Mean Minimum Inhibitory Concentration Values Research Articles

Green Synthesis, Characterization, and Evaluation of the Antimicrobial Properties and Compressive Strength of Hydroxyapatite Nanoparticle-Incorporated Glass Ionomer Cement.

Background Glass ionomer cement (GIC) plays a vital role in dental restorative procedures, serving purposes such as filling, luting, and adhesion. However, its inadequate mechanical properties pose challenges, especially in areas experiencing significant stress. To overcome this limitation, nanohydroxyapatite (nHA), known for its bioactive phosphate content, is added to the GIC at specific concentrations to improve its properties. Aim We aim to evaluate the antimicrobial property and compressive strength of green-mediated nHA-incorporated GIC. Material and methods Green synthesis of hydroxyapatite nanoparticles was prepared using Moringa oleifera extract in a solvent form and eggshell waste served as the calcium source. These nHApowders were then integrated into the GICat varying concentrations (3%, 5%, and 10%) designated as Group I, Group II, and Group III, respectively, while Group IV (control) consisted of conventional GIC. Specimens were fabricated and subjected to chemical structure analysis through Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX), and scanning electron microscopy (SEM). The antimicrobial activity and compressive strength of all groups were investigated. The antimicrobial activity against Streptococcus mutans and Lactobacillus was evaluated through the minimum inhibitory concentration (MIC) test, while compressive strength was evaluated by measuring the maximum force endured by the specimen before fracturing. Data analysis utilized IBM SPSS Statistics software, employing repeated measures ANOVA to determine mean MIC values and compressive strength, with Tukey's posthoc test for pairwise comparisons. Results The results of the study showed that the antimicrobial efficacy of nHA GIC improved with increasing weight percent (% wt) of the additive, exhibiting significantly enhanced activity against Streptococcus mutans and Lactobacillus compared to the control group (Group IV) with statistical significance (p < 0.05). Moreover, the compressive strength exhibited notable enhancements in the modified groups, including Group I (172.55 ± 0.76), Group II (178.16 ± 0.760), and Group III (182.45 ± 0.950), when compared to the control (162.46 ± 1.606), with statistically significant differences (p < 0.05). Conclusion The study demonstrates that the incorporation of green-mediated nHA-containing GIC results in superior antimicrobial efficacy and compressive strength compared to the control group (Group IV). In particular, the highest concentration of nHA-modified GIC (10%) exhibited the most favorable antimicrobial properties along with increased strength. Therefore, utilizing green-mediated nHA in the GIC shows promise as an effective restorative material. Future investigations should delve into the molecular chemistry and bonding mechanisms to further explore its potential.

Antimicrobial activity of selected nutraceutical plants used in Northern Uganda

Background: Nutraceutical plants (NP) play a vital role as supportive treatment with antiretroviral drugs (ARVs). However, there is limited scientific evidence on the efficacy of NP to justify their extensive use. This study aimed to evaluate the antibacterial activity of three nutraceutical plants which are commonly used as antimicrobials.&#x0D; Methodology: Leaves of Cajanus cajan L. Millsp. and Eucalyptus globulus Labill., and stem bark of Mangifera indica L. were collected from Northern Uganda. The three samples of each NP were extracted with acetone and the minimum inhibitory concentration (MIC) values of the extracts against Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa and Klebsiella pneumoniae were determined using the serial broth microdilution technique [1]. The mean MIC values of the extracts against each bacterial species were recorded.&#x0D; Results: The three NP extracts were active against all the four bacteria species with MIC ranging from 0.08 to 2.5 mg/ml. The extract of Cajanus cajan was very active against Klebsiella pneumoniae with the lowest recorded MIC value of 0.08 mg/ml. The extract of Mangifera indica bark was very active against Pseudomonas aeruginosa with the lowest MIC of 0.08 mg/ml.&#x0D; Conclusion: The results of the present study support the traditional use of the nutraceutical plants as antimicrobials.

Antibacterial activity of &lt;i&gt;Citrullus lanatus&lt;/i&gt; seed extract against clinical isolates of &lt;i&gt;Klebsiella pneumoniae&lt;/i&gt; and &lt;i&gt;Staphylococcus aureus&lt;/i&gt;

As a result of increased emergence of bacterial resistance to the conventionally used antibiotics, it is necessary to search for alternatives from other sources like plant materials. This study was aimed at evaluating the in vitro antibacterial activity of Citrullus lanatus seed extract against isolates of Klebsiella pneumoniae from urine and Staphylococcus aureus from wound. The seeds were extracted using distilled water and methanol via cold maceration and then analysed for the presence of phytochemicals using standard methods. Tannins, steroids, cardiac glycosides and carbohydrates were present in both extracts. Only the aqueous extract contained alkaloids. The antibacterial activity of the two extracts was determined by agar well diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using broth dilution method. The aqueous extract had better activity than the methanol extract, having inhibition zones of 20 mm and 23 mm at 200 mg/mL and, 10 mm and 11 mm at 25 mg/mL against Klebsiella pneumoniae isolates respectively, and mean zone of inhibition between 27.50 mm to 29.33 mm at 200 mg/mL and, 16.50 mm to 17.33 mm at 25 mg/mL against Staphylococcus aureus isolates with MIC and MBC values of 0.195 mg/mL and 0.39 mg/mL against Klebsiella pneumoniae and, mean MIC and MBC values ranging from 0.30 mg/mL to 0.39 mg/mL and 0.78 mg/mL to 2.73 mg/mL against Staphylococcus aureus isolates. The results obtained reveal the potential use of Citrullus lanatus seeds in the development of standard antibiotics.

Activity of Cefotaxime versus Ceftriaxone against Pathogens Isolated from Various Systemic Infections: A Prospective, Multicenter, Comparative, In vitro Indian Study

Abstract Objectives To determine the susceptibility of isolated pathogens with different samples collected from patients taking cefotaxime as compared with ceftriaxone. Methods In vitro susceptibility study was conducted at microbiology laboratories of east (Bhubaneshwar), west (Ahmedabad), north (Delhi), and south (Srikakulam) India. Samples of treatment naïve patients with various clinical infections were included if they were positive for bacterial culture. Minimum inhibitory concentration (MIC) and zone of inhibitions (ZoIs) for each isolate were determined using Ezy MIC strip test and disk diffusion methods, respectively. Findings of MIC and ZoI were interpreted as per the Clinical and Laboratory Standards Institute guidelines. Appropriate statistical tests were used. Results Four hundred clinical samples of urinary tract infection (42.75%), lower respiratory tract infection (20.75%), skin and soft tissue infection (16.75%), and sepsis (12.75%) were evaluated. Escherichia coli (47.75%) was the most common organism isolated followed by Klebsiella (26%), Salmonella (7.75%), and Proteus mirabilis (3.75%). The mean MIC values for E. coli, Klebsiella, Staphylococcus, Citrobacter koseri, and Serratia marcescens were found to be lower when treated with cefotaxime compared with ceftriaxone, although the difference was not statistically significant. However, cefotaxime produced significantly (p &lt; 0.05) more ZoI for E. coli, Klebsiella, and Salmonella as compared with ceftriaxone. Conclusion Cefotaxime has shown better sensitivity profile in terms of MIC and ZoI to most of the isolated organisms as compared with ceftriaxone and thus can be preferred for empirical treatment of such patients.

Effectiveness of various solvent-produced thyme (Thymus vulgaris) extracts in inhibiting the growth of Listeria monocytogenes in frozen vegetables

The objective of this study was to evaluate the efficiency of thyme extracts in preventing the growth of Listeria monocytogenes in frozen vegetables. In order to investigate the microbiological properties of thyme extracts, Listeria strains were isolated from frozen vegetables and identified, as well as the minimum inhibitory concentration (MIC) of thyme extracts (in vitro study) and their activity in vegetable samples (in vivo study) were determined. Thyme extracts were prepared using ethanol, acetone, and water (cold and hot) from whole plants and different morphological parts of the thyme plant (seeds, leaves, and stems). Selected thyme extracts were assessed for their content of bioactive compounds (total phenolic compounds, flavonoids, carotenoids, and chlorophylls). Furthermore, the profiles of phenolic acids and flavonoids were analyzed using high-performance liquid chromatography (HPLC). The study results showed that 67.2% of the vegetable samples were contaminated by L. monocytogenes strains, with carrots and stir fry mixtures being the most infected samples. The ethanolic and acetone extracts from thyme leaves and seeds were effective bactericidal agents at a concentration of 0.5 of the mean MIC values and proved effective in reducing L. monocytogenes at <2 log CFU/g. The strongest antibacterial activity was found for the acetone extracts from leaves, while the ethanolic extract from seeds exhibited the lowest activity. However, the ethanolic extract from leaves was more effective at a lower concentration. The greatest number of bioactive compounds (including phenolic compounds, carotenoids, and chlorophylls) were determined in the ethanolic and acetone extracts from thyme leaves.

P053 Invasive Mucormycosis (Zygomycosis) -Pre-Covid Era and Covid Era: a retrospective study at a tertiary care centre, chennai

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PMObjectivesTo compare the prevalence and clinical presentation of Mucormycosis in pre-COVID era (January 2017-December 2019) and COVID era (January 2020-till date).To compare the AFST pattern of the zygomycetes causing Mucormycosis in pre-COVID era and COVID era.MethodsThis is a retrospective, hospital-based descriptive study. This study included patients admitted during the pre-COVID and COVID era at a tertiary care center, Chennai. The cases were categorized into two: (1) possible mucormycosis cases which included direct microscopy [Potassium hydroxide (KOH) and histopathological examination] positives and (2) confirmed cases which included direct microscopy and culture positives. Direct microscopic examinations like KOH wet mount and histopathological examination (H and E stain and special stains) were performed. Samples were cultured on Sabourauds dextrose agar and identification was done by analyzing the microscopic morphology using lactophenol cotton blue mount. AFST was performed for culture positive isolates with amphotericin B, itraconazole, posaconazole, voriconazole and isavuconazole by microbroth dilution method according to CLSI M38-A2.ResultsDuring the Pre-COVID era, out of the 365 samples received in the laboratory, 35 were possible mucormycosis cases. Only 17 were confirmed cases, out of which 16 grew Rhizopus oryzae and 1 grew Apophysomyces elegans. During the COVID era, among 886 samples received in the laboratory, 143 were possible mucormycosis cases, and 31 were confirmed cases that grew Rhizopus oryzae (26), Rhizomucor pusillus (2), Mucor sp (2), and Basidiobolus ranarum (1). Though the risk factors were common during the pre-COVID and COVID era, additional risk factors like steroid therapy (19.2%), and COVID infection (28.7%) were seen during the COVID era. Though clinical presentations were common during both pre-COVID and COVID era, additional complications like epistaxis (0.57%), orbital cellulitis (32.7%), and loss of smell (8.04%) were seen during COVID era. The prevalence of complications was more during COVID era compared to pre-COVID era. Treatment received during the pre-COVID era was only amphotericin B, whereas during the COVID era majority of the patients received posaconazole (74.5%) followed by liposomal amphotericin B (25.5%). The antifungal susceptibility test showed the following mean minimum inhibitory concentration (MIC) values: amphotericin B (1.8 μg/ml), itraconazole (3.6 μg/ml), posaconazole (0.31 μg/ml), and voriconazole (1.61 μg/ml) during the pre-COVID era while the mean MIC values during the COVID era had the following variations: amphotericin B (0.97 μg/mL), itraconazole (13.6 μg/ml), Posaconazole (13.4 μg/ml), voriconazole (14.5 μg/ml), and isavuconazole (1.10 μg/ml).ConclusionHigh incidence of Mucormycosis during the COVID-19 era may be related to common risk factors of COVID and mucormycosis. Though most of the risk factors and clinical presentations were similar during the pre-COVID and COVID era, serious complications like loss of vision and the percentage of complications were more during COVID era which may be attributed to the increased invasiveness of Zygomycetes during COVID infection. The high mean MIC value of amphotericin B during pre-COVID era and higher mean MIC value of posaconazole during COVID era may be contributed to the higher usage of these antifungals. Usage of the antifungal agents is the main contributor toward the resistance. Newer azole like isavuconazole which had a low mean MIC in our study, can be considered as a good therapeutic option for the future management of resistant infections. Hence timely management of the patients with an appropriate antifungal agent by performing AFST will help in the reduction of resistance in the future.

Comparison of Antifungal Activity of Jaftex Mouthwash and Nystatin Suspension against the Growth of Candida albicans.

Objective: Oral candidiasis is an opportunistic fungal infection in the oral cavity caused by an overgrowth of Candida species, especially Candida albicans. Various herbal agents have been designed to target Candida albicans. The aim of this study was to evaluate the antifungal activity of Jaftex mouthwash and nystatin suspension on the growth of Candida albicans. Materials and methods:In the present in vitro study, a standard strain of Candida albicans was prepared in the form of lyophilized ampoules. Jaftex mouthwash was prepared with an active ingredient (10 g per 100 cc) of aqueous extract of oak fruit hull (Jaft), Zataria multiflora and Satureja bachtiarica. Nystatin oral suspension (100,000 IU/mL) was also prepared. Both mouthwashes were serially diluted using the two-fold serial dilution method (Jaftex: eight-fold dilutions; nystatin suspension: nine-fold dilutions). A volume of 10 ìL of each dilution of Jaftex mouthwash and nystatin suspension was placed on the discs that were linearly inoculated on culture medium and stored in an incubator for 24 hours at 37 °C. The minimum inhibitory concentration (MIC) of the two antifungal agents was determined using the modified E-test. Data were analyzed using SPSS Version 26.0. A p-value less than 0.05 was considered statistically significant. Results:The mean MIC values of Jaftex mouthwash and nystatin suspension were 0.0625 (mg/mL) and 0.0015 (mg/mL), respectively. There was a significant difference between the antifungal effect of Jaftex mouthwash and nystatin suspension on the growth of Candida albicans. Nystatin showed the lowest MIC and greater antifungal activity compared with Jaftex mouthwash. Conclusion:Nystatin increasingly suppressed the growth of Candida albicans. Jaftex mouthwash inhibited the growth of Candida albicans. Since nystatin may show allergic reactions, Jaftex mouthwash can be used as an alternative to nystatin. Due to the synergistic effect of nystatin with thymol, Jaftex mouthwash can be prescribed with nystatin.

Chemical composition analysis of essential oils of four plants from Aurès region of Algeria and their antibacterial and antibiofilm activities against coagulase-negative staphylococci

Background: The altitudinal and geographical variability of the Aurès mountains of Algeria favored the existence of some endemic and rare varieties of medicinal plants. The aim of the present work is to determine the chemical composition, antimicrobial and antibiofilm properties of the essential oils (EOs) from aerial parts of four medicinal plants from Aurès region of Algeria; Juniperus thurifera L., Juniperus oxycedrus L., Salvia officinalis L. and Thymus ciliatus ssp. munbyanus (Boiss. &amp; Reut.) Batt. on coagulase negative staphylococci (CoNS) isolates.&#x0D; Methodology: Extraction of EOs from the four plant materials was carried out by hydro-distillation, and the EO yield expressed in gram of the distillate per 100 grams of dry matter. The chemical composition of the EOs was analyzed by gas chromatography-mass spectrometry (GC-MS) method. In vitro antibacterial and antibiofilm activities of the EOs were evaluated against CoNS previously isolated at the Anti-Cancer Center of Batna, Algeria using the agar disc diffusion assay and biofilm inhibition study, respectively. Minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) of the EOs of S. officinalis L. and T. ciliatus ssp. munbyanus were determined by the dilution method.&#x0D; Results: Twenty-seven and 41 compounds rich in monoterpene hydrocarbons were identified from J. oxycedrus and J. thurifera plants respectively, while 45 and 32 compounds, constituted mainly by oxygenated monoterpenes, were identified from S. officinalis L. and T. ciliatus ssp. munbyanus, respectively. The EOs of T. ciliatus ssp. munbyanus showed the most inhibitory activity of all the four plants on CoNS isolates (n=66) with mean inhibition zone diameter of 24.99±6.29mm, and mean MIC and MBC values of 2.65±3.77mg/ml and 5.31±7.41mg/ml respectively, followed by S. officinalis L., with mean inhibition zone diameter of 13.38± 6.52mm, and mean MIC and MBC values of 27.53±28.2 mg/ml and 31.97±33.19 mg/ml respectively (p&lt;0.0001 by one-way ANOVA). Also, percentage biofilm inhibition of CoNS isolates (n=59) was high for EOs of T. ciliatus ssp. munbyanus (65.63±10.71%) and S. officinalis L. (53.13±5.83%), although was significantly higher for T. ciliatus ssp. munbyanus compared to S. officinalis L. (p&lt;0.0001, t=7.874).&#x0D; Conclusion: Essential oils from T. ciliatus ssp. munbyanus and S. officinalis L. could represent an alternative to classical antibiotics against planktonic cells and biofilms of CoNS.

Disinfection Strategies for Carbapenem-Resistant Klebsiella pneumoniae in a Healthcare Facility.

Disinfectant resistance is evolving into a serious problem due to the long-term and extensive use of disinfectants, which brings great challenges to hospital infection control. As a notorious multidrug-resistant bacterium, carbapenem-resistant Klebsiella pneumoniae (CRKP) is one of the most common and difficult pathogens of nosocomial infection. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests of seven kinds of disinfectants (0.1% benzalkonium bromide, 4% aqueous chlorhexidine, 75% alcohol, entoiodine II, 2% glutaraldehyde, 2000 mg/L chlorine-containing disinfectants, and 3% hydrogen peroxide) were detected by the broth dilution method. Three efflux pump genes (oqxA, oqxB, and qacE∆1-sul1) were detected by PCR. The mean MIC value of aqueous chlorhexidine from the intensive care unit (ICU) (0.0034%) was significantly higher than that from non-ICUs (0.0019%) (p < 0.05). The positive rates of three efflux pump genes oqxA, oqxB and qacE∆1-sul1 were 60.9% (39/64), 17.2% (11/64) and 71.9% (46/64) in the detected CRKP isolates, respectively. This study discovered that CRKP strains demonstrated extensive resistance to clinical disinfectants and suggest that it is necessary to perform corresponding increases in the concentration of aqueous chlorhexidine and chlorine-containing disinfectants on the basis of current standards in the healthcare industry.

In-vitro Evaluation of Antimicrobial Activity of Nargenicin-A1 against Gram Positive Clinical Isolates and its Comparison with Various Antibiotics

Introduction: The development of multidrug resistance is a serious health problem, which demands the quest and development of many antibacterial agents. The class Actinomycetes represents best source for many antimicrobial agents. The present focus on Actinomycetes has yielded many antimicrobial agents including Nargenicin-A1. The Nargenicin-A1 belonging to class macrolides was found to have strong antibacterial activity against Staphylococcus and Streptococcus. Aim: To determine the Minimum Inhibitory Concentration (MIC) of Nargenicin-A1 against clinically isolated aerobic gram positive bacteria and comparing its antimicrobial activities with various antibiotics. Materials and Methods: A prospective, hospital-based, observational study was conducted at the Department of Microbiology, Raichur Institute of Medical Sciences, Raichur, Karnataka, India, from August 2015 to July 2016. All the clinical samples like pus, sputum, urine, ear swabs, wound swabs and body fluids received for culture and sensitivity testing at the Department of Microbiology during the study period was included. The antimicrobial activity was determined by measuring the MIC of Nargenicin-A1 by broth dilution method following standard procedure and the mean MIC was calculated. Pearson’s coefficient of correlation was calculated to find out correlation between MIC of Nargenicin-A1 and MIC of various antibiotics effective against gram positive bacteria. Results: The most common isolate was Staphylococcus followed by Enterococcus and Streptococcus. The least mean MIC of Nargenicin-A1 was observed for Streptococcus (0.017 μg/mL) followed by S. aureus (3.97 μg/mL), and the highest mean MIC value was recorded for Enterococcus (27.34 μg/ mL). Among Staphylococcus aureus, the mean MIC value of Nargenicin-A1 for Methicillin Sensitive Staphylococcus aureus (MSSA), Methicillin Resistant Staphylococcus aureus (MRSA) and Vancomycin Resistant Staphylococcus aureus (VRSA) was 0.06 μg/mL, 0.12 μg/mL and 25 μg/mL, respectively. When compared Nargenicin-A1 with various antibiotics in terms of their MICs, the activity of Nargenicin-A1 was in close proximity to that of vancomycin and linezolid against MSSA, MRSA, and Enterococci and marginally with linezolid against VRSA. Conclusion: Nargenicin-A1 exhibits strong antibacterial property against a broad spectrum of aerobic gram positive bacteria, including VRSA. The study revealed that Nargenicin-A1 can be considered as a potential alternative against multidrug resistant gram positive bacteria.

A Clinico-mycological, Antifungal Drug Sensitivity and Therapeutic Study of Extensive Dermatophytosis in Coastal Andhra Pradesh.

In India, an increased prevalence of chronic, recurrent, and recalcitrant dermatophytosis is being observed. The present study assesses the clinico-mycological profile, antifungal drug sensitivity and therapeutic efficacy of various systemic antifungal drug regimens, in extensive dermatophytosis patients of coastal Andhra Pradesh. One hundred and fifty clinically diagnosed cases of extensive dermatophytosis affecting more than one body region were enrolled. Skin samples were taken for direct microscopy and fungal culture. Antifungal drug sensitivity testing was done with broth microdilution test. Therapeutic efficacy of systemic antifungal drug regimens was determined by randomly dividing the patients into 5 groups of 30 each. The most common clinical patterns observed were tinea corporis et cruris (62.7%) followed by extensive tinea corporis (11.3%). KOH and culture positivity were seen in 132 (88%) and 84 cases (56%) respectively. Trichophyton mentagrophytes was isolated in 78 cases (92.8%) followed by Microsporum gypseum in 6 patients (7.1%). The overall mean minimum inhibitory concentration values for itraconazole (0.04 μg/mL) were low when compared to griseofulvin (4.61 μg/mL) and terbinafine (6.9 μg/mL) (P < 0.05). Combination of itraconazole and griseofulvin achieved highest clinical and mycological cure rates (93.1%). Among patients receiving single drugs, itraconazole had higher cure rates (71.4%) compared to terbinafine (59.2%) and griseofulvin (53.8%) (P < 0.05). Trichophyton mentagrophytes has replaced Trichophyton rubrum as the predominant species causing dermatophytosis in Andhra Pradesh, presenting with a severe phenotype. Itraconazole was found to be the most effective drug both in vivo and in vitro. A combination of systemic drugs should be considered in cases of monotherapy failure and in recalcitrant dermatophytosis.

The Synergistic Activity of Eugenol and Fluconazole on the Induction of Necrosis and Apoptosis in Candida Krusei Isolates of HIV+ Patients With Oral Candidiasis

Aims: The oral cavity contains more than 200 microbial species. Candida species are also part of the fungal flora of the oral cavity. In recent years, Candida krusei, as a common oral candida in AIDS patients, has been shown resistant to some antifungal drugs. The emergence of multidrug-resistant fungi, especially in immunodeficient populations, is a major global problem. Today, medicinal plants and their pure compounds in treating infectious diseases have provided a new horizon. This study aimed to investigate the synergistic activity of eugenol and fluconazole on the necrosis and apoptosis of Candida krusei (C. krusei) isolates from HIV+ patients with oral candidiasis. Methods &amp; Materials: The antifungal susceptibility tests were performed using the broth microdilution (CLSI, M27-A2) method, and the synergy between eugenol and fluconazole was evaluated using the checkerboard method. Necrotic and apoptotic effects of different antifungal agents against C. krusei were analyzed using the flow cytometry method. Findings: In antifungal susceptibility tests by microdilution broth, the mean minimum inhibitory concentration (MIC) values of eugenol and fluconazole for C. krusei isolates were 755.06 and 60.1 µg/mL, respectively. According to the checkerboard test results, eugenol in combination with fluconazole exhibited significant synergistic effects against most of the yeast isolates tested (P&lt;0.05). Eugenol decreased approximately 81.81% of the MIC value of fluconazole in growth inhibition of C. krusei. The flow cytometry test results indicated that eugenol plus fluconazole has significant necrotic effects on C. krusei isolates compared with the control group (P&lt;0.05). In contrast, minor early and late apoptotic effects of this compound were observed. Conclusion: Eugenol can be used to reduce fluconazole dose, inhibit the growth of fluconazole-resistant C. krusei, and the necrosis of yeast cells.

Effects of Bunium persicum essential oil on the reduction of spore germination, growth, and expression of FUM1 and FUM14 genes in Fusarium verticillioides isolates.

Background and Purpose: Black Cumin of Kerman (Bunium persicum) is an Iranian plant that is commonly used as an antispasmodic, carminative, and antimicrobial substance. The present study aimed to assess different components of the essence of B. persicum and its effect on antifungal activity, spore germination inhibition, and expressions of FUM1 and FUM14 genes in Fusarium verticillioides strains.Materials and Methods: The essence was extracted by hydrodistillation and analyzed through gas chromatography-mass spectroscopy. A broth microdilution method was used for the determination of the minimum inhibitory concentration (MIC). In addition, the expression of FUM1 and FUM14 genes of toxigenic F. verticillioides was assessed by using the real-time polymerase chain reaction (RT-PCR) technique.Results: Based on the findings, most of the essence consisted of γ-terpinene (15.56%), propanal, and 2-methyl-3-phenyl (14.18%). The oil showed a good antifungal activity (mean MIC value: 2556.8 μg/ml) as well as the inhibition of spore germination and mycelial growth (P<0.05). The RT-PCR demonstrated that the expression levels of FUM1 and FUM14 of B. persicum-treated F. verticillioides were 0.43 and 0.53 folds lower than the control samples, respectively.Conclusion: These findings revealed that the essential oil of B. persicum has different components responsible for the inhibition of mycelial growth and spore germination of F. verticillioides as well as reduction of expressions of FUM1 and FUM14 genes involving fumonisin production.

Assessment of (-) epicatechin as natural additive for improving safety and functionality in fresh "Piel de Sapo" melon juice.

Epicatechin (EC) is a very abundant flavonoid in vegetable tissues that presents high antioxidant activity in living systems. The minimum inhibitory concentration (MIC) of (‐)EC was determined in three species of bacteria commonly associated with foodborne illness of plant origin: Listeria (L.) monocytogenes, Escherichia (E.) coli ‐serogroups O157: H7 and O111‐ and Bacillus (B.) cereus; two strains of probiotic‐type lactic acid bacteria (PT‐LAB) and two control strains. All 10 strains were assayed under three temperature conditions (30º, 10º, and 4ºC) and at each temperature under two pH conditions (6.7 and 5.5). Mean EC MIC values were generally lower at refrigeration (4º and 10ºC) temperatures and at standard pH (6.7). By inoculating with each of the strains separately, both melon juice (MJ) and MJ supplemented with EC (ECSMJ), at the accepted maximum sensorial limit, and storing them at 4ºC for 10 days; the final counts (CFU/mL) were lower for ECSMJ than for plain MJ both for pathogenic bacteria and for PT‐LAB. The presence of EC during refrigerated storage counteracted the ability of MJ as a growth medium for all the pathogenic bacteria. ECSMJ increased the antioxidant activity of MJ significantly to levels similar to those of EC alone. (‐) Epicathechin would be a promising ingredient for increasing the functional properties of “Piel de Sapo” MJ (phenolic compounds and antioxidant ability) while contributing to improving the safety of this type of juice during prolonged refrigerated storage at 4ºC.

Green tea catechins showed antibacterial activity on streptococcus mutans -An in vitro study.

The main bacterial aetiological agents in caries formation are the α-haemolytic Streptococcal species Streptococcus mutans, which has been found to be the initiator of most dental caries. The leaves of Camellia sinensis known as green tea, has properties, such as antibacterial and anti-cariogenic. Epigallocatechin-3-gallate (EGCG) one of the most abundant catechins found in green tea is known to contribute to these effects. To evaluate the antibacterial effect of green tea catechins namely EGCG on S. mutans with two different methods at different concentrations. 1) To assess the antimicrobial efficacy of EGCG by disc diffusion test at concentrations of 100, 75, and 50 μg/mL. 2) To assess the antimicrobial efficacy of EGCG by Minimum inhibitory concentration (MIC) test at concentrations ranging from 0.2 to 100 μg/mL. Commercially available purest form of green tea polyphenol EGCG was used in the study. Disc diffusion test on agar medium and MIC test was used to determine the susceptibility of the S. mutans to green tea catechins EGCG. The results of the agar well diffusion method showed that the EGCG extract has shown zones of inhibition against S. mutans at concentrations of 100 μg/mL (28.67 mm), 75 μg/mL (15.33 mm), 50 μg/mL (10.33 mm) while that of MIC test of EGCG extract of concentrations ranging from 0.2 to 100 μg/mL against S. mutans shows that the mean MIC value was 1.07. Catechins in the tea are potentially anti-cariogenic agents which can reduce bacterial presence in the oral cavity and have the potential to be further used for the preparation of dentifrice and mouthwash.

Comparison of antimicrobial activity of mycelium and spore of Ganoderma Lucidum on Prevotella Intermedia isolated from chronic periodontitis patients

Aim: The study aimed at comparing the antimicrobial activity of mycelium and spore of Ganoderma lucidum on Prevotella intermedia isolated from subgingival plaque of chronic periodontitis patients. Settings and Design: Written informed consent was obtained from each subject enrolled in the study. The institutional ethics committee granted ethical clearance for the study. Materials and Methods: Twenty patients diagnosed with chronic periodontitis were included in the study. Using sterile curettes, pooled subgingival plaque samples were collected from the deepest sites of periodontal pockets. The collected samples were then transported in 1 mL of reduced transport fluid. The organisms were cultured and confirmed and were used for the minimum inhibitory concentration (MIC) procedure. Statistical Analysis: Mean of the MIC value obtained was calculated. Comparison between the antimicrobial activity of mycelium and spore against P. intermedia groups with respect to mean MIC value (in mcg/ml) was done by Mann–Whitney U test. Comparison of antimicrobial activity of mycelium and spores of G. lucidum against P. intermedia expressed by the MIC value at different concentrations was done by Chi-square test. Results: The mean MIC obtained for mycelium was 5.64 mcg/ml. The mean MIC obtained for spore was 3.62 mcg/ml. Results of the comparison of antimicrobial activity implied that the antimicrobial activity of mycelium and spore of G. lucidum was comparable. Conclusions: Both mycelium and spore of G. lucidum with its bioactivity could be used as an antimicrobial, in combination with conventional therapy in periodontal disease.

Minimum Inhibitory Concentration of Glyphosate and of a Glyphosate-Containing Herbicide Formulation for Escherichia coli Isolates - Differences Between Pathogenicand Non-pathogenic Isolates and Between Host Species.

Glyphosate is the most extensively used herbicide in the world. However, concerns regarding its safety, side effects, and impact on other organisms have increased in recent years. This is the first study to analyze a large set of recent and historical Escherichia coli isolates varying in pathogenicity and beta-lactam resistance from different host species for their susceptibility to glyphosate isopropylamine salt (IPA), the active ingredient of the herbicide, and to a complete glyphosate-containing formulation (Roundup LB Plus). For this, minimum inhibitory concentrations (MIC) were determined for 238 E. coli isolates by broth microdilution in Mueller Hinton I media followed by the statistical analyses using Mann-Whitney-U test, multivariable analysis of variance (ANOVA) and a multivariable proportional-odds ordinal regression model. While the overall MIC distribution was narrow and lacked a highly resistant sub-population for both substances, statistical analyses revealed small but significant associations between glyphosate resistance levels and different factors tested. Mean MIC values for the entire dataset showed a higher level of resistance to the complete glyphosate-containing formulation (40 mg/ml IPA) than to pure glyphosate (10 mg/ml IPA) in E. coli. Isolates that originated from poultry had significantly higher MIC values for both pure glyphosate and the complete formulation. Pathogenic and non-extended-spectrum beta-lactamase (non-ESBL) E. coli isolates each showed significantly higher MIC values compared to commensals and ESBL-producing E. coli in pure glyphosate, but not in the complete formulation. Recently sampled isolates showed statistically higher MICs than the isolates of the historic standard E. coli collection of reference in pure glyphosate, when tested by nonparametric Mann-Whitney-U test, but not in the multivariable model. Further investigations are necessary to confirm whether these associations have a casual relationship with the glyphosate use or are the consequence of co-selection due to the increased application rates of antibiotics, heavy metals or other biocides. A possible accumulation of pathogenic bacteria in livestock animals fed with glyphosate-containing feed should also be considered.

Molecular types of Cryptococcus neoformans and Cryptococcus gattii in Western Australia and correlation with antifungal susceptibility

Cryptococcus neoformans and Cryptococcus gattii species complexes have a worldwide distribution; however, there is geographical variation in the prevalence of different molecular types. Additionally, antifungal susceptibility differences between molecular types have been demonstrated. This study investigates the distribution of cryptococcal molecular types among human clinical isolates over a 10-year period from a Western Australian population. Molecular type was determined based on polymorphisms in the phospholipase gene locus identified through amplification and sequencing. Minimum inhibitory concentrations (MICs) were identified for fluconazole, 5-fluorocytosine, posaconazole, itraconazole, voriconazole, and amphotericin B. Most isolates were C. neoformans complex (42) of which over half were molecular type VNI (22) followed by VNII (20). Among the remaining C. gattii complex (13) the majority were VGI (11) with VGII (2) uncommonly found. All isolates demonstrated low MICs to antifungal agents including fluconazole. Geometric mean MIC values against 5-fluorocytosine for VNI (1.741mg/l) were significantly higher than those for VGI (0.47mg/l, P = .002). Similarly fluconazole geometric mean MICs against fluconazole for VNI (2.3mg/l) were significantly higher than VNII (0.87mg/l, P = .036). These data reveal the presence of four molecular types (VNI, VNII, VGI and VGII) within clinical Western Australian cryptococcal isolates and, while elevated antifungal MICs were not encountered, significant molecular type dependent differences in susceptibility were found.

Impact of heavy metals on inhibitory concentration of Escherichia coli-a case study of river Yamuna system, Delhi, India.

The occurrence of resistant bacteria to specific heavy metals can be associated with increasing load of the metals in the environment. River Yamuna is polluted by various toxic heavy metals discharged by several industrial and agricultural sources. Therefore, the use of heavy metal-resistant bacteria as an indicator of metal pollution was tested in the present study. For the purpose of the study, the heavy metal resistance status of 42 Escherichia coli strains isolated from River Yamuna water from 7 sampling sites within a span of 2years was determined using growth curves and plate dilution method in terms of minimum inhibitory concentration (MIC) values by comparing with MIC value of control strain. Seasonally, the lowest mean MIC value was observed for bacterial strains isolated in post-monsoon (December) 2013 and highest mean MIC value was observed for bacterial strains isolated in monsoon (August) 2015. Site-wise analysis of the maximum mean MIC values for all the isolated strains showed the highest mean Ni MIC value for the bacterial strains isolated from site S4 (ITO), highest mean Cu MIC, Cr MIC, and Fe MIC values for the bacterial strains isolated from site S2 (Najafgarh drain intermixing zone) and highest mean Cd MIC, Pb MIC, and Zn MIC values for the bacterial strains isolated from site S7 (Shahdara drain intermixing zone). Correlation analysis between mean MIC site-wise results with mean heavy metal site-wise concentrations showed significant positive correlation indicating that the higher the mean concentration of a given heavy metal at a given site, the higher the mean MIC value for the strains isolated from the same site indicating higher level of resistance. Overall, the present study has shown that the presence of heavy metals in River Yamuna caused due to indiscriminate discharge of various effluents from different kind of sources as well as due to insufficient treatment capacity of sewage treatment plants as well as common effluent treatment plants, has serious impacts on its bacterial microflora as it leads to the development of resistant strains.

Antibacterial Activity of Pomegranate (Punica granatum L.) Seed and Peel Alcoholic Extracts on Staphylococcus aureus and Pseudomonas aeruginosa Isolated From Health Centers

Introduction: Pomegranate (Punica granatum L.) is an ancient fruit with numerous phytochemical bioactive compounds. In this study, the antibacterial activity of ethanolic extracts of pomegranate peels and seeds were investigated against Pseudomonas aeruginosa and Staphylococcus aureus clinical isolates from Tabriz health centers (2017). Materials and Methods: The ethanolic extracts of pomegranate seed and peel were prepared and GC-MS chromatogram analyzed using Agilent 7890B gas chromatography. The antibacterial activities of extracts were evaluated by agar diffusion and microbroth dilution methods against clinical isolates of P. aeruginosa (n = 10), S. aureus (n = 10) and standard strains. Results: The ethanolic extracts of pomegranate seed and peel showed inhibitory effects on clinical isolates of P. aeruginosa and S. aureus. The minimum inhibitory concentrations (MICs) of pomegranate peel and seed extracts were 12.5 and 25.0 mg/mL, respectively. In addition, the minimum bactericidal concentrations (MBCs) of pomegranate peel and seed extracts were found to be 25.0 and 50 mg/mL, respectively. In all of the studied bacterial isolates, the MICs and MBCs values for pomegranate seed extract were significantly higher than those for pomegranate peel extract (P < 0.05). The mean inhibition zones and MICs values indicated that the antibacterial activity of pomegranate peel extract had more potent effect on studied bacterial isolates compared with pomegranate seed extract. Conclusions: According to the findings, the pomegranate peel and seed extracts showed antibacterial activities against bacterial isolates in this study; however, the peel extract had a stronger antibacterial effect than the seed extract. Therefore, further studies including cell toxicity assay and in vivo investigations are recommended. © 2018 The Author(s).