the extracellular matrix can act as a robust barrier to prevent the penetration of antibiotics and resist environmental stress. As a result, the inability to completely eliminate bacteria and biofilms often leads to persistent infection, implant failure, and device damage. Therefore, it is of paramount importance to develop alternative antimicrobial agents while avoiding the generation of bacterial resistance. Taking lessons from natural enzymes for destroying cellular structural integrity or interfering with metabolisms such as proliferation, quorum sensing, and programmed death, the construction of artificial enzymes to mimic the enzyme functions will provide unprecedented opportunities for combating bacteria. Moreover, compared to natural enzymes, artificial enzymes possess much higher stability against stringent conditions, easier tunable catalytic activity, and large-scale production for practical use. In this Account, we will focus on our recent progress in the design and synthesis of artificial enzymes as a new generation of "antibiotics", which have been demonstrated as promising applications in planktonic bacteria inactivation, wound/lung disinfection, as well as biofilm inhibition and dispersion. First, we will introduce direct utilization of the intrinsic catalytic activities of artificial enzymes without dangerous chemical auxiliaries for killing bacteria under mild conditions. Second, to avoid the toxicity caused by overdose of H 2 O 2 in conventional disinfections, we leveraged artificial enzymes with peroxidase-mimic activities to catalyze the generation of hydroxyl radicals at low H 2 O 2 levels while achieving efficient antibacterial outcomes. Importantly, the feasibility of these artificial enzymes was further demonstrated in vivo by mitigating mice wound and lung disinfection. Third, by combining artificial enzymes with stimuli-responsive materials, smart on-demand therapeutic modalities were constructed for thwarting bacteria in a controllable manner. For instance, a photoswitchable "Band-Aid"-like hydrogel doped with artificial enzymes was developed for efficiently killing bacteria without compromising mammal cell proliferation, which was promising for accelerating wound healing. Lastly, regarding the key roles that extracellular DNAs (eDNAs) play in maintaining biofilm integrity, we further designed a multinuclear metal complex-based DNase-mimetic artificial enzyme toward cleaving the eDNA for inhibiting biofilm formation and dispersing the established biofilms. We expect that our rational designs would boost the development of artificial enzymes with different formulations as novel antibacterial agents for clinical and industrial applications.

As common reactive oxygen species, H 2 O 2 is widely used for bacterial inactivation and wound disinfection. However, the concentrations used are always higher than physiological levels, which frequently result in potential toxicity to healthy tissue and even delay wound healing. Here we report highly efficient nanozyme hybrids that are capable of activating biologically relevant concentrations of H 2 O 2 for defending bacterial infections. The integration of AuNPs with ultrathin graphitic carbon nitride (g-C 3 N 4 ) provides excellent peroxidase-activity, which can catalyze the decomposition of H 2 O 2 to OH radicals much more efficiently, allowing the use of bio-safety levels of H 2 O 2 for the first time. Furthermore, our system not only exhibits striking bactericidal performance against both DR Gram-negative and DR Gram-positive bacteria, but also shows high efficiency in breaking down the existing DR-biofilms and prevented formation of new biofilms in vitro. More importantly, in vivo experiments indicate that our system could significantly prevent bacterial infections and accelerate the healing rate of wounds., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

In this work, a novel multifunctional NIR-sensitive nanoplatform has been developed for synergistic eradication of antibiotic-resistant bacteria based biofilms in vitro and in vivo. With high biocompatibility and an outstanding synergistic effect, our system provides a promising avenue to preventing and combating biofilm-associated infections.

Airborne bacteria play key roles in terrestrial and marine ecosystems and human health, yet our understanding of bacterial communities and their response to the environmental variables lags significantly behind that of other components of PM2.5 Here, atmospheric fine particles obtained from urban and suburb Shanghai were analyzed by using the qPCR and Illumina Miseq sequencing. The bacteria with an average concentration of 2.12 × 103 cells/m3, were dominated by Sphingomonas, Curvibacter, Acinetobacter, Bradyrhizobium, Methylobacterium, Halomonas, Aliihoeflea, and Phyllobacterium, which were related to the nitrogen, carbon, sulfur cycling and human health risk. Our results provide a global survey of bacterial community across urban, suburb, and high-altitude sites. In Shanghai (China), urban PM2.5 harbour more diverse and dynamic bacterial populations than that in the suburb. The structural equation model explained about 27%, 41%, and 20%–78% of the variance found in bacteria diversity, concentration, and discrepant genera among urban and suburb sites. This work furthered the knowledge of diverse bacteria in a coastal Megacity in the Yangtze river delta and emphasized the potential impact of environmental variables on bacterial community structure. [ABSTRACT FROM AUTHOR]

Background: The reduced amounts of Mycobacterium leprae (M. leprae) among paucibacillary (PB) patients reflect the need to further optimize methods for leprosy diagnosis. An increasing number of reports have shown that droplet digital polymerase chain reaction (ddPCR) is a promising tool for diagnosis of infectious disease among samples with low copy number. To date, no publications have investigated the utility of ddPCR in the detection of M. leprae. The aim of this study was to develop and evaluate a ddPCR assay for the diagnosis of PB leprosy. Methodology: The two most sensitive DNA targets for detection of M. leprae were selected from electronic databases for assessment of sensitivity and specificity by quantitative polymerase chain reaction (qPCR) and ddPCR. Control patients (n = 59) suffering from other dermatological diseases were used to define the cut-off of the duplex ddPCR assay. For comparative evaluation, qPCR and ddPCR assays were performed in 44 PB patients and 68 multibacillary (MB) patients. Principal findings: M. leprae-specific repetitive element (RLEP) and groEL (encoding the 65 kDa molecular chaperone GroEL) were used to develop the ddPCR assay by systematically analyzing specificity and sensitivity. Based on the defined cut-off value, the ddPCR assay showed greater sensitivity in detecting M. leprae DNA in PB patients compared with qPCR (79.5% vs 36.4%), while both assays have a 100% sensitivity in MB patients. Conclusions/Significance: We developed and evaluated a duplex ddPCR assay for leprosy diagnosis in skin biopsy samples from leprosy patients. While still costly, ddPCR might be a promising diagnostic tool for detection of PB leprosy. [ABSTRACT FROM AUTHOR]

Genome wide association studies (GWASs) have revealed multiple genetic variants associated with leprosy in the Chinese population. The aim of our study was to utilize the genetic variants to construct a risk prediction model through a weighted genetic risk score (GRS) in a Chinese set and to further assess the performance of the model in identifying higher-risk contact individuals in an independent set. The highest prediction accuracy, with an area under the curve (AUC) of 0.743 (95% confidence interval (CI): 0.729–0.757), was achieved with a GRS encompassing 25 GWAS variants in a discovery set that included 2,144 people affected by leprosy and 2,671 controls. Individuals in the high-risk group, based on genetic factors (GRS > 28.06), have a 24.65 higher odds ratio (OR) for developing leprosy relative to those in the low-risk group (GRS≤18.17). The model was then applied to a validation set consisting of 1,385 people affected by leprosy and 7,541 individuals in contact with leprosy, which yielded a discriminatory ability with an AUC of 0.707 (95% CI: 0.691–0.723). When a GRS cut-off value of 22.38 was selected with the optimal sensitivity and specificity, it was found that 39.31% of high risk contact individuals should be screened in order to detect leprosy in 64.9% of those people affected by leprosy. In summary, we developed and validated a risk model for the prediction of leprosy that showed good discrimination capabilities, which may help physicians in the identification of patients coming into contact with leprosy and are at a higher-risk of developing this condition. [ABSTRACT FROM AUTHOR]

Extracellular DNA (eDNA) is an essential structural component during biofilm formation, including initial bacterial adhesion, subsequent development, and final maturation. Herein, the construction of a DNase-mimetic artificial enzyme (DMAE) for anti-biofilm applications is described. By confining passivated gold nanoparticles with multiple cerium(IV) complexes on the surface of colloidal magnetic Fe3O4 /SiO2 core/shell particles, a robust and recoverable artificial enzyme with DNase-like activity was obtained, which exhibited high cleavage ability towards both model substrates and eDNA. Compared to the high environmental sensitivity of natural DNase in anti-biofilm applications, DMAE exhibited a much better operational stability and easier recoverability. When DMAE was coated on substratum surfaces, biofilm formation was inhibited for prolonged periods of time, and the DMAE excelled in the dispersion of established biofilms of various ages. Finally, the presence of DMAE remarkably potentiated the efficiency of traditional antibiotics to kill biofilm-encased bacteria and eradiate biofilms. [ABSTRACT FROM AUTHOR]

Abstract: The diesel contaminants in the sediments of Huangpu-Yangtze River estuary (HYRE) affect the ecosystem seriously. The effects of four species of indigenous plants, Scirpus triqueter (Scirpus tripueter L.; STL), reed (Phragmites australis; PA), Herba caricis phacotae (Carex phacota Spr.; CPS) and Sagittaria sagittifolia (S. sagittifolia L.; SSL), with oil-degrading bacteria (M) isolated from the oily HYRE wetland on the degradation ratio of diesel were evaluated by simulation experiments. The results showed that oil-degrading bacteria enhanced the degradation ratio of diesel. Besides, the indigenous plants combine with oil-degrading bacteria further improved the degradation ration. The diesel amount decreased about 76–80% (at 15,000 mg kg−1 diesel level) in the presence of PA & M, STL & M, SSL & M and CPS & M during the 60 d of experimental period. STL & M, SSL & M exhibited preferable degradation ratio at various diesel concentration throughout the whole experiment. The wetland plants with the oil-degrading bacteria showed a marked capability to degrade diesel contaminants. [Copyright &y& Elsevier]

The fabrication of functional nanoplatforms for combating multidrug‐resistant bacteria is of vital importance. Among them, silver nanoparticles (Ag NPs) have shown an antibacterial effect; however, the remainder cores of Ag NPs after use might have a toxic effect on humans. Thus, Ag ions based materials have been fabricated to substitute Ag NPs for antibacterial applications. Nevertheless, the always‐on release state leads to the low biocompatibility, which limits their biomedical applications. In addition, the single effect also restricts their antibacterial ability. Herein, a powerful surface‐adaptive, on‐demand antimicrobial nanoplatform is fabricated by coating hyaluronic acid (HA) on Ag ions loaded photosensitive metal‐organic frameworks to exhibit a strong synergistic effect. The nanoplatform shows good biocompatibility with nontargeted cells, as negatively charged HA can prevent the release of Ag ions. While in the presence of targeted bacteria, the secreted hyaluronidase can degrade HA on the nanoplatform and produce positively charged nanoparticles, which display increased affinity to bacteria and show a strong synergistic antibacterial effect owing to the released Ag ions and generated reactive oxygen species under visible light irradiation. Importantly, due to the outstanding on‐demand antimicrobial performance, the nanoplatform also shows great effects on treating multidrug‐resistant bacteria infected wounds in mice models. In this paper, a powerful surface‐adaptive, on‐demand antimicrobial nanoplatform with a strong synergistic effect is fabricated and utilized for bacteria killing and wound disinfection. The nanoplatform shows good biocompatibility to nontargeted cells. While in the presence of targeted bacteria, the surface‐adaptive nanoplatform can display increased affinity to them and show strong synergistic antibacterial effect originated from released Ag ions and reactive oxygen species. [ABSTRACT FROM AUTHOR]