Determination of mercury and organomercurial resistance in obligate anaerobic bacteria

1985 ◽  
Vol 31 (3) ◽  
pp. 276-281 ◽  
Author(s):  
James T. Rudrik ◽  
Roger E. Bawdon ◽  
Stephen P. Guss
Keyword(s):  
Escherichia Coli ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Anaerobic Bacteria ◽  
Enterobacter Cloacae ◽  
Mercury Resistance ◽  
Plasmid Content ◽  
Obligate Anaerobic ◽  
Resistant Strains

A methodology for determining the minimum inhibitory concentration of inorganic and organomercurial compounds for obligate anaerobic bacteria is described. A wide variation in the susceptibility of anaerobic clinical and sewage isolates was observed. Isolates of Bacteroides ruminicola and Clostridium perfringens resistant to mercury were examined for their plasmid content and ability to demonstrate inducible resistance. None of the resistant anaerobes contained any plasmids, while resistant facultative isolates from the same source contained several plasmids. In 24 h, resistant strains of Clostridia and Bacteroides volatilized 20 and 43% of the 203Hg2+ added to cultures, while Escherichia coli R100 and a sewage isolate of Enterobacter cloacae volatilized 63 and 27%, respectively, of the added 203Hg2+. Attempts to induce mercury resistance in the aerobic isolates were successful, but no induction was seen in the anaerobes. Thus, mercury resistance in these anaerobic isolates was neither inducible nor plasmid mediated.

scholarly journals Determination of the carbapenem resistance in Escherichia coli isolated from samples obtained from Shahrekord hospitals and determination of their minimum inhibitory concentration

2019 ◽  
Vol 21 (6) ◽  
pp. 280-283
Author(s):  
Farshad Kakian ◽  
Behnam Zamanzad ◽  
Abolfazle Gholipour ◽  
Kiarash Zamanzad
Keyword(s):  
Escherichia Coli ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Carbapenem Resistance ◽  
Test Strip ◽  
Major Step ◽  
Accurate Identification ◽  
E Coli ◽  
Tract Infections

Background and aims: Carbapenems are the final-line treatments for multidrug-resistant, gram-negative infections. The patterns of resistance to carbapenems among hospital bacterial pathogens vary widely across different hospitals in a country. Considering that Escherichia coli is one of the most important causes of nosocomial infections, it is essential to study its drug resistance. Methods: In this descriptive-analytical study, a total of 80 samples of E. coli isolated from inpatients with urinary tract infections (UTIs) were collected in different wards (i.e., women, urology, infectious, and ICU) of Shahrekord hospitals. After the diagnosis and confirmation of bacteria by standard bacteriological methods, their sensitivity to imipenem and meropenem was investigated by the antibiogram (diskdiffusion) method. Then, the minimum inhibitory concentration (MIC) was determined by the E-test strip according to the Clinical and Laboratory Standards Institute (CLSI) standard. Results: In this study, resistance to meropenem and imipenem by antibiogram (disc diffusion) was observed in 21 (25.26%) and 20 (25%) of the isolates, respectively. Twenty isolates had MIC ≥4 μg/mL for meropenem, 13 isolates demonstrated MIC≥4 μg/mL for imipenem, and 14 isolates had 1≤MIC<4 μg/mL and were semi-sensitive. Conclusion: In general, E. coli had significant resistance to carbapenems. Therefore, rapid and accurate identification of these strains can be a major step to the treatment and control of these strains and prevention of the spread of the resistance.

scholarly journals Transcriptome analysis of Escherichia coli K1 after therapy with hesperidin conjugated with silver nanoparticles

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Abdulkader Masri ◽  
Naveed Ahmed Khan ◽  
Muhammad Zarul Hanifah Md Zoqratt ◽  
Qasim Ayub ◽  
Ayaz Anwar ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Silver Nanoparticles ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Neonatal Meningitis ◽  
E Coli ◽  
Drug Candidates ◽  
Metabolic Genes ◽  
Genetic Mechanisms ◽  
Cell Stress Response

Abstract Backgrounds Escherichia coli K1 causes neonatal meningitis. Transcriptome studies are indispensable to comprehend the pathology and biology of these bacteria. Recently, we showed that nanoparticles loaded with Hesperidin are potential novel antibacterial agents against E. coli K1. Here, bacteria were treated with and without Hesperidin conjugated with silver nanoparticles, and silver alone, and 50% minimum inhibitory concentration was determined. Differential gene expression analysis using RNA-seq, was performed using Degust software and a set of genes involved in cell stress response and metabolism were selected for the study. Results 50% minimum inhibitory concentration with silver-conjugated Hesperidin was achieved with 0.5 μg/ml of Hesperidin conjugated with silver nanoparticles at 1 h. Differential genetic analysis revealed the expression of 122 genes (≥ 2-log FC, P< 0.01) in both E. coli K1 treated with Hesperidin conjugated silver nanoparticles and E. coli K1 treated with silver alone, compared to untreated E. coli K1. Of note, the expression levels of cation efflux genes (cusA and copA) and translocation of ions, across the membrane genes (rsxB) were found to increase 2.6, 3.1, and 3.3- log FC, respectively. Significant regulation was observed for metabolic genes and several genes involved in the coordination of flagella. Conclusions The antibacterial mechanism of nanoparticles maybe due to disruption of the cell membrane, oxidative stress, and metabolism in E. coli K1. Further studies will lead to a better understanding of the genetic mechanisms underlying treatment with nanoparticles and identification of much needed novel antimicrobial drug candidates.

scholarly journals Synergism of the Combination of Traditional Antibiotics and Novel Phenolic Compounds against Escherichia coli

Pathogens ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 811
Author(s):  
Md. Akil Hossain ◽  
Hae-Chul Park ◽  
Sung-Won Park ◽  
Seung-Chun Park ◽  
Min-Goo Seo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Rattus Norvegicus ◽  
Inhibitory Concentration ◽  
Epicatechin Gallate ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
Resistant Strains ◽  
Novel Approaches ◽  
Rapid Emergence

Pathogenic Escherichia coli (E. coli)-associated infections are becoming difficult to treat because of the rapid emergence of antibiotic-resistant strains. Novel approaches are required to prevent the progression of resistance and to extend the lifespan of existing antibiotics. This study was designed to improve the effectiveness of traditional antibiotics against E. coli using a combination of the gallic acid (GA), hamamelitannin, epicatechin gallate, epigallocatechin, and epicatechin. The fractional inhibitory concentration index (FICI) of each of the phenolic compound-antibiotic combinations against E. coli was ascertained. Considering the clinical significance and FICI, two combinations (hamamelitannin-erythromycin and GA-ampicillin) were evaluated for their impact on certain virulence factors of E. coli. Finally, the effects of hamamelitannin and GA on Rattus norvegicus (IEC-6) cell viability were investigated. The FICIs of the antibacterial combinations against E. coli were 0.281–1.008. The GA-ampicillin and hamamelitannin-erythromycin combinations more effectively prohibited the growth, biofilm viability, and swim and swarm motilities of E. coli than individual antibiotics. The concentration of hamamelitannin and GA required to reduce viability by 50% (IC50) in IEC-6 cells was 988.54 μM and 564.55 μM, correspondingly. GA-ampicillin and hamamelitannin-erythromycin may be potent combinations and promising candidates for eradicating pathogenic E. coli in humans and animals.

scholarly journals Understanding and predicting ciprofloxacin minimum inhibitory concentration in Escherichia coli with machine learning

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Bálint Ármin Pataki ◽  
◽  
Sébastien Matamoros ◽  
Boas C. L. van der Putten ◽  
Daniel Remondini ◽  
...  
Keyword(s):  
Machine Learning ◽  
Escherichia Coli ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Model Concept ◽  
Susceptibility Data ◽  
Genome Wide ◽  
Antimicrobial Resistance Genes ◽  
Machine Learning Approach ◽  
Near Future

Abstract It is important that antibiotics prescriptions are based on antimicrobial susceptibility data to ensure effective treatment outcomes. The increasing availability of next-generation sequencing, bacterial whole genome sequencing (WGS) can facilitate a more reliable and faster alternative to traditional phenotyping for the detection and surveillance of AMR. This work proposes a machine learning approach that can predict the minimum inhibitory concentration (MIC) for a given antibiotic, here ciprofloxacin, on the basis of both genome-wide mutation profiles and profiles of acquired antimicrobial resistance genes. We analysed 704 Escherichia coli genomes combined with their respective MIC measurements for ciprofloxacin originating from different countries. The four most important predictors found by the model, mutations in gyrA residues Ser83 and Asp87, a mutation in parC residue Ser80 and presence of the qnrS1 gene, have been experimentally validated before. Using only these four predictors in a linear regression model, 65% and 93% of the test samples’ MIC were correctly predicted within a two- and a four-fold dilution range, respectively. The presented work does not treat machine learning as a black box model concept, but also identifies the genomic features that determine susceptibility. The recent progress in WGS technology in combination with machine learning analysis approaches indicates that in the near future WGS of bacteria might become cheaper and faster than a MIC measurement.

scholarly journals Assessment of antimicrobial activity of Cola milleni seed and pulp extracts against Staphylococcus aureus, Escherichia coli and Penicillium notatum

2020 ◽  
Vol 12 (1) ◽  
pp. 71-75
Author(s):  
A.M. Aliyu ◽  
S.J. Oluwafemi ◽  
S. Kasim
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Ethanol Extract ◽  
Bioactive Components ◽  
Zone Of Inhibition ◽  
Penicillium Notatum ◽  
Standard Techniques

All over the world, hundreds of plants have been identified based on researchers and experimental evidence as good sources of medicinal agents. The bioactive components (phytochemicals) of both the seeds and pulp of Cola milleni were extracted using ethanol as solvent. The bioactive components detected were alkaloids, tanins, saponins, cardiac glycosides, carbohydrates, sterols, resins and terpenes while Flavonoids, anthraquinones, anthracyanides and phenol were not detected for both the seed and pulps. Antimicrobial activity of the ethanol extract (Seed and pulp) against Staphylococcus aureus, Escherichia coli and Penicillium notatum was carried out using standard techniques. Staphylococcus aureus had the highest zone of inhibition for pulp having a range of 9.7mm±0.58mm - 19.7mm±2.52mm while Penicllium notatum had the least with 0.00mm. S.aureus also had the highest zone of inhibition range of 14.3mm±2.08mm - 21.3mm±1.53mm for the seed extract while penicillium had the least inhibition range of 5.0mm±1.00mm - 5.7mm±0.58. E.coli showed the highest minimum inhibitory concentration with ethanol extract of the pulp (160mg/ml) while penicillium notatum was not reactive. The minimum inhibitory concentration of seed against penillium notatum was the highest (160mg/ml) while staphylococcus aureus showed the lowest of 40mg/ml. The antimicrobial activity is as a result of the presence of phytochemicals detected, which suggest the use of the plant for the treatment of diseases caused by these organisms. Key words: Cola millenii, Phytochemical, Antimicrobial activity, Bacteria, Fungi

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