scholarly journals Antibacterial Activity and Optimal Treatment of Ceftazidime-Avibactam and Aztreonam-Avibactam Against Bloodstream Infections Caused by Carbapenem-Resistant Klebsiella pneumoniae

2021 ◽  
Vol 12 ◽  
Author(s):  
Wei Yu ◽  
Yunbo Chen ◽  
Ping Shen ◽  
Jinru Ji ◽  
Chaoqun Ying ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Klebsiella Pneumoniae ◽  
Inhibitory Concentration ◽  
Bloodstream Infections ◽  
Second Step ◽  
Infusion Therapy ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Carbapenem Resistant ◽  
Agar Dilution

Objectives: This work was to investigate the activity and optimal treatments of ceftazidime-avibactam (CZA) and aztreonam-avibactam (AZA) against bloodstream infections caused by carbapenem resistant Klebsiella pneumoniae (BSIs-CRKP).Methods: A total of 318 nonduplicate BSIs-CRKP isolates were collected from Blood Bacterial Resistant Investigation Collaborative System (BRICS) program. The minimum inhibitory concentration (MIC) of CZA and AZA were determined by agar dilution method. Carbapenemase genes and multilocus sequence typing were amplified by PCR. Monte Carlo simulation (MCS) was conducted to calculate cumulative fraction of response (CFR) of different CZA or AZA administrations.Results: The MIC90 of CZA and AZA were 128/4 and 1/4 mg/L, respectively. There are 87.4 and 3.5% isolates carried blaKPC-2 and blaNDM-1. A total of 68 ST types were identified and 29 novel ST types. ST11 accounted for 66.6%. Further MCS showed CFR of CZA using two-step infusion therapy (rapid first-step 0.5 h infusion and slow second-step 3 h infusion, TSIT) (2.5 g 0.5 h, 3.75 g every 8 h with 3 h infusion and 3.75 g 0.5 h, 2.5 g every 8 h with 3 h infusion) was above 89%. The CFR of AZA with TSIT was above 96%.Conclusion: TSIT with sufficient pharmacokinetic conditions could be useful for enhancing the therapeutic efficacy of CZA and AZA against BSIs-CRKP.

scholarly journals Drug resistance of yeasts isolated from oropharyngeal candidiasis in aids patients

1998 ◽  
Vol 29 (4) ◽  
pp. 271-275
Author(s):  
Maria do Rosário Rodrigues Silva ◽  
Claudete Rodrigues de Paula ◽  
Soraya Cristina Silva ◽  
Théo Rodrigues Costa ◽  
Márcio Rodrigues Costa
Keyword(s):  
Amphotericin B ◽  
High Frequency ◽  
Inhibitory Concentration ◽  
Serum Levels ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Oropharyngeal Candidiasis ◽  
Candida Spp ◽  
Aids Patients ◽  
Agar Dilution

Candida spp was isolated from 59 (68.60%) out of eighty six samples of oral mucosa of AIDS patients. The identification, based or the production of a germ tube and chlamydospores, and on the assimilation and fermentation of carbohydrates, revealed 52 strains (88.13%) of C. albicans, 4 (6.77%) of C. tropicalis and 3 (5.08%) of C. krusei. The susceptibility of these strains to amphotericin B, flucytosine, itraconazole, fluconazole and ketoconazole was determined using the agar dilution method. Comparing the minimum inhibitory concentration values found in the susceptibility test with the serum levels achieved by these drugs, only 8.47% and 5.08% of the yeasts strains proved to be resistant to amphotericin B and flucitosyne, respectively. A high frequency of strains resistant to azole derivatives (25.42%, to itraconazole, 45.76%, to ketoconazole and 66.10% to fluconazole) was observed.

scholarly journals Characterization of Clinical Isolates ofEnterococciwith Special Reference to Glycopeptide Susceptibility at a Tertiary Care Center of Eastern Nepal

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Aasish Karna ◽  
Ratna Baral ◽  
Basudha Khanal
Keyword(s):  
Multidrug Resistance ◽  
Minimum Inhibitory Concentration ◽  
Antimicrobial Susceptibility ◽  
Inhibitory Concentration ◽  
Tertiary Care ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disc Diffusion ◽  
Diffusion Technique ◽  
Agar Dilution

Background. Enterococci, once considered as a harmless commensal of intestine, have now emerged as medically important pathogens and are associated with both community-acquired and nosocomial infections. They bear the potential to exhibit resistance against all commonly used antibiotics either by inherent or acquired mechanism, posing a therapeutic challenge.Objectives. This study aimed to characterize enterococci up to the species level and study their antibiogram with special regard to vancomycin.Methods. A descriptive cross-sectional study was conducted in the Department of Microbiology, B.P. Koirala Institute of Health Sciences, Dharan, Nepal, from February to May 2017. A total of 91 enterococcal isolates recovered from clinical specimens were investigated in this study. Their identification and speciation were done according to standard microbiological guidelines. Kirby–Bauer disc diffusion technique was used to study antimicrobial susceptibility pattern, whereas minimum inhibitory concentration of vancomycin was determined by the agar dilution method, with reference to Clinical and Laboratory Standards Institute guidelines.Results. Seven different species of enterococci were isolated,E. faecalisandE. faeciumaccounting about 45% each. The other species encountered wereE.avium,E.cecorum,E.dispar,E.durans, andE.raffinosus. Highest proportion of antimicrobial susceptibility was recorded for linezolid (97.8%), followed by teicoplanin (95.6%) and high-level gentamicin (81.3%). Sensitivity to vancomycin was seen in 79.1% isolates. Likewise, 82.1% of urinary strains were susceptible to nitrofurantoin. A total of 4 disparities were observed between the disc diffusion technique and agar dilution method in determining vancomycin resistance. Multidrug resistance was observed in 31.9% isolates. The overall prevalence of vancomycin-resistant enterococci based on the standard minimum inhibitory concentration method was 25.3%.Conclusions.Enterococcus faecalisandE. faeciumwere the predominant species in causing enterococcal infections. The alarming rise in prevalence of vancomycin and multidrug resistance strains warrants immediate, adequate, and efficient surveillance program to prevent and control its spread.

scholarly journals STUDY ON ANTI-MICROBIAL PROPERTIES OF Enicosanthum membranifolium SINCLAIR AND Enicosanthum cupulare (KING) AIRY-SHAW

2015 ◽  
Vol 3 (1) ◽  
pp. 62
Author(s):  
Mai Efdi ◽  
Mamoru Koketsu ◽  
Kunitomo Watanabe ◽  
Nurainas
Keyword(s):  
Ethyl Acetate ◽  
Inhibitory Concentration ◽  
Ethyl Acetate Fraction ◽  
Antimicrobial Activities ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Microbial Properties ◽  
Agar Dilution

 ABSTRACT n-Hexane and ethyl acetate fractions of methanol extracts of two species of Annonaceae, Enicosanthum membranifolium Sinclair and Enicosanthum cupulare (King) Airy-Shaw, were screened for antimicrobial activity against eighteen bacterial strains using agar dilution method. The ethyl acetate fraction of the two Annonaceae plants showed higher antimicrobial activities than the n-hexane fraction. The extracts of the plants tested were significantly more active against gram-positive with minimum inhibitory concentration (MICs) ranging from 0.0625 to 4 mg/mL than against gram negative bacteria (MICs >4 mg/mL). Keywords: Antibacterial activity; Enicosanthum membranifolium Sinclair; Enicosanthum cupulare (King) Airy-Shaw

scholarly journals FORMULATION AND DEVELOPMENT OF TOPICAL ANTI ACNE FORMULATION OF SPIRULINA EXTRACT

2018 ◽  
Vol 10 (6) ◽  
pp. 229 ◽  
Author(s):  
Badduri Nihal ◽  
N. Vishal Gupta ◽  
D. V. Gowda ◽  
Manohar M.
Keyword(s):  
Antimicrobial Activity ◽  
Staphylococcus Epidermidis ◽  
Inhibitory Concentration ◽  
Water Soluble ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Drug Diffusion ◽  
Good Consistency ◽  
Agar Dilution ◽  
Dialysis Method

Objective: The objective of this research was to formulate and evaluate anti-acne ointment of C-phycocyanin(C-PC) extracted from spirulina.Methods: C-PC was successfully extracted from spirulina by using sonication and cold-maceration process and further purified by dialysis method. By employing disc diffusion and agar dilution method, antimicrobial activity and minimum inhibitory concentration(MIC) of C-PC as determined against Propionibacterium acne (P. acne) and Staphylococcus epidermidis(S. epidermidis). Further, the two different formulations were prepared by using water soluble and oleaginous bases, and the formulations were characterized for particle size, viscosity, pH, consistency, drug diffusion, antimicrobial activity, and antioxidant effect and stability studies.Results: C-PC showed MIC value of 1.5±0.1 mg/ml and 1.8±0.2 mg/ml against P. acne and S. epidermidis respectively. The developed formulation had a globule diameter of 5.44 mm, pH of 6.8±0.09, the viscosity of 175±0.2cps, spreadability of an 8.6±0.12g. cm/sec and had good consistency. Both formulations were found stable among which, formulation B(FB) had maximum drug content of 95±0.6% and drug release was up to 92±0.8%.Conclusion: The prepared topical C-PC ointment can be successfully employed in the treatment of acneagainstP. acne and S. epidermidis.

scholarly journals In Vitro Activities of Linezolid Alone and in Combination with Amoxicillin, Clarithromycin, and Metronidazole againstHelicobacter pylori

2000 ◽  
Vol 44 (7) ◽  
pp. 1977-1979 ◽  
Author(s):  
Alexander M. Hirschl ◽  
Petra Apfalter ◽  
Athanasios Makristathis ◽  
Manfred L. Rotter ◽  
Margit Wimmer
Keyword(s):  
Helicobacter Pylori ◽  
Inhibitory Concentration ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Fractional Inhibitory Concentration ◽  
Agar Dilution

ABSTRACT Linezolid was tested against 70 strains of Helicobacter pylori by the agar dilution method. The MIC range and MICs at which 50 and 90% of strains were inhibited were 8 to 64, 16, and 32 μg/ml, respectively. With minimum and maximum fractional inhibitory concentration summation values of 0.31 and 2.50, respectively, the combination of linezolid with amoxicillin, clarithromycin, or metronidazole showed either partial synergy or indifference for the majority of strains.

scholarly journals Comparison of in vitro activity of five antifungal agents against dermatophytes, using the agar dilution and broth microdilution methods

2009 ◽  
Vol 42 (3) ◽  
pp. 250-254 ◽  
Author(s):  
Crystiane Rodrigues Araújo Mota ◽  
Karla Carvalho Miranda ◽  
Janine de Aquino Lemos ◽  
Carolina Rodrigues Costa ◽  
Lúcia Kioko Hasimoto e Souza ◽  
...  
Keyword(s):  
Inhibitory Concentration ◽  
Reference Method ◽  
Trichophyton Mentagrophytes ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Microsporum Canis ◽  
Broth Microdilution ◽  
In Vitro Susceptibility ◽  
Agar Dilution

The purpose of this study was to compare the agar dilution and broth microdilution methods for determining the minimum inhibitory concentration (MIC) of fluconazole, itraconazole, ketoconazole, griseofulvin and terbinafine for 60 dermatophyte samples belonging to the species Trichophyton rubrum, Trichophyton mentagrophytes and Microsporum canis. The percentage agreement between the two methods, for all the isolates with < 2 dilutions that were tested was 91.6% for ketoconazole and griseofulvin, 88.3% for itraconazole, 81.6% for terbinafine and 73.3% for fluconazole. One hundred percent agreement was obtained for Trichophyton mentagrophytes isolates evaluated with ketoconazole and griseofulvin. Thus, until a reference method for testing the in vitro susceptibility of dermatophytes is standardized, the similarity of the results between the two methods means that the agar dilution method may be useful for susceptibility testing on these filamentous fungi.

scholarly journals Examination of the minimum inhibitory concentration of amoxicillin and marbofloxacin against Streptococcus suis using standardised methods

2020 ◽  
Vol 65 (No. 9) ◽  
pp. 377-386
Author(s):  
D Sperling ◽  
H Karembe ◽  
M Zouharova ◽  
K Nedbalcova
Keyword(s):  
Inhibitory Concentration ◽  
Streptococcus Suis ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Microdilution Method ◽  
Linear Relationships ◽  
Broth Microdilution Method ◽  
Significant Difference ◽  
Agar Dilution ◽  
Good Agreement

The results of the antimicrobial susceptibility testing of clinical isolates Streptococcus suis to amoxicillin and marbofloxacin obtained by the agar dilution method and broth microdilution method with the results obtained by the commercially available E-test were compared. Comparisons between the methods based on the determination of the minimal inhibitory concentration (MIC) of the antimicrobials were assessed based on the degree and frequency of the categorical agreement (Agar dilution method as a reference system) and the percentage of the categorical agreement and error rate. A statistical evaluation was determined using the Bland-Atman method. The presented MIC values, determined for the isolates in the E-test, were slightly different from the MIC values determined by the dilution tests, mainly due to the different defined testing concentrations. For the E-test as the test system and agar-dilution method as the reference system, no error of any class was detected (very major, major and minor error) and a complete categorical agreement was obtained between the evaluated methods for amoxicillin. For amoxicillin, the regression and correlation analysis show linear relationships between the E-test and the two dilution methods with significant coefficients of determination (0.62 and 0.75). The slopes of the equality and regression lines were not significantly different. However, the E-test tends to slightly overestimate the MIC values when compared to the microdilution. The reverse is true when compared with the agar dilution. There was good agreement between the E-test and the dilution methods with a low bias (0.001 3 and −0.005 0), all the experimental data were within the computed limits of agreement. For marbofloxacin, the same trends were observed with lower coefficients of determination (0.42 and 0.73) and a less favourable agreement. The E-test constantly underestimated the MIC values when compared to the two dilution methods. No significant difference between the microdilution and agar dilution was obtained.

scholarly journals Reduced ceftazidime and ertapenem susceptibility due to production of OXA-2 in Klebsiella pneumoniae ST258

2019 ◽  
Vol 74 (8) ◽  
pp. 2203-2208
Author(s):  
Alina Iovleva ◽  
Roberta T Mettus ◽  
Christi L McElheny ◽  
Mustapha M Mustapha ◽  
Daria Van Tyne ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Kinetic Studies ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Class 1 Integron ◽  
E Coli ◽  
Relative Contribution ◽  
Class D ◽  
Class 1 ◽  
Agar Dilution

Abstract Background OXA-2 is a class D β-lactamase that confers resistance to penicillins, as well as narrow-spectrum cephalosporins. OXA-2 was recently reported to also possess carbapenem-hydrolysing activity. Here, we describe a KPC-2-encoding Klebsiella pneumoniae isolate that demonstrated reduced susceptibility to ceftazidime and ertapenem due to production of OXA-2. Objectives To elucidate the role of OXA-2 production in reduced ceftazidime and ertapenem susceptibility in a K. pneumoniae ST258 clinical isolate. Methods MICs were determined by the agar dilution method. WGS was conducted to identify and compare resistance genes between isolates. Expression of KPC-2 was quantified by quantitative RT–PCR and immunoblotting. OXA-2 was expressed in Escherichia coli TOP10, as well as in K. pneumoniae ATCC 13883, to define the relative contribution of OXA-2 in β-lactam resistance. Kinetic studies were conducted using purified OXA-2 enzyme. Results K. pneumoniae 1761 belonged to ST258 and carried both blaKPC-2 and blaOXA-2. However, expression of blaKPC-2 was substantially reduced due to an IS1294 insertion in the promoter region. K. pneumoniae 1761, K. pneumoniae ATCC 13883 and E. coli TOP10 carrying blaOXA-2-harbouring plasmids showed reduced susceptibility to ertapenem and ceftazidime, but meropenem, imipenem and cefepime were unaffected. blaOXA-2 was carried on a 2910 bp partial class 1 integron containing aacA4-blaOXA-2-qacEΔ1-sul1 on an IncA/C2 plasmid, which was not present in the earlier ST258 isolates possessing blaKPC-2 with intact promoters. Hydrolysis of ertapenem by OXA-2 was confirmed using purified enzyme. Conclusions Production of OXA-2 was associated with reduced ceftazidime and ertapenem susceptibility in a K. pneumoniae ST258 isolate.

scholarly journals Antibacterial Activity Tests of Staphylococcus Aureus and Phytochemical Screening in Family Asteraceae, Clusiaceae, Phyllanthaceae

2020 ◽  
Vol 55 (6) ◽  
Author(s):  
Prasetyorini Djarot ◽  
Novi Fajar Utami ◽  
Noerma Veonicha ◽  
Anggita Rahmadini ◽  
Afrizal Nur Iman
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Pathogenic Bacteria ◽  
Inhibitory Concentration ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Skin Infections ◽  
Inhibitory Ability ◽  
Agar Dilution ◽  
Concentration Test ◽  
Material Extraction

Infection is a type of disease that affects many residents of developing countries, including Indonesia. One pathogenic bacteria that is quite dangerous and causes skin infections both sporadically and endemically is S aureus. Several studies intensively report that some of the Asteraceae, Clusiaceae and Phyllanthaceae family plants contain alkaloids, flavonoids, saponins and tannins that have potential as antibacterial S aureus. Therefore, this study aims to identify effective plants to deal with infections caused by S aureus bacteria. To this end, the ingredients used are the leaves of G. procumbens, E. scaber, G. mangostana, G atroviridis, G. xanthochymus, leaves and bark of A. neurocarpum. Plant material extraction was done by maceration using 90% ethanol solvent. Next, an antibacterial test was conducted, which was begun by testing the Minimum Inhibitory Concentration followed by testing the Obstacle Area Width. The Minimum Inhibitory Concentration test was carried out using the agar dilution method, and the Obstacle Area Width test was carried out with paper diffusion discs. The results showed that all the plants have potential as antibacterials, and the mangosteen leaf extract has the largest Obstacle Area Width of 5.1 mm with a concentration of extract of 30% and a fairly strong inhibitory ability.

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