Agar Dilution Method Research Articles

Nourseothricin as a novel therapeutic agent against Neisseria gonorrhoeae: in vitro and in vivo evaluations using Galleria mellonella-a pilot study.

Neisseria gonorrhoeae has developed resistance to multiple antibiotics, making the search for novel antimicrobial agents essential. This pilot study evaluates the in vitro and in vivo efficacy of nourseothricin, a streptothricin family antibiotic mixture primarily composed of streptothricin F, against N. gonorrhoeae, a previously unexplored therapeutic option. The minimum inhibitory concentrations (MICs) of nourseothricin were determined using the agar dilution method on a panel of N. gonorrhoeae strains, including multidrug-resistant isolates. The in vivo efficacy was assessed using the Galleria mellonella infection model, where larvae were infected with N. gonorrhoeae and treated with varying concentrations of nourseothricin. Survival rates were compared to those of ceftriaxone-treated and untreated control groups. Nourseothricin inhibited the growth of all tested N. gonorrhoeae strains, with MIC values ranging from 16 to 32 µg/mL, independent of resistance to ceftriaxone, ciprofloxacin, or azithromycin. In vivo, treatment with nourseothricin significantly improved larval survival compared to the untreated control group (P < 0.01). The highest survival rate was observed with a 32 µg/mL dose, comparable to that of ceftriaxone-treated groups. Nourseothricin exhibited in vitro activity against N. gonorrhoeae, including multidrug-resistant strains. The in vivo results, obtained in a Galleria mellonella larval model, suggest that nourseothricin may warrant further investigation as a candidate compound for the treatment of gonorrhea, although its clinical potential remains to be evaluated in mammalian systems.IMPORTANCEThe emergence of multidrug-resistant Neisseria gonorrhoeae has made the development of new treatments a critical priority. This study is the first to evaluate the in vivo efficacy of nourseothricin against N. gonorrhoeae, demonstrating its activity even against resistant strains. In addition to its in vitro efficacy, treatment with nourseothricin improved survival in an in vivo infection model, suggesting its potential as a therapeutic option. Given the increasing limitations of existing antibiotics, these findings support further investigation into nourseothricin as a candidate for future gonorrhea treatment.

Association of capsular types with antibiotic resistance and clinical prognosis in Acinetobacter baumannii

Objective: Analysis of antimicrobial resistance and clinical outcomes in patients infected with different KL types of Acinetobacter baumannii. Methods: This is a cross-sectional study. From 2011 to 2021, 675 non-repetitive A. baumannii strains were isolated from patients with bloodstream infection (BSI, 234 cases), hospital acquired pneumonia (HAP, 423 cases), intra-abdominal infection (IAI, 17 cases) and urinary tract infection (UTI, 1 case) in 10 hospitals across 8 provinces of China. KL types and resistance genes were identified using bioinformatics methods. The minimum inhibitory concentrations of different antibiotics against 675 A.baumannii strains were determined by agar or microbroth dilution method. Ten strains were randomly selected from each KL type using simple random sampling for whole blood survival experiments. Differences in hospitalization duration and clinical outcomes were analyzed among patients infected with different KL types. Results: The 675 patients were aged (59±20) years, including 460 males. The predominant KL types included KL2 (22.0%, 149 strains), KL3 (17.5%, 118 strains), KL210 (7.0%, 47 strains) and KL160 (7.0%, 47 strains), while non-predominant KL types accounted for 314 strains (46.5%). The four predominant KL types showed higher overall resistance rates to most antibiotics compared with non-predominant KL types (all P<0.05). KL2 (92.6%, 113 strains) showed higher resistance to sulfamethoxazole-trimethoprim than KL3 (55.9%, 66 strains) (P<0.05). KL2 (87.2%, 130 strains) and KL210 (91.5%, 43 strains) showed higher resistance to minocycline than KL3 (67.8%, 80 strains) and KL160 (66.0%, 31 strains) (all P<0.05). KL2 exhibited stronger whole blood survival capacity [(58.36±20.33)%] than other KL types (all P<0.05). The fatality rate of KL2-infected patients was 30.9% (46 cases), higher than that of patients infected with KL3 (11.9%, 14 cases) and KL210 (6.4%, 3 cases) (all P<0.05). The hospitalization duration [M(Q1,Q3)] of KL2-infected patients was 46.00 (26.50, 74.00) days, longer than that of patients infected with KL3 [30.00 (15.25, 40.75) days], KL210 [27.00 (21.00, 44.00) days], KL160 [27.00 (20.00, 34.00) days] and non-predominant KL types [25.00 (12.00, 40.00) days] (all P<0.05). Conclusions: Different KL types of A.baumannii show variations in antimicrobial resistance and clinical outcomes of infected patients. KL2 demonstrates higher resistance rates and is associated with poorer clinical prognosis.

Medicinal Plants Antifungal Agents against Pathogenic Dermatophytes and Phenol Content Measurement

Introduction: Dermatophytes are a class of fungi that invade keratinized tissues in humans and other animals, including hair, skin, and nails, causing dermatophytoses. The high cost of therapy, side effects of drugs, and occasionally microbial resistance to synthetic drugs are some of the issues that have prompted efforts to find new medicines. This research aimed to study the antifungal properties of ethanolic and methanolic extracts of Rumex acetosella, Teucrium polium, and Glycyrrhiza glabra plants against Microsporum canis, Microsporum gypseum, and Trichophyton mentagrophytes and to ascertain the phenol content of these plants. Methods: Following the collection and identification of R. acetosella, T. polium, and G. glabra for this descriptive comparative study, they were washed and dried in the shade. Next, the Soxhlet apparatus was used to obtain methanolic and ethanolic extracts from these plants. The antifungal activity of these extracts was examined in vitro against M. canis, M. gypseum, and T. mentagrophytes using the diffusion and agar dilution method according to CLSI guidelines. The Minimum Inhibitory Concentration [MIC] and the Minimum Fungicidal Concentration [MFC] of the extracts were also determined compared to griseofulvin. Additionally, the phenol content of these extracts was measured by an optical spectrophotometer. Results: The methanolic extract of T. polium at 200 mg/ml led to the maximum inhibition zones of T. mentagrophytes PTCC 5054, M. canis PTCC 5069, and M. gypseum PTCC 5070 that were 23.41, 23.45, and 25.30 mm, respectively. The highest growth rates of T. mentagrophytes, M. canis, and M. gypseum in agar dilution method were found in 2.5 mg/ml of G. glabra ethanolic extract at 19.07, 18.32, and 17.81 mm, respectively. The smallest growth of T. mentagrophytes, M. canis, and M. gypseum were observed in the plate containing 40 mg/ml of the methanolic extract of T. polium, with 5.62, 3.72, and 5.41 mm diameters, respectively. MIC was less than 6.25 mg/ml for methanolic extract of T. polium. The tannic acid in the ethanolic and methanolic extracts of T. polium, R. acetosella, and G. glabra were 227.33 and 482.89 μg/ml, 94 and 475.48 μg/ml, and 27.33 and 60.67 μg/ml, respectively. Conclusion: The results revealed that methanolic extracts of the plants under study, particularly T. polium, had a stronger inhibitory impact than ethanolic extracts. Following rigorous toxicity testing and in vivo research, methanolic extracts of these plants may prove to be effective options as adjuvants or alternatives to chemical drugs.

Prevalence and antimicrobial susceptibility of Salmonella enterica Typhi in febrile patients: a cross-sectional study.

Typhoid fever, caused by Salmonella Typhi, is a serious health problem, especially in developing countries like Pakistan where antibiotics are usually prescribed without susceptibility testing or epidemiological surveillance. Consequently, antibiotic-resistant typhoid bacteria appear, but are not reported to the authorities. There is limited research on the prevalence and antibiotic susceptibility patterns of S. Typhi among febrile patients in Swabi, Pakistan. This study aimed to address this gap at the Bacha Khan Medical Complex in Swabi. Laboratory records of hospitalized patients who received a blood culture from September 2022 to August 2023 were reviewed in this retrospective, cross-sectional study. Every isolate of S. Typhi underwent antibiotic susceptibility test using modified Kirby-Bauer disk diffusion and agar-dilution methods to measure the isolates' minimum inhibitory concentration (MIC) for ciprofloxacin and azithromycin. The data were analyzed using SPSS version 24.0. 4.85% of febrile patients were positive for S. Typhi, with a higher prevalence in the 0-14 years age group. Male gender and seasonal variation were significant factors. The isolates were resistant to ampicillin, amoxicillin, cefotaxime, and ciprofloxacin; and sensitive to azithromycin, and carbapenems. The MICs for ciprofloxacin were between 0.06 to 16 µg/mL. Among the isolates, 1.094% were sensitive and 98.90% were resistant to ciprofloxacin; and 100% isolates were susceptible to azithromycin. Azithromycin and carbapenem were a suitable empirical therapy choice. However, the isolates were highly resistant to conventional first-line antibiotics (ampicillin, amoxicillin), second generation fluoroquinolones (ciprofloxacin), and third-generation cephalosporins (ceftriaxone, cefotaxime), that are considered vital in typhoid treatment.

Antibacterial activity of Piper betle L. (Piperaceae) and its products

Introduction: Piper betle L. is a common species in many countries and is used in the production of natural products mainly for its antibacterial activity. Objective: To investigate the antibacterial ability of 96%, 70%, 50% ethanol extracts, essential oils, and products from P. betle. Research methods: agar disc diffusion and dilution methods to determine MIC (minimum inhibitory concentration). Results: The extracts and essential oils of P. betle have good effects on 2 strains of bacteria E.coli and S.aureus, in which the extract with the best MIC is 96% ethanol extract (0.312 mg/mL and 0.078 mg/mL for E. coli and S. aureus, respectively). The MICs of essential oils were 0.5% and 0.0312% for E. coli and S. aureus, respectively, while products from P. betle were only active against S. aureus but had no effect on E.coli strains. Conclusion: Extracts, essential oils, and preparations from P.betle have antibacterial activity against two strains of bacteria, E.coli and S.aureus. Research should be directed to other strains of bacteria for more comprehensive evaluation.

Heavy Metal Detection and Antibiotic Resistance in Bacteria Isolated from Water Hyacinth Compost

Identified bacteria isolates were subjected to antibiotics sensitivity test using the Kirby Bauer disc Bacterial isolates exhibit synergistic resistance to heavy metals and antibiotics through comparable mechanisms. Antibiotic resistance genes in the environment may be amplified by this synergy and then transmitted to clinical settings. Assessing antibiotic resistance and heavy metals in bacteria isolated from water hyacinth compost was the goal of this investigation. sample taken from new Calabar River, Nigeria. Using established techniques, the microbiological analysis, physicochemical analysis, antibiotic sensitivity test, and total heterotrophic bacteria count (THBC) were all performed. diffusion method, and the resulting multidrug resistant (MDR) isolates were tested for heavy metal tolerance using the agar dilution method with increasing doses of the heavy metals under study (50, 100, 150, 200, and 250 μg/ml). 2.31± 0.43 x108 was the THBC. Seven isolates were tested for antibiotic sensitivity. Among them, WHC 1 (Bacillus sp), WHC 2 (Vibrio sp), WHC 3 (E. coli), WHC 6 (Pseudomonas sp), WHC 7 (Bacillus sp), WHC 9 (Aeromonas sp), and WHC 10 (Staphylococcus sp) were 100% resistant to numerous treatments. WHC 3 and WHC had the lowest level of antibiotic resistance (r=3), but WHC 6 and WHC 9 had the highest level (r=6). With the exception of cadmium and lead, all test isolates were 100% susceptible to chromium, vanadium, and cobalt at 250 μg/ml. At the lowest dose (50 μg/ml), all MDR isolates were able to withstand all heavy metals. The control isolate was sensitive to all concentrations of heavy metals but only resistant to cobalt and chromium at 50 μg/ml. According to this finding, bacteria that were separated from water hyacinth compost are resistant to both heavy metals and antibiotics.

Synthesis of Phenoxy Substituted Imidazo[1,2-b]Pyridazine-Based Amide Derivatives for Antibacterial and Anti-Tubercular Activities.

A series of 10 phenoxy-substituted imidazo[1,2-b]pyridazine amide derivatives were synthesized from 6-chloro-2-methyl-8-phenoxyimidazo[1,2-b]pyridazine-3-carboxylic acid and respective amines. All these 10 compounds were characterized using spectroscopic analysis (1H, 13C, HPLC, and ESI). Furthermore, the molecular structure obtained with spectroscopic analysis was confirmed by single-crystal x-ray diffraction (SXRD) analysis with a compound 12. All the 10 newly synthesized compounds were screened for in vitro antibacterial activities with the agar dilution method against two Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and two Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). Compounds 11 and 13 both showed MIC values, 6.25µg/mL, and comparable antibacterial activity to the positive control with the reference drug. Similarly, Mycobacterium tuberculosis H37Rv using the Microplate Alamar Blue Assay (MABA) and compounds 9 and 12 displayed moderate tubercular activities at a concentration of 25µg/mL. The molecular docking studies correlated with biological activity against the active sites of PDB ID: 5JZX.

Neisseria gonorrhoeae antimicrobial susceptibility testing: application of traditional agar dilution to a high-throughput 96-well microtiter assay.

The global rise in Neisseria gonorrhoeae infections and increasing antimicrobial resistance underscores the urgent need for accessible and efficient antimicrobial susceptibility testing methods. While accurate, the gold standard agar dilution method is labor-intensive and resource-demanding, limiting its practicality for research. To address this, we developed and validated a high-throughput 96-well microtiter assay as a viable alternative for measuring minimum inhibitory concentrations (MIC). In addition, we assessed the use of the simple-defined Kellogg's supplement compared to the CLSI-recommended complex-defined growth supplement. Using 17 standard laboratory strains with different resistance profiles, we evaluated the assay against azithromycin, ceftriaxone, ciprofloxacin, and gentamicin. Both 96-well microtiter assays demonstrated no major errors for any antimicrobial, with some minor errors with azithromycin and consistent minor errors with gentamicin. Essential agreement (EA) and categorical agreement (CA) ranged from 33% to 100%, with gentamicin contributing the most variability across methods. This study establishes the 96-well microtiter assay with Kellogg's supplement as a reliable and scalable tool for N. gonorrhoeae antimicrobial susceptibility testing, reducing the time and resources required for resistance profiling.IMPORTANCEThe rapid emergence of antimicrobial resistance in Neisseria gonorrhoeae presents a critical challenge for global public health. Accurate and accessible methods for assessing antimicrobial susceptibility are essential for monitoring resistance trends and guiding effective treatment strategies. However, traditional methods, such as agar dilution, are labor-intensive and resource-intensive, limiting their widespread application in research. Our study introduces a 96-well microtiter assay that simplifies and scales up susceptibility testing while maintaining the accuracy of the gold standard. By validating the use of the simpler alternative, Kellogg's supplement, we further lower the barriers to adoption in research settings. This innovation supports timely and efficient antimicrobial resistance surveillance and enhances the capacity for high-throughput testing of novel therapeutic compounds. By increasing the feasibility of susceptibility testing, this method can potentially improve response strategies against drug-resistant gonorrhea and other fastidious pathogens.

Fosfomycin resistance determinants in Escherichia coli isolates of human and animal origin from Iran.

Fosfomycin has regained clinical interest over the last years due to its superior activity against multidrug-resistant bacterial pathogens. In the current study we aimed to characterize genotypic and phenotypic features of fosfomycin resistant (FosR) Escherichia coli isolates originating from human and animal. Five FosR bacteria were selected from a population of 150 E. coli isolates of human and broiler chickens. The sequence types of isolates were determined by multi-locus sequencing typing. Fosfomycin MICs were determined by agar dilution and gradient diffusion methods. Molecular detection of plasmid encoded fosfomycin resistance genes, fosA, fosA3, fosA4, fosA5 and fosC2 was performed by PCR. The modifications of fosfomycin target (MurA), transporters (GlpT, UhpT), and transporter regulator (PtsI) were investigated by gene sequencing. The MICs of fosfomycin were found to be ≥ 128mg/L according to agar dilution and > 1024mg/L according to gradient diffusion method. FosR isolates belonged to sequence types ST10 (n = 2), ST361, ST209 and ST1158 (n = 1). While all FosR isolates carried fos genes (fosA3 (n = 2), fosA5 (n = 2) and fosA4(n = 1)), only three isolates revealed amino acid substations in MurA, PtsI and GlpT with MurA P99S change being predicted to have deleterious impact on the function of protein. Emergence of fosfomycin resistance among studied isolates was mainly attributed to plasmid genes coding for fosfomycin modifying enzymes. The similarity in fosfomycin resistance determinants among clonally diverse E. coli isolates of human and animals indicates a possible cross-sectoral dissemination of fos genes by epidemic plasmids between bacterial isolates of clinical settings and those from animals.

Evolving Landscape of Paediatric Pneumococcal Meningitis in Argentina (2013–2023)

The introduction of pneumococcal conjugate vaccination (PCV) into the Argentinian Childhood National Immunization Program in 2012 marked a significant milestone in public health. Our study aims to assess the impact of this intervention on pneumococcal meningitis cases, serotype distribution, and antimicrobial resistance among pediatric populations from 2013 to 2023. Specifically, we compared the early post-PCV period (2013–2014) to the late post-PCV period (2022–2023). A total of 333 pneumococcal isolates were analyzed between 2013 and 2023. Gold standard pneumococcal serotyping was performed to identify the serotypes associated with infection in children < 6 years in Argentina, and the agar dilution method was carried out to determine their profiles to antimicrobial agents. Our findings underscore the importance of PCV implementation, revealing notable shifts in pneumococcal epidemiology over the study period. The proportions of serotypes 1 (6.7% to 0.0%), 5 (5.6% to 0.0%), and 14 (7.8% to 1.8%) decreased, whereas the proportions of serotypes 10A (3.3% to 10.7%), 15B/C (2.2% to 10.7%), and 24B (0.0% to 8.9%) increased. The top five rated serotypes in the 2022–2023 period were serogroup 24 (21.4%), 10A (10.7%), 15B/C (10.7%), 23B (7.1%), and 12F (5.4%). Regarding antimicrobial resistance, we found that a total of 115/311 isolates (37%) were not suceptible to penicillin, and 2.9% were not suceptible to cefotaxime. Twenty-five percent of the isolates were microbial drug resistant, with resistance to penicillin, erythromycin, tetracycline/doxicycline, and/or cotrimoxazol. Among the PCV13 serotypes, 19A remained the most commonly associated with MDR. The non-PCV13 serotypes, particularly 24F, 24A, and 24B, were prevalent among MDR isolates. The observed trends demonstrate the need for the continued expansion of pneumococcal vaccination policies, including consideration for vaccines offering enhanced indirect protection, thereby extending benefits beyond the pediatric population to encompass adults as well. Such strategies are pivotal in reducing the burden of pneumococcal disease and safeguarding public health.

대구-경북지역의 헬리코박터 파일로리 항균제 내성률 현황

Recent trends have shown reduced success rates of the standard triple therapy, underscoring the need for updated data on the antimicrobial resistance of Helicobacter pylori. This study aimed to assess the antibiotic resistance rates of H. pylori strains in the Daegu-Kyungpook region and compare them with other regions in South Korea to provide evidence for eradication therapy guidelines. Between September 2022 and February 2024, samples from 100 patients aged 20-80 years with suspected H. pylori infections were collected across five medical institutions in the Daegu-Kyungpook region. The cultured strains were subjected to antimicrobial susceptibility testing. The minimum inhibitory concentrations for antibiotics were established using agar dilution methods, with breakpoints set at >0.125 μg/mL for amoxicillin, >0.25 μg/mL for clarithromycin, >1 μg/mL for tetracycline, >1 μg/mL for levofloxacin, and >8 μg/mL for metronidazole. Among the 100 samples collected, cultures were performed for 98 samples, excluding 2 that tested negative in the rapid urease test or polymerase chain reaction. Of these, 73 (74%) samples were successfully cultured, while 25 (26%) failed. Among the 73 successful cultures, resistance was observed in 20 (27%) samples for amoxicillin, 25 (34%) for clarithromycin, 34 (47%) for metronidazole, 19 (26%) for tetracycline, and 27 (37%) for levofloxacin. This study showed an overall increasing trend in antibiotic resistance rates, particularly in clarithromycin resistance, emphasizing the need to reconsider first-line triple therapy. This study is the first multicenter investigation of H. pylori antibiotic resistance in the Daegu-Kyungpook region, contributing valuable insights for developing region-specific treatment guidelines.

Comparison Of The Antibacterial Activity Of Palm Kernel Oil (PKO) &amp; Virgin Coconut Oil (VCO) Against Pseudomonas Aeruginosa Bacteria

Pseudomonas aeruginosa, a gram-negative bacterium, is a significant cause of nosocomial infections and exhibits high levels of multidrug resistance, necessitating the exploration of alternative antibacterial agents. This study investigates the antibacterial activity of Palm Kernel Oil (PKO) and Virgin Coconut Oil (VCO) against Pseudomonas aeruginosa, employing a true experimental post-test design with microdilution and agar dilution methods. Conducted at the Universitas Muslim Indonesia, the study determined the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of PKO, VCO, and gentamicin. Results revealed that PKO had an MIC of 4096 µg/mL and an MBC of 8192 µg/mL, while VCO exhibited an MIC of 2048 µg/mL and an MBC of 4096 µg/mL. Gentamicin, used as a control, demonstrated superior antibacterial effectiveness with an MIC of 2 µg/mL and an MBC of 4 µg/mL. Statistical analysis indicated that VCO, with its higher lauric and myristic acid content, was more effective than PKO in inhibiting bacterial growth, although both oils were less effective than gentamicin. The study highlights the potential of VCO as a natural antibacterial agent, suggesting further research to optimize its efficacy through formulation modifications and combinations with other antimicrobial agents. Additionally, evaluating the effectiveness of VCO and gentamicin against other bacterial strains is recommended to expand the understanding of VCO's antibacterial capabilities. These findings contribute to the growing body of evidence supporting the use of natural products in combating antibiotic-resistant infections.

Presencia de Enterococcus spp. resistentes a metales pesados y antimicrobianos en aves silvestres y de corral de la provincia de Chubut, Argentina

[Introduction]: In Latin America, poor management of industrial effluents and the massive use of antibiotics in medicine and livestock farming are problems that affect human and animal health. Wild and poultry birds can act as a natural reservoir of enterococci resistant to chemicals released into the environment, contributing to their spread. [Objective]: To evaluate resistance to antimicrobials and heavy metals in enterococci isolated from wild and farmed birds in the Valle Inferior del Río Chubut region, Peninsula Valdés, Patagonia, Argentina. [Methodology]: The bacteria were isolated from 250 fresh stool samples collected from March 2019 to February 2020 and then identified by phenotypic and genotypic techniques. Resistance to heavy metals and antimicrobials was determined by the agar dilution method. [Results]: Among the 163 isolates, no resistance against cadmium and mercury was observed, while resistance was detected against nickel, copper, and zinc (99 %), chromium (98 %), and lead (95.7 %). Vancomycin and gentamicin were the most effective antimicrobials compared to the rest; only 2 strains exhibited resistance in both cases. The most frequent resistance was to ampicillin (96.9 %), followed by streptomycin (49.1 %) and tetracycline (21.5 %). [Conclusions]: Our data suggest that the presence of Enterococcus resistant to antimicrobials and heavy metals in poultry and wild birds in urban areas can become a reservoir, contributing to its spread and consequently affecting public health.

Application of Silver Nanoparticles and Fungicides for &lt;i&gt;in vitro&lt;/i&gt; Suppression of &lt;i&gt;Pestalotiopsis psidii&lt;/i&gt;, a Pathogen Associated with Guava Stem Cracking

Guava (Psidium guajava L) is a widely cultivated fruit plant in tropical and subtropical countries, including Pakistan, where it is attacked by numerous pathogenic fungi. Guava stem cracking is caused by a destructive disease that significantly affects the stem and other parts of the plant. This study was conducted to isolate the causative pathogen of stem cracking and its management with chemicals and silver nanoparticles (AgNPs). Samples were obtained from seven different locations of Punjab, Pakistan, and the pathogen was isolated and purified on PDA using the hyphal tip technique. After the confirmation of pathogenicity, spore suspension was plated in a 96-well plate for chemical evaluation and a 9-day-old culture was used to find the AgNPs effect by the agar dilution method. Antifungal activity was measured in terms of optical density (OD) for chemicals and percent growth inhibition (PGI) for AgNPs. Four fungicides (Mancozeb, Iprodione, Chlorothalonil and Deconil) were evaluated at 7 different concentrations (50mg/ml, 25 mg/ml, 12.5 mg/ml, 6.25 mg/ml, 3.12 mg/ml, 1.56 mg/ml and 0.78 mg/ml) against P. psidii and the maximum antifungal effect was seen at the concentration of 50mg/ml. In vitro evaluation of fungicides showed Iprodione maximum spore growth inhibition against P. psidii. Silver nanoparticles were used to analyze their antifungal potential at different concentrations (1 ppm, 10 ppm, 100 ppm), whereas the maximum inhibition zone was seen at 100 ppm of AgNPs. Data was statistically analyzed by using factorial design under Complete Randomized Design (CRD). The outcomes of the present study revealed that using chemicals and silver nanoparticles can help to manage guava stem canker.

Comparison of microbroth dilution and e-test methods for detecting Fosfomycin susceptibility in pseudomonas aeruginosa.

Comparison of microbroth dilution and e-test methods for detecting Fosfomycin susceptibility in pseudomonas aeruginosa.

An examination of the antioxidant and antibacterial capabilities, as well as the phenolic compounds, of Silene macrodonta and Silene chaetodonta

In this study, Silene macrodonta Boiss. and S. chaetodonta Boiss. plant species belonging to the Caryophyllaceae family growing in the Gaziantep region were examined in terms of antioxidant, antimicrobial and phenolic compounds. Total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI) values of S. macrodonta and S. chaetodonta Boiss. plant species were determined using Rel Assay kits. It was determined that the TAS value of S. macrodonta was higher with 5.983±0.156, the TOS value of S. chaetodonta was higher with 15.686±0.188, and the OSI value of S. chaetodonta was higher with 0.341±0.010. Within the scope of this study, the antimicrobial activity of plant species was examined by the Agar dilution method, and it was determined that S. chaetodonta showed higher antimicrobial activity than S. macrodonta. Phenolic contents of plants were examined using LC-MS/MS device. For some of the standards used, the presence of phenolic compounds in the plant was detected. As a result of the studies, it was determined that S. macrodonta and S. chaetodonta plants have high biological activity.

Fungistatic and Bactericidal Activity of Hydroalcoholic Extracts of Root of Jatropha dioica Sessé.

Jatropha dioica Sessé (JD) is a plant from arid and semiarid zones of Mexico related to local therapeutic uses and possible use in food and agriculture as a control agent of pest organisms that helps to reduce impacts on the environment, human health and resistance by phytopathogens. In vitro bactericidal activity was evaluated with the well diffusion method in doses of 1000, 2500, 5000, 7500, 10,000 and 20,000 µg mL-1, and fungistatic activity was evaluated with the agar dilution method (500, 1000, 1500, 2000 and 4000 µg mL-1) in Pseudomonas syringae, Botrytis cinerea and Fusarium oxysporum using hydroalcoholic extracts of J. dioica root in a completely randomized design with five replications. Total phenol and flavonoid contents were recorded by the Folin-Ciocalteu and aluminum chloride methods. Ethanol and methanol extracts showed fungistatic activity on B. cinerea, inhibiting from 42.27 ± 1.09 to 46.68 ± 0.98 mg mL-1, with an IC50 of 5.04 mg mL-1, with no differences by solvent type. In F. oxysporum, inhibition ranged from 14.77 ± 1.08 to 29.19 ± 0.89 mg mL-1, and the methanol extract was more efficient, generating a stress response to the ethanol extract. The bactericidal activity on P. syringae recorded inhibition zones of 17.66 ± 0.33 and 16.66 ± 0.33 mg mL-1, with ethanol being more efficient. The phenol content ranged from 8.92 ± 0.25 to 12.10 ± 0.34 mg EAG g-1 and flavonoid content ranged from 20.49 ± 0.33 to 28.21 ± 0.73 mg QE g-1 of sample dry weight. The results highlight the biological activity of J. dioica as an alternative to biopesticides that minimize agrochemical applications and generate pathogen resistance. These advances contribute to the revaluation and conservation of the species.

Prevalence of azithromycin resistance after the COVID-19 era in clinical bacterial isolates from a tertiary care hospital in Gurugram, India.

The increasing prevalence of antibiotic resistance in pathogenic bacteria poses a great healthcare problem worldwide. Azithromycin (AZM) is a very effective macrolide antibiotic to treat many bacterial infections, but increasing azithromycin resistance in clinical bacteria decreases the effectiveness of this vital antibiotic, which is a major concern. The primary aim of the present study was to investigate the prevalence of azithromycin resistance and the occurrence of mphA gene in bacteria isolated from various clinical samples in Gurugram, India. For this, 138 pure bacterial isolates were obtained from the Department of Microbiology, Faculty of Medicine and Health Sciences, SGT Medical College, Hospital & Research Institute, Gurugram, India, from February to June 2024. All the isolates were identified by VITEK 2 system, and E. coli (22.5%) was found to be the most common pathogen in urine samples. Screening for azithromycin resistance by agar dilution and minimum inhibitory concentration (MIC) method found 30 azithromycin-resistant bacterial isolates. The present study found the prevalence of azithromycin resistance in pathogenic bacteria from clinical samples is 22%, indicating an increase in prevalence after the COVID-19 era, which is a major concern. Antibiotic profiling data revealed that 100% of the azithromycin-resistant isolates were multidrug-resistant, which is a serious issue. Furthermore, plasmid-mediated mphA gene was successfully amplified by the PCR method from 11 bacterial isolates, which may be responsible for azithromycin resistance. Our findings indicate the rapid emergence of azithromycin resistance in pathogenic bacteria, highlighting the urgency of stringent surveillance and control measures.

In-vitro Activities of Zoliflodacin and Solithromycin Against Neisseria gonorrhoeae Isolates from Korea.

Novel antimicrobial agents are continually developed to address the global threat of multidrug-resistant Neisseria gonorrhoeae. Promising candidates include zoliflodacin and, possibly, solithromycin. We evaluated their in-vitro activities against gonococcal isolates collected in Korea. In total, 250 N. gonorrhoeae isolates obtained across Korea between 2016 and 2018 were used to determine the minimum inhibitory concentrations (MICs) of 10 therapeutic agents using the CLSI agar dilution method. Most isolates (94.8%, 237/250) demonstrated non-susceptibility to penicillin G, tetracycline, and ciprofloxacin, and susceptibility to ceftriaxone and spectinomycin was substantially high. The half-maximal IC (MIC50) and 90% IC (MIC90) values for zoliflodacin were 0.03 and 0.06 μg/mL, respectively; 0.06 and 0.12 μg/mL, respectively, for solithromycin; and 0.03 and 0.12 μg/mL, respectively, for ceftriaxone. Notably, no cross-resistance was observed between zoliflodacin and ciprofloxacin, despite both targeting DNA topoisomerase II enzymes. Zoliflodacin and solithromycin demonstrated significant in-vitro activity against multidrug-resistant N. gonorrhoeae isolates, and zoliflodacin has shown non-inferiority to ceftriaxone/azithromycin dual therapy in a clinical phase 3 trial. Collectively, our findings highlight the potential of zoliflodacin as a novel therapeutic agent for gonococcal infections, particularly in the context of rising multidrug resistance, and highlight the need for continued surveillance and development of alternative antimicrobial strategies.

In vitro antimicrobial activity of selected herbal extracts against Mycobacterium tuberculosis

Background: Tuberculosis (TB) is one of the deadliest infectious diseases worldwide, causing approximately two million deaths annually. Multidrug resistance presents a significant global challenge in TB treatment, necessitating prolonged medication use and extended treatment durations. There is an urgent need to discover alternative novel antimicrobial compounds. Herbal medicine offers promising prospects for drug discovery and development, warranting the screening of plant-derived compounds with favorable safety margins. Objectives: This study aimed to investigate the in vitro antimicrobial activity of extracts from five medicinal plants against Mycobacterium tuberculosis in vitro.Methods: Extracts from five herbs —Morinda citrifolia L, Nicotiana spp.L, Centella asiatica L, Allium sativum L, and Annona muricata L, —were investigated for their in vitro antimicrobial activity against M. tuberculosis using Lowenstein-Jensen medium. Antimicrobial activity was assessed by comparing bacterial colony growth on extract-containing media with that on extract-free control media. The agar dilution method was used to determine antimicrobial activity.Results: Among the tested extracts, Nicotiana spp L and Annona muricata L exhibited the strongest antimicrobial activity. These herbs contain various bioactive compounds, including alkaloids, flavonoids, and steroids, which are presumed to contribute to bacterial susceptibility. Conclusions: The findings suggest that Nicotiana spp. L. and Annona muricata L. may have therapeutic potential in TB treatment. These herbs could serve as alternative agents for combating TB and may help mitigate the adverse effects associated with standard anti-tuberculosis drugs.