Minimum Inhibitory Concentration Test Research Articles

Uji Kadar Hambat Minimum (KHM) dan Kadar Bunuh Minimum (KBM) ekstrak daun kirinyuh (Chromolaena odorata) dari geothermal Ie Seum Aceh Besar terhadap Staphylococcus aureus

Background: Chromolaena odorata plant is a weed that grows abundantly in various places, including geothermal areas. Its leaves contain chemical compounds such as alkaloids, flavonoids, steroids, and tannins that can function as antibacterials.Objectives: The study aims to determine the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of ethanol extract of Chromolaena odorata leaves grown in the geothermal area of Ie Seum Aceh Besar against Staphylococcus aureus.Methods: The study was conducted at the Fundamental Microbiology Laboratory of Aceh Besar in June 2022. The MIC and MBC tests of ethanol extract of Chromolaena odorata leaves from the geothermal area of Ie Seum Aceh Besar were performed using the liquid dilution method. The concentrations of the extract used were 1%, 3%, 5%, 7%, and 10%. The MIC was determined based on the turbidity or clarity of the test solution, while the MBC was determined by streaking each concentration of the extract/test solution on agar media. Data analysis was performed descriptively in terms of the lowest concentration of the extract that could inhibit and kill Staphylococcus aureus.Results: The results showed that the ethanol extract of Chromolaena odorata leaves from the geothermal area of Ie Seum Aceh Besar had a MIC value of 5% and an MBC value of 7% in inhibiting the growth of Staphylococcus aureus.Conclusion: Based on the study, it can be concluded that the ethanol extract of Chromolaena odorata leaves from the geothermal area of Ie Seum Aceh Besar is able to inhibit the growth of Staphylococcus aureus from a concentration of 5% and able to kill Staphylococcus aureus from a concentration of 7%.

Determination of potential combination of non-β-lactam, β-lactam, and β-lactamase inhibitors/β-lactam enhancer against class D oxacillinases producing Acinetobacter baumannii: Evidence from in-vitro, molecular docking and dynamics simulation.

Carbapenem-resistant Acinetobacter baumannii, a predominant nosocomial pathogen in hospitals of intensive care units, is associated with bacteremia and ventilator-associated pneumonia with a high-risk mortality rate. To increase the effectiveness of the β-lactam (BL) antibiotics, the use of β-lactamase inhibitors (BLI) acts as a booster when given in combination with BL antibiotics. To this aspect, we selected BL antibiotics of cefiderocol, cefepime, non-BL antibiotic eravacycline, BLI of durlobactam, avibactam, and a β-lactam enhancer (BLE) of zidebactam. To prove our hypothesis, we determined the minimum inhibitory concentration (MIC) of various BL or non-BL/BLI or BLE combinations using broth microdilution method followed by in silico analysis of molecular docking, molecular dynamics (MD) simulation, and molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) identifies the potential combination. In MIC testing, eravacycline, cefepime/zidebactam, cefiderocol/zidebactam, and eravacycline in combination with zidebactam or durlobactam were found to be effective against oxacillinases (OXAs) (OXA-23/24/58 like) expressing A. baumannii isolates. The docking results of the selected ligands toward OXA-23, OXA-24, and OXA-58 had an excellent binding score ranging from -5.8 to -9.3 kcal/mol. Further, the docked complexes were subjected and evaluated using gromacs for molecular dynamics simulation of 50 ns toward selected class D OXAs. The binding energies obtained from MM-PBSA shed light on the binding efficiencies of each non-BL, BL, and BLI/BLE, thereby helping us to propose the drug combinations. Based on the MD trajectories scoring acquired, we propose using eravacycline, cefepime/zidebactam, cefiderocol/zidebactam, and eravacycline in combination with durlobactam or zidebactam would be promising for treating OXA-23, OXA-24, and OXA-58 like expressing A. baumannii infections.

Evaluation of the antibacterial activity of cultivated Caucasian whortleberry (Vaccinium arctostaphylos L.) against fish pathogens

Abstract Bacterial diseases are one of the major factors hampering aquaculture sustainability. Antibiotics are used widely to treat or prevent infectious bacterial diseases in aquaculture. However, because of growing problems of antibiotic resistance caused by the imprudent use of antibiotics, sourcing environmentally benign alternatives, such as herbal/medicinal plants, is now the focus of many researchers. Hence, in this study, a minimum inhibitory concentration (MIC) test with broth microdilution was performed to determine the in vitro antibacterial activity of an aqueous methanolic extract of cultivated Caucasian whortleberry (Vaccinium arctostaphylos L.) against various fish pathogens, i.e., Yersinia ruckeri, Pseudomonas putida, P. luteola, Aeromonas salmonicida, A. hydrophila, and A. sobria. The results revealed that the MIC values of the aqueous methanolic extract against Y. ruckeri, P. putida, P. luteola, A. salmonicida, and A. hydrophila were 8.75 mg mL−1, while against A. sobria it was 2.19 mg mL−1. This study indicated that the medicinal plant V. arctostaphylos L. can potentially be used against all the fish pathogens tested thanks to its various important bioactive compounds. However, to assess the potential of this plant, further in vivo studies should be carried out.

P36 | Adapted minimal inhibitory concentration testing protocol as screening tool for gut health and related products

Journal of Veterinary Pharmacology and TherapeuticsVolume 46, Issue S1 p. 102-103 POSTER PRESENTATIONS P36 | Adapted minimal inhibitory concentration testing protocol as screening tool for gut health and related products First published: 11 June 2023 https://doi.org/10.1111/jvp.13315Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. Volume46, IssueS1Special Issue: 15th International Congress of the European Association for Veterinary Pharmacology and Toxicology held Bruges, Belgium, July 2–5, 2023June 2023Pages 102-103 RelatedInformation

Antibacterial Activity Test of Tembelekan Leaf Extract (Lantana camara linn) against Edwardsiella tarda bacteria

The purpose of this study was to analyze the optimal dose of Tembelekan leaf extract (Lantana camara Linn) which has antibacterial properties in inhibiting or killing Edwardsiella tarda bacteria. The method used in this research is Completely Randomized Design (CRD). The results of the research yield obtained from tembelakan leaf extract amounted to 8.9%. The positive phytochemical test results contained active compounds, namely flavonoids, alkaloids, tannins, triterpenoids, and saponins. GC MS analysis of tembelekan leaf extract showed that the most components were 4H-1-Benzopyran-4-one, 5,7-dihydroxy-6-methoxy-2-(4-methoxyphenyl)-,2,1,3-Benzothiadiazole, Benzisot hiadiazole , 3,4-Benzo-1,2,5-thia diazole. This compound is a class of isoflavonoids compounds. The MIC (Minimum Inhibitory Concentration) test results obtained the lowest absorbance value at a concentration of 100 mg/L with a value of 0.602 close to the positive control. Results of discs with doses of 50, 100, 150, 200, and 250 mg/L. The disc results showed that the dose of 200 mg/L had the strongest inhibition zone with a value of 12.63 mm. Tembelekan leaf extract which contains dominant compounds such as flavonoids and alkaloids can be useful as an antibacterial which inhibits the growth of E. tarda bacteria

Development of a high-throughput minimum inhibitory concentration (HT-MIC) testing workflow.

The roots of the minimum inhibitory concentration (MIC) determination go back to the early 1900s. Since then, the test has undergone modifications and advancements in an effort to increase its dependability and accuracy. Although biological investigations use an ever-increasing number of samples, complicated processes and human error sometimes result in poor data quality, which makes it challenging to replicate scientific conclusions. Automating manual steps using protocols decipherable by machine can ease procedural difficulties. Originally relying on manual pipetting and human vision to determine the results, modern broth dilution MIC testing procedures have incorporated microplate readers to enhance sample analysis. However, current MIC testing procedures are unable to simultaneously evaluate a large number of samples efficiently. Here, we have created a proof-of-concept workflow using the Opentrons OT-2 robot to enable high-throughput MIC testing. We have further optimized the analysis by incorporating Python programming for MIC assignment to streamline the automation. In this workflow, we performed MIC tests on four different strains, three replicates per strain, and analyzed a total of 1,152 wells. Comparing our workflow to a conventional plate MIC procedure, we find that the HT-MIC method is 800% faster while simultaneously boasting a 100% accuracy. Our high-throughput MIC workflow can be adapted in both academic and clinical settings since it is faster, more efficient, and as accurate than many conventional methods.

Silver resistance in Pseudomonas aeruginosa and Acinetobacter baumannii isolated from burn patients

Introduction: Burn infections are a serious obstacle to the patient’s recovery. Infection is estimated to account for 75% of burn patient mortality. Widespread and often indiscriminate administration of antibiotics and lack of basic infection control methods are major factors in the emergence of drug-resistant bacteria. Due to the growing and serious threat of antibiotic resistance, interest in silver compounds has grown in modern medicine. Objectives: The aim of this descriptive study was to evaluate the frequency of sil genes and its phenotypic expression in Pseudomonas aeruginosa and Acinetobacter baumannii isolates isolated from the burn ward of Imam Khomeini hospital in Urmia. Patients and Methods: P. aeruginosa (n=16) and A. baumannii (n=32) isolates were collected from burn wound samples in an 8-month period from August to March 2017 from the burn ward of the hospital. The minimum inhibitory concentration of silver nitrate on the clinical isolates was determined using microdilution method. The presence of silP, silE and silS silver resistance genes was investigated by polymerase chain reaction (PCR). Results: The results of minimum inhibitory concentration (MIC) test showed that 62.5% (n = 10) of P. aeruginosa isolates and 56.25% (n = 18) of A. baumannii isolates showed MIC above 512 mg/ml. Polymerase chain reaction results revealed that only one P. aeruginosa isolate had silE gene and among A. baumannii isolates, 20 isolates had silE gene and six isolates had silS gene. None of the isolates showed positive results for the silP gene. Conclusion: Based on the results, A. baumannii was the most common microorganism of burn wounds in the burn ward of our hospital in Urmia. This study showed a high degree of phenotypic resistance to silver in A. baumannii and P. aeruginosa isolates which silE and silS genes were also observed in some isolates.

Evaluation of the Synergistic Effect of LL-37 and Oncorhyncin II Recombinant Proteins on Staphylococcus aureus Under In Vitro Conditions

Background: The treatment of Staphylococcus aureus infections has become a public health crisis due to the extensive development of antimicrobial resistance. Antimicrobial peptides (AMPs) have been introduced as promising naturally-derived antimicrobial alternatives to antibiotics. LL-37 and oncorhyncin II are 2 AMPs with notable proven antibacterial effects. Objectives: This study aimed to produce recombinant LL-37 and oncorhyncin II and investigate their synergistic effects on S. aureus (ATCC25923). Methods: The synthetic genes of LL-37 and oncorhyncin II were individually ligated into the pET32a expression vector. Transformed pET32a was introduced into Escherichia coli BL21 as an expression host. The protein expression and purification steps were optimized, and the biological effectiveness of the peptides was evaluated by assessing the minimum inhibitory concentration (MIC), time-kill, and growth kinetic tests against S. aureus. Results: The MIC assay confirmed the effective antibacterial performances of LL-37 and oncorhyncin II against S. aureus at 30.6 and 47.93 µg/mL, respectively. The peptides’ synergistic activity was validated by the checkerboard method. A combination of LL-37 and oncorhyncin II at 2 × MIC showed a sharp decline of the viable cells with over 3-time reductions in log 10 colony-forming units (CFU)/mL within the first 5 hours. The growth kinetic results confirmed the high effectiveness of the peptides’ combination in eliminating the bacterial inoculum turbidity by 50% reduction during the first hour of exposure. Conclusions: The produced recombinant LL-37 and oncorhyncin II showed effective antimicrobial function against S. aureus. The synergistic performance of the peptides was repeatedly confirmed through checkerboard, time-kill, and growth kinetic assays.

In Vitro Activities of Ceftobiprole, Dalbavancin, Tedizolid and Comparators against Clinical Isolates of Methicillin-Resistant Staphylococcus aureus Associated with Skin and Soft Tissue Infections.

Skin and soft tissue infections (SSTIs) are associated with significant morbidity and healthcare costs, especially when caused by methicillin-resistant Staphylococcus aureus (MRSA). Vancomycin is a preferred antimicrobial therapy for the management of complicated SSTIs (cSSTIs) caused by MRSA, with linezolid and daptomycin regarded as alternative therapeutic options. Due to the increased rates of antimicrobial resistance in MRSA, several new antibiotics with activity against MRSA have been recently introduced in clinical practice, including ceftobiprole, dalbavancin, and tedizolid. We evaluated the in vitro activities of the aforementioned antibiotics against 124 clinical isolates of MRSA obtained from consecutive patients with SSTIs during the study period (2020-2022). Minimum inhibitory concentrations (MICs) for vancomycin, daptomycin, ceftobiprole, dalbavancin, linezolid and tedizolid were evaluated by the MIC Test Strip using Liofilchem strips. We found that when compared to the in vitro activity of vancomycin (MIC90 = 2 μg/mL), dalbavancin possessed the lowest MIC90 (MIC90 = 0.094 μg/mL), followed by tedizolid (MIC90 = 0.38 μg/mL), linezolid, ceftobiprole, and daptomycin (MIC90 = 1 μg/mL). Dalbavancin demonstrated significantly lower MIC50 and MIC90 values compared to vancomycin (0.064 vs. 1 and 0.094 vs. 2, respectively). Tedizolid exhibited an almost threefold greater level of in vitro activity than linezolid, and also had superior in vitro activity compared to ceftobiprole, daptomycin and vancomycin. Multidrug-resistant (MDR) phenotypes were detected among 71.8% of the isolates. In conclusion, ceftobiprole, dalbavancin and tedizolid exhibited potent activity against MRSA and are promising antimicrobials in the management of SSTIs caused by MRSA.

Predicting antimicrobial resistance of bacterial pathogens using time series analysis.

Antimicrobial resistance (AMR) is arguably one of the major health and economic challenges in our society. A key aspect of tackling AMR is rapid and accurate detection of the emergence and spread of AMR in food animal production, which requires routine AMR surveillance. However, AMR detection can be expensive and time-consuming considering the growth rate of the bacteria and the most commonly used analytical procedures, such as Minimum Inhibitory Concentration (MIC) testing. To mitigate this issue, we utilized machine learning to predict the future AMR burden of bacterial pathogens. We collected pathogen and antimicrobial data from >600 farms in the United States from 2010 to 2021 to generate AMR time series data. Our prediction focused on five bacterial pathogens (Escherichia coli, Streptococcus suis, Salmonella sp., Pasteurella multocida, and Bordetella bronchiseptica). We found that Seasonal Auto-Regressive Integrated Moving Average (SARIMA) outperformed five baselines, including Auto-Regressive Moving Average (ARMA) and Auto-Regressive Integrated Moving Average (ARIMA). We hope this study provides valuable tools to predict the AMR burden not only of the pathogens assessed in this study but also of other bacterial pathogens.

Phytochemical screening and antimicrobial activity of methanolic leaf extract of Securidaca longipedunculata Fresen (Polygalaceae)

The present occurrence of drug resistance by most microorganisms has posed an enormous problem in the health care and triggered the need for continuous research for better and safe therapeutic agents. Securidaca longipedunculata is locally used in treating skin infections. Thus this study was designed to investigate the phytochemical constituents and antimicrobial activities of methanol leaf extract of Securidaca longipedunculata against Streptococcus pyogenes, Staphylococcus aureus and Candida albicans which are known to cause skin infections. Antimicrobial activity against the organisms was determined using agar well diffusion method. Four concentrations of the leaf extract were prepared and used in the study (800 mg/ml, 400 mg/ml, 200 mg/ml, and 100 mg/ml). Minimum Bactericidal Concentration (MBC) and Minimum Fungicidal Concentration (MFC) of the extract were also analysed. Upon extraction, the phytochemical constituents of the leaf were found to be carbohydrate, saponins, flavonoids, alkaloids, steroids, cardiac glycosides, tanins and anthraquinones. There was no activity observed at 200 and 100 mg/ml concentrations of the extract on all the test organisms. For the Minimum Inhibitory Concentration (MIC) test against all the tested bacterial isolates, the MIC was found to be 400 mg/ml. In the MBC test, the test showed that S. pyogenes and S. aureus were not killed by the leaf extract but rather they were inhibited from growing this is the same with C. albicans in the MFC. This study the use of the leaf of S. longipedunculata in traditional medicine for topical application in skin infections.

Mycobacterium tuberculosis Intra-Host Evolution Among Drug-Resistant Tuberculosis Patients Failing Treatment.

Understanding Mycobacterium tuberculosis (Mtb) intra-host evolution of drug resistance is important for successful drug-resistant tuberculosis (DR-TB) treatment and control strategies. This study aimed to characterise the acquisition of genetic mutations and low-frequency variants associated with treatment-emergent Mtb drug resistance in longitudinally profiled clinical isolates from patients who experienced DR-TB treatment failure. We performed deep Whole Genome Sequencing on 23 clinical isolates obtained longitudinally across nine timepoints from five patients who experienced DR-TB treatment failure enrolled in the CAPRISA 020 InDEX study. The minimum inhibitory concentrations (MICs) were established on the BACTEC™ MGIT 960™ instrument on 15/23 longitudinal clinical isolates for eight anti-TB drugs (rifampicin, isoniazid, ethambutol, levofloxacin, moxifloxacin, linezolid, clofazimine, bedaquiline). In total, 22 resistance associated mutations/variants were detected. We observed four treatment-emergent mutations in two out of the five patients. Emerging resistance to the fluoroquinolones was associated with 16- and 64-fold elevated levofloxacin (2-8 mg/L) and moxifloxacin (1-2 mg/L) MICs, respectively, resulting from the D94G/N and A90V variants in the gyrA gene. We identified two novel mutations associated with elevated bedaquiline MICs (>66-fold): an emerging frameshift variant (D165) on the Rv0678 gene and R409Q variant on the Rv1979c gene present from baseline. Genotypic and phenotypic resistance to the fluoroquinolones and bedaquiline was acquired in two out of five patients who experienced DR-TB treatment failure. Deep sequencing of multiple longitudinal clinical isolates for resistance-associated mutations coupled with phenotypic MIC testing confirmed intra-host Mtb evolution.

Antimicrobic On KAFFIR LIME (Citrus hystrix) leaves against Bacillus cereus : KILL TEST METHOD

Kaffir lime (Citrus hystrix) is a horticultural plant that is widely used as a natural flavor in various food and beverage products. The content in lime leaves is useful for health, including flavonoids, minerals, vitamin C, limonoids, and carotenoids. Bacillus cereus causes a diarrheal disease that attacks the intestines. This study aims to determine the kaffir lime leaf extract in inhibiting the growth of Bacillus cereus bacteria using the Time-Kill Test method. This study used the Minimum Inhibitory Concentration (MIC) and Time-Kill Test methods. The MIC results in kaffir lime leaf extract that can inhibit bacteria at 2 mg/mL, while the Time-Kill Test shows a death phase at 24 hours. Kaffir lime leaf extract has a bacteriostatic effect at 0, 4, 8, and 24 hours, while amoxicillin and the combination of amoxicillin and extract have a bacteriostatic effect at 4, 8, and 24 hours. Based on the results of the One Way ANOVA test with a 95% confidence level (p <0,05) showed a significant effect of kaffir lime leaf extract on the growth of Bacillus cereus.

Antibiofilm Effect of Moringa oleifera Leaf Extract Against Staphylococcus aureus, Cytotoxicity, Biochemical aspects, Anti-Inflammatory potential, and Interference on the Activity of Antimicrobial Drugs

Abstract: There is a growing technical difficulty to treat infectious diseases due to molecular mechanisms of resistance to antimicrobial drugs, such as biofilm formation. Here we provide evidence of the antimicrobial potential of the hydroethanolic extract of Moringa oleifera leaves, traditionally used to treat disorders like cardiovascular and endocrine diseases, on clinical isolates of Staphylococcus aureus. The extract was chemically characterized using classic techniques and by ultra performance liquid chromatography (UPLC). We carried out minimum inhibitory concentration tests, as well as minimal bactericidal concentration and minimal biofilm eradication concentration tests. Moreover, we tested the anti-inflammatory potential and assessed the toxicity of the extract on buffalo green monkey (BGM) cells. We also investigated the effects of combining the extract to clinically relevant antimicrobial drugs (i.e., synergistic or antagonistic interactions). The extract was active at 8 g/mL and 16 g/mL for planktonic cells and biofilms, respectively. Its anti-inflammatory potential was confirmed, and it lacked cytotoxicity. No significant interference of the extract on antimicrobial drugs was observed. Flavonoids, tannins, proteins, carbohydrates and vitamin C were detected in the extract. Our data open doors for further studies with isolated molecules of the extract in order to conduct in vivo antimicrobial tests.

Antimicrobial use and its association with the isolation of and antimicrobial resistance in Campylobacter spp. recovered from fecal samples from Canadian dairy herds: A cross-sectional study

Campylobacteriosis is one of the most common zoonotic diseases in North America. As opposed to humans, animal infections caused by Campylobacter spp. are often asymptomatic. In this study, data collected through the Canadian Dairy Network for Antimicrobial Stewardship surveillance system were used to determine the proportion of Campylobacter spp. and antimicrobial resistant isolates recovered from dairy cattle herds. Additionally, the association of antimicrobial use (AMU) with fecal carriage and antimicrobial resistance (AMR) of Campylobacter spp. were investigated. Pooled fecal samples from 5 animals from each production phase (pre-weaned calves, post-weaned heifers, lactating cows), and a manure storage sample were collected from 140 dairy herds across Canada. Samples were cultured using selective media, and Campylobacter isolates were speciated using matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Antimicrobial susceptibilities were determined using the minimum inhibitory concentration test, and interpretation was made according to the Clinical and Laboratory Standards Institute. Two multilevel logistic regression models were used to investigate the association between the AMU with the isolation and antimicrobial resistance in Campylobacter spp. Of 560 samples, 63.8% were positive for Campylobacter spp., and 96% of the participating farms had at least one sample source (i.e., calves, heifers, lactating cows, or manure storage) positive for Campylobacter spp. Overall, 54.3% of the Campylobacter spp. isolates were resistant to at least one antimicrobial. Resistance to tetracycline was observed in 49.7% of the Campylobacter spp. isolates, followed by ciprofloxacin (19.9%) and nalidixic acid (19.3%). The proportion of multi-drug resistant (≥3 antimicrobial classes) Campylobacter spp. isolates was low (0.3%); however, 15.6% were resistant to two different classes of antimicrobials. Samples collected from lactating cows, heifers, and manure storage were more likely to be positive for Campylobacter spp. compared to calves. Total AMU was associated with a decreased probability of recovering Campylobacter spp. In addition, AMR to either tetracycline or ciprofloxacin had an interaction with antimicrobial use. The probability of resistance to tetracycline increased for each unit increase in the total AMU (Defined Course Dose/100 animal-years), while the probability of resistance to ciprofloxacin decreased. Campylobacter coli isolates were more likely to be resistant to ciprofloxacin and tetracycline when compared to C. jejuni. Our study demonstrated that Campylobacter spp. is widespread among Canadian dairy farms, and a higher proportion of resistance to tetracycline was identified. The total AMU was associated with increased resistance to tetracycline in Campylobacter spp. isolates; however, for ciprofloxacin the AMU was associated with decreased resistance.

Decrease in vancomycin MICs and prevalence of hGISA in MRSA and MSSA isolates from a German pediatric tertiary care center

PurposeResistance of Staphylococcus aureus to vancomycin includes a general increase of minimal inhibitory concentrations (MIC) within the susceptible range over time (Vancomycin MIC Creep) and the presence of a subset of the bacterial population that expresses resistance (heterogeneous glycopeptide-intermediate S. aureus; hGISA). Increased MICs have been associated with adverse clinical outcomes. However, the vancomycin MIC creep is not a uniform trend suggesting the importance of regional surveys.MethodsWe performed a retrospective analysis at a German pediatric tertiary care hospital. Isolates from 2002 to 2017 were selected which were newly identified methicillin-resistant S. aureus (MRSA) or samples from invasive methicillin-susceptible S. aureus (MSSA) or MRSA infections. Vancomycin and oxacillin MICs as well as GISA/hGISA were measured using MIC test strips and resistance was evaluated over time.ResultsA total of 540 samples were tested, 200 from the early (2002–2009) and 340 from the later period (2010–2017). All samples were vancomycin susceptible, but the MIC was higher for the earlier samples as compared to the later ones (1.11 vs 0.99; p < 0.001). 14% of the samples were hGISA, GISA strains were not detected. Again, vancomycin resistance decreased over time with 28 vs. 6% hGISA (p < 0.001). There was no significant difference between MRSA and MSSA samples with respect to vancomycin MIC and hGISA prevalence.ConclusionThis study shows a decreasing trend for both MIC values and presence of hGISA strains highlighting the importance of monitoring local susceptibilities. Vancomycin remains a first-line treatment option for suspected severe infection with Gram-positive cocci and proven infection with MRSA.

The conjunctival fungal microflora of horses in a North Queensland tropical environment and their in vitro susceptibilities to antifungal agents

Fungi are ubiquitous in the environment and part of the commensal microflora on the conjunctiva of equine eyes. North Queensland, being tropical, presents an ideal environment for fungi growth. When the cornea is injured, fungi can invade the corneal stroma, resulting in keratomycosis. The objectives of this study were to determine the fungal species specific to the eyes of horses in the Townsville region; to investigate the potential risk factors associated with the presence of fungi; and to test their susceptibility to antifungals to create an empirical guide for treatment. The eyes of forty ophthalmologically normal horses from James Cook University were sampled throughout the summer months of December 2017, January 2018, and January and February 2020. Cultured fungi were identified morphologically, and their identity confirmed by comparing partial 18sRNA DNA sequences with the NCBI nucleotide database. Minimum inhibitory concentration testing of common antifungal medications was performed. Sixty-one out of eighty conjunctival samples grew fungi, and 21 different fungi genera were isolated. The most common genera were Aspergillus (18%, 26/141), Curvularia (14%,20/141), Rhodotorula (12%,17/141) and Penicillium (12%,17/141). No significant association was found between age or environmental factors and fungal culture status. Most fungi were highly susceptible to voriconazole and ketoconazole but resistant to fluconazole and amphotericin B. This adds to the body of evidence on which species of fungi are present as normal ocular microflora of horses living in tropical regions of Australia, and an avenue for treating them.

The impact of biosynthesized ZnO nanoparticles from Olea europaea (Common Olive) on Pseudomonas aeruginosa growth and biofilm formation

There is a limitation in the range of effectual antibiotics due to the Pseudomonas aeruginosa (PA) infection due to its innate antimicrobial resistance. Researchers have therefore been concentrating their efforts to discover advanced and cost effective antibacterial agents among the ever-increasing PA bacterial resistance strains. It has been discovered that various nanoparticles can be employed as antimicrobial agents. Here, we evaluated the antibacterial properties of the Zinc Oxide nanoparticles (ZnO NPs), which was biosynthesized, being examined on six hospital strains of PA alongside a reference strain (ATCC 27853). A chemical approach was applied to biosynthesize the ZnO NPs from Olea europaea was performed, and confirmed by using X-ray diffraction and Scanning Electron Microscopes. The nanoparticles then applied their antibacterial properties to examine them against six clinically isolated PA strains alongside the reference strain. This process tested for the results of the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). The Growth, biofilm formation and eradication were analyzed. The influence of the differentiating degrees ZnO NPs in regard to Quorom sensing gene expression were further examined. The ZnO NPs exhibited a crystalline size and diameter (Dc) of 40–60 nm and both the MIC and MBC tests revealed positive outcomes of concentrations of 3 and 6 mg/ml for each PA strain, respectively. At sub inhibitory concentration, The ZnO NPs were found to significantly inhibit the growth and biofilm formation of all PA strains and decreases in the biomass and metabolic behavior of PA established biofilms; these decreases varied depending on the dosage. At ZnO NPs concentrations of 900 µg/ml, the expression of majority of quorum sensing genes of all strains were significantly reduced, at ZnO NPs concentrations of 300 µg/ml, few genes were significantly impacted. In conclusion, the treatment of PA and could be other antibiotic resistant bacteria can therefore be approached by using ZnO NPs as it has been uncovered that they withhold advanced antibacterial properties.

DAYA HAMBAT EKSTRAK DAUN CENGKEH (Syzygium aromaticum L.) TERHADAP PERTUMBUHAN JAMUR Rhizoctonia solani Kuhn. PENYEBAB PENYAKIT HAWAR PELEPAH PADA TANAMAN PADI (Oryza sativa L.)

Rhizoctonia solani Kuhn. is a fungal pathogen that causes sheath blight in rice plants. Sheath blight disease can reduce rice production for the people of Indonesia. To prevent blight, fungicides are used. The continuous use of synthetic fungicides with inappropriate doses can have a negative impact, so it is necessary to look for alternatives with vegetable fungicides, one of which is clove leaf (Syzygium aromaticum L.). The aim of this study was to determine the ability of clove leaf extract to inhibit the fungus R. Solani and the class of compounds contained in the extract. Data were collected and collected using the MIC (Minimum Inhibitory Concentration) test using the well-diffusion method, the inhibition percentage of clove leaf extract using the colony method, and the content of compounds using the phytochemical test. The minimum concentration (MIC) of clove leaf extract capable of inhibiting the fungus R. solani is 0.5%. The percentage of inhibitory activity can be reduced by 100% at an extract concentration of 1.5%. Clove leaf extract contains groups of alkaloids, tannins, flavonoids, saponins, phenols, steroids and terpenoids.&#x0D;

Copper(II) and Cobalt(II) Complexes Based on Abietate Ligands from Pinus Resin: Synthesis, Characterization and Their Antibacterial and Antiviral Activity against SARS-CoV-2

Co-abietate and Cu-abietate complexes were obtained by a low-cost and eco-friendly route. The synthesis process used Pinus elliottii resin and an aqueous solution of CuSO4/CoSO4 at a mild temperature (80 °C) without organic solvents. The obtained complexes are functional pigments for commercial architectural paints with antipathogenic activity. The pigments were characterized by Fourier-transform infrared spectroscopy (FTIR), mass spectrometry (MS), thermogravimetry (TG), near-edge X-ray absorption fine structure (NEXAFS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and colorimetric analysis. In addition, the antibacterial efficiency was evaluated using the minimum inhibitory concentration (MIC) test, and the antiviral tests followed an adaptation of the ISO 21702:2019 guideline. Finally, virus inactivation was measured using the RT-PCR protocol using 10% (w/w) of abietate complex in commercial white paint. The Co-abietate and Cu-abietate showed inactivation of >4 log against SARS-CoV-2 and a MIC value of 4.50 µg·mL-1 against both bacteria Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The results suggest that the obtained Co-abietate and Cu-abietate complexes could be applied as pigments in architectural paints for healthcare centers, homes, and public places.