scholarly journals Curcumin, a Natural Antimicrobial Agent with Strain-Specific Activity

2020 ◽  
Vol 13 (7) ◽  
pp. 153
Author(s):  
Artur Adamczak ◽  
Marcin Ożarowski ◽  
Tomasz M. Karpiński
Keyword(s):  
Inhibitory Concentration ◽  
Specific Activity ◽  
Curcuma Longa ◽  
Antimicrobial Properties ◽  
Antiviral Agent ◽  
Multidrug Resistant ◽  
Gram Negative Bacteria ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Bioactive Substance

Curcumin, a principal bioactive substance of turmeric (Curcuma longa L.), is reported as a strong antioxidant, anti-inflammatory, antibacterial, antifungal, and antiviral agent. However, its antimicrobial properties require further detailed investigations into clinical and multidrug-resistant (MDR) isolates. In this work, we tested curcumin’s efficacy against over 100 strains of pathogens belonging to 19 species. This activity was determined by the broth microdilution method and by calculating the minimum inhibitory concentration (MIC). Our findings confirmed a much greater sensitivity of Gram-positive than Gram-negative bacteria. This study exhibited a significantly larger variation in the curcumin activity than previous works and suggested that numerous clinical strains of widespread pathogens have a poor sensitivity to curcumin. Similarly, the MICs of the MDR types of Staphylococcus aureus, S. haemolyticus, Escherichia coli, and Proteus mirabilis were high (≥2000 µg/mL). However, curcumin was effective against some species and strains: Streptococcus pyogenes (median MIC = 31.25 µg/mL), methicillin-sensitive S. aureus (250 µg/mL), Acinetobacter lwoffii (250 µg/mL), and individual strains of Enterococcus faecalis and Pseudomonas aeruginosa (62.5 µg/mL). The sensitivity of species was not associated with its affiliation to the genus, and it could differ a lot (e.g., S. pyogenes, S. agalactiae and A. lwoffii, A. baumannii). Hence, curcumin can be considered as a promising antibacterial agent, but with a very selective activity.

scholarly journals Ceftazidime–avibactam and ceftolozane–tazobactam susceptibility of multidrug resistant Pseudomonas aeruginosa strains in Hungary

2020 ◽  
pp. 1-5 ◽  
Author(s):  
Dustin O'Neall ◽  
Emese Juhász ◽  
Ákos Tóth ◽  
Edit Urbán ◽  
Judit Szabó ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Inhibitory Concentration ◽  
Carbapenem Resistance ◽  
Multidrug Resistant ◽  
Test Results ◽  
Diffusion Test ◽  
Microdilution Method ◽  
Carbapenem Resistant ◽  
Gradient Diffusion ◽  
Broth Microdilution Method

Abstract Our objective was to compare the activity ceftazidime-avibactam (C/A) and ceftolozane–tazobactam (C/T) against multidrug (including carbapenem) resistant Pseudomonas aeruginosa clinical isolates collected from six diagnostic centers in Hungary and to reveal the genetic background of their carbapenem resistance. Two hundred and fifty consecutive, non-duplicate, carbapenem-resistant multidrug resistant (MDR) P. aeruginosa isolates were collected in 2017. Minimal inhibitory concentration values of ceftazidime, cefepime, piperacillin/tazobactam, C/A and C/T were determined by broth microdilution method and gradient diffusion test. Carbapenem inactivation method (CIM) test was performed on all isolates. Carbapenemase-encoding blaVIM, blaIMP, blaKPC, blaOXA-48-like and blaNDM genes were identified by multiplex PCR. Of the isolates tested, 33.6& and 32.4& showed resistance to C/A and C/T, respectively. According to the CIM test results, 26& of the isolates were classified as carbapenemase producers. The susceptibility of P. aeruginosa isolates to C/A and C/T without carbapenemase production was 89& and 91&, respectively. Of the CIM-positive isolates, 80& were positive for blaVIM and 11& for blaNDM. The prevalence of Verona integron-encoded metallo-beta-lactamase (VIM)-type carbapenemase was 20.8&. NDM was present in 2.8& of the isolates. Although the rate of carbapenemase-producing P. aeruginosa strains is high, a negative CIM result indicates that either C/A or C/T could be effective even if carbapenem resistance has been observed.

Evaluation of the in vitro interaction of fosfomycin and meropenem against metallo-β-lactamase–producing Pseudomonas aeruginosa using Etest and time-kill assay

2020 ◽  
pp. jim-2020-001573
Author(s):  
Sanjida Jahan ◽  
Heather Davis ◽  
Deborah S Ashcraft ◽  
George A Pankey
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Inhibitory Concentration ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Time Kill ◽  
In Vitro Interaction ◽  
Antimicrobial Combinations

Pseudomonas aeruginosa is a nosocomial pathogen containing various resistance mechanisms. Among them, metallo-β-lactamase (MBL)–producing Pseudomonas are difficult to treat. Fosfomycin is an older antibiotic that has recently seen increased usage due to its activity against a broad spectrum of multidrug-resistant organisms. Our aim was to evaluate the combination of fosfomycin and meropenem against 20 MBL-producing P. aeruginosa (100% meropenem-resistant and 20% fosfomycin-resistant) using both an Etest minimal inhibitory concentration (MIC): MIC method and time-kill assay. MICs for fosfomycin and meropenem were determined by Etest and by broth microdilution method for the latter. The combination demonstrated synergy by Etest in 3/20 (15%) isolates and 5/20 (25%) isolates by time-kill assay. Results from the Etest method and time-kill assay were in agreement for 14/20 (70%) of isolates. No antagonism was found. Comparing both methods, Etest MIC: MIC method may be useful to rapidly evaluate other antimicrobial combinations.

scholarly journals Enhancement of Antibiotic Activity by 1,8-Naphthyridine Derivatives against Multi-Resistant Bacterial Strains

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7400
Author(s):  
José B. de Araújo-Neto ◽  
Maria M. C. da Silva ◽  
Cícera D. de M. Oliveira-Tintino ◽  
Iêda M. Begnini ◽  
Ricardo A. Rebelo ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Bacterial Resistance ◽  
Antimicrobial Properties ◽  
Multidrug Resistant ◽  
Antibiotic Activity ◽  
Bacterial Strains ◽  
Microdilution Method ◽  
Fluoroquinolone Antibiotics ◽  
Broth Microdilution Method ◽  
Resistant Strains

The search for new antibacterial agents has become urgent due to the exponential growth of bacterial resistance to antibiotics. Nitrogen-containing heterocycles such as 1,8-naphthyridine derivatives have been shown to have excellent antimicrobial properties. Therefore, the purpose of this study was to evaluate the antibacterial and antibiotic-modulating activities of 1,8-naphthyridine derivatives against multi-resistant bacterial strains. The broth microdilution method was used to determine the minimum inhibitory concentration (MIC) of the following compounds: 7-acetamido-1,8-naphthyridin-4(1H)-one and 3-trifluoromethyl-N-(5-chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide. The antibiotic-modulating activity was analyzed using subinhibitory concentrations (MIC/8) of these compounds in combination with norfloxacin, ofloxacin, and lomefloxacin. Multi-resistant strains of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus were used in both tests. Although the compounds had no direct antibacterial activity (MIC ≥ 1.024 µg/mL), they could decrease the MIC of these fluoroquinolones, indicating synergism was obtained from the association of the compounds. These results suggest the existence of a structure–activity relationship in this group of compounds with regard to the modulation of antibiotic activity. Therefore, we conclude that 1,8-naphthyridine derivatives potentiate the activity of fluoroquinolone antibiotics against multi-resistant bacterial strains, and thereby interesting candidates for the development of drugs against bacterial infections caused by multidrug resistant strains.

scholarly journals Antimicrobial Activity of Ceftazidime-Avibactam against Gram-Negative Bacteria Isolated from Patients Hospitalized with Pneumonia in U.S. Medical Centers, 2011 to 2015

2017 ◽  
Vol 61 (4) ◽  
Author(s):  
Helio S. Sader ◽  
Mariana Castanheira ◽  
Robert K. Flamm
Keyword(s):  
Multidrug Resistant ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Content Type ◽  
Negative Results ◽  
Highly Active ◽  
Microdilution Method ◽  
Medical Centers ◽  
Broth Microdilution Method ◽  
Gram Negative Organisms

ABSTRACT Bacterial isolates were collected from patients hospitalized with pneumonia (PHP), including ventilator-associated pneumonia (VAP), from 76 U.S. medical centers in 2011 to 2015. The Gram-negative organisms (n = 11,185, including 1,097 from VAP) were tested for susceptibility to ceftazidime-avibactam and comparators by the broth microdilution method. β-Lactamase-encoding genes were screened using a microarray-based assay on selected isolates. Pseudomonas aeruginosa and Klebsiella spp. were the most common Gram-negative bacteria isolated from PHP and VAP. Ceftazidime-avibactam was very active against P. aeruginosa (n = 3,402; MIC50/MIC90, 2 and 4 μg/ml; 96.6% susceptible), including isolates nonsusceptible to meropenem (86.3% susceptible to ceftazidime-avibactam), piperacillin-tazobactam (85.6% susceptible), or ceftazidime (80.6% susceptible). Ceftazidime-avibactam was also highly active against Enterobacteriaceae (MIC50/MIC90, 0.12 and 0.5 μg/ml; 99.9% susceptible), including carbapenem-resistant Enterobacteriaceae (CRE) (n = 189; MIC50/MIC90, 0.5 and 2 μg/ml; 98.0% susceptible) and multidrug-resistant (MDR) (n = 674; MIC50/MIC90, 0.25 and 1 μg/ml; 98.8% susceptible) and extensively drug-resistant (XDR) (n = 156; MIC50/MIC90, 0.5 and 2 μg/ml; 98.1% susceptible) Enterobacteriaceae isolates, as well as Klebsiella species isolates showing an extended-spectrum β-lactamase (ESBL) screening-positive phenotype (n = 433; MIC50/MIC90, 0.25 and 1 μg/ml; 99.5% susceptible). Among Enterobacter spp. (24.8% ceftazidime nonsusceptible), 99.8% of the isolates, including 99.4% of ceftazidime-nonsusceptible isolates, were susceptible to ceftazidime-avibactam. The most common β-lactamases detected among Klebsiella pneumoniae and E. coli isolates were K. pneumoniae carbapenemase (KPC)-like and CTX-M-15, respectively. Only 8 of 6,209 Enterobacteriaceae isolates (0.1%) were ceftazidime-avibactam nonsusceptible, three NDM-1-producing strains with ceftazidime-avibactam MIC values of >32 μg/ml and five isolates with ceftazidime-avibactam MIC values of 16 μg/ml and negative results for all β-lactamases tested. Susceptibility rates among isolates from VAP were generally similar or slightly higher than those from all PHP.

scholarly journals In VitroAntistaphylococcal Effects ofEmbelia schimperiExtracts and Their Component Embelin with Oxacillin and Tetracycline

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Johana Rondevaldova ◽  
Olga Leuner ◽  
Alemtshay Teka ◽  
Ermias Lulekal ◽  
Jaroslav Havlik ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Medicinal Plants ◽  
Bacterial Infections ◽  
Inhibitory Concentration ◽  
Developed Countries ◽  
Positive Interactions ◽  
Fractional Inhibitory Concentration ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Broth Microdilution Method

Bacterial infections are in less-developed countries traditionally treated by remedies prepared from medicinal plants.Embelia schimperi(Vatke) is a plant used as a taenicide or disinfectant in Ethiopia, very often taken mixed with another plant species. In the present study, we examined two extracts prepared from seeds and twigs with leaves ofE. schimperiand its main present secondary metabolite embelin for their antibacterial combinatory effect with oxacillin and tetracycline against sensitive and resistantStaphylococcus aureusstrains. Minimum inhibitory concentrations were determined through the broth microdilution method, whereas the combinatory effect was evaluated through fractional inhibitory concentration sum (ΣFIC) indices. Results show many positive interactions and synergy occurring in embelin and oxacillin combinations against 4 out of 9 strains (ΣFIC 0.203–0.477) and for embelin and tetracycline combination against 3 out of 9 strains (ΣFIC 0.400–0.496). Moreover, the resistance to oxacillin has been overcome in 2 strains and to tetracycline in 3 strains. According to our knowledge, this is the first study showing antimicrobial combinatory effect ofE. schimperias well as of embelin. These findings can be used for the further research targeted on the development of new antistaphylococcal agents.

scholarly journals Susceptibility trends of ceftolozane/tazobactam and comparators when tested against European Gram-negative bacterial surveillance isolates collected during 2012–18

2020 ◽  
Vol 75 (10) ◽  
pp. 2907-2913 ◽  
Author(s):  
Helio S Sader ◽  
Cecilia G Carvalhaes ◽  
Leonard R Duncan ◽  
Robert K Flamm ◽  
Dee Shortridge
Keyword(s):  
Eastern Europe ◽  
Active Compound ◽  
Western Europe ◽  
Antimicrobial Agents ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Systemic Infections

Abstract Background The Program to Assess Ceftolozane/Tazobactam Susceptibility (PACTS) monitors the in vitro activity of ceftolozane/tazobactam and numerous antimicrobial agents against Gram-negative bacteria worldwide. Objectives To evaluate the activity of ceftolozane/tazobactam and resistance trends among Pseudomonas aeruginosa and Enterobacterales isolates in Europe between 2012 and 2018. Methods P. aeruginosa (7503) and Enterobacterales (30 582) isolates were collected from 53 medical centres in 26 countries in Europe and the Mediterranean region and tested for susceptibility by reference broth microdilution method in a central laboratory. MIC results were interpreted using EUCAST criteria. Results Ceftolozane/tazobactam was the most active compound tested against P. aeruginosa isolates after colistin, with overall susceptibility rates of 94.1% in Western Europe and 80.9% in Eastern Europe. Moreover, ceftolozane/tazobactam retained activity against 75.2% and 59.2% of meropenem-non-susceptible P. aeruginosa isolates in Western and Eastern Europe, respectively. Tobramycin was the third most active compound tested against P. aeruginosa, with susceptibility rates of 88.6% and 70.9% in Western and Eastern Europe, respectively. Ceftolozane/tazobactam was active against 94.5% of all Enterobacterales and 96.1% of meropenem-susceptible isolates from Western Europe. In Eastern Europe, ceftolozane/tazobactam was active against 79.4% of Enterobacterales overall and 86.2% of meropenem-susceptible isolates. Discussion Antimicrobial susceptibility rates for agents commonly used to treat serious systemic infections varied widely among nations and geographic regions and were generally lower in Eastern Europe compared with Western Europe. Ceftolozane/tazobactam demonstrated potent activity against P. aeruginosa, including MDR strains, and retained activity against most meropenem-susceptible Enterobacterales causing infection in European medical centres.

scholarly journals 528. Longitudinal Evaluation of Chlorhexidine Resistance Among Multidrug-Resistant Organisms in Relation to Intervention of Daily Chlorhexidine Bathing in Adult Intensive Care Units

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S254-S254
Author(s):  
Min Ja Kim ◽  
You Seung Chung ◽  
Hojin Lee ◽  
Jin Woong Suh ◽  
Yoojung Cheong ◽  
...  
Keyword(s):  
Intensive Care ◽  
Intensive Care Units ◽  
Clinical Laboratory ◽  
Multidrug Resistant ◽  
University Hospital ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Multidrug Resistant Organisms ◽  
Before And After ◽  
The Republic

Abstract Background Chlorhexidine digluconate (CHG), the most widely used antiseptic, has recently been applied to patient washing to decolonize the multidrug-resistant organisms (MDROs), but there are little data on susceptibilities of MDROs to CHG. The purpose of this study was to evaluate CHG resistance among MDROs before and after the intervention of daily CHG bathing in adult intensive care units (ICUs). Methods The intervention of daily body washing with 2% CHG cloths were taken in adult patients the medical or surgical ICU of 23-bed by a crossover manner for 6 months (MICU, July to December 2017; SICU, January to June 2018) in a 1,050-bed, university hospital in the Republic of Korea. Available MDRO isolates were randomly selected from clinical cultures of ICU patients within 6 months before, during and after the intervention, including MRSA, MR-CoNS, VRE, Carbapenem-resistant Pseudomonas aeruginosa (CR-PA), CR-Acinetobacter baumannii (CR-AB). Minimum inhibitory concentrations (MICs) were determined using the broth microdilution method set by the Clinical Laboratory Standards Institute. Determination of the minimum bactericidal concentrations (MBCs) was performed by subculturing 10 µL from each well without visible microbial growth. Cumulative amounts of CHG used in both ICUs was estimated across the study period from January 2008 to June 2018. Results The cumulative CHG consumption from both ICUs increased sharply from 27,503 g to 29,556 g after one-year intervention. The ranges of MICs and MBCs of CHG among MDRO clinical isolates selected by a 6-month phase are summarized in Table 1. Particularly, CR-PA and CR-AB isolates revealed four to eight times higher MICs and MBCs compared with the majority of Gram-positives excepting some VRE isolates. On the other hand, neither MICs and MBCs ranges of CHG from the MDRO isolates nor the monthly incidence of the MDROs from both ICUs were significantly increased before and after the intervention of daily CHG bathing. Conclusion This study indicates that some Gram-negative MDRO isolates with higher MICs and MBCs of CHG might be from longstanding exposure to CHG or efflux pumps. Although 2% daily CHG bathing uses over 1,000 times higher concentrations than the lethal concentration, it might be needed to monitor CHG resistance among MDROs. Disclosures All authors: No reported disclosures.

scholarly journals Composition and Antimicrobial Properties of Essential Oils of Laser Trilobum Rhizomes and Fruits

2017 ◽  
Vol 12 (3) ◽  
pp. 1934578X1701200
Author(s):  
Milica Drobac ◽  
Silvana Petrović ◽  
Marina Milenković ◽  
Maria Couladis ◽  
Jelena Kukić-Marković ◽  
...  
Keyword(s):  
Essential Oils ◽  
Antimicrobial Properties ◽  
Antimicrobial Effect ◽  
Reference Compound ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Fruit Oil ◽  
Total Oil ◽  
Dark Blue ◽  
Better Than

The compositions of hydrodistillated essential oils of Laser trilobum (L.) Borkh. rhizomes and fruits from Serbia, were investigated using GC and GC/MS. In the dark-blue rhizome oil forty-six compounds (93.1% of the total oil) were identified, with α-pinene (31.5%), γ-terpinene (9.0%), p-cymene (7.9%), β-pinene (6.1%) and 1,4-dimethylazulene (6.0%) as the major components. In the colorless fruits oil, twenty components (96.8% of the total oil) were identified, and the main constituents were limonene (51.6%) and perillaldehyde (26.8%). The antimicrobial activity of the oils was tested using the broth microdilution method against nine bacterial and two fungal strains. The oils revealed significant antimicrobial effect, mainly better than that of thymol, used as a reference compound. The strongest activity was recorded for the rhizome oil against Escherichia coli, Klebsiella pneumoniae and Candida albicans (MICs=25 μg/mL), and the fruit oil against C. albicans ATCC 10259 (MIC=12.5 μg/mL).

scholarly journals Antibacterial Activity of 2-(3’,5'-Dibromo-2'-methoxyphenoxy)-3,5-dibromophenol Isolated from Phyllospongia papyracea

2017 ◽  
Vol 12 (4) ◽  
pp. 1934578X1701200 ◽  
Author(s):  
Shi Sun ◽  
Corene Canning ◽  
Kuiwu Wang ◽  
Wenjun Zhu ◽  
Fei Yang ◽  
...  
Keyword(s):  
Antibacterial Agents ◽  
Inhibitory Concentration ◽  
Methanol Extract ◽  
Minimal Bactericidal Concentration ◽  
Antimicrobial Compound ◽  
Highly Active ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Bioassay Guided Fractionation ◽  
And Staphylococcus Aureus

A principal active antimicrobial compound, 2-(3’,5'-dibromo-2'-methoxyphenoxy)-3,5-dibromophenol, was isolated from the methanol extract of Phyllospongia papyracea via bioassay-guided fractionation and isolation. The crude extract and the purified compound were assayed to determine the minimal inhibitory concentration and minimal bactericidal concentration (MBC) using the broth microdilution method. The purified compound was found to be highly active against Bacillus subtilis and Staphylococcus aureus at MIC=1 μg/mL, Campylobacter jejuni at MIC=2 μg/mL, Pseudomonas aeruginosa at MIC=4 μg/mL, and Streptococcus pneumoniae and Listeria monocytogenes at MIC = 8 μg/mL. The activity of this compound was found to be comparable with antibiotics commonly used to control these species of bacteria. The results establish 2-(3’,5'-dibromo-2'-methoxyphenoxy)-3,5-dibromophenol as a potential lead molecule for the development of antibacterial agents.

scholarly journals In Vitro Interaction of Caspofungin Acetate with Voriconazole against Clinical Isolates of Aspergillus spp

2002 ◽  
Vol 46 (9) ◽  
pp. 3039-3041 ◽  
Author(s):  
Sofia Perea ◽  
Gloria Gonzalez ◽  
Annette W. Fothergill ◽  
William R. Kirkpatrick ◽  
Michael G. Rinaldi ◽  
...  
Keyword(s):  
Inhibitory Concentration ◽  
Fractional Inhibitory Concentration ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
In Vitro Interaction ◽  
Vitro Data ◽  
In Vitro Data

ABSTRACT The interaction between caspofungin acetate and voriconazole was studied in vitro by using 48 clinical Aspergillus spp. isolates obtained from patients with invasive aspergillosis. MICs were determined by the NCCLS broth microdilution method. Synergy, defined as a fractional inhibitory concentration (FIC) index of <1, was detected in 87.5% of the interactions; an additive effect, defined as an FIC index of 1.0, was observed in 4.2% of the interactions; and a subadditive effect, defined as an FIC index of 1.0 to 2.0, was found in 8.3% of the interactions. No antagonism was observed. Animal models are required to validate the in vivo significance of these in vitro data presented for the combination of caspofungin and voriconazole.

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