Iranian Journal of Microbiology最新文献

{"title":"Isolation and characterization of bacteriophages against antibiotic-resistance <i>Pseudomonas aeruginosa</i>.","authors":"Parisa Abedi Elkhichi, Sara Bahonar, Hanieh Shirazi, Aghil Bahramian, Maryam Kazemi Aghdam, Mona Ghazi","doi":"10.18502/ijm.v18i4.22193","DOIUrl":"https://doi.org/10.18502/ijm.v18i4.22193","url":null,"abstract":"<p><strong>Background and objectives: </strong>As an important opportunistic pathogen, <i>Pseudomonas aeruginosa</i> is associated with severe infections and increasing antimicrobial resistance. The growing prevalence of multidrug-resistant (MDR) strains has renewed interest in bacteriophages as alternative antibacterial agents. The present study sought to isolate and characterize lytic bacteriophages from hospital wastewater active against antibiotic-resistant clinical <i>P. aeruginosa</i> isolates.</p><p><strong>Materials and methods: </strong>Fifty clinical isolates of <i>P. aeruginosa</i> were obtained and tested for antimicrobial susceptibility. Bacteriophages were isolated from hospital wastewater by enrichment and spot assay screening, followed by plaque purification and titration using the double-layer agar method. The host range of purified phages was evaluated against the clinical isolates. Adsorption assays and one-step growth experiments were performed to determine adsorption efficiency, latent period, and burst size. Transmission electron microscopy (TEM) was used to examine phage morphology.</p><p><strong>Results: </strong>A considerable proportion of the clinical isolates showed multidrug-resistant phenotypes, and a considerable number were also classified as extensively drug-resistant. Four lytic bacteriophages, designated HSP1-HSP4, were successfully isolated and purified. All produced clear plaques and reached high titers. Host range analysis showed variable lytic spectra, with HSP1 exhibiting the broadest activity and showing lytic activity against 70% of the tested isolates, followed by HSP2 (58%), HSP3 (48%), and HSP4 (40%). Adsorption analysis indicated that over 80% of phage particles attached to their host cells within 10 minutes, while HSP1 exhibited the highest adsorption efficiency at 93.6%. A short latent period of approximately 20 minutes was observed for all four phages, and burst sizes ranged from 56 to 65 PFU/cell. Transmission electron microscopy revealed isometric heads and contractile tails, morphologically consistent with tailed phages of the class <i>Caudoviricetes</i>.</p><p><strong>Conclusion: </strong>Hospital wastewater can serve as a practical source for the isolation of lytic bacteriophages active against antibiotic-resistant <i>P. aeruginosa.</i> The in vitro properties of the isolated phages support their further evaluation as candidate antibacterial agents against resistant <i>P. aeruginosa</i>. However, genomic characterization, phage-antibiotic interaction analyses, and in vivo investigations are required before their broader applicability can be determined.</p>","PeriodicalId":14633,"journal":{"name":"Iranian Journal of Microbiology","volume":"18 4","pages":"499-508"},"PeriodicalIF":1.9,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13490637/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148792990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unravelling the cellulolytic and hemicellulolytic potential of <i>Streptomyces griseoincarnatus</i> SSPJ4 from semi-arid agricultural region: genome analysis and saccharification studies.","authors":"Prakriti Jhilta, Vikram Poria, Arjun Singh, Vishal Singh Somvanshi, Ram Karan, Surender Singh","doi":"10.18502/ijm.v18i4.22199","DOIUrl":"https://doi.org/10.18502/ijm.v18i4.22199","url":null,"abstract":"<p><strong>Background and objectives: </strong>Second-generation bioethanol, a sustainable and environmentally friendly alternative to fossil fuels, can significantly contribute to the economy. However, saccharification accounts for approximately 20-25% of total bioethanol production costs, which can be reduced by using the improved enzyme cocktails. Therefore, the present study aimed to isolate and characterize potent cellulolytic <i>Streptomyces</i> strains capable of enhancing the hydrolytic conversion of lignocellulosic biomass.</p><p><strong>Materials and methods: </strong>Degraded wood and soil samples were collected and enriched with paddy straw. The isolates were obtained using standard methods and characterized by 16S rRNA sequencing. The best isolate was subjected to whole-genome sequencing to identify hydrolytic genes involved in agro-waste degradation. Saccharification assays were performed using crude culture filtrate in combination with the commercial cellulase cocktail Celluclast® to evaluate sugar release from alkali-pretreated paddy straw.</p><p><strong>Results: </strong>Among the 38 isolates obtained, five were identified as potential cellulolytic <i>Streptomyces</i> strains based on 16S rRNA gene sequencing: <i>Streptomyces tunisiensis</i> SSPJ1, <i>Streptomyces griseoincarnatus</i> SSPJ4, <i>Streptomyces werraensis</i> SSPJ14, <i>Streptomyces ardesiacus</i> SSPJ32, and <i>Streptomyces tendae</i> SSPJ48. <i>S. griseoincarnatus</i> SSPJ4 emerged as the most promising isolate, demonstrating significantly higher enzyme activities. <i>S. griseoincarnatus</i> SSPJ4 was subjected to whole-genome sequencing using the GALAXY tool for assembly and annotation, with an assembled genome of 7.3 Mb, 72.38% G+C content, and 6678 genes. Biosynthetic gene clusters (23) were identified using antiSMASH, and 226 proteins were annotated with CAZy domains, of which 121 belonged to the glycoside hydrolase (GH) family. Supplementation of Celluclast® with the crude enzyme preparation from <i>S. griseoincarnatus</i> SSPJ4 enhanced the saccharification of alkali-pretreated paddy straw, resulting in a 1.55-fold higher sugar yield compared with Celluclast® alone.</p><p><strong>Conclusion: </strong>The findings demonstrate the considerable potential of <i>S. griseoincarnatus</i> SSPJ4 as a source of accessory lignocellulolytic enzymes for improving biomass saccharification. Its enzyme repertoire could be exploited to develop cost-effective and efficient enzymatic formulations for second-generation bioethanol production.</p>","PeriodicalId":14633,"journal":{"name":"Iranian Journal of Microbiology","volume":"18 4","pages":"561-573"},"PeriodicalIF":1.9,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13490904/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148792963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reducing catheter urinary tract infection risk through biofilm prevention: evidence-based strategies for urinary catheter management.","authors":"Wani Devita Gunardi, Ade Dharmawan, Kris Herawan Timotius","doi":"10.18502/ijm.v18i4.22191","DOIUrl":"https://doi.org/10.18502/ijm.v18i4.22191","url":null,"abstract":"<p><strong>Background and objectives: </strong>Catheter-associated urinary tract infections (CAUTIs) are common healthcare-associated infections mainly caused by biofilm formation on urinary catheters. This study aimed to provide evidence-based catheter management strategies to reduce CAUTI risk through biofilm prevention.</p><p><strong>Materials and methods: </strong>This prospective observational study included 109 adult patients undergoing urinary catheterization between September 2017 and January 2018. Urine samples were collected after catheter insertion and before catheter removal. Bacteriuria was screened using flow cytometry and confirmed by urine culture. Removed catheters were cultured to assess biofilm formation, while isolates were tested for biofilm-forming ability using Congo Red Agar (CRA).</p><p><strong>Results: </strong>The mean catheterization duration was 5.6 ± 2.1 days, and most patients were catheterized for ≥5 days. Bacteriuria was significantly associated with catheterization (p = 0.029). Antibiotic use reduced bacteriuria incidence (p < 0.001) but did not significantly reduce biofilm formation (73.4%, p > 0.05). CRA-positive isolates showed 1.5-fold greater biofilm-forming potential. Female sex, early bacteriuria, and catheterization >5 days were associated with biofilm formation.</p><p><strong>Conclusion: </strong>Urinary catheterization promotes biofilm and increases CAUTI risk. Although antibiotics reduced bacteriuria, they showed limited efficacy against biofilms. Early bacteriuria screening, routine monitoring, biofilm prevention, and limiting catheter duration may help reduce CAUTI incidence.</p>","PeriodicalId":14633,"journal":{"name":"Iranian Journal of Microbiology","volume":"18 4","pages":"482-489"},"PeriodicalIF":1.9,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13490630/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148792969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surveying a <i>Pseudomonas aeruginosa</i>-derived oxidoreductase activity.","authors":"Maliheh Mohammadkhani, Shamsozoha Abolmaali, Shakiba Darvishalipour Astaneh","doi":"10.18502/ijm.v18i4.22196","DOIUrl":"https://doi.org/10.18502/ijm.v18i4.22196","url":null,"abstract":"<p><strong>Background and objectives: </strong>Flavoprotein monooxygenases (FPMOs) participate in various biological processes, including lignin degradation, natural product biosynthesis, and xenobiotic detoxification. This study aimed to investigate the heterologous expression of FPMO and assess its functional activity by examining its capacity to inactivate ampicillin.</p><p><strong>Materials and methods: </strong><i>In silico</i> analyses were performed to predict the enzyme's secondary and tertiary structures. The target gene was isolated from <i>Pseudomonas aeruginosa</i>, cloned into the pET-22b vector, and expressed in <i>Escherichia coli</i> BL21 (DE3). Heterologous protein expression was examined using SDS-PAGE, and the protein was purified through nickel-affinity chromatography. Enzymatic activity was measured by spectrophotometric monitoring of NADPH oxidation at 340 nm. Antibacterial activity was tested using an agar well-diffusion assay, measuring the inhibition zone diameter in <i>E. coli</i> treated with ampicillin.</p><p><strong>Results: </strong>Homology modeling indicated that the 3D structure of FPMO is very similar to cyclohexanone monooxygenase, supporting its classification as a Baeyer-Villiger monooxygenase (BVMO). Molecular docking proposed that ampicillin might be a substrate for FPMO, with predicted interactions at Ile141 and Val159. Enzymatic assays confirmed that FPMO catalyzes the oxidation of ampicillin, using FAD and NADPH as cofactors. Additionally, well-diffusion tests showed decreased ampicillin antibacterial activity after treatment. The enzyme's activity was further confirmed using an ampicillin inactivation assay.</p><p><strong>Conclusion: </strong>The heterologously expressed protein was functionally active. These findings suggest that the studied FPMO may play a role in antibiotic resistance in <i>P. aeruginosa</i> by oxidatively inactivating ampicillin.</p>","PeriodicalId":14633,"journal":{"name":"Iranian Journal of Microbiology","volume":"18 4","pages":"533-543"},"PeriodicalIF":1.9,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13490897/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148792935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Utility of RGM medium for recovery of <i>Mycobacterium abscessus</i> from presumptive pulmonary tuberculosis patients and its molecular phylogenetic characterization.","authors":"Usha Kattamanchi, Rakesh Kodati, Neelima Angaali, Patil Madhusudhan, Vishunukanth Govindaraj, Gongati Kruparao Paramjyothi, Kumar Ebineshan, Noyal Mariya Joseph","doi":"10.18502/ijm.v18i4.22198","DOIUrl":"https://doi.org/10.18502/ijm.v18i4.22198","url":null,"abstract":"<p><strong>Background and objectives: </strong>Non-tuberculous mycobacteria (NTM), especially <i>Mycobacterium abscessus</i>, are emerging causes of pulmonary disease and are often misdiagnosed as tuberculosis in high TB burden countries. Conventional culture methods are time-consuming and may reduce viable organism recovery. Rapidly growing mycobacteria (RGM) medium enables direct inoculation of respiratory specimens and improved recovery of rapidly growing NTM. This study evaluated the utility of RGM medium for isolation of <i>M. abscessus</i> from presumptive pulmonary tuberculosis patients and characterized the isolates using molecular and phylogenetic analyses.</p><p><strong>Materials and methods: </strong>A total of 223 sputum samples collected from presumptive pulmonary tuberculosis patients. Untreated sputum samples were inoculated onto RGM medium with selective antibiotics and incubated at 30°C for 10 days. Suspected colonies were confirmed by Ziehl-Neelsen staining. Identification was performed by PCR and sequencing of <i>hsp65</i> and <i>rpoB</i> genes. Phylogenetic analysis was done using the Neighbour-Joining method in MEGA12. <i>Mycobacterium abscessus</i> isolates were further analysed using the GenoType NTM-DR assay.</p><p><strong>Results: </strong>Among the 223 sputum samples processed, 7.6% (17/223) demonstrated positive growth on RGM medium. Of the culture-positive isolates, 64.7% (11/17) were identified as <i>Mycobacterium abscessus</i>, while 35.3% (6/17) were identified as other non-tuberculous mycobacterial (NTM) species. All isolates were positive for the <i>rpoB</i> and <i>hsp65</i> genes. Eleven <i>M. abscessus</i> isolates were further analysed using the GenoType NTM-DR assay, and no resistance-associated mutations were detected in the <i>erm(41)</i>, <i>rrl</i>, or <i>rrs</i> genes. Additionally, all isolates were found to be susceptible to macrolides and aminoglycosides.</p><p><strong>Conclusion: </strong>RGM medium demonstrated good utility for recovery of clinically significant rapidly growing mycobacteria, particularly <i>M. abscessus</i>, directly from sputum samples. Molecular and phylogenetic analyses enabled accurate species identification and characterization. The absence of resistance-associated mutations suggests retained susceptibility to key therapeutic agents. These findings support the use of RGM medium for improved detection of pulmonary NTM infections in TB-endemic settings.</p>","PeriodicalId":14633,"journal":{"name":"Iranian Journal of Microbiology","volume":"18 4","pages":"553-560"},"PeriodicalIF":1.9,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13490901/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148793024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Antifungal effect of <i>Lacticaseibacillus rhamnosus</i> GG against oral candidiasis in diabetic rats.","authors":"Vedam Venkata Kanthi Vaishnavi, Urmila Banik, Candy Chuah, Subramani Parasuraman","doi":"10.18502/ijm.v18i4.22202","DOIUrl":"https://doi.org/10.18502/ijm.v18i4.22202","url":null,"abstract":"<p><strong>Background and objectives: </strong>Diabetes mellitus (DM) increases the risk of oral candidiasis by impairing immunity and enhancing <i>Candida</i> virulence. Although <i>Lacticaseibacillus rhamnosus</i> GG (LGG) has antifungal potential, its effect in diabetes remains unclear. This study evaluated the efficacy of LGG against <i>C. albicans</i> and <i>C. tropicalis</i> in diabetic rats.</p><p><strong>Materials and methods: </strong>A fungal suspension (1×10⁷ CFU/mL) was applied to the tongue for three days in the controls and experimental groups of male alloxan-induced diabetic Sprague-Dawley rats. Then, LGG (0.3 mL of 1×10⁸ CFU/mL) was administered for 28 days in the experimental groups. Weekly oral swabs were analyzed, and blood and tongue tissues were evaluated using biochemical, histopathological, and molecular methods (TLR2, TLR4, and Msp1/p75).</p><p><strong>Results: </strong>Diabetic rats showed weight loss and increased oral <i>Candida</i> growth. LGG reduced <i>C. albicans</i> and <i>C. tropicalis</i> counts and stabilized body weight. Haematological and biochemical parameters improved with probiotic treatment. Histopathological examination showed reduced inflammation, and molecular analyses indicated modulation of Msp1/p75 and TLR2/TLR4. Overall, LGG provided antifungal and immunomodulatory benefits in diabetic rats with oral candidiasis.</p><p><strong>Conclusion: </strong>This study assessed the efficacy of LGG against <i>C. albicans</i> and <i>C. tropicalis</i> in diabetic rats. Administration of LGG reduced <i>Candida</i> colonization and maintained normal physiological parameters. These results suggest that LGG has potential as a safe complementary antifungal therapy.</p>","PeriodicalId":14633,"journal":{"name":"Iranian Journal of Microbiology","volume":"18 4","pages":"595-606"},"PeriodicalIF":1.9,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13490902/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148793160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exposure to thermal stress induces overexpression of protein-L-iso aspartate-O-methyl transferase (PIMT) in <i>Pseudomonas aeruginosa</i>.","authors":"Suman Agrawalla, Prasanta Kumar Koustasa Mishra, Srinivas Sathapathy, Ashok Kumar Sethi, Debasis Dash, Archana Mahapatra, Radhakrishna Sahu","doi":"10.18502/ijm.v18i4.22206","DOIUrl":"https://doi.org/10.18502/ijm.v18i4.22206","url":null,"abstract":"<p><strong>Background and objectives: </strong>Apart from spontaneous deamidation and isomerization of Asp/Asn residues, factors like ageing, oxidative stress, salinity and heat stress may also form abnormal isoaspartate (iso-Asp) residues compromising protein structure and function. PIMT helps in restoration of such iso-Asp residues. <i>Pseudomonas aeruginosa</i> is a gram-negative bacteria responsible for diseases with varied degree of pathogenesis in humans and animals. They can survive a wide range of temperature between 25°C to 42°C. The objective of the current study was to monitor the expression dynamics of PIMT in <i>Pseudomonas aeruginosa</i> upon exposure to different thermal stresses.</p><p><strong>Materials and methods: </strong>The mid log phase culture of <i>Pseudomonas aeruginosa</i> was exposed to different temperature (37°C, 42°C, 56°C, 80°C) for an hour. The expression levels of PIMT were quantified by Western blot and ELISA.</p><p><strong>Results: </strong>A relatively higher level of expression of PIMT was observed in the group exposed to 42°C, 56°C, 80°C in comparison to 37°C. The expression of PIMT increased around 1.5 times in the group exposed to 42°C.</p><p><strong>Conclusion: </strong>A temperature dependent overexpression of PIMT was observed in <i>Pseudomonas aeruginosa.</i></p>","PeriodicalId":14633,"journal":{"name":"Iranian Journal of Microbiology","volume":"18 4","pages":"629-632"},"PeriodicalIF":1.9,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13490891/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148793020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development and evaluation of an indigenous <i>Salmonella gallinarum</i> ghost vaccine for the control of fowl typhoid in poultry.","authors":"Asad Ullah Ghalib, Sajjad Hussain, Waseem Shahzad, Rashid Mir, Bushra Muneer","doi":"10.18502/ijm.v18i4.22200","DOIUrl":"https://doi.org/10.18502/ijm.v18i4.22200","url":null,"abstract":"<p><strong>Background and objectives: </strong><i>Salmonella gallinarum</i>, causes fowl typhoid, continues to be a significant limitation to poultry production in developing nations, with continuously rising antimicrobial resistance. The current research was design and test an indigenous <i>S. gallinarum</i> ghost vaccine and to measure its immunogenicity and protective effect on layer birds.</p><p><strong>Materials and methods: </strong>Bacteriological culture of suspected clinical cases of fowl typhoid was performed, and isolates were verified by PCR against the 16S rRNA gene, after which they were sequenced, and phylogenetic analysis was performed. To obtain bacterial ghost cells, a representative native isolate was subjected to a detergent-based chemical lysis procedure, followed up by scanning electron microscopy. 120-day-old layer chicks were divided into six groups randomly and immunized at the age of seven days using oral, intramuscular, air-spray, intramuscular with oil adjuvant or eye-drop routes. There was a 1^st dose at 26 days of age in all vaccinated groups and the challenge of virulent <i>S. gallinarum</i> at 42 and 93 days of age. ELISA was used to test humoral immune response at different time points.</p><p><strong>Results: </strong>The highest antibody titers were found in vaccinated groups compared to controls (p < 0.05), and the intramuscular route generated the best and most enduring response in systemic immunity. Mucosal pathways elicited not high but rather significant antibody responses and provided protection against clinical disease.</p><p><strong>Conclusion: </strong>The research contributes to the feasibility of ghost-based vaccination in the role of a sustainable alternative to the disease control measures that are highly reliant on antibiotics in endemic poultry production systems.</p>","PeriodicalId":14633,"journal":{"name":"Iranian Journal of Microbiology","volume":"18 4","pages":"574-583"},"PeriodicalIF":1.9,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13490892/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148792760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Antiviral activity of biogenic silver nanoparticles against HSV-1: integrating computational modeling and experimental validation.","authors":"Mahsa Soltani, Ameneh Elikaei, Parinaz Ghadam, Sona Ayadi Hassan","doi":"10.18502/ijm.v18i4.22201","DOIUrl":"https://doi.org/10.18502/ijm.v18i4.22201","url":null,"abstract":"<p><strong>Background and objectives: </strong>This study aimed to investigate the effects of biogenic silver nanoparticles (AgNPs) on Herpes simplex virus type 1 (HSV-1), focusing on the influence of plant-derived capping agents and their metal cores on antiviral efficacy and mechanism of action.</p><p><strong>Materials and methods: </strong>Biosynthesized AgNPs using aqueous extracts of <i>Juglans regia</i> (<i>J. regia</i>) and <i>Malva sylvestris</i> (<i>M. sylvestris</i>) were characterized, and their zeta potential was assessed. Molecular docking studies were performed to illuminate the interaction between AgNPs and viral particles. The antiviral activity was evaluated using viral titer quantification and a cytotoxicity assay, both performed on Vero cells.</p><p><strong>Results: </strong>AgNPs exhibited zeta potentials of -8.87 mV and -5.49 mV for <i>J. regia</i> and <i>M. sylvestris</i>, respectively, indicating their stability and potential for interaction with viral particles. Strong binding affinities between AgNPs and viral glycoprotein D (gD) were revealed by molecular docking, which obtained negative MolDock scores. The antiviral assays demonstrated a ten-thousand-fold reduction in viral titers.</p><p><strong>Conclusion: </strong>This research underscores the critical roles of capping agents and the metallic core in modulating the antiviral efficacy of plant-derived AgNPs against <i>HSV-1</i>, establishing them as a promising platform for novel antiviral therapeutics.</p>","PeriodicalId":14633,"journal":{"name":"Iranian Journal of Microbiology","volume":"18 4","pages":"584-594"},"PeriodicalIF":1.9,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13490894/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148793136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mutation analysis of dihydrofolate reductase (<i>dfr</i>) and dihydropteroate synthase (<i>sul</i>) genes in trimethoprim-sulfamethoxazole-resistant <i>Escherichia coli</i> from urinary tract infections.","authors":"Conny Riana Tjampakasari, Fithriyah Sjatha, Andi Yasmon, Agus Syahrurachman, Nadia Guntari","doi":"10.18502/ijm.v18i4.22197","DOIUrl":"https://doi.org/10.18502/ijm.v18i4.22197","url":null,"abstract":"<p><strong>Background and objectives: </strong><i>Escherichia coli</i> is the leading cause of urinary tract infections (UTIs) and has shown increasing resistance to trimethoprim-sulfamethoxazole (TMP-SMX). Resistance to TMP-SMX is commonly associated with the acquisition of resistance genes such as <i>dfr</i> and <i>sul</i>, often mediated by horizontal gene transfer. This study aimed to characterize the presence of <i>dfr</i> (<i>dfr</i>A1, <i>dfr</i>A5, <i>dfr</i>A7/17) and <i>sul</i> (<i>sul</i>1 and <i>sul</i>2) genes and to describe sequence variations in selected <i>E. coli</i> isolates.</p><p><strong>Materials and methods: </strong>Urine culture samples were obtained from 678 patients suspected of having UTIs, and 21 samples yielded positive culture results. This study further analyzed 11 <i>E. coli</i> isolates, consisting of eight TMP-SMX-resistant isolates, two susceptible isolates, and one <i>E. coli</i> ATCC 25922 strain as a control. The clinical isolates were provided by the Clinical Microbiology Laboratory, Faculty of Medicine, Universitas Indonesia. PCR amplification and agarose gel electrophoresis were used to identify <i>dfr</i> and <i>sul</i> genes, followed by Sanger sequencing of selected amplicons. Sequence data were analyzed with BioEdit software and aligned against reference sequences from NCBI.</p><p><strong>Results: </strong>The distribution of resistance genes varies among resistant isolates. Some isolates carry the <i>dfr</i>A5 gene, while <i>dfr</i>A1 was detected in one isolate. The <i>sul</i>2 gene was present in a number of resistant isolates, while <i>sul</i>1 was identified but showed no differences from the reference sequence. Further sequence analysis revealed amino acid changes in the <i>dfr</i>A1, <i>dfr</i>A5, and <i>sul</i>2 genes, although these changes were not consistently found in all isolates.</p><p><strong>Conclusion: </strong>This study characterizes the distribution of <i>dfr</i> and <i>sul</i> genes and their sequence variations in a limited number of <i>E. coli</i> isolates. The results suggest that TMP-SMX-resistant isolates may contain diverse genetic determinants associated with resistance. Nevertheless, the limited isolate number restricts the broader interpretation of these findings. Larger-scale studies, supported by functional analyses, are required to determine the contribution of these genes and their sequence variations to antibiotic resistance.</p>","PeriodicalId":14633,"journal":{"name":"Iranian Journal of Microbiology","volume":"18 4","pages":"544-552"},"PeriodicalIF":1.9,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13490903/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148792986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}