Indian Journal of Microbiology最新文献

Glycopeptides have emerged as life-saving therapeutics in treating various gram-positive bacterial infections. Vancomycin being the first therapeutically approved glycopeptide has turned out as a blockbuster drug in the mitigation of gram-positive infections. However, long-term misuse of these glycopeptides led to the development of resistance which became a bottleneck in tackling various infections. Antimicrobial resistance has become a global threat exposing their impact on the public health domain. Concomitant to this the second-generation glycopeptides were developed through structural alterations and were approved by the USFDA which are serving as a last resort for an effective treatment. However, resistance against these also might develop shortly when misused. In this aspect, strategic approaches concerning structural activity for enhancing the antimicrobial activity and overcoming resistance were conferred. The clinical use of glycopeptides were also limited due to associated toxicity concerns and unusual pharmacokinetics. Understanding the pharmacokinetics of glycopeptides in different clinical conditions are necessary in tackling drug-induced resistance due to overdosing. Hence, dose optimization and therapeutic drug monitoring in different clinical conditions is necessary for better safety profiles and toxicity reduction. So, this review provides insights into glycopeptide-induced resistances, aspects of structural modifications to overcome resistance and their implications on pharmacokinetics and pharmacodynamics in different clinical conditions.

Multidrug resistance is a paramount impediment to successful treatment of most hospital acquired bacterial infections. A plethora of bacterial genera exhibit differential levels of resistance to the existing antibiotics. Prevalent Uropathogenic Escherichia coli or UPEC conduce high mortality among them. Multi-Drug Resistant bacterial strains utilize precise mechanisms to bypass effects of antibiotics. This is probably due to their familiar genomic origin. In this article drug repositioning method have been utilised to target 23 enzymes of UPEC strains viz. CFT073, 536 and UTI89. 3-D drug binding motifs have been predicted using SPRITE and ASSAM servers that compare amino acid side chain similarities. From the hit results anti-viral drugs have been considered for their uniqueness and specificity. Out of 14 anti-viral drugs 3 anti-HIV drugs viz. Amprenavir, Darunavir and Saquinavir have selected for maximum binding score or drug targetability. Finally, active sites of the enzymes were analyzed using GASS-WEB for eloquent drug interference. Further analyses with the active sites of all the enzymes showed that the three selected anti-HIV drugs were very much potent to inhibit their active sites. Combination or sole application of Amprenavir, Darunavir and Saquinavir to MDR-UPEC infections may leads to cure and inhibition of mortality.

Agarwood oil is one of the costliest essential oils used in perfumery, medicine and aroma. Production of the oil traditionally involves a soaking/fermentation step. Studies have indicated a definite role of the diverse microorganisms growing during the open soaking step, and in the emergent aroma of the essential oil. However, the temporal nature of fermentation and a key functional aspect i.e., the enzymatic properties of the microbes from the fermentation basin have not been studied yet. A total of 20 bacteria and 14 fungi isolated from fermentation basins located in Assam, India, at different soaking periods classified as early (0–20 days), medium (20–40 days) and late (40–60 days) clearly pointed towards an early fungal domination followed by succession of bacteria. The physico-chemical transformations of the wood are controlled by enzymatic properties (cellulase, xylanase, amylase and lipase) of the isolates. The results indicated a strong lignocellulosic substrate modulation potential in the four isolates, viz- Purpureocillium lilacinum (0.354 mg/mL), Mucor circinelloides (0.331 mg/mL), Penicillium citrinum (0.324 mg/mL) and Bacillus megaterium (0.152 mg/mL). The highest culturable abundance (CFU/mL) was found in M. circinelloides (2 × 10⁹) among fungi and B. megaterium (4.5 × 10⁹) among bacteria. The highest cellulase activity was shown by P. lilacinum (0.354 mg/mL) while xylanase and lipase by M. circinelloides (0.873 and 0.128 mg/mL). An interesting revelation was that a substantial proportion of the isolates (70% bacteria and 78% fungi) were positive for lipase activity. This is the first report on the “culturable microbiome” of the agarwood fermentation basin from a temporal and functional bioactivity perspective.

The emergence of various diseases such as cardiovascular, aging and cancer are due to oxidative stress as well as the shortage of enough antioxidant materials. Our study was intended to analyze the anticancer, antimicrobial, wound healing as well as hepatoprotective activities of purified sulfated polysaccharides derived from P. pavonica. The sulfated polysaccharide was subjected to partial purification using DEAE cellulose. The sulfated fraction was identified by HPLC, FTIR, ¹H-NMR and GC–MS. The results showed that the presence of fucopyranose in sulfated polysaccharide was attached to the O-acetyl groups confirmed by ¹H-NMR analysis. Further P. pavonica was carried out for the antioxidant profiling of sulfated polysaccharide through various standard assays. Bioactive principles of sulfated polysaccharides in medicinal fields were confirmed by anticancer activity on MDA-MB-231 breast cancer cells and wound healing activity in four groups of albino rats. The hepatoprotective activity of sulfated fraction was determined based on their biochemical parameters. Emulsification activity of sulfated polysaccharide was also evaluated. Also, it has antimicrobial properties. Our report has pointed out that the supplementation of sulfated polysaccharides would prevent the formation of cancer and oxidative damage of biomolecules.

Typhoid fever is a serious infectious disease caused by Salmonella typhi and Salmonella Paratyphi A. Although there are several drugs available for the treatment of Salmonella infection, however, the rising cases of bacterial resistance against common drugs necessitate new drug discovery against S. typhi. So Typhoid fever can be managed in a better way. Therefore we carried out the phytochemical analysis of Cotinus coggygria by FTIR and GC–MS analysis followed by antibacterial activity against S. typhi. Moreover, We also conducted molecular docking to find out important phytochemicals; methanol (48 compounds) and ethyl acetate (66 compounds) and 6 molecular targets; glycosidehydrolase (PDB Id: 4hzm), OmpF (PDB Id; 4kra), DNA gyrase (PDB Id;5ZTJ), AvrA (PDB Id; 6BE0), RamR (PDB Id; 6IE9), and tryptophan Synthase (PDB Id; 7L03). Results show that the ethyl acetate extracts of C. coggygria have the highest antibacterial activity against S. typhi, with inhibition zones ranging from 23 ± 2.8 to 18 ± 0.5 mm at different concentrations as compared to methanol extracts. Based on the docking score, DNA gyrase (5ZTJ) was found as the most suitable molecular target. DNA gyrase (5ZTJ). Further molecular dynamics simulation study resulted in 7 potential inhibitors from ethyl acetate extract and 5 potential inhibitors from methanol extracts as they had lower free binding energy than the reference drug ciprofloxacin. Based on this study we conclude that the top four phytochemicals that may be used for therapeutic purposes and drug development against salmonella activity are Lanosterol, Lup-20(29)-en-3-one, 9,19-Cyclolanost-24-en-3-ol, (3. beta.)-), and Periplogenin acetate.

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Antibiotic resistance in urinary tract infections (UTIs) is a growing concern due to extensive antibiotic use. The study explores a drug repurposing approach to find non-antibiotic drugs with antibacterial activity. In the present study, 8 strains of Pseudomonas spp. were used that were clinically isolated from UTI-infected patients. Amlodipine, a cardiovascular drug used in this study, has shown potential antimicrobial effect in reducing the various virulence factors, including swimming and twitching motility, biofilm, rhamnolipid, pyocyanin, and oxidative stress resistance against all the strains. Amlodipine exhibited the most potent antimicrobial activity with MIC in the range of 6.25 to 25 µg/ml. Significant inhibition in biofilm production was seen in the range of 45.75 to 76.70%. A maximum decrease of 54.66% and 59.45% in swimming and twitching motility was observed, respectively. Maximum inhibition of 65.87% of pyocyanin pigment was observed with the effect of amlodipine. Moreover, a significant decrease in rhamnolipids production observed after amlodipine treatment was between 16.5 and 0.001 mg/ml as compared to the control. All bacterial strains exhibited leakage of proteins and nucleic acids from their cell membranes when exposed to amlodipine which suggests the damage of the structural integrity. In conclusion, amlodipine exhibited good antimicrobial activity and can be used as a potential candidate to be repurposed for the treatment of urinary tract infections.

Klebsiella pneumoniae is considered as the most common pathogen of hospital-acquired pneumonia. K. pneumoniae has emerged as the superbug which had shown multidrug resistance (MDR) as well as extensively drug resistance. Carbapenem resistant K. pneumoniae (CRKP) has become a menace for the treatment with monotherapy of the patients mainly admitted in intensive care units. Hence, in the present study we collected total 187 sputum isolates of K. pneumoniae and performed the antimicrobial susceptibility testing by using the automated Vitek-2 system and broth micro-dilution method (67 CRKP). The combination study of solithromycin with meropenem, colistin, cefotaxime, piperacillin and tazobactam, nitrofurantoin, tetracycline, levofloxacin, curcumin and nalidixic acid was performed by using checkerboard assay. We observed the high rate of resistance towards ampicillin, cefotaxime, ceftriaxone, cefuroxime and aztreonam. The colistin and tigecycline were the most sensitive drugs. The CRKP were 36%, maximum were from the patients of ICUs. The best synergistic effect of solithromycin was with meropenem and cefotaxime (100%), colistin and tetracycline (80%). So, these combinations can be a choice of treatment for the infections caused by MDR CRKP and other Gram-negative bacteria where the monotherapy could not work.

Asthma is a chronic respiratory disease that affects children worldwide. Increasing evidence suggests that Staphylococcus aureus contributes to the pathology of asthma. The aim of this study was to evaluate the nasal carriage, antimicrobial susceptibility profile, and presence of enterotoxin genes from S. aureus isolated from children with asthma. Nasal swab samples were collected from 158 children, including 98 children with asthma and 60 healthy controls. S. aureus isolates were identified using phenotypic methods and the presence of the nuc gene. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disc diffusion method. Polymerase chain reaction (PCR) confirmed the presence of the mecA gene and enterotoxin genes. The nuc gene was confirmed in 83 isolates, resulting in a nasal carriage of 52.5% (83/158). The nasal carriage of S. aureus was higher among asthma cases (72.4%), with a significant association of S. aureus nasal carriage observed among asthma cases (OR 0.201, 95% CI 0.063–0.645, p = 0.007). Methicillin-resistant S. aureus (MRSA) nasal carriage was 11.4%. The S. aureus isolates showed high resistance to cefoxitin (99%) and penicillin (92%) but were sensitive to gentamicin (25%). Furthermore, 67.5% of the isolates were multi-drug resistant. The staphylococcal enterotoxin c gene (sec) was the most prevalent enterotoxin (19.7%) among cases and controls. These findings highlight the need for improved antibiotic stewardship in paediatric medicine and implementation of infection control policies.

Beta vulgaris var. crassa is undoubtedly a very important plant that is not used enough in the world. In this study, it was aimed to determine the cytotoxic activities of the components (essential oils, fatty acids, total phenol and flavonoid) found in the leaf parts of Beta vulgaris var. crassa against PC-3, MCF-7 and HeLa cancer cell lines. In addition, the effectiveness of these ingredients against bacteria and fungi that can cause serious health problems in humans was tested. In experiments, three tumor cell lines were exposed to various plant extract concentrations (31.25, 62.5, 125, 250, 500 and 1000 µg/mL) for 72 h. It was found that plant extracts showed high (SI: 2.14 > 2) cytotoxicity to PC-3 cells, moderate (SI: 1.62 < 2) to HeLa cells, and low (SI: 0.93 < 2) cytotoxicity to MCF-7 cells. Also, different plant extract concentrations were found to cause an inhibition rate of 16.3–22.3% in Staphylococcus aureus, 16.8–23.5% in Streptococcus pyogenes and 12–16.2% in Cutibacterium acnes. Similarly, inhibition rates were determined between 9.5–20.7% for Candida albicans, 3.5–7.7% for Candida auris, and 5.5–15.1% for Candida glabrata. The results showed that the plant extract exhibited a concentration-dependent cytotoxic and antimicrobial effect against both cancer cell lines and microbial pathogens.

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Research for novel compounds that may block bacterial development has continued and prompted by antibiotic-resistant bacteria. The expenses of community for health care as a result of antibiotic resistance has indeed been remarkable during the last decades and demand immediate of medical attention. Consequently, this research presents the antibacterial effect of genuine metal oxide nanoparticles against Escherichia coli (E. coli) and Klebsiella pneumoniae that have been isolated from urinary tract infection patients. This is because metal oxide nanomaterials have already been utilised a compromise with some of its comprehensive implementations throughout the pharmaceutical and biological disciplines of nano-biotechnology. The biological activity of zirconium oxide (ZrO₂) nanoparticles against bacteria is investigated using agar well diffusion approach. The antibacterial efficiency of nanoparticles on E. coli and Klebsiella pneumoniae using both qualitative and quantitative assessment approaches is appraised. Specifically, an aseptic technique is used to collect fifty urine samples into sterile tubes. To inoculate the patients' midstream urine on both blood agar and MacConkey agar plates, the direct streaking approach is employed. Scanning electron microscopy (SEM) and X–Ray diffraction (XRD) techniques are used to signify the physical features nanoparticle including shape and size. The identified cubic components of SEM and XRD techniques indicate the existence of ZrO₂ nanoparticles and magnetic nanoparticles of particle size ranges between 5 to 50 nm. According to the data, ZrO₂ nanoparticles have a bacteriostatic effect at 0.1 mg/ml with an absorption of 0.2 and a bactericidal effect at 2 mg/ml with an absorption of 0.007 on E. col isolates. Additionally, ZrO₂ nanoparticles exhibit bacteriostatic (at 0.1 mg/ml with absorption of 0.3) and bactericidal (at 2 mg/ml with absorption of 0.001) effects on Klebsiella pneumoniae isolates. Among all the antibiotics utilised, gentamicin shows the lowest rate of resistance, suggesting that it is more effective against E. coli and Klebsiella pneumoniae when ZrO₂ is presented.