scholarly journals Characterization and partial purification of an antibacterial agent from halophilic actinomycetes Kocuria sp. strain rsk4

Bioimpacts ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 253-261 ◽  
Author(s):  
Ravi Ranjan Kumar ◽  
Vasantba J Jadeja
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Broad Spectrum ◽  
Antibacterial Agent ◽  
Pathogenic Bacteria ◽  
Inhibitory Concentration ◽  
Flash Chromatography ◽  
Resistant Bacteria ◽  
Antibiotic Resistant ◽  
Antibacterial Compound ◽  
Halophilic Actinomycetes

Introduction: The inevitable rise of antibiotic-resistant bacteria is a global health problem. These pathogens erode the utility of available antibiotics. Staphylococcus aureus is one of the major causes of community-acquired infections. The aim of work was to evaluate the marine actinomycetes for production of the antibacterial agent against pathogens. Methods: Halophilic actinomycetes were isolated, characterized and screened for production of antibacterial agent against pathogenic bacteria. The antibacterial compounds were extracted by solvent extraction and separated by TLC based bioautography. Antibacterial compound was further purified by flash chromatography followed by high-performance liquid chromatography (HPLC) techniques. The active fraction was characterized by spectroscopy techniques. The minimum inhibitory concentration of antibiotic was determined against pathogens. Results: A new halophilic actinomycetes strain rsk4 was isolated from marine water. It was designated as Kocuria sp. based on the physiological, biochemical and 16S rDNA sequence-based characters. It was able to produce broad-spectrum antibacterial compound and exhibited significant inhibitory activities against antibiotic-resistant S. aureus. The antibacterial compound was secreted optimally at 5% NaCl and neutral pH in the starch casein medium during stationary phase. The crude ethyl acetate extract was separated by chloroform-methanol, 24:1, v/v having Rf value 0.45. Bioassay of HPLC fractions confirms the presence of antibiotics picks at retention time: 3.24 minutes. The UV-Visible and mass spectra of the compound revealed that the active compound was different from other known antibiotics. The lowest minimum inhibitory concentration was recorded against S. aureus (30 µg/mL). Conclusion: The result suggests that a broad-spectrum antibacterial compound obtained from halophilic actinomycetes is effective against pathogenic bacteria. This compound may be a good alternative treatment against antibiotic-resistant pathogen S. aureus.

scholarly journals Effective inhibition of Clostridioides difficile by the novel peptide CM-A

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257431
Author(s):  
Sirirak Arthithanyaroj ◽  
Surang Chankhamhaengdecha ◽  
Urai Chaisri ◽  
Ratchaneewan Aunpad ◽  
Amornrat Aroonnual
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Cell Membrane ◽  
Inhibitory Concentration ◽  
Cell Permeability ◽  
Resistant Bacteria ◽  
Microscopy Imaging ◽  
Antibiotic Resistant ◽  
Clostridioides Difficile ◽  
Novel Approach ◽  
Cell Depolarization

Clostridioides difficile infection is the most common cause of nosocomial and antibiotic-associated diarrhea. C. difficile treatment is increasingly likely to fail, and the recurrence rate is high. Antimicrobial peptides are considered an alternative treatment for many infectious diseases, including those caused by antibiotic resistant bacteria. In the present study, we identified a CM peptide, a hybrid of cecropin A and melittin, and its derivative which possesses potent antimicrobial activity against C. difficile strain 630. CM peptide exhibited antibacterial activity with minimum inhibitory concentration of 3.906 μg/ml (2.21 μM). A modified derivative of CM, CM-A, exhibited even greater activity with a minimum inhibitory concentration of 1.953 μg/ml (1.06 μM) and a minimum bactericidal concentration of 7.8125 μg/ml (4.24 μM), which indicates that CM-A peptide is more efficient than its parent peptide. A fluorescence-activated cell sorter analysis revealed that the membrane of C. difficile 630 could be an important target for CM-A. This peptide induced high levels of cell depolarization and cell permeability on C. difficile cell membrane. Moreover, electron microscopy imaging showed that CM-A interferes with the C. difficile cell membrane. Hence, the antimicrobial peptide CM-A may represent a promising novel approach for the treatment of C. difficile infections.

Synergistic Effects of Three Moroccan Thyme Essential Oils with Antibiotic Cefixime

2018 ◽  
Vol 16 (S1) ◽  
pp. S149-S154 ◽  
Author(s):  
C. Alaoui Jamali ◽  
A. Kasrati ◽  
M. Fadli ◽  
L. Hassani ◽  
D. Leach ◽  
...  
Keyword(s):  
Essential Oils ◽  
Pathogenic Bacteria ◽  
Inhibitory Concentration ◽  
Synergistic Effects ◽  
Synergistic Interaction ◽  
Resistant Bacteria ◽  
Antibiotic Resistant ◽  
Promising Solution ◽  
First Time ◽  
Concentration Indices

The association of essential oils (EOs) with antibiotics provides a promising solution towards combating resistant bacteria. Thus, the aim of this study was to examine for the first time the possible synergistic interaction between EOs of three Moroccan thymes, namely Thymus leptobotrys (carvacrol [79.1%]), Thymus pallidus (γ-terpinene [29.6%], thymol [26.8%] and p-cymene [18.9%]) and Thymus ciliatus (carvacrol [26.2%], p-cymene [19.6%], thymol [17.3%] and γ-terpinene [14.6%]) and the antibiotic cefixime against selected pathogenic bacteria. The results showed that all thyme EOs presented interesting antibacterial potency and important synergistic effects with cefixime. Thymus leptobotrys EO showed the strongest efficacy against all tested bacteria (minimum inhibitory concentration values 0.14 mg/mL to 73.92 mg/mL), and the best synergistic effect (fractional inhibitor concentration indices: 0.26 to 0.5; gain: 4- to 130- fold). This synergistic interaction between the studied thyme EOs and cefixime may provide a basis for future applications for the control of antibiotic-resistant bacteria.

scholarly journals Synergistic Combinations of Antibiotics with Cumin, Oregano and Rosewood Oils as a Strategy to Preserve the Antibiotic Repertoire

2019 ◽  
Vol 5 (4) ◽  
pp. 337-353
Author(s):  
Lucy Owen ◽  
Katie Laird
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Resistant Bacteria ◽  
Positive Interactions ◽  
Antibiotic Resistant ◽  
Test Species ◽  
Clinical Sensitivity ◽  
E Coli ◽  
Time Kill ◽  
Synergistic Combinations

Background: Formulations employing synergistic combinations of antibiotics with Essential Oils (EOs) could help preserve the antibiotic repertoire by improving their activity against resistant bacteria. Objective: Antimicrobial interactions between double and triple combinations of EOs, EO components and antibiotics were determined using the checkerboard method. The most active triple combinations were then assessed by a time-kill assay. Methods: Two synergistic EO-antibiotic combinations and eight additive EO-antibiotic combinations reduced the antibiotic minimum inhibitory concentration below clinical sensitivity breakpoints according to the checkerboard method. However, all the tested combinations were additive according to the time-kill assay; while the combinations completely killed S. aureus, E. coli and P. aeruginosa cells in 2 h. At least one EO compound from the combination alone completely killed the cells of test species. Results: Two synergistic EO-antibiotic combinations and eight additive EO-antibiotic combinations reduced the antibiotic minimum inhibitory concentration below clinical sensitivity breakpoints according to the checkerboard method. However, all the tested combinations were additive according to the time-kill assay; while the combinations completely killed S. aureus, E. coli and P. aeruginosa cells in 2 h. At least one EO compound from the combination alone completely killed the cells of test species. Conclusion: Positive interactions support the use of EOs or EO components to enhance antibiotic efficacy against antibiotic resistant bacteria. The EO-antibiotic combinations tested by the time kill assay were indifferent; therefore, the observed antimicrobial activity did not arise from synergistic mechanisms as indicated by the checkerboard method. Investigation of other synergistic combinations identified by the checkerboard method could reveal more promising candidates.

scholarly journals Bacteria and Their Antibiotic Resistance Profiles in Ambient Air in Accra, Ghana, February 2020: A Cross-Sectional Study

2021 ◽  
Vol 6 (3) ◽  
pp. 110
Author(s):  
Godfred Saviour Kudjo Azaglo ◽  
Mohammed Khogali ◽  
Katrina Hann ◽  
John Alexis Pwamang ◽  
Emmanuel Appoh ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Pathogenic Bacteria ◽  
Ambient Air ◽  
Cross Sectional Study ◽  
Bacillus Species ◽  
Resistant Bacteria ◽  
Cross Sectional ◽  
Antibiotic Resistant ◽  
Bacterial Counts ◽  
Inappropriate Use

Inappropriate use of antibiotics has led to the presence of antibiotic-resistant bacteria in ambient air. There is no published information about the presence and resistance profiles of bacteria in ambient air in Ghana. We evaluated the presence and antibiotic resistance profiles of selected bacterial, environmental and meteorological characteristics and airborne bacterial counts in 12 active air quality monitoring sites (seven roadside, two industrial and three residential) in Accra in February 2020. Roadside sites had the highest median temperature, relative humidity, wind speed and PM10 concentrations, and median airborne bacterial counts in roadside sites (115,000 CFU/m3) were higher compared with industrial (35,150 CFU/m3) and residential sites (1210 CFU/m3). Bacillus species were isolated in all samples and none were antibiotic resistant. There were, however, Pseudomonas aeruginosa, Escherichia coli, Pseudomonas species, non-hemolytic Streptococci, Coliforms and Staphylococci species, of which six (50%) showed mono-resistance or multidrug resistance to four antibiotics (penicillin, ampicillin, ciprofloxacin and ceftriaxone). There was a positive correlation between PM10 concentrations and airborne bacterial counts (rs = 0.72), but no correlations were found between PM10 concentrations and the pathogenic bacteria nor their antibiotic resistance. We call for the expansion of surveillance of ambient air to other cities of Ghana to obtain nationally representative information.

Antibiotic susceptibility pattern against pathogenic bacteria causing Dental Caries

2011 ◽  
Vol 1 (1) ◽  
pp. 31-35
Author(s):  
Deepak Dwivedi ◽  
Tejram Kushwah ◽  
Mukesh Kushwah ◽  
Vinod Singh
Keyword(s):  
Dental Caries ◽  
Antibiotic Susceptibility ◽  
Pathogenic Bacteria ◽  
Resistant Bacteria ◽  
Susceptibility Pattern ◽  
Antibiotic Resistant ◽  
Antibiotic Susceptibility Pattern ◽  
Penicillin V ◽  
Antibiotics Susceptibility ◽  
Susceptibility Tests

Antibiotics to treat dental caries infection are routinely prescribed which led to the increased resistance against bacteria. The purpose of this investigation was to perform antibiotic susceptibility tests on a panel of pathogenic bacteria isolated from dental caries infection. Bacteria were isolated from caries site of patients and identified at the species level. Each of 150 species of bacteria was tested for antibiotics susceptibility to a five antibiotics using Etest. The antibiotics used were Amoxicillin, Cloxocillin, Erythromycin, Tetracycline and Penicillin‐V. The obtained resistance percentage for each antibiotic were Penicillin V: 72/150 (48%), Tetracycline: 99/150 (66%), Amoxicillin: 135/150 (90%), Cloxocillin: 117/150 (78%), and Erythromycin: 90/150 (60%) (Table 1). In case of combinatorial antibiotic exposure, the resistance percentage of Penicillin V/Amoxicillin and Amoxicillin/ Erythromycin was 39/150 (26%), and 45/150 (30%) respectively. The study has well demonstrated the clinical picture of antibiotic resistance and susceptibility pattern of bacteria causing dental caries. The obtained comprehensive data will allow investigating the spatial distribution of pathogenic, antibiotic resistant bacteria among dental caries patients which further may help into development of novel diagnostic and treatment approaches for the same.

scholarly journals Bacteriophages: the possible solution to treat infections caused by pathogenic bacteria

2017 ◽  
Vol 63 (11) ◽  
pp. 865-879 ◽  
Author(s):  
Ayman El-Shibiny ◽  
Salma El-Sahhar
Keyword(s):  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Phage Therapy ◽  
Multidrug Resistant ◽  
Clinical Applications ◽  
Western World ◽  
Resistant Bacteria ◽  
Vaccine Production ◽  
Bacterial Populations ◽  
Antibiotic Resistant

Since their discovery in 1915, bacteriophages have been used to treat bacterial infections in animals and humans because of their unique ability to infect their specific bacterial hosts without affecting other bacterial populations. The research carried out in this field throughout the 20th century, largely in Georgia, part of USSR and Poland, led to the establishment of phage therapy protocols. However, the discovery of penicillin and sulfonamide antibiotics in the Western World during the 1930s was a setback in the advancement of phage therapy. The misuse of antibiotics has reduced their efficacy in controlling pathogens and has led to an increase in the number of antibiotic-resistant bacteria. As an alternative to antibiotics, bacteriophages have become a topic of interest with the emergence of multidrug-resistant bacteria, which are a threat to public health. Recent studies have indicated that bacteriophages can be used indirectly to detect pathogenic bacteria or directly as biocontrol agents. Moreover, they can be used to develop new molecules for clinical applications, vaccine production, drug design, and in the nanomedicine field via phage display.

scholarly journals Detection of pathogenic bacteria associated with earphones used by students of Stamford University Bangladesh

2020 ◽  
Vol 10 (1) ◽  
pp. 1-4
Author(s):  
Omor Ahmed Chowdhury ◽  
Md Raihan Ahmed ◽  
Md Raihan Dipu ◽  
Md Aftab Uddin
Keyword(s):  
Pathogenic Bacteria ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Bacterial Isolates ◽  
Biochemical Tests ◽  
Disk Diffusion Method ◽  
Antibiotic Resistant ◽  
Potential Source ◽  
Different Types ◽  
Staphylococcus Spp

The use of earphones has increased in recent times throughout the world especially among the different level of students such as school, college or university who have a higher tendency of sharing these among them. Unlike airline headsets, headphones and stethoscope ear-pieces, ear phones are often shared by multiple users and can be a potential medium for transmission of pathogens, which can give rise to various ear related infections. The objective of this study was to detect the pathogenic bacteria from the ear-phones used by the students of Stamford University Bangladesh. A total of 16 ear-phone swabs were collected by sterile cotton swabs. The swabs were inoculated onto blood agar and incubated aerobically overnight at 37oC. Microscopic observation and standard biochemical tests were performed to confirm the identification of all the bacterial isolates. Six presumptively identified Staphylococcus spp. (38%) were tested against six different types of antibiotics following Kirby-Bauer disk diffusion method. Isolates were found to be 84% resistant against Cotrimoxazole and demonstrated 100% sensitivity to Vancomycin and Ciprorofloxacin. The findings of this study suggest the users to disinfect their respective ear phones and not to exchange them as they may act as a potential source to transfer pathogenic and antibiotic resistant bacteria among the ear phone users. Stamford Journal of Microbiology, Vol.10 (1) 2020: 1-4

scholarly journals Antibiogram signatures of non-cholera causing Vibrio species recovered from environmental niches in Eastern Cape, South Africa.

2021 ◽  
Author(s):  
Oluwakemi Victoria Ayodele ◽  
Anthony Ifeanyi Okoh
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Nalidixic Acid ◽  
Vibrio Parahaemolyticus ◽  
Inhibitory Concentration ◽  
Vibrio Vulnificus ◽  
Diffusion Method ◽  
Morbidity Rate ◽  
Antibiotic Resistant ◽  
Mortality And Morbidity ◽  
Vibrio Fluvialis

Abstract Background: The use of antibiotics globally has helped reduce mortality and morbidity rate due to its ability to effectively treat bacterial infections in both humans and animals. However, the menace of antimicrobial resistance has become a challenge to public health due to its increased mortality and morbidity rate. This study determined the antibiogram pattern of non-cholera causing Vibrio species against a panel of 11 antibiotics that are wildly used for treatment. Multiple antibiotic resistance phenotype, multiple antibiotic resistant indices and minimum inhibitory concentration (MIC) of test antibiotics were also determined.Results: Polymerase chain reaction (PCR) was used to confirm 100 isolates of Vibrio parahaemolyticus, 82 and 46 isolates of Vibrio vulnificus and Vibrio fluvialis respectively, collected from the culture collections of the Applied and Environmental Microbiology Research Group (AEMREG), University of Fort Hare. Thereafter, disc diffusion method was used to determine the antibiogram pattern of target non-cholera causing Vibrio species against a panel of 11 antibiotics that are of clinical importance. The highest rate of Vibrio parahaemolyticus resistance was observed against tetracycline (22 %) and nalidixic acid (16 %). Vibrio fluvialis also displayed highest rate of resistance against tetracycline (28 %) and nalidixic acid (28 %), while Vibrio vulnificus isolates exhibited highest rate resistance against imipenem (40 %) and tetracycline (22 %). A total of 38 MARP patterns were observed and the MAR indices ranged between 0.3 and 0.8. Against the resistant Vibrio parahaemolyticus and Vibrio fluvialis isolates, minimum inhibitory concentration ranged from 16 µg/ml to 2048 µg/ml for both tetracycline and nalidixic acid, while against Vibrio vulnificus isolates, minimum inhibitory concentration ranged from 8 µg/ml to 256 µg/ml for both imipenem and nalidixic acid. Conclusions: Results obtained from this study is an indication that antibiotic resistant bacteria that could pose as threat to health of humans and animals are present in the environment.

scholarly journals A Degradation Product from Hydrolysate of Imipenem with Imis Broad-Spectrum Inhibits Metallo-β-Lactamases

2020 ◽  
Vol 13 (10) ◽  
Author(s):  
Ying Ge ◽  
Li-Wei Xu ◽  
Jian-Bin Zhen ◽  
Cheng Chen ◽  
Miao Lv ◽  
...  
Keyword(s):  
Broad Spectrum ◽  
Degradation Product ◽  
Substrate Inhibition ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Antibiotic Resistant Bacteria ◽  
Antibiotic Resistant ◽  
Leaving Group ◽  
Ic50 Values ◽  
Hydrolysis Of

Background: Infections caused by metallo-β-lactamases (MβLs)-producing antibiotic-resistant bacteria pose a severe threat to public health. The synergistic use of current antibiotics in combination with MβL inhibitors is a promising therapeutic mode against these antibiotic-resistant bacteria. Objectives: The study aimed to probe the inhibition of MβLs and obtain the active component, P1, in the degradation product after imipenem was hydrolyzed by ImiS. Methods: The hydrolysis of two carbapenems with MβL ImiS was monitored by UV-Vis in real-time, and the degradation product from the leaving group produced after imipenem was hydrolyzed (but not for faropenem) was purified by HPLC to give one component, P1. Results: Kinetic assays revealed that P1 exhibited a broad-spectrum inhibition against VIM-2, NDM-1, ImiS, and L1, from three sub-classes of MβLs, with IC50 values of 8 - 32, 13.8 - 29.3, and 14.2 - 19.2 µM, using imipenem, cefazolin, and nitrocefin as substrates, respectively. Also, P1 showed synergistic antibacterial efficacy against drug-resistant Escherichia coli producing VIM-2, NDM-1, ImiS, and L1, in combination with antibiotics, restoring 16 to 32-fold and 32 to 128-fold efficacies of imipenem and cefazolin, respectively. Spectroscopic and Ellman's reagent analyses suggested that P1, a mercaptoethyl-form imidamide, is a mechanism-based inhibitor, while faropenem has no substrate inhibition, due to the lack of a leaving group. Conclusions: This work reveals that the hydrolysate of imipenem, a carbapenem with a good leaving group, can be used in screening for broad-spectrum inhibitors of MβLs.

scholarly journals The Antibacterial Potential of Honeydew Honey Produced by Stingless Bee (Heterotrigona itama) against Antibiotic Resistant Bacteria

Antibiotics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 871
Author(s):  
Wen-Jie Ng ◽  
Nam-Weng Sit ◽  
Peter Aun-Chuan Ooi ◽  
Kah-Yaw Ee ◽  
Tuck-Meng Lim
Keyword(s):  
Honey Bee ◽  
Pathogenic Bacteria ◽  
Apis Cerana ◽  
Stingless Bee ◽  
Morphological Alteration ◽  
Resistant Bacteria ◽  
Antibacterial Effects ◽  
Electron Microscopic ◽  
Antibiotic Resistant ◽  
E Coli

Scientific studies about the antibacterial effects of honeydew honey produced by the stingless bee are very limited. In this study, the antibacterial activities of 46 blossom and honeydew honeys produced by both honey bees and stingless bees were evaluated and compared. All bacterial isolates showed varying degrees of susceptibility to blossom and honeydew honeys produced by the honey bee (Apis cerana) and stingless bee (Heterotrigona itama and Geniotrigona thoracica) in agar-well diffusion. All stingless bee honeys managed to inhibit all the isolates but only four out of 23 honey bee honeys achieved that. In comparison with Staphylococcus aureus, Escherichia coli was found to be more susceptible to the antibacterial effects of honey. Bactericidal effects of stingless bee honeys on E. coli were determined with the measurement of endotoxins released due to cell lysis. Based on the outcomes, the greatest antibacterial effects were observed in honeydew honey produced by H. itama. Scanning electron microscopic images revealed the morphological alteration and destruction of E. coli due to the action of this honey. The combination of this honey with antibiotics showed synergistic inhibitory effects on E. coli clinical isolates. This study revealed that honeydew honey produced by H. itama stingless bee has promising antibacterial activity against pathogenic bacteria, including antibiotic resistant strains.

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