Indian Journal of Microbiology最新文献

Antimicrobial resistance (AMR) has emerged as a global health menace which has caused millions of deaths and still continues to grow. The announcement of World Antimicrobial Awareness Week, 18–24 November 2022 by WHO further highlights the terrifying situation. Injudicious use of antibiotics is the major cause of emerging AMR. Therefore, new age antimicrobials are required for treating multi drug resistant (MDR) infections. In this quest, we synthesized novel green copper nanoparticles (BS-CuNPs) using cell free extracts of Bacillus subtilis (MTCC 441) and tested their bactericidal potential against various MDR pathogenic bacteria viz Staphylococcus aureus MRSA, E. coli Anp2A, E. coli Bi2A, Pseudomonas aeruginosa VTCCBAA2, Enterobacter cloacae Bu59. Antioxidant properties were also investigated using the DPPH and H₂O₂ radical scavenging techniques in terms of IC₅₀ (concentrations required for 50% inhibition) and IC₉₀ (concentrations required for 90% inhibition) values. The TEM micrographs of bacteriologically synthesized BS-CuNPs displayed size of 11.47 ± 2.6 nm with spherical configuration. BS-CuNPs also showed excellent colloidal and thermal stability in terms of zeta potential (− 26.9 meV) and thermogravimetric analysis (TGA). The MICs and MBCs of the BS-CuNPs against test MDR bacteria were ≤ 0.625 mg/ml which was significantly lesser (p < 0.05) than the same exhibited by CuNPs. The strongest effects were seen on Enterobacter cloacae Bu59 with MIC values of 0.156 mg/ml. The IC₅₀ and IC₉₀ of BS-CuNPs in DPPH assay exhibited significantly lower values, i.e. 42.97 and 128.31 µg/ml, respectively as compared to the chemically synthesized CuNPs, indicating potent antioxidant activity. These results from the performed studies clearly demonstrate the potential use of biogenic BS-CuNPs as novel antimicrobial in the field of biomedicine.

Multidrug-resistant or extended drug resistance has created havoc when it comes to patient treatment, as options are limited because of the spread of pathogens that are extensively or multidrug-resistant (MDR or XDR) and the absence of novel antibiotics that are effective against these pathogens. Physicians have therefore started using more established antibiotics such as polymyxins, tetracyclines, and aminoglycosides. Fosfomycin has just come to light as a result of the emergence of resistance to these medications since it continues to be effective against MDR and XDR bacteria that are both gram-positive and gram-negative. Fosfomycin, a bactericidal analogue of phosphoenolpyruvate that was formerly utilised as an oral medication for uncomplicated urinary tract infections, has recently attracted the interest of clinicians around the world. It may generally be a suitable therapy option for patients with highly resistant pathogenic infections, according to the advanced resistance shown by gram-negative bacteria. This review article aims to comprehensively evaluate the impact of fosfomycin on gram negative infections, highlighting its mechanism of action, pharmacokinetics, clinical efficacy, and resistance patterns.

Paddy fields include two interconnected ecosystems—soil and floodwater. Microbes and viruses are an integral component of these ecosystems, yet the viral communities have not been extensively studied. We present an analysis of the viromes of paddy floodwater collected during the two cropping seasons in India, the kharif and rabi seasons respectively. The overall taxonomic and functional characteristics appeared to be similar in both seasons, suggesting stability of the viral community. Taxonomically, the families of tailed bacteriophages dominated. The predominance of functional roles related to lytic phages further confirmed this. We reconstructed two complete and several partial viral genomes from the assembled data. The genomes did not align with any known sequences, thus representing novel viruses of the floodwater ecosystem.

Fungi are among the predominant pathogens seen in a greater proportion of infections acquired in healthcare settings. A common fungus that causes infections in medical settings is Candida species. Hospitalized patients who suffer from fungal diseases such as candidiasis and candidemia often have elevated rates of mortality and morbidity. It is evident that longer hospital stays have the possibility of bacterial and fungal recurrence and also have a negative economic impact. If left untreated, a Candida infection can spread to other organs and cause a systemic infection that can result in sepsis. Clinicians can treat patients quickly when fungal infections are timely detected, this enhances the results of clinical trials. Developing novel, sensitive, and quick methods for detecting Candida species is imperative. Conventional detection techniques are unsuitable for clinical settings and point-of-care systems as they require expensive equipment and take a longer detection time. This review examines a few of the most widely used biosensor systems for the detection of Candida species, their sensitivity, and the limit of detection. It focuses on various biorecognition elements used and follows utilization and advances in nanotechnology in the context of sensing. In addition to enabling general analysis and quick real-time analysis, crucial for detecting Candida species, biosensors provide an intriguing alternative to more conventional techniques.

The Cepheid Xpert Carba-R assay has been demonstrated to be reliable for rapid detection of carbapenemase-producing orgnisms (CPO) directly from rectal swabs but the performance of which remains unclear in Asia.We searched PubMed, EMBASE and Cochrane Library databases to identify studies according to predetermined criteria. STATA 13.0 software was used to analyze the tests for sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), area under the summary receiver operating characteristic curves (AUC). QUADAS-2 was used to assess the quality of included studies with RevMan 5.2. A total of 5 unique studies involving 10807 samples met the inclusion criteria. The pooled sensitivity, specificity, PLR, NLR, and the AUC with 95% CIs of Xpert Carba-R were 0.91 (0.72–0.97), 0.99 (0.96–1.00), 71.24 (25.41–199.73), 0.09 (0.03–0.32), 0.99 (0.98–1.00), respectively. Deeks’funnel plot showed no publication bias.The present meta-analysis showed the Xpert Carba-R assay had good sensitivity and perfect specificity for detecting CPOs on rectal swabs.

In the era of deep space exploration, extremophile research represents a key area of research w.r.t space survival. This review thus delves into the intriguing realm of ‘Space and Astro Microbiology’, providing insights into microbial survival, resilience, and behavioral adaptations in space-like environments. This discussion encompasses the modified behavior of extremophilic microorganisms, influencing virulence, stress resistance, and gene expression. It then shifts to recent studies on the International Space Station and simulated microgravity, revealing microbial responses that impact drug susceptibility, antibiotic resistance, and its commercial implications. The review then transitions into Astro microbiology, exploring the possibilities of interplanetary transit, lithopanspermia, and terraforming. Debates on life's origin and recent Martian meteorite discoveries are noted. We also discuss Proactive Inoculation Protocols for selecting adaptable microorganisms as terraforming pioneers. The discussion concludes with a note on microbes’ role as bioengineers in bioregenerative life support systems, in recycling organic waste for sustainable space travel; and in promoting optimal plant growth to prepare Martian and lunar basalt. This piece emphasizes the transformative impact of microbes on the future of space exploration.

The demand for energy resources is constantly increasing. That means need more fossil fuels to provide them. People consume a lot of food and this produces many wastes. Microbial fuel cells (MFCs) represent a new technological method with the potential to generate bioelectricity by the action of electrogenic bacteria on food wastes while reducing the amount of food wastes. This study investigated the possibility of usage of real restaurant wastewater as a fuel (substrate) for microbial fuel cell and its effects on the bacterial consortium attached to the electrodes. Mathematical (R² > 0.96) and statistical (R² > 0.99) models were conducted for the MFC performance focusing on the polarization curves. The study demonstrated that the highest COD removal (88.69%) in the semi-batch mode and (99.64%) in continuous mode, and power density (10.9 mW/m²) and (56.8 mW/m²) in semi-batch and continuous mode, respectively. The Bacterial diagnosis for anodophilic biofilm showed important differences in distribution and density of a heavy growth consortium after operation. This research offers restaurants an eco-friendly solution. This is because it demonstrates the benefits of using their own wastewater for power generation, reducing costs and saving the environment.

Antibiotics are the super drugs that have revolutionized modern medicine by curing many infectious diseases caused by various microbes. They efficiently inhibit the growth and multiplication of the pathogenic microbes without causing adverse effects on the host. However, prescribing suboptimal antibiotic and overuse in agriculture and animal husbandry have led to the emergence of antimicrobial resistance, one of the most serious threats to global health at present. The efficacy of a new antibiotic is high when introduced; however, a small bacterial population attains resistance gradually and eventually survives. Understanding the mode of action of these miracle drugs, as well as their interaction with targets is very complex. However, it is necessary to fulfill the constant need for novel therapeutic alternatives to address the inevitable development of resistance. Therefore, considering the need of the hour, this article has been prepared to discuss the mode of action and recent advancements in the field of antibiotics. Efforts has also been made to highlight the current scenario of antimicrobial resistance and drug repurposing as a fast-track solution to combat the issue.

Candida auris is the most common, globally detected nosocomial fungal pathogen with multi-drug resistance. The high prevalence of C. auris infections has raised concern about drug resistance and adverse effects, compounded by a lack of effective alternative drugs. Bioengineered nanomaterials play a significant role in combating nosocomial infections. Silver nanoparticles (AgNPs) have emerged as an extensively used nanomaterial due to their prominent antimicrobial properties. One of the most promising approaches is to incorporate herbal extracts that contain a range of phytoconstituents, being used for curing various chronic illnesses. This study aimed to produce eco-friendly, cost-effective green synthesized AgNPs with trans-Himalayan medicinal plant extracts (Trillium govanianum & Bergenia ligulata) and assess their anticandidal and antibiofilm potential. The green-synthesized AgNPs formation and crystalline nature were confirmed by UV–visible spectroscopy, dynamic light scattering and X-ray diffraction analysis. The UV–Vis spectra of the AgNPs revealed bands in the range of 415–430 nm. Phytoconstituents as reducing agents were involved in the stabilization of AgNPs as identified by FTIR spectra. HR-TEM of AgNPs’ displayed a spherical shape with size in the range of 10–100 nm. Results of activity tests performed using various C. auris clinical strains showed half maximum growth inhibition (IC₅₀) at 8.02 µg/mL, which inhibited 65% of biofilm for T. govanianum extract. The free radical scavenging activity evaluated for green synthesized AgNPs using DPPH showed more than 90% antioxidant activity. Green synthesized AgNPs displayed potent growth inhibition (IC₅₀) at 4.01 µg/mL with 87.0% biofilm inhibition. Green synthesized AgNPs coated bandages and catheters inhibited the growth of C. auris. This study concluded that green synthesized AgNPs formulation in conjunction with antifungal agents exhibits potential biomedical application and also could be used as alternative therapeutics.

Detailed phenotypic and genotypic characterization was done to establish the taxonomic position of a novel bacterial strain GG226^T, frequently been isolated from the gut of Lepidocephalichthys guntea. Strain GG226^T a Gram-negative, facultatively anaerobic, rod-shaped, motile, alkaliphilic bacterium. The 16S rRNA gene sequences analysis disclosed that GG226^T belongs to genus Verticiella due to its maximum sequence identity with Verticiella sediminum XH089^T (98.4%), the sole representative of this genus. A genome BLAST distance phylogeny (GBDP) tree, single nucleotide polymorphism (SNP) tree, and multi locus species tree (MLST) reconfirmed that GG226^T shares its closest taxonomic identity with Verticiella sediminum XH089^T. The DNA G + C content was estimated to be 67 mol%. When compared with Verticiella sediminum XH089^T the DNA-DNA hybridization (dDDH) value was 21.90% and the average nucleotide identity (ANI) value was 80.13%; both of which were sufficiently below the threshold value (≤ 70% and ≤ 95–96%) for new prokaryotic species validation. The dominant fatty acids (> 5% of total fatty acids) were C_16:0, summed feature 3 (C_16:1ω7c/C_16:1ω6c), C_17:0 cyclo, and C_12:0 3-OH. The strain GG226^T has shown significant growth in pH 9 and 10, and noticeable high resistance to sodium arsenate (MIC: > 500 mM). The results of biochemical tests, phenotypic characteristics, genotypic data, and physiological properties could differentiate strain GG226^T from its closest taxonomic relative. Hence, characterization based on chemotaxonomic, phenotypic, genomic, and phylogenetic evidence demonstrated that the strain GG226^T represents a novel species of the genus Verticiella, for which the name Verticiella alkaliphila sp. nov. (type strain GG226^T = MCC 5181^T = JCM 36073^T) is proposed.