Minimum Inhibitory Concentration Levels Research Articles

MIC distribution analysis identifies differences in AMR between population sub-groups

Background Phenotypic data, such as the minimum inhibitory concentrations (MICs) of bacterial isolates from clinical samples, are widely available through routine surveillance. MIC distributions inform antibiotic dosing in clinical care by determining cutoffs to define isolates as susceptible or resistant. However, differences in MIC distributions between patient sub-populations could indicate strain variation and hence differences in transmission, infection, or selection. Methods The Vivli AMR register contains a wealth of MIC and metadata for a vast range of bacteria-antibiotic combinations. Using a generalisable methodology followed by multivariate regression, we explored MIC distribution variations across 4 bacteria, covering 7,135,070 samples, by key population sub-groups such as age, sex and infection type, and over time. Results We found clear differences between MIC distributions across various patient sub-groups for a subset of bacteria-antibiotic pairings. For example, within Staphylococcus aureus, MIC distributions by age group and infection site displayed clear trends, especially for levofloxacin with higher resistance levels in older age groups (odds of 2.17 in those aged 85+ compared to 19–64), which appeared more often in men. This trend could reflect greater use of fluoroquinolones in adults than children but also reveals an increasing MIC level with age, suggesting either transmission differences or accumulation of resistance effects. We also observed high variations by WHO region, and over time, with the latter likely linked to changes in surveillance. Conclusions We found that MIC distributions can be used to identify differences in AMR levels between population sub-groups. Our methodology could be used more widely to unveil hidden transmission sources and effects of antibiotic use in different patient sub-groups, highlighting opportunities to improve stewardship programmes and interventions, particularly at local scales.

Does PAD and microcirculation status impact the tissue availability of intravenously administered antibiotics in patients with infected diabetic foot? Results of the DFIATIM substudy.

The aim of this substudy (Eudra CT No:2019-001997-27)was to assess ATB availability in patients with infected diabetic foot ulcers(IDFUs)in the context of microcirculation and macrocirculation status. For this substudy, we enrolled 23 patients with IDFU. Patients were treated with boluses of amoxicillin/clavulanic acid(AMC)(12patients) or ceftazidime(CTZ)(11patients). After induction of a steady ATB state, microdialysis was performed near the IDFU. Tissue fluid samples from the foot and blood samples from peripheral blood were taken within 6 hours. ATB potential efficacy was assessed by evaluating the maximum serum and tissue ATB concentrations(Cmax and Cmax-tissue)and the percentage of time the unbound drug tissue concentration exceeds the minimum inhibitory concentration (MIC)(≥100% tissue and ≥50%/60% tissue fT>MIC). Vascular status was assessed by triplex ultrasound, ankle-brachial and toe-brachial index tests, occlusive plethysmography comprising two arterial flow phases, and transcutaneous oxygen pressure(TcPO2). Following bolus administration, the Cmax of AMC was 91.8 ± 52.5 μgmL-1 and the Cmax-tissue of AMC was 7.25 ± 4.5 μgmL-1(P<0.001). The Cmax for CTZ was 186.8 ± 44.1 μgmL-1 and the Cmax-tissue of CTZ was 18.6 ± 7.4 μgmL-1(P<0.0001). Additionally, 67% of patients treated with AMC and 55% of those treated with CTZ achieved tissue fT>MIC levels exceeding 50% and 60%, respectively. We observed positive correlations between both Cmax-tissue and AUCtissue and arterial flow. Specifically, the correlation coefficient for the first phase was r=0.42; (P=0.045), and for the second phase, it was r=0.55(P=0.01)and r=0.5(P=0.021). Bactericidal activity proved satisfactory in only half to two-thirds of patients with IDFUs, an outcome that appears to correlate primarily with arterial flow.

Role of MIC levels and 23S rRNA mutation sites to clarithromycin in 14-day clarithromycin bismuth quadruple therapy for Helicobacter pylori eradication: A prospective trial in Beijing

BackgroundRising clarithromycin resistance undermines Helicobacter pylori (H. pylori) treatment efficacy. We aimed to determine clarithromycin's minimum inhibitory concentration (MIC) levels and identify specific mutation sites in the 23S ribosomal subunit (23S rRNA) that predict treatment outcomes in a 14-day regimen of clarithromycin bismuth quadruple therapy (amoxicillin 1g, clarithromycin 500 mg, rabeprazole 10 mg, and colloidal bismuth pectin 200 mg). Materials and methodsWe included adult H. pylori patients who hadn't previously undergone clarithromycin-based treatment, either as initial or rescue therapy. Exclusions were made for penicillin allergy, recent use of related medications, severe illnesses, or inability to cooperate. Patients underwent a 14-day clarithromycin bismuth quadruple therapy. Gastric mucosa specimens were obtained during endoscopy before eradication. MIC against amoxicillin and clarithromycin was determined using the E-test method. The receiver operating characteristic (ROC) curve helped to find the optimal clarithromycin resistance MIC breakpoint. Genetic sequences of H. pylori 23S rRNA were identified through Sanger Sequencing. (ChiCTR2200061476) ResultsOut of 196 patients recruited, 92 met the inclusion criteria for the per-protocol (PP) population. The overall intention-to-treat (ITT) eradication rate was 80.00 % (84/105), while the modified intention-to-treat (MITT) and PP eradication rates were 90.32 % (84/93) and 91.30 % (84/92) respectively. No amoxicillin resistance was observed, but clarithromycin resistance rates were 36.19 % (38/105), 35.48 % (33/93), and 34.78 % (33/92) in the ITT, MITT, and PP populations respectively. Compared with the traditional clarithromycin resistance breakpoint of 0.25 μg/mL, a MIC threshold of 12 μg/mL predicted better eradication. Among 173 mutations on 152 sites in the 23S rRNA gene, only the 2143A > G mutation could predict eradication outcomes (p < 0.000). ConclusionsInterpretation of elevated MIC values is crucial in susceptibility testing, rather than a binary "susceptible" or "resistant" classification. The 2143A > G mutation has limited specificity in predicting eradication outcomes, necessitating further investigation into additional mutation sites associated with clarithromycin resistance.

Study of the sensitivity of methicillin-resistant &lt;i&gt;Staphylococcus aureus&lt;/i&gt; to antibiotics and bacteriophage preparations

Objective. To evaluate the sensitivity of methicillin-resistant Staphylococcus aureus strains to antibiotics and therapeutic and prophylactic preparations of bacteriophages. Materials and methods. The antibiotic sensitivity of strains of methicillin-resistant S.aureus was studied by the disco-diffusion method, the determination of the minimum inhibitory concentrations of vancomycin and linezolid by broth microdilution method, and ceftaroline by E-tests. The sensitivity of methicillin-resistant S.aureus to bacteriophage preparations was studied. Results. It has been established that linezolid and vancomycin are quite active drugs against methicillin-resistant S.aureus (MRSA), however, resistance to them begins to develop. MRSA resistance to fluoroquinolones and cefoxitin was the highest of all antibiotics tested; the results obtained with cefoxitin can be interpreted for other cephalosporins (except ceftaroline) and all penicillins. Only 67.9% of MRSA strains retained sensitivity to ceftaroline, but ceftaroline-resistant strains had low levels of minimal inhibitory concentration. The preparations of the bacteriophages “Sextaphage” and “Piobacteriophage Phagio” showed their lytic activity only in relation to 35.8% and 18.9% of MRSA isolates, respectively. Conclusion. Monitoring the development of antibiotic resistance in methicillin-resistant S.aureus is an important part of the strategy of rational antibiotic therapy for staphylococcal infections. Only taking into account the preliminary step-by-step determination of the phage sensitivity of the causative agent of the disease, bacteriophage preparations can be considered as a completely possible alternative to antibiotics for the treatment of purulent inflammatory diseases caused by MRSA.

Polish honeys exhibit activity against Pseudomonas aeruginosa isolated from wounds

Pseudomonas aeruginosa is recognized as an opportunistic pathogen and a common contributor to wound infections. This study focused on evaluating the antibacterial activity of selected Polish honeys against P. aeruginosa. Six bacterial strains isolated from wounds and four types of honeys (multifloral, linden, buckwheat, and heather) were utilized. The minimal inhibitory concentrations (MIC) were determined through the micro-dilution method employing 96-well plates, while antibiofilm activity was assessed using fluorescence microscopy after a 4-hour incubation period with the honeys. Results indicated diverse antibacterial efficacy among honeys, with linden and heather honeys demonstrating the most potent activity. Linden honey displayed an average MIC of 20.8%, while heather honey exhibited an MIC of 25%. Both honeys significantly reduced biofilm formation, with linden honey achieving a reduction of 54-67% and heather honey of 45-58%. Buckwheat and multifloral honeys exhibited lower activity, demonstrating average MIC levels of 37.5% and 41.7%, respectively, and a biofilm reduction below 20%. Conclusively, Polish honeys exhibited promising activity against both planktonic and biofilm forms of P. aeruginosa. These findings suggest potential applications in wound healing treatments, emphasizing the need for further research in this area. The study contributes valuable insights to the limited literature on the antibacterial activity of Polish honeys.

NaClO Co-selects antibiotic and disinfectant resistance in Klebsiella pneumonia: Implications for the potential risk of extensive disinfectant use during COVID-19 pandemic

The inappropriate use of antibiotics is widely recognized as the primary driver of bacterial antibiotic resistance. However, less attention has been given to the potential induction of multidrug-resistant bacteria through exposure to disinfectants. In this study, Klebsiella pneumonia, an opportunistic pathogen commonly associated with hospital and community-acquired infection, was experimentally exposed to NaClO at both minimum inhibitory concentration (MIC) and sub-MIC levels over a period of 60 days. The result demonstrated that NaClO exposure led to enhanced resistance of K. pneumonia to both NaClO itself and five antibiotics (erythromycin, polymyxin B, gentamicin, tetracycline, and ciprofloxacin). Concurrently, the evolved resistant strains exhibited fitness costs, as evidenced by decreased growth rates. Whole population sequencing revealed that both concentrations of NaClO exposure caused genetic mutations in the genome of K. pneumonia. Some of these mutations were known to be associated with antibiotic resistance, while others had not previously been identified as such. In addition, 11 identified mutations were located in the virulence factors, demonstrating that NaClO exposure may also impact the pathogenicity of K. pneumoniae. Overall, this study highlights the potential for the widespread use of NaClO-containing disinfectants during the COVID-19 pandemic to contribute to the emergence of antibiotic-resistant bacteria. Environmental ImplicationConsidering the potential hazardous effects of disinfectant residues on environment, organisms and biodiversity, the sharp rise in use of disinfectants during COVID-19 pandemic has been considered highly likely to cause worldwide secondary disasters in ecosystems and human health. This study demonstrated that NaClO exposure enhanced the resistance of K. pneumonia to both NaClO and five antibiotics (erythromycin, polymyxin B, gentamicin, tetracycline, and ciprofloxacin), highlighting the widespread use of NaClO-containing disinfectants during the COVID-19 pandemic may increase the emergence of antibiotic-resistant bacteria in the environment.

Unusual and Unconsidered Mechanisms of Bacterial Resilience and Resistance to Quinolones.

Quinolone resistance has been largely related to the presence of specific point mutations in chromosomal targets, with an accessory role of impaired uptake and enhanced pump-out. Meanwhile the relevance of transferable mechanisms of resistance able to protect the target of pump-out or inactivate quinolones has been increasingly reported since 1998. Nevertheless, bacteria have other strategies and mechanisms allowing them to survive and even proliferate in the presence of quinolones, which might be qualified as resistance or resilience mechanisms. These include decreasing levels of quinolone target production, transient amoeba protection, benthonic lifestyle, nutrient-independent slow growth, activation of stringent response, inactivation or degradation of quinolones as well as apparently unrelated or forgotten chromosomal mutations. These mechanisms have been largely overlooked, either because of the use of classical approaches to antibiotic resistance determination or due to the low increase in final minimum inhibitory concentration levels. This article is devoted to a review of a series of these mechanisms.

Can Nanobubble Ozone Liposomes Be A New Agent In The Fight Against Foodborne Infections?

In this study, a nanobubble ozone liposome solution containing 2% ZnCl2 was used. The aging tests were conducted according to the ASTM F 1980 [1] standards. The minimum inhibitory concentration (MIC) level of the nanobubble ozone liposome solution with 2% ZnCl2 was determined as 1.562 ppm for strains of Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) by the CLSI M07 A9 [2] standard test method. To assess the time-dependent antibacterial effect of the nanobubble liposome solution with 2% ZnCl2, the solution's efficiency at a concentration of 2000 ppm and for different time intervals was tested on strains of Salmonella enterica subsp. enterica (ATCC® 14028™) and Listeria monocytogenes (ATCC® 7644™). The results showed that the antibacterial activity of the strains of S. enterica subsp. enterica started at the end of the 10th minute and the solution was effective after 30 minutes. For strains of L. monocytogenes, it was observed that the activity started at the end of the 2nd minute and the product was effective after the 10th minute. According to the ASTM F 1980 standards, it was found that the nanobubble ozone liposome solution retained its effectiveness in one-year stability tests. As a result, the nanoparticle liposome solution, a new product, does not lose its stability and effectiveness for a long time, contrary to what is known. Although the half-life of gaseous ozone is as short as 20 minutes, the stability in the nanoparticle liposome solution has been determined as at least one year. Since nanoparticle liposome solution is a natural and slow-release product, nanobubble ozone liposome solution with 2% ZnCl2 may be used as a newly developed agent against contaminations in food processing facilities caused by biofilm-forming microorganisms through the use in disinfections of surfaces that are in direct contact with food products.

Antibacterial and antioxidant activities in various parts of Artocarpuslacucha Buch. Ham. ethanolic extract.

Artocarpus lacucha is an endemic plant to North Sumatera, Indonesia. This plant has pharmacological activities, including acting as an antioxidant and antibacterial. The aim of the present study was to analyze the antibacterial and antioxidant activities, and determine the flavonoid compounds from four parts of A. lachuca, namely leaves, barks, twigs and fruits. Antioxidant activity was investigated using the 2,2-diphenyl 1-picrylhydrazyl (DPPH) and cupric reducing antioxidant capacity (CUPRAC) methods. Antibacterial activity was analyzed using disk diffusion and microdilution methods. Several flavonoids, such as luteolin-7-O-glucoside, rutin, quercetin, kaempferol and apigenin, were determined using high performance liquid chromatography. Based on the antioxidant activity test results using the DPPH method, the bark ethanolic extract provided the highest antioxidant capacity, while the CUPRAC method indicated that the twig ethanolic extract had the highest antioxidant capacity. The antibacterial activity test results demonstrated that at a low concentration of 750 µg/disk the bark ethanolic extract obtained the highest inhibition zone and minimum inhibitory concentration level against six of nine pathogenic bacteria. Therefore, A. lachuca bark ethanolic extract could be potentially developed as antioxidant and antibacterial agents.

Efficacy of Various Herbal Preparations Against Oral Candida: A Lab-Based Study

ABSTRACT Aim: This research was done to analyze the effectiveness related to herbal chemicals in tackling candidiasis. Materials and Methods: Grounded and ethanol-extracted residues of plants like Avicennia marina, Fagonia indica, Portulaca oleracea, Lawsania inermis, Ziziphus spina, Asphodelus tenuifolius, and Salvadora persica were used in the study. The extract was used against candida species, after which the antibacterial as well as cytotoxicity toward the former were evaluated. Results: L. inermis and P. oleracea with minimal inhibitory concentration of approx. 10 cenmL had an increased activity against candida species. The preparations of these plants acted against Candida albicans during its stages related to pathogenesis during biofilm production. Superadded infections like in case of bacterial infections along with candida can be difficult to cure. On human RBCs, these plant preparations had no toxicity at their minimum inhibitory concentration level. Conclusion: We concluded that, as far as being anti-candida and acting against MDR bacterial infections, preparations of plants were effective as an alternative to allopathic drugs.

The Value of in-vitro Local Ceftriaxone Interrupted Irrigation for Soft Tissue Autograft in Arthroscopic ACL Reconstruction

Background: Postoperative septic arthritis of the knee joint is an uncommon complication with serious consequences following anterior cruciate ligament reconstruction (ACLR). Systemic antibiotics received preoperatively and presoaking the soft tissue autograft with antibiotics result in a lower infection rate. Preoperative intravenous antibiotics may not be sufficient enough to reach minimum inhibitory concentration (MIC) levels due to poor vascularity of hamstring tendons in addition the harvested graft is prone to infection from skin flora. Aim of the study: To assess the efficacy of local antibiotic (ceftriaxone drug 1g.) solution diluted in (500 mL 0.9% sodium chloride N/S) for invitro interrupted irrigation of harvested soft tissue ACL graft as prophylaxis in reducing the infection rate during knee joint arthroscopic procedure. Patients and Methods: A Prospective comparative study of forty patients fit for arthroscopic anterior cruciate ligament reconstruction were enrolled in the study. The timeline period from April 2022 to July 2023.patients divided into (group A), twenty patients (received local ceftriaxone irrigation 1gm. solution diluted in 500 mL 0.9% NaCl for presoaking soft tissue autograft) and (Group B), twenty patients received (plain NaCl 0.9% ) only for irrigation of harvested graft. All patients in both groups received intravenous ceftriaxone at time of induction of anesthesia. Patients with history of injury more than 2years, open procedure, intravenous drug abuse, alcoholism steroid use, revision cases, and a prior history of infection in the knee were excluded from the study. Patients were followed postoperatively by clinical, laboratory, and imaging studies. The chi-square test was used for the comparison of categorical data. A student T-test and ANOVA were conducted to demonstrate the differences in postoperative inflammatory markers. Results: Presoaking of soft tissue autograft with ceftriaxone was performed in 20 patients (the study group), while 20 patients (the control group) were soaked only with plain N/S. In the control group, two patients (10%) developed postoperative infection after 2 weeks postoperatively, while no case developed infection in the study group. There was no statistically significant difference (p &gt;0.05) between the study and control groups in terms of demographic characteristics, type of graft (p = 0.34), associated arthroscopic procedure (p = 0.35), and Lysholm score (p = 0.58). In the study group, there was a significant decrease in ESR (P = 0.01) after 4 weeks, Total lymphocyte count (p = 0.04), and Polymorphonuclear (p = 0.03) after 6 weeks postoperatively. Conclusion: Presoaking of hamstring autograft with ceftriaxone intraoperative may be alternative for other antibiotics in reducing rate of infection following arthroscopic anterior cruciate ligament reconstruction.

Pharmacokinetic analysis of ceftazidime and cefazolin in the treatment of continuous ambulatory peritoneal dialysis-related peritonitis

Objective Peritoneal dialysis-related peritonitis (PDRP) presents a significant challenge for nephrologists. Continuous intraperitoneal cefazolin and ceftazidime are recommended for the treatment of peritonitis. However, some pharmacokinetic studies have shown that doses of 15–20 mg/kg/d may not achieve sufficient therapeutic levels. In this study, we investigated the pharmacokinetics of ceftazidime and cefazolin in patients with continuous ambulatory peritoneal dialysis-related peritonitis and compared the pharmacokinetic characteristics between traditional and modified treatment groups. Methods From February 2017 to December 2019, 42 PDRP patients (17 males, 25 females; mean age: 50.7 ± 12.1 years; mean body weight: 60.9 ± 11.8 kg) were recruited for the study, all participants were anuric. Twenty patients were enrolled in the traditional group and treated with cefazolin (1.0 g) and ceftazidime (1.0 g) via intraperitoneal administration once daily for 14 days. Twenty-two patients were enrolled in the modified group and received the same dose of antibiotics twice daily for the initial five days, followed by once daily for the subsequent nine days. Serum and dialysate samples were collected after days 1, 2, 3, 5, 7, 10, and 14 and analyzed via liquid chromatography-mass spectrometry. Results In the traditional group, the highest and lowest serum concentrations of ceftazidime were 35.9 and 21.7 µg/mL, respectively. The highest concentration of cefazolin was 54.6 µg/mL on day 5 and the lowest concentration was 30.4 µg/mL on day 1. In the modified group, the highest and lowest serum concentrations of ceftazidime were 102.2 and 54.8 µg/mL, respectively. The highest concentration of cefazolin was 141.7 µg/mL and the lowest concentration was 79.8 µg/mL. All antibiotic concentrations were above the minimum inhibitory concentration (MIC) level (8 µg/mL of ceftazidime and 2 µg/mL of cefazolin) throughout the treatment period. However, on day 1, the concentration of ceftazidime in the third bag of dialysate effluent from the traditional group fell below the MIC level. Despite remaining above the MIC, cefazolin concentration was consistently lower in the third bag of dialysate effluent from the traditional group throughout the treatment period. Conclusions Intraperitoneal administration of cefazolin and ceftazidime at a dose of 1 g twice daily for 5 days and then once daily for the rest of the treatment period ensured adequate therapeutic levels of antibiotics for treating anuric PDRP patients.

Anti-infective Efficacy of Duloxetine against Catheter-Associated Urinary Tract Infections Caused by Gram-Positive Bacteria.

Catheter-associated urinary tract infections (CAUTIs) frequently occur following the insertion of catheters in hospitalized patients, often leading to severe clinical complications. These complications are exacerbated by biofilm-forming organisms such as Staphylococcus aureus, contributing to the emergence of multidrug-resistant (MDR) strains, which complicates treatment strategies. This study aims to investigate the antibacterial, antibiofilm, and antiadhesive properties of duloxetine against S. aureus in the context of CAUTI. Our findings demonstrate that duloxetine exhibits significant antibacterial activity, as evidenced by the agar diffusion method. A minimal inhibitory concentration (MIC) of 37.5 μg/mL was established using the microdilution method. Notably, duloxetine displayed inhibitory effects against biofilm formation on polystyrene surfaces up to its MIC level, as demonstrated by the crystal violet method. Intriguingly, the study also revealed that duloxetine could prevent biofilm formation at lower concentrations and reduce mature biofilms, as confirmed by scanning electron microscopy (SEM) and quantitative biofilm assays. Furthermore, duloxetine-coated silicone catheter tubes exhibited antibacterial properties against S. aureus in a bladder model, visualized by confocal laser scanning microscopy (CLSM) and corroborated through FDA and PI staining, highlighting noticeable morphological changes in S. aureus post-treatment. In conclusion, this study presents duloxetine as a promising alternative agent with antibacterial and antiadhesive properties against S. aureus in the prevention and management of CAUTI, warranting further exploration in the clinical setting.

The Comparisons of Phenotypic and Genotypic Resistance of Staphylococcus aureus Isolates Against β-lactam and Tetracycline Antibiotics

Staphylococcus aureus (S. aureus) is a Gram-positive bacteria that causes various diseases in humans and animals. Treatment of S. aureus infection generally uses antibiotics, but what happens is, S. aureus resistance to antimicrobial agents is an increasing global problem. This study aims to compare the phenotypic and genotypic characters of S. aureus from animals isolates against β-lactam and tetracycline antibiotics class. Determination of resistance characteristics of 8 S. aureus isolates was carried out phenotypically by Kirby Bauer and Minimum Inhibitory Concentration (MIC) methods, while genotypically by detecting the blaZ and tet genes. The results of the study showed a relationship between resistance genes and phenotypic test results using the Kirby Bauer and MIC methods. Isolates C, D, F, and TLK with resistance gene characters blaZ-, tetK-, and tetM- showed a sensitive interpretation of the results of the Kirby Bauer and MIC tests. On the other hand, DMG, J, PGT, and KRG isolates were resistant to one or two antibiotics tested, both phenotypic and genotypic (blaZ+, tetK+/tetM+). It found that the MIC levels of some respective isolates were relatively high, isolates J and KRG had an ampicillin MIC level of 32 μg/ml, while isolates J and PGT had 256 μg/ml for oxytetracycline. Although the identification of resistance genes and Kirby Bauer can determine the character of bacterial resistance, MIC determination is necessary to provide qualitative and quantitative information for the benefit of making therapeutic decisions and infection control strategies.

Optimizing extraction of Pelargonium sidoides roots: Impact of ethanol concentration on biological activity of extracts

Pelargonium sidoides DC. (Geraniaceae) is an important indigenous medicinal plant in South Africa, historically employed by various ethnic groups to treat respiratory and gastrointestinal ailments. The proprietary herbal tincture, Umckaloabo®, utilizes an ethanolic extract (EPs® 7630) from the roots of P. sidoides, and has demonstrated effectiveness in alleviating symptoms of respiratory infections.P. sidoides roots contain numerous highly oxygenated coumarins and phenolic metabolites, notably the marker compound umckalin. While Umckaloabo® is prepared using 11 % ethanol extraction, the South African commercial market predominantly employs 60 % ethanol extraction due to its consistent umckalin yield and antimicrobial activity. The effects of these extraction methods on chemical composition and in vitro pharmacological activity remain poorly understood.This study confirmed superior antibacterial and antifungal activity in the 60 % ethanol extracts prepared from six root samples compared to the 11 % ethanol extracts. MIC values for both Gram-negative and Gram-positive bacteria ranged from 0.078 to 2.5 mg/mL in the 60 % extracts. Remarkably, two of the root extracts exhibited excellent to very good activity against C. albicans and C. neoformans with MIC values of 0.039 and 0.078 mg/mL, respectively.A positive correlation was identified between total minimum inhibitory concentration (MIC) levels and polyphenol content, rather than umckalin levels. The influence of these extracts on the pro-inflammatory cytokine IL-6 was assessed. Both 60 % and 11 % root extracts of P. sidoides at 100 µg/mL significantly reduced IL-6 production, with the 60 % extracts demonstrating a more pronounced effect (p = 0.008).Statistical analysis revealed significant differences between 11 % and 60 % ethanol extractions in terms of average MIC overall, average Gram-negative MIC, average Gram-positive MIC, fungal MIC, and IL-6 levels. Extracts with higher polyphenol values exhibited superior antimicrobial activity and antioxidant potential, suggesting that polyphenol content may serve as a more reliable indicator of antimicrobial activity than umckalin levels. Additionally, polyphenol levels in the roots may vary with altitude and other environmental factors, warranting further research.

Hyphae-specific genes: Possible molecular targets for magnetic iron oxide nanoparticles alone and combined with visible light in Candida albicans

Candida albicans readily develops resistance to fluconazole. Magnetic iron oxide nanoparticles (denoted as MION) and antimicrobial photodynamic therapy are attracting attention as therapeutic agents. This study aims to investigate the inhibitory efficacy of MION alone and combined with visible light against C. albicans and expression analysis of hyphal wall protein 1 (HWP1) and agglutinin-like sequence 1 (ALS1) genes in C. albicans. Antifungal susceptibility testing, photodynamic activity assay, reactive oxygen species (ROS) production assay and gene expression analysis were determined in C. albicans treated with MION alone and combined with visible light. MION at 1 × minimum inhibitory concentration (MIC) level (500 μg/mL) exhibited antifungal activity against C. albicans isolates. Further, 1 × MIC levels of MION alone and combined with visible light displayed remarkable fungicidal effects at 24 and 48 h after treatment. The MION combined with visible light caused the highest levels of ROS production by all C. albicans isolates. The relative RT-PCR data showed significant downregulation of HWP1 and ALS1 genes which are the key virulence genes in C. albicans. Differences in gene expression of HWP1 and ALS1 were more significant in MION combined with visible light treatments than MION alone. Our study sheds a novel light on facile development of effective treatment of C. albicans especially fluconazole-resistant C. albicans infections. The hyphae-specific genes HWP1 and ALS1 could be probable molecular targets for MION alone and combined with visible light in C. albicans.

Mobe leaf (Artocarpus lakoocha Buch. Ham) ethanol extract’s antibacterial activity on Streptococcus mutans cell membrane leakage and biofilm formation: An in vitro study

Background: Using fixed orthodontic appliances inhibits oral hygiene, which can lead to the increased development of biofilms and Streptococcus mutans, a cariogenic bacterium that is well known for causing dental caries, derived from bacteria of the Streptococcus genus. In order to decrease biofilm and the degree of cariogenic bacteria in the oral cavity, a variety of herbal ingredients are used. Among these, mobe (Artocarpus lakoocha Buch. Ham) leaves are herbal ingredients with antibacterial properties. Purpose: This study aimed to investigate the antibacterial activity, antibiofilm, and leakage of DNA and protein from mobe leaves. Methods: The diffusion method was used to assess antibacterial activity and determine the minimum inhibitory concentration. The antibiofilm activity was evaluated with Ultraviolet–visible (UV-Vis) spectrophotometry (600 nm), using violet crystal staining. The detection of DNA and protein leakage was carried out by checking for absorbance values using the UV-Vis spectrophotometry (260 nm and 280 nm). An increase in the absorbance value in the measured cell indicated an increase in the level of cell content produced by the cell. One-way analysis of variance was used statistically analyze the results of this study (P &lt; 0.05). Results: Mobe leaf (A. lakoocha) extract’s minimum inhibitory concentration level was 3.125 mg/ml, the effective concentration of ethanol extract for inhibiting biofilm formation was 3.125 mg/ml, and the effective concentration of ethanol extract that could cause DNA and protein leakage was 50 mg/ml. Conclusions: Mobe leaf extract has good MIC for S. mutans.

Identification and characterization of a novel chromosomal aminoglycoside 3'-O-phosphotransferase, APH(3')-Id, from Kluyvera intermedia DW18 isolated from the sewage of an animal farm.

Aminoglycosides, as important clinical antimicrobials, are used as second-line drugs for treating multidrug-resistant tuberculosis or combined with β-lactam drugs for treating severe infections such as sepsis. Aminoglycoside-modifying enzyme (AME) is the most important mechanism of aminoglycoside resistance and deserves more attention. The bacterium Kluyvera intermedia DW18 was isolated from the sewage of an animal farm using the conventional method. The agar dilution method was used to determine the minimum inhibitory concentrations (MICs) of antimicrobials. A novel resistance gene was cloned, and the enzyme was expressed. The kinetic parameters were measured by a SpectraMax M5 multifunctional microplate reader. Bioinformatic analysis was performed to reveal the genetic context of the aph(3')-Id gene and its phylogenetic relationship with other AMEs. A novel aminoglycoside 3'-O-phosphotransferase gene designated aph(3')-Id was identified in K. intermedia DW18 and shared the highest amino acid identity of 77.49% with the functionally characterized aminoglycoside 3'-O-phosphotransferase APH(3')-Ia. The recombinant plasmid carrying the novel resistance gene (pMD19-aph(3')-Id/E. coli DH5α) showed 1,024-, 512-, 128- and 16-fold increased MIC levels for kanamycin, ribostamycin, paromomycin and neomycin, respectively, compared with the reference strain DH5α. APH(3')-Id showed the highest catalytic efficiency for ribostamycin [kcat/Km of (4.96 ± 1.63) × 105 M-1/s-1], followed by paromomycin [kcat/Km of (2.18 ± 0.21) × 105 M-1/s-1], neomycin [kcat/Km of (1.73 ± 0.20) × 105 M-1/s-1], and kanamycin [kcat/Km of (1.10 ± 0.18) × 105 M-1/s-1]. Three conserved functional domains of the aminoglycoside phosphotransferase family and ten amino acid residues responsible for the phosphorylation of kanamycin were found in the amino acid sequence of APH(3')-Id. No mobile genetic element (MGE) was discovered surrounding the aph(3')-Id gene. In this work, a novel aminoglycoside 3'-O-phosphotransferase gene designated aph(3')-Id encoded in the chromosome of the environmental isolate Kluyvera intermedia DW18 was identified and characterized. These findings will help clinicians select effective antimicrobials to treat infections caused by pathogens with this kind of resistance gene.

Application of Three Compounds Extracted from Cynodon dactylon against Streptococcus mutans Biofilm Formation to Prevent Oral Diseases.

Streptococcus mutans bacteria form a biofilm called plaque that causes oral diseases, including tooth decay. Therefore, inhibition of biofilm formation is essential to maintaining good oral health. The health and nutritional benefits of Cynodon dactylon are well documented, but very little is known about its use to treat against oral diseases. The aim of this study was to detect the adhesion strength of the S. mutans bacterial biofilm in 100 cases in the Rajshahi region and evaluate the inhibitory activity of different compound extracts of C. dactylon on the S. mutans bacterial biofilm by determining the composition of isolated compounds using phytochemical analysis. Nuclear magnetic resonance (NMR) spectroscopy confirmed that three specific compounds from C. dactylon were discovered in this study: 3,7,11,15 tetramethyl hexadec-2-4dien 1-o1, compound 3,7,11,15 tetramethylhexadec-2-en-1-o1 from phytol derivatives, and stigmasterol. Results indicated that the compound of 3,7,11,15-tetramethyl-hexadec-2-en-1-ol exhibited higher antibiofilm activities on S. mutans than those of the other compound extracts. A lower level of minimum inhibitory concentration was exposed by 3, 7, 11,15 tetramethyl hexadeca-2-en-1-o1 (T2) on S. mutans at 12.5 mL. In this case, the compound of 3,7,11,15 tetramethyl hexadec 2en-1-o1 was used, and patients showed a mean value and standard error reduced from 3.42 ± 0.21 to 0.33 ± 0.06 nm. The maximum inhibition was (80.10%) in the case of patient no. 17, with a value of p < 0.05 found for S. mutans to which 12.5 μL/mL ethyl acetate extract was applied. From these findings, it may be concluded that C. dactylon extracts can be incorporated into various oral preparations to prevent tooth decay.

Comparative study of the antibacterial and anti-inflammatory activities of the seed coat vs. seed kernel extracts from the plant Mangifera indica L. in inflammatory acne treatment

Introduction: The present study was developed to investigate and compare the extraction yield, the contents of polyphenols and mangiferin, the activities against Propionibacterium acnes, Staphylococcus aureus, and Escherichia coli bacteria, and the anti-inflammatory activities of ethanol extracts of mango seed kernels vs. seed coats. Methods: Mango seed kernels and seed coats were extracted using ethanol as the solvent and tested against microorganisms using the disc diffusion method. The minimum inhibitory concentration (MIC) levels of extracts were determined by the agar dilution method. The anti-inflammatory activities were assessed both in vitro and in vivo by albumin denaturation method and carrageenan-induced paw edema test, respectively. Results: Both extracts yielded high contents of mangiferin and phenolic compounds. The antibacterial activities of both extracts showed inhibition of the tested microorganisms Propionibacterium acnes and Staphylococcus aureus but not Escherichia coli. Seed kernel extract (0.2 g/kg) reduced paw edema by 44.8% at 3 hours after λ-carrageenan administration. Meanwhile, 0.5 g/kg seed coat extract reduced paw edema less than the seed kernel extract (23.1% vs. 44.8%). Mango seed kernel extract, mango seed coat extract, and diclofenac sodium displayed concentration-dependent inhibition of heat-induced protein denaturation with IC50 values of 137.23 μg/mL, 292.12 μg/mL, and 6.64 μg/mL, respectively. Conclusion: The obtained results confirmed the antibacterial and anti-inflammatory potential of mango seed kernel and seed coat extracts. The mango seed kernel extract was proven to be more effective than the mango seed coat extract and thus can be used in cosmetics as an anti-inflammatory and antibacterial agent.