Minimum Inhibitory Concentration (MIC) versus Minimum Biofilm Eliminating Concentration (MBEC) in Evaluation of Antibiotic Sensitivity of Gram-negative Bacilli Causing Peritonitis

2004 ◽  
Vol 24 (1) ◽  
pp. 65-67 ◽  
Author(s):  
Farshad Sepandj ◽  
Howard Ceri ◽  
Allan Gibb ◽  
Ronald Read ◽  
Merle Olson
Keyword(s):  
Escherichia Coli ◽  
Peritoneal Dialysis ◽  
Minimum Inhibitory Concentration ◽  
Antibiotic Susceptibility ◽  
Inhibitory Concentration ◽  
Antibiotic Sensitivity ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Planktonic State

Objective Minimum inhibitory concentration (MIC) and minimum biofilm eliminating concentration (MBEC) results were compared to determine changes in the pattern of antibiotic sensitivity of gram-negative bacilli from the planktonic to the biofilm phase of growth. Methodology The MIC and MBEC assays were conducted on stored isolates obtained from patients presenting with peritoneal dialysis-related gram-negative peritonitis with Escherichia coli or Pseudomonas. Results The antibiotic sensitivities of planktonic organisms tested by the MIC assays were significantly higher than the antibiotic sensitivities of the same organisms in their biofilm state, as tested by the MBEC assays. Conclusions In their biofilm state, gram-negative bacteria are much less susceptible to antibiotics compared to their antibiotic susceptibility in the planktonic state.

scholarly journals Evaluation of antibacterial and anti-biofilm properties of kojic acid against five food-related bacteria and related subcellular mechanisms of bacterial inactivation

2018 ◽  
Vol 25 (1) ◽  
pp. 3-15 ◽  
Author(s):  
Yu Wu ◽  
Yu-gang Shi ◽  
Lu-yao Zeng ◽  
Ying Pan ◽  
Xin-ying Huang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Minimum Inhibitory Concentration ◽  
Zeta Potential ◽  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
Kojic Acid ◽  
Gram Negative Bacteria ◽  
Bacterial Inactivation ◽  
Intracellular Enzyme ◽  
Gram Negative

Although the antimicrobial properties of kojic acid have been recognized, the subcellular mechanism of bacterial inactivation caused by it has never been clearly elucidated. In the present study, the antibacterial and anti-biofilm activity of kojic acid was evaluated against five foodborne pathogens including Listeria monocytogenes, Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Salmonella typhimurium. The antibacterial activity was determined by minimum inhibitory concentration, minimum bactericidal concentration, and the time-kill assay. Among them, the susceptibility of Escherichia coli was significant with the lowest minimum inhibitory concentration and minimum bactericidal concentration values of 10 and 20 mM, respectively. Subcellular mechanism of bacterial inactivation related to kojic acid was revealed through comprehensive factors including cell morphology, membrane permeability, K+ leakage, zeta potential, intracellular enzyme, and DNA assay. Results demonstrated that bacterial inactivation caused by kojic acid, especially for Gram-negative bacteria, was primarily induced by the pronounced damage to the cell membrane integrity. Leakage of intracellular enzyme to the supernatants implied that the cell membrane permeability was compromised. Consequently, the release of K+ from the cytosol leads to the alterations of the zeta potential of cells, which would disturb the subcellular localization of some proteins and thereby cause the bacterial inactivation. The free −CH2OH group at the C-2 of kojic acid could play more significant role in the antimicrobial performance of kojic acid against Gram-negative bacteria. Moreover, remarkable interaction with DNA was also observed. Kojic acid at sub-minimum inhibitory concentration inhibited biofilm formation by these bacteria.

Antimicrobial and cytotoxic activity of Macrophomina phaseolina isolated from gummosis infected citrus reticulata

2013 ◽  
pp. 125-133
Author(s):  
Rubal C Das ◽  
Rajib Banik ◽  
Robiul Hasan Bhuiyan ◽  
Md Golam Kabir
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Brine Shrimp ◽  
Inhibitory Concentration ◽  
Lethal Dose ◽  
Macrophomina Phaseolina ◽  
Chloroform Extract ◽  
Citrus Reticulata ◽  
Gram Negative Bacteria ◽  
Gram Negative

Macrophomina phaseolina is one of the pathogenic organisms of gummosis disease of orange tree (Citrus reticulata). The pathogen was identified from the observation of their colony size, shape, colour, mycelium, conidiophore, conidia, hyaline, spore, and appressoria in the PDA culture. The crude chloroform extracts from the organism showed antibacterial activity against a number of Gram positive and Gram-negative bacteria. The crude chloroform extract also showed promising antifungal activity against three species of the genus Aspergillus. The minimum inhibitory concentration (MIC) of the crude chloroform extract from M. phaseolina against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Shigella sonnie were 128 ?gm, 256 ?gm, 128 ?gm and 64 ?gm/ml respectively. The LD50 (lethal dose) values of the cytotoxicity assay over brine shrimp of the crude chloroform extract from M. phaseolina was found to be 51.79 ?gm/ml. DOI: http://dx.doi.org/10.3329/cujbs.v5i1.13378 The Chittagong Univ. J. B. Sci.,Vol. 5(1 &2):125-133, 2010

scholarly journals 5-Bromo-1-(4-chlorobenzyl)-1H-indole-2-carboxamides as new potent antibacterial agents

2018 ◽  
Vol 24 (6) ◽  
pp. 327-332 ◽  
Author(s):  
Yogesh D. Mane ◽  
Smita S. Patil ◽  
Dhanraj O. Biradar ◽  
Bhimrao C. Khade
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Antibacterial Agents ◽  
Inhibitory Concentration ◽  
Antibacterial Activities ◽  
Gram Negative Bacteria ◽  
Internal Standards ◽  
Gram Negative ◽  
E Coli ◽  
High Antibacterial Activity

Abstract Ten 5-bromoindole-2-carboxamides were synthesized, characterized and evaluated for antibacterial activity against pathogenic Gram-negative bacteria Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Salmonella Typhi using gentamicin and ciprofloxacin as internal standards. Compounds 7a–c, 7g and 7h exhibit high antibacterial activity with a minimum inhibitory concentration (MIC) of 0.35–1.25 μg/mL. Compounds 7a–c exhibit antibacterial activities that are higher than those of the standards against E. coli and P. aeruginosa.

scholarly journals Colistin-resistant Escherichia coli clinical isolate harbouring the mcr-1 gene in Ecuador

2016 ◽  
Vol 144 (14) ◽  
pp. 2967-2970 ◽  
Author(s):  
D. ORTEGA-PAREDES ◽  
P. BARBA ◽  
J. ZURITA
Keyword(s):  
Escherichia Coli ◽  
Minimum Inhibitory Concentration ◽  
Clinical Isolate ◽  
Inhibitory Concentration ◽  
Resistance Mechanism ◽  
Sequence Type ◽  
Colistin Resistance ◽  
Gram Negative ◽  
E Coli ◽  
Commensal Strain

SUMMARYColistin resistance mediated by the mcr-1 gene has been reported worldwide, but to date not from the Andean region, South America. We report the first clinical isolate of Escherichia coli harbouring the mcr-1 gene in Ecuador. The strain was isolated from peritoneal fluid from a 14-year-old male with acute appendicitis, and subjected to molecular analysis. The minimum inhibitory concentration of colistin for the strain was 8 mg/ml and it was susceptible to carbapenems but resistant to tigecycline. The strain harboured mcr-1 and blaCTX-M-55 genes and was of sequence type 609. The recognition of an apparently commensal strain of E. coli harbouring mcr-1 serves as an alert to the presence in the region of this recently described resistance mechanism to one of the last line of drugs available for the treatment of multi-resistant Gram-negative infections.

scholarly journals Antibacterial Activity of Murrayaquinone A and 6-Methoxy-3,7-dimethyl-2,3-dihydro-1H-carbazole-1,4(9H)-dione

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Biswanath Chakraborty ◽  
Suchandra Chakraborty ◽  
Chandan Saha
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Bacillus Subtilis ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Antibacterial Activities ◽  
Gram Positive ◽  
Gram Negative ◽  
Naturally Occurring

The antibacterial activity of Murrayaquinone A (10), a naturally occurring carbazoloquinone alkaloid, and 6-methoxy-3,7-dimethyl-2,3-dihydro-1H-carbazole-1,4(9H)-dione (11), a synthetic carbazoloquinone, both obtained during the development of the synthesis of Carbazomycin G, having unique quinone moiety, was studied against Gram-positive (Bacillus subtilisandStaphylococcus aureus) and Gram-negative (Escherichia coliandPseudomonassp.) bacteria. Compound10showed antibacterial activities against both ofEscherichia coliandStaphylococcus aureuswhereas compound11indicated the activity againstStaphylococcus aureusonly. Both compounds10and11exhibited minimum inhibitory concentration (MIC) of 50 μg mL−1againstStaphylococcus aureus.

scholarly journals Bacteriological Profile, Antibiotic Susceptibility Pattern and Predictors of bacteremia among Children with Bloodstream Infection

2021 ◽  
Author(s):  
Samina Nazir Chaki ◽  
Levina Msuya ◽  
Deborah Mchaile ◽  
Michael Johnson Mahande ◽  
Ronald Mwitalemi Mbwasi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Bloodstream Infection ◽  
Antibiotic Susceptibility ◽  
Klebsiella Pneumonia ◽  
Gram Negative Bacteria ◽  
Susceptibility Pattern ◽  
Gram Positive ◽  
Antibiotic Susceptibility Pattern ◽  
Gram Negative

Abstract Background: Bloodstream infections are major causes of morbidity and mortality among children in Sub-Saharan countries. This study aimed to determine the prevalence of bacteremia, etiological agents’ antibiotic susceptibility pattern and predictors of bacteremia among children with bloodstream Infection.Methodology: This hospital-based cross-section study involved children aged two months to thirteen years. All children meeting the inclusion criteria during the study period were enrolled. All consenting parents were interviewed via a questionnaire to collect data, followed by a thorough physical assessment and venipuncture was done to collect blood samples. Data were analysed using SPSS version 23.Results: Among 242 study participants, 154(63.6%) were male and blood cultures were positive in 37(15.3%). Gram-positive and gram-negative bacteria constituted 32(80%) and 8(20%), respectively. The frequent pathogen found was Staphylococcus aureus 25(62.5%), followed by Enterococcus spp. 4(10%), Escherichia coli 4(10%), Pseudomonas aeruginosa 3(7.5%), Streptococcus pyogenes 3(7.5%) and 1(2.5%) Klebsiella pneumonia. The majority of bacterial isolates showed high resistance to commonly used antibiotics in the study area. Predictors of bacteremia were severe malnutrition, hydrocephalus, hyperglycemia, lethargy and BSI with no foci of infection. Conclusion: Prevalence of bacteremia was 15.3%. Gram-positive bacteria were more prevalent than gram-negative bacteria. Staphylococcus aureus and Escherichia coli were the prevalent isolates causing BSI. Effective antibiotics for both gram-negative & gram-positive organisms are imipenem, meropenem and piperacillin-tazobactam followed by amikacin; vancomycin & clindamycin for gram-positive organisms. To curb the growing antimicrobial resistance that we see in this and other studies, continuous antimicrobial stewardship is necessary, else we risk failing to treat BSI.

scholarly journals Minimum Inhibitory Concentration (MIC) Of Liquid Smoke Produced from Piper Betle L Against Salmonella sp and Staphylococcus aureus

2020 ◽  
Vol 11 (1) ◽  
pp. 89-98
Author(s):  
Dodi Irwandi ◽  
Ai Emalia Sukmawati
Keyword(s):  
Staphylococcus Aureus ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Piper Betle ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Betel Leaf ◽  
Liquid Smoke ◽  
Grade 3 ◽  
And Staphylococcus Aureus

The betel (Piper betle L) is an herb that has one of the properties, namely as an antibacterial. Several studies have shown green betel leaf extract can inhibit the growth of Gram-positive and Gram negative bacteria. In this study, the antibacterial activity of liquid smoke produced from betel leaf by pyrolysis using a simple pyrolysis reactor was tested. Tests are carried out on 2 types of liquid smoke namely grade 3 which is the first product of the pyrolysis process and grade 2 which is the result of distillation from grade 3. Both types of liquid smoke are prepared into concentration of 100%, 75%, 50%, 25% respectively water as a solvent. Two types of bacteria are used, namely Salmonella sp as Gram-negative bacteria and Staphylococcus aureus as Gram-positive. The test results show that grade 3 and grade 2 liquid smoke give minimum inhibitory concentration (MIC) at the same concentration of 50% against Salmonella sp and, Staphylococcus aureus at 25%, 75% concentrations, respectively.

scholarly journals Effect of chitosan membranes against gram-negative bacteria isolated from cutaneous ulcers

2021 ◽  
Vol 20 (1) ◽  
pp. e806
Author(s):  
Dalia I. Sánchez-Machado ◽  
Jaime López-Cervantes ◽  
Ana A. Escárcega-Galaz ◽  
R. David Valenzuela-Rojo ◽  
Olga N. Campas-Baypoli ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Sensitivity ◽  
Enterobacter Aerogenes ◽  
Multidrug Resistant ◽  
In Vitro Tests ◽  
Gram Negative Bacteria ◽  
Safe Alternative ◽  
Gram Negative ◽  
Skin Ulcers

The objective of this study was to evaluate the in vitro effectiveness of membranes developed with pure chitosan and chitosan in a mixture with glycerol-honey against gram-negative bacteria isolated from skin ulcers. The membranes were prepared by the solvent evaporation technique. The identification and antibiotic sensitivity of microorganisms were determined in microplates, and in vitro tests were developed by the agar diffusion technique. The most frequently isolated microorganism was Escherichia coli with 43.75 % prevalence. All membranes showed antimicrobial effects by direct contact against Proteus mirabilis, Escherichia coli, Enterobacter aerogenes, Pseudomonas aeruginosa, Klebsiella pneumoniae and Morganella morganii. Antibiograms showed that most of these microorganisms are multi-resistant to antibiotics. All of this suggests that chitosan-based membranes are a safe alternative for the treatment of infected cutaneous ulcers compared to traditional antibiotics. The outcomes of this study confirm that membranes made of a biodegradable polymer, such as chitosan have activity against multidrug-resistant gram-negative bacteria that grow in infected skin ulcers.

MIC versus MBEC to Determine the Antibiotic Sensitivity ofStaphylococcus aureusin Peritoneal Dialysis Peritonitis

2010 ◽  
Vol 30 (6) ◽  
pp. 652-656 ◽  
Author(s):  
Louis P. Girard ◽  
Howard Ceri ◽  
Allan P. Gibb ◽  
Merle Olson ◽  
Farshad Sepandj
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Peritoneal Dialysis ◽  
Inhibitory Concentration ◽  
Recurrent Infection ◽  
Antibiotic Sensitivity ◽  
Phenotypic Change ◽  
Chi Square ◽  
Gram Negative ◽  
Planktonic Form

BackgroundPeritoneal dialysis (PD)-related peritonitis is a common and morbid complication of PD. Bacteria are able to create a biofilm on the PD catheter, which can be a source of recurrent infection. Biofilms undergo a phenotypic change resulting in increased antibiotic resistance.Methods21 clinical isolates of different patients with PD peritonitis secondary to Staphylococcus aureus were collected. They were analyzed for their antibiotic susceptibility in the planktonic form using the standard minimum inhibitory concentration (MIC) and in a biofilm using minimum biofilm eradication concentration (MBEC). Chi-square was used to compare the sensitivity results.ResultsThe isolates were susceptible to all the antibiotics tested using MIC. Every antibiotic except gentamicin lost its efficacy when the bacteria were grown in a biofilm ( p > 0.05). The change in susceptibility was statistically significant to a level of p < 0.001 for all antibiotics tested.DiscussionIn PD peritonitis that is long standing, recurrent, or not responsive to therapy, MBEC testing should be considered as a biofilm may be present. Gentamicin should be strongly considered over other agents for empiric gram-negative coverage as it may be providing synergy in the setting of Staphylococcus aureus. Also, the newer anti-staphylococcal drugs should be tested for their performance in a biofilm using the MBEC method.

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