Nosocomial Infections and Role of Nanotechnology

Comparative evaluation of Vitek®2 and broth microdilution method for colistin susceptibility testing of Gram-negative isolates from intensive care unit in a tertiary care hospital

INTRODUCTION

Colistin is the last resort treatment against resistant Gram-negative bacteria, necessitating reliable and rapid means for sensitivity testing of colistin. Automated systems like VITEK®2 are adopted to determine the minimum inhibitory concentration (MIC) due to easy usage. Broth microdilution (BMD) for colistin MIC was suggested by EUCAST and CLSI.

OBJECTIVE

To compare and evaluate colistin MIC by BMD and VITEK®2 against Gram-negative organisms from the ICU in a tertiary care hospital.

METHOD

Clinically significant organisms isolated from ICU patients were included. MIC was determined using BMD and VITEK®2. Very major error (VME), major error (ME), essential agreement (EA), categorical agreement (CA), positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity were analysed.

RESULT

533 isolates were obtained from blood (435,81.60%), respiratory samples (57,10.70%), pus and exudates (20,3.80%), urine (18,3.40%), and CSF (3,0.60%). The Enterobacterales were K. pneumoniae (185,34.70%) E. coli (73,13.70%) and E. cloacae (26,4.90%) while non-fermenters were A. baumannii (209,39.20%) and P. aeruginosa (40,7.50%). The VITEK®2 sensitivity was >99%; specificity ranged from 14.28 to 52.94%. PPV was 93.81% while NPV was 93.75%. VME ranged from 47 to 100% between isolates. ME was up to 20%. The highest VME was obtained in E. coli (100%). The total EA and CA observed were 68.5% and 99.79% respectively.

CONCLUSION

Automated system VITEK®2 failed to detect the resistance in 32 (60%) isolates. The obtained VME and ME values were >3%, which is unacceptable as per the standard guidelines. EA of ≥90% wasn't obtained. Sensitivity for VITEK®2 was >99%, but had low specificity (14.28%). Hence, VITEK®2 is not reliable for colistin susceptibility testing.

Exploring the efficacy of tryptone-stabilized silver nanoparticles against respiratory tract infection-causing bacteria: a study on planktonic and biofilm forms

Respiratory tract infections (RTIs) are a common cause of mortality and morbidity in the human population. The overuse of antibiotics to overcome such infections has led to antibiotic resistance. The emergence of multidrug resistant bacteria is necessitating the development of novel therapeutic techniques in order to avoid a major global clinical threat. Our study aims to investigate the potential of tryptone stabilised silver nanoparticles (Ts-AgNPs) on planktonic and biofilms produced byKlebsiella pneumoniae(K. pneumoniae)and Pseudomonas aeruginosa(P. aeruginosa). The MIC50of Ts-AgNPs was found to be as low as 1.7 μg ml-1and 2.7 μg ml-1forK. pneumoniae and P.aeruginosarespectively. Ts-AgNPs ability to alter redox environment by producing intracellular ROS, time-kill curves showing substantial decrease in the bacterial growth and significantly reduced colony forming units further validate its antimicrobial effect. The biofilm inhibition and eradication ability of Ts-AgNPs was found to be as high as 93% and 97% in both the tested organisms. A significant decrease in the eDNA and EPS quantity in Ts-AgNPs treated cells proved its ability to successfully distort the matrix and matured biofilms. Interestingly Ts-AgNPs also attenuated QS-induced virulence factors production. This study paves way to develop Ts-AgNPs as novel antibiotics against RTIs causing bacterial biofilms.

Progressing nanotechnology to improve targeted cancer treatment: overcoming hurdles in its clinical implementation

The use of nanotechnology has the potential to revolutionize the detection and treatment of cancer. Developments in protein engineering and materials science have led to the emergence of new nanoscale targeting techniques, which offer renewed hope for cancer patients. While several nanocarriers for medicinal purposes have been approved for human trials, only a few have been authorized for clinical use in targeting cancer cells. In this review, we analyze some of the authorized formulations and discuss the challenges of translating findings from the lab to the clinic. This study highlights the various nanocarriers and compounds that can be used for selective tumor targeting and the inherent difficulties in cancer therapy. Nanotechnology provides a promising platform for improving cancer detection and treatment in the future, but further research is needed to overcome the current limitations in clinical translation.

Nanoremediation strategies to address environmental problems

A rapid rise in population, extensive anthropogenic activities including agricultural practices, up-scaled industrialization, massive deforestation, etc. are the leading causes of environmental degradation. Such uncontrolled and unabated practices have affected the quality of environment (water, soil, and air) synergistically by accumulating huge quantities of organic and inorganic pollutants in it. Environmental contamination is posing a threat to the existing life on the Earth, therefore, demands the development of sustainable environmental remediation approaches. The conventional physiochemical remediation approaches are laborious, expensive, and time-consuming. In this regard, nanoremediation has emerged as an innovative, rapid, economical, sustainable, and reliable approach to remediate various environmental pollutants and minimize or attenuate the risks associated with them. Owing to their unique properties such as high surface area to volume ratio, enhanced reactivity, tunable physical parameters, versatility, etc. nanoscale objects have gained attention in environmental clean-up practices. The current review highlights the role of nanoscale objects in the remediation of environmental contaminants to minimize their impact on human, plant, and animal health; and air, water, and soil quality. The aim of the review is to provide information about the applications of nanoscale objects in dye degradation, wastewater management, heavy metal and crude oil remediation, and mitigation of gaseous pollutants including greenhouse gases.

Green Biofabrication of Silver Nanoparticles of Potential Synergistic Activity with Antibacterial and Antifungal Agents against Some Nosocomial Pathogens

Nosocomial bacterial and fungal infections are one of the main causes of high morbidity and mortality worldwide, owing to the high prevalence of multidrug-resistant microbial strains. Hence, the study aims to synthesize, characterize, and investigate the antifungal and antibacterial activity of silver nanoparticles (AgNPs) fabricated using Camellia sinensis leaves against nosocomial pathogens. The biogenic AgNPs revealed a small particle diameter of 35.761 ± 3.18 nm based on transmission electron microscope (TEM) graphs and a negative surface charge of −14.1 mV, revealing the repulsive forces between nanoparticles, which in turn indicated their colloidal stability. The disk diffusion assay confirmed that Escherichia coli was the most susceptible bacterial strain to the biogenic AgNPs (200 g/disk), while the lowest sensitive strain was found to be the Acinetobacter baumannii strain with relative inhibition zones of 36.14 ± 0.67 and 21.04 ± 0.19 mm, respectively. On the other hand, the biogenic AgNPs (200 µg/disk) exposed antifungal efficacy against Candida albicans strain with a relative inhibition zone of 18.16 ± 0.14 mm in diameter. The biogenic AgNPs exposed synergistic activity with both tigecycline and clotrimazole against A. baumannii and C. albicans, respectively. In conclusion, the biogenic AgNPs demonstrated distinct physicochemical properties and potential synergistic bioactivity with tigecycline, linezolid, and clotrimazole against gram-negative, gram-positive, and fungal strains, respectively. This is paving the way for the development of effective antimicrobial combinations for the effective management of nosocomial pathogens in intensive care units (ICUs) and health care settings.

The role of nanotechnology-based approaches for clinical infectious diseases and public health

Given the high incidence of infection and the growing resistance of bacterial and viral infections to the traditional antiseptic, the need for novel antiseptics is critical. Therefore, novel approaches are urgently required to reduce the activity of bacterial and viral infections. Nanotechnology is increasingly being exploited for medical purposes and is of significant interest in eliminating or limiting the activity of various pathogens. Due to the increased surface-to-volume ratio of a given mass of particles, the antimicrobial properties of some naturally occurring antibacterial materials, such as zinc and silver, increase as particle size decreases into the nanometer regime. However, the physical structure of a nanoparticle and the way it interacts with and penetrates the bacteria also appear to provide unique bactericidal mechanisms. To measure the efficacy of nanoparticles (diameter 100 nm) as antimicrobial agents, it is necessary to comprehend the range of approaches for evaluating the viability of bacteria; each of them has its advantages and disadvantages. The nanotechnology-based disinfectants and sensors for SARS-CoV-2 provide a roadmap for creating more effective sensors and disinfectants for detecting and preventing coronaviruses and other infections. Moreover, there is an increasing role of nanotechnology-based approaches in various infections, including wound healing and related infection, nosocomial infections, and various bacterial infections. To meet the demand for patient care, nanotechnology-based disinfectants need to be further advanced with optimum approaches. Herein, we review the current burden of infectious diseases with a focus on SARS-CoV-2 and bacterial infection that significantly burdens developed healthcare systems and small healthcare communities. We then highlight how nanotechnology could aid in improving existing treatment modalities and diagnosis of those infectious agents. Finally, we conclude the current development and future perspective of nanotechnology for combating infectious diseases. The overall goal is to update healthcare providers on the existing role and future of nanotechnology in tackling those common infectious diseases.

Rhamnolipid Nano-Micelles Inhibit SARS-CoV-2 Infection and Have No Dermal or Eye Toxic Effects in Rabbits

Hand hygiene is considered to be the key factor in controlling and preventing infection, either in hospital care settings or in the community. Alcohol-based hand sanitizers are commonly used due to their rapid action and broad spectrum of microbicidal activity, offering protection against bacteria and viruses. However, their frequent administration during COVID-19 pandemic was associated with serious hazards, such as skin toxicity, including irritation, skin dermatitis, skin dryness or cracking, along with peeling redness or itching, with the higher possibility of getting infections. Thus, there is a need to find alternative and novel approaches for hand sanitation. In our previous publications, we reported that rhamnolipids nano-micelles had a comparable antibacterial activity to alcohol-based hand sanitizer and a lower cytotoxicity against human dermal fibroblast cells. In the current study, we investigated the antiviral activity of rhamnolipids nano-micelles against SARS-CoV-2. There was no cytotoxic effect on Vero cells noted at the tested concentrations of rhamnolipids nano-micelles. The rhamnolipids nano-micelles solution at 20, 78, and 312 µg/mL all demonstrated a significant (p < 0.05) decrease of virus infectivity compared to the virus only and the blank vehicle sample. In addition, an acute irritation test was performed on rabbits to further ascertain the biosafety of rhamnolipids nano-micelles. In the eye and skin irritation tests, no degree of irritation was recorded after topical application of rhamnolipids nano-micelles. In addition, histopathological, biomarker, and hematological analyses from animals treated with rhamnolipids nano-micelles were identical to those recorded for untreated animal. From the above, we can conclude that rhamnolipids nano-micelles are a good candidate to be used as a hand sanitizer instead of alcohol-based hand sanitizers. However, they must still be tested in the future among healthcare workers (HCW) in a health care setting to ascertain their antimicrobial efficacy and safety compared to alcohol-based hand sanitizers.

Alternating magnetic field and NIR energy conversion on magneto-plasmonic Fe3O4@APTES–Ag heterostructures with SERS detection capability and antimicrobial activity

Fe3O4@APTES–Ag is a potential multipurpose platform for biological applications such as photomagnetic therapies, analytic probes exploiting the SERS effect and antibacterial activity.