scholarly journals DEVELOPMENT OF IN VITRO METHODOLOGIES FOR INHIBITION OF PATHOGENIC BACTERIA BY POTENTIAL PROBIOTIC LACTOBACILLUS SPS; AN EVIDENCE FOR PRODUCTION OF ANTIMICROBIAL SUBSTANCES

Author(s):  
Prabhurajeshwar C. ◽  
Kelmani Chandrakanth R.

<p><strong>Objective: </strong>Probiotic products consist of specific strains of live bacteria that have potentially favorable health effects. A number of studies provide evidence that milk products with probiotics may be beneficial for digestive health and may improve various digestive problems. The purpose of the present study was to investigate <em>Lactobacillus</em> species with potential activities isolated from different cheese samples of local market.</p><p><strong>Methods: </strong>A total 42 lactic acid bacteria strains were isolated, fourteen (14/42) best <em>Lactobacillus</em> isolates were selected by preliminary screening as potential probiotics with antimicrobial activity against pathogenic bacteria. All the fourteen <em>Lactobacillus</em> isolates were then characterized <em>in vitro</em> for their probiotic features and antimicrobial activities against pathogens.</p><p><strong>Results: </strong>The results noticed that all selected <em>Lactobacillus</em> isolates (CH3, CH4 and CH6) were screened and confirmed as <em>Lactobacillus. </em>The isolates were able to grow at different pH, NaCl and bile salts, also exhibited the best antimicrobial activities against pathogens. All the isolates were susceptible to antibiotics used and isolates were also revealed the noticeable aggregation and hydrophobicity studies.<strong></strong></p><p><strong>Conclusion: </strong>Selected <em>Lactobacillus </em>isolates were considered as ideal, effective probiotic bacteria. Thus, they could be examined further and contribute to preventing and controlling several infections associated with intestine and for human health benefits.</p>

2021 ◽  
Vol 32 (4) ◽  
pp. 743-749
Author(s):  
Victoria Yulita Fitriani ◽  
Budi Suprapti ◽  
Muhammad Amin

Abstract Objectives This study aims to determine the characteristics of Lactobacillus acidophilus and Lactobacillus reuteri from fermented soursop fruit juice and cow’s milk, respectively as probiotic candidate based on exposure to pH, bile salts, pathogenic bacteria, and antibiotics. Methods In vitro studies were conducted to examine the resistance of Lactobacillus acidophilus and Lactobacillus reuteri in pH 2, 2.5, 3.2, and 7.2, resistance to bile salts, resistance to pathogenic bacteria (Escherichia coli, Staphylococcus aureus and Enterococcus faecalis) and antituberculosis antibiotics. Results Viability of Lactobacillus acidophilus and Lactobacillus reuteri isolates remained unchanged (6.3 × 107 CFU/mL and 5.03 × 107 CFU/mL) at various acidic pH, and had a low survival rate in Ox gall 0.3% (bile salts). These isolates also showed antibacterial properties against pathogens in the gastrointestinal tract. Both of these bacteria are quite safe to be used together with ofloxacin, linezolid, moxifloxacin, and levofloxacin, antibiotic for tuberculosis therapy. Conclusions The results showed that Lactobacillus acidophilus and Lactobacillus reuteri from fermented soursop fruit juice and cow’s milk respectively fulfilled the characteristics of probiotic and could potentially be used as adjunct therapy in tuberculosis drug-resistance.


Author(s):  
Pannapa Powthong ◽  
Apichai Sripean ◽  
Pattra Suntornthiticharoen

Objective: The objectives of this study were to isolate microorganisms and screen for potential antimicrobial activities from the soil. Methods: In this study, a total of 425 isolates were isolated from 100 soil samples. The preliminary screening for antimicrobial activities of these isolates was performed by modified cross-streak, agar diffusion, and modified icrodilution technique against 16 pathogenic bacteria and fungi.Results: In the anti-microbial activity, there were three isolates, namely, 277, 303, and 307 exhibited inhibitory activity against methicillin-resistantStaphylococcus aureus and Salmonella typhimurium respectively. This study also examined the various enzymes producing from soil microorganisms including chitinase, chitosanase, amylase, cellulose, caseinase, gelatinase, esterase, and lipase production of different selective media for 24 and 48hrs using the direct spot method. The results revealed that 28 isolates could produce various enzymes with strong activity. Most of them produced gelatinase (5.65%) and caseinase (5.18%). There were four isolates that produce broad-spectrum enzyme. In addition, the investigation of selectedmicroorganism identification showed that they can be divided into three groups: Burkholderia spp., Pseudomonas spp., and Rhodococcus spp.Conclusion: This study demonstrated that the microorganisms from soil are capable of producing potential, antibacterial, and bioactive enzymes.Keywords: Antimicrobial activity, Extracellular enzyme, Soil microbial, Drug-resistant bacteria.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Ji-yin Li ◽  
Xue-jin Wang ◽  
Li-na Wang ◽  
Xiao-xia Ying ◽  
Xiang Ren ◽  
...  

In order to investigate the potential of short antimicrobial peptides (AMPs) as alternative antibacterial agents during the treatment of peri-implantitis, the cytotoxic activity of three short AMPs, that is, Pac-525, KSL-W, and KSL, was determined using the MTT assay. The antimicrobial activity of these AMPs, ranging in concentration from 0.0039 mg/mL to 0.5 mg/mL, against the predominant planktonic pathogens, includingStreptococcus sanguis, Fusobacterium nucleatum, andPorphyromonas gingivalis, involved in peri-implantitis was investigated. Furthermore, 2-day-oldP. gingivalisbiofilms cultured on titanium surfaces were treated with Pac-525 and subsequently observed and analysed using confocal laser scanning microscopy (CLSM). The average cell proliferation curve indicated that there was no cytotoxicity due to the three short AMPs. The minimum inhibitory concentration and minimum bactericidal concentration values of Pac-525 were 0.0625 mg/mL and 0.125 mg/mL, respectively, forP. gingivalisand 0.0078 mg/mL and 0.0156 mg/mL, respectively, forF. nucleatum. Using CLSM, we confirmed that compared to 0.1% chlorhexidine, 0.5 mg/mL of Pac-525 caused a significant decrease in biofilm thickness and a decline in the percentage of live bacteria. These data indicate that Pac-525 has unique properties that might make it suitable for the inhibition the growth of pathogenic bacteria around dental implants.


2014 ◽  
Vol 37 (2) ◽  
pp. 145-158 ◽  
Author(s):  
Sarkar MA Kawsar ◽  
Abul K MS Kabir ◽  
Mohammad M R Bhuiyan ◽  
Jannatul Ferdous ◽  
Mohammad S Rahman

Regioselective pentanoylation of methyl 4,6-O-(4-methoxybenzylidene)-?-D-glucopyranoside by the direct acylation method provided the methyl 4,6-O-(4-methoxybenzylidene)-2-O-pentanoyl- ?-D-glucopyranoside in good yield. A number of 3-O-acyl derivatives of this 2-O-pentanoylation product were also prepared in order to obtain new compounds and also gather additional information for structure elucidation. The chemical structure of the newly synthesized compounds was characterized by analytical and spectral methods. Synthesized acylated derivatives of Dglucopyranoside were screened for in vitro antimicrobial activities against ten human pathogenic bacteria and four plant pathogenic fungi. The study revealed that the acylated products exhibited moderate to good antimicrobial activities. It was interesting to observe that the selected compounds were more sensitive against fungal phytopathogens than those of the bacterial strains. DOI: http://dx.doi.org/10.3329/jbas.v37i2.17554 Journal of Bangladesh Academy of Sciences, Vol. 37, No. 2, 145-158, 2013


2020 ◽  
Vol 16 (2) ◽  
pp. 207-212
Author(s):  
Wissam Zam ◽  
Ali Ali ◽  
Walaa Ibrahim

Background and Objective: With the significant increase in the prevalence of infectious diseases and the development of drug resistance by human pathogenic bacteria, there is a continuous need to discover new antimicrobial compounds from plants. Methods: Four extracts of wild Myrtus communis L. berries (myrtle berries) were prepared with the addition of Cinnamomum verum and Eugenia caryophyllata. The extracts were screened in vitro for their antimicrobial activities using agar-well diffusion method against Escherichia coli, Staphylococcus aureus, Enterobacter cloacae, Listeria monocytogenes, Pseudomonas aeruginosa and Proteus mirabilis cultures. Results: The inhibition zones ranged from 12 to 22 mm. The MICs values of extracts lies between the ranges of 30 to 100 mg/ml. Of the extracts studied, the most active ones were those obtained from the myrtle berries:cloves, myrtle berries:cinnamon:cloves with the highest inhibition zones 22 mm and 17mm against S. aureus and L. monocytogenes at 50 mg/ml and 80 mg/ml, respectively. None of the extracts was active against E. coli and P. mirabilis. Conclusion: The present investigations have exposed that the myrtle berries:cloves, myrtle berries: cinnamon:cloves extracts could be used in traditional medicine as natural antimicrobial agents in treatment the bacterial infections.


2010 ◽  
Vol 50 (7) ◽  
pp. 660 ◽  
Author(s):  
Pak-Lam Yu ◽  
Danitsja S. van der Linden ◽  
Haryadi Sugiarto ◽  
Rachel C. Anderson

The development of antimicrobial resistance by pathogenic bacteria has fuelled the search for alternatives to conventional antibiotics. Endogenous antimicrobial peptides have the potential to be used as new antimicrobial substances because they have low minimum inhibitory concentration in vitro, have broad-spectrum activity, neutralise lipopolysaccharides, promote wound healing and have synergistic effects with conventional antibiotics. Farm animals, in particular the blood that is a by-product of the meat and poultry industries, are an abundant, and currently underutilised, source of such antimicrobial peptides. These antimicrobial peptides could be isolated and developed into high-value products such as biopreservatives, topical neutraceutical products and pharmaceuticals. There have been some clinical trials of antimicrobial peptides as pharmaceutical products, but up to now, the trials have shown disappointing results. Further research and development is still needed before such peptides can be commercialised and full advantage taken of this waste product of the meat and poultry industries.


mBio ◽  
2016 ◽  
Vol 7 (5) ◽  
Author(s):  
Lillian J. Juttukonda ◽  
Walter J. Chazin ◽  
Eric P. Skaar

ABSTRACT During infection, bacterial pathogens must adapt to a nutrient metal-limited environment that is imposed by the host. The innate immune protein calprotectin inhibits bacterial growth in vitro by chelating the divalent metal ions zinc (Zn 2+ , Zn) and manganese (Mn 2+ , Mn), but pathogenic bacteria are able to cause disease in the presence of this antimicrobial protein in vivo. One such pathogen is Acinetobacter baumannii , a Gram-negative bacterium that causes pneumonia and bloodstream infections that can be complicated by resistance to multiple antibiotics. A. baumannii inhibition by calprotectin is dependent on calprotectin Mn binding, but the mechanisms employed by A. baumannii to overcome Mn limitation have not been identified. This work demonstrates that A. baumannii coordinates transcription of an NRAMP family Mn transporter and a urea carboxylase to resist the antimicrobial activities of calprotectin. This NRAMP family transporter facilitates Mn accumulation and growth of A. baumannii in the presence of calprotectin. A. baumannii is found to utilize urea as a sole nitrogen source, and urea utilization requires the urea carboxylase encoded in an operon with the NRAMP family transporter. Moreover, urea carboxylase activity is essential for calprotectin resistance in A. baumannii . Finally, evidence is provided that this system combats calprotectin in vivo , as deletion of the transporter impairs A. baumannii fitness in a mouse model of pneumonia, and this fitness defect is modulated by the presence of calprotectin. These findings reveal that A. baumannii has evolved mechanisms to subvert host-mediated metal sequestration and they uncover a connection between metal starvation and metabolic stress. IMPORTANCE Acinetobacter baumannii is a bacterium that causes bloodstream, wound, urinary tract, and pneumonia infections, with a high disease burden in intensive care units. Treatment of A. baumannii infection is complicated by resistance to most antibiotics in use today, and resistance to last-resort therapies has become commonplace. New treatments for A. baumannii infection are desperately needed, but our current understanding of the bacterial factors required to cause infection is limited. We previously found that the abundant innate immune protein calprotectin inhibits the growth of A. baumannii by withholding essential metals . Despite this, A. baumannii is still able to infect wild-type mice, which produce calprotectin during infection. Here, we identify factors employed by A. baumannii during infection to overcome calprotectin-mediated metal sequestration. Moreover, we expose a connection between metal starvation and metabolism that may be a “chink in the armor” of A. baumannii and lead to new treatment options.


2016 ◽  
Vol 6 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Sudipti Arora ◽  
A. A. Kazmi

The application of vermifiltration could reduce the load of chemical and biological pollutants present in wastewater, reducing the pressure over water requirements and allowing the reclamation of the treated water. In the present study, vermifiltration has shown a great potential for chemical pollutants and pathogen removal in wastewater through the synergistic interactions of earthworms and microorganisms. The results of a pilot-scale study showed a higher percentage removal of biochemical oxygen demand (88%), chemical oxygen demand (78%), total suspended solids (83%) and log removal of fecal coliforms (2.61), fecal streptococci (2.50), Salmonella (2.20) and Escherichia coli (2.48) to the levels considered acceptable for reuse in irrigation purposes. Specifically, earthworms in the vermifilter were able to transform insoluble organic material to soluble form followed by selective digestion of the material to finer size, and further degradation by the microorganisms in the reactor. In vitro antimicrobial assay tests also showed that the present microflora had strong inhibitory efficiency against Staphylococcus aureus, E. coli, Pseudomonas aeruginosa and Klebsiella aerogenes. The observed inhibitory effect was found to be responsible for the phenomenon mentioned above, with release of antimicrobial substances by earthworms and associated microflora that showed antimicrobial potency against pathogenic bacteria. The kinetics evaluation showed the predominance of a first order removal model during vermifiltration.


2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Ramalingam Peraman ◽  
Rajendran Kuppusamy ◽  
Sunil Kumar Killi ◽  
Y. Padmanabha Reddy

Considering quinoxaline as a privileged structure for the design of potent intercalating agents, some new sugar conjugates of quinoxaline were synthesized and characterized by IR, 1HNMR, 13C NMR, and mass spectral data. In vitro testing for antitubercular and antimicrobial activities was performed against Mycobacterium tuberculosis H37Rv and some pathogenic bacteria. Results revealed that conjugate containing ribose moiety demonstrated the most promising activity against Mycobacteria and bacteria with minimum inhibitory concentrations (MIC) of 0.65 and 2.07 μM, respectively. Other conjugates from xylose, glucose, and mannose were moderately active whilst disaccharides conjugates were found to be less active. In silico docking analysis of prototype compound revealed that ATP site of DNA gyrase B subunit could be a possible site for inhibitory action of these synthesized compounds.


Author(s):  
H. Tkachenko ◽  
L. Buyun ◽  
Z. Osadovskyy ◽  
M. Truhan ◽  
Ye. Sosnowski ◽  
...  

In the current investigation, screening of ethanolic extract obtained from Ficus lyrata leaves against pathogenic bacteria has been done in order to assess the antimicrobial activity aimed at detecting new sources of antimicrobial agents. The antimicrobial activity of the extract was determined using agar disc diffusion method. The antibacterial activity of leaf extract of F. lyrata was tested against human pathogenic bacteria — both Gram-positive (Staphylococcus aureus, methicillin-resistant S. aureus and Streptococcus pneumoniae) and Gram-negative strains (Klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli). The results of this study provide evidence that the ethanolic extract of F. lyrata leaves has a mild antimicrobial activities, apparently, attributed to the presence of various secondary metabolites, which confirm the traditional use of this plant for the treatment of diseases caused by pathogens. These data allow us to suggest that the extracts of F. lyrata can be used to discover antibacterial substances for developing new pharmaceuticals to control clinically important pathogens responsible for severe disorders.


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