scholarly journals Marine Bacterial Secondary Metabolites: A Treasure House for Structurally Unique and Effective Antimicrobial Compounds

Marine Drugs ◽  
2021 ◽  
Vol 19 (10) ◽  
pp. 530
Author(s):  
Ramanathan Srinivasan ◽  
Arunachalam Kannappan ◽  
Chunlei Shi ◽  
Xiangmin Lin

The prevalence of antimicrobial resistance reduces the effectiveness of antimicrobial drugs in preventing and treating infectious diseases caused by pathogenic organisms, such as bacteria, fungi, and viruses. Because of the burgeoning growth of microbes with antimicrobial-resistant traits, there is a dire need to identify and develop novel and effective antimicrobial agents to treat infections from antimicrobial-resistant strains. The marine environment is rich in ecological biodiversity and can be regarded as an untapped resource for prospecting novel bioactive compounds. Therefore, exploring the marine environment for antimicrobial agents plays a significant role in drug development and biomedical research. Several earlier scientific investigations have proven that bacterial diversity in the marine environment represents an emerging source of structurally unique and novel antimicrobial agents. There are several reports on marine bacterial secondary metabolites, and many are pharmacologically significant and have enormous promise for developing effective antimicrobial drugs to combat microbial infections in drug-resistant pathogens. In this review, we attempt to summarize published articles from the last twenty-five years (1996–2020) on antimicrobial secondary metabolites from marine bacteria evolved in marine environments, such as marine sediment, water, fauna, and flora.

Author(s):  
Nilushi Indika Bamunu Arachchige ◽  
Fazlurrahman Khan ◽  
Young-Mog Kim

Background: The treatment of infection caused by pathogenic bacteria becomes one of the serious concerns globally. The failure in the treatment was found due to the exhibition of multiple resistance mechanisms against the antimicrobial agents. Emergence of resistant bacterial species has also been observed due to prolong treatment using conventional antibiotics. To combat these problems, several alternative strategies have been employed using biological and chemically synthesized compounds as antibacterial agents. Marine organisms considered as one of the potential sources for the isolation of bioactive compounds due to the easily available, cost-effective, and eco-friendly. Methods: The online search methodology was adapted for the collection of information related to the antimicrobial properties of marine-derived compounds. These compound has been isolated and purified by different purification techniques, and their structure also characterized. Furthermore, the antibacterial activities have been reported by using broth microdilution as well as disc diffusion assays. Results: The present review paper describes the antimicrobial effect of diverse secondary metabolites which are isolated and purified from the different marine organisms. The structural elucidation of each secondary metabolite has also been done in the present paper, which will help for the in silico designing of the novel and potent antimicrobial compounds. Conclusion: A thorough literature search has been made and summarizes the list of antimicrobial compounds that are isolated from both prokaryotic and eukaryotic marine organisms. The information obtained from the present paper will be helpful for the application of marine compounds as antimicrobial agents against different antibiotic-resistant human pathogenic bacteria.


2018 ◽  
Vol 6 (6) ◽  
pp. 1-6
Author(s):  
Yao KANGA ◽  
CAMARA Djeneb ◽  
KOUASSI Kouadio Aubin ◽  
ZIRIHI Guédé Noël

The emergence of multi-drug resistant strains and limitations of present antimicrobial drugs have led to continuous search for natural products as curative agents for Anti-methicillin resistantinfections. The aim of this study was to evaluate antibacterial activity of an ethanolic extract from Albizia lebbeckstem bark against Anti-methicillin resistant. Methods and Results : The methods of dissemination swab on muller-hinton agar and double dilution were used to evaluate the antibacterial activity of 70 % ethanolic extract of stem bark of Albizia lebbeck.All multi-resistant strains of Staphylococcus aureus and the reference strain (ATCC 25923) were sensitive to 70 % ethanolic extract of the stem bark of Albizia lebbeck. The MBCvary from 0,49 mg/mL to 2mg/mL. Also, the phytochemical screening of this extract revealed the presence of  Polyphenols, Gallic tannins, Catechin tanninsand Flavonoids. These findings confirm that an 70 % ethanolic extract from Albizia lebbeck stem bark inhibited growth of Anti-methicillin resistant at low concentration and could be utilised as an alternative Anti-methicillin resistantagent.


Author(s):  
ALI MOHAMMED ABDULLAH BAWAZIR ◽  
PALAKSHA ◽  
MANJULA SHANTARAM ◽  
MANJULA SHANTARAM

This review conceptualizes about the actinomycetes and its contribution to human health by playing a key role as bioactive secondary metabolites, such as enzymes, antibiotics and pigments, leading to their diverse applications and use in various industries. These searches have been uncommonly successful, and around 66% of naturally happening antibiotics, including many medically important, have been isolated from actinomycetes. The speedy occurrence of antimicrobial resistance among pathogens has led to a renewed interest to search for novel antimicrobial agents, but these antibiotics are not enough for the treatment of all diseases because there is a berserk requirement for a novel actinomycetes to combat against the antibiotic-resistant strains of pathogenic microorganisms, which are quickly expanding bit by bit. Actinomycetes are the important providers to the pharmaceutical and other industries and are well known for their capacity to produce secondary metabolites many of which are active against pathogenic microorganisms.


2020 ◽  
Vol 3 (3) ◽  
pp. 556
Author(s):  
Gayan Kanchana Wijesinghe ◽  
Thaís Rossini de Oliveira ◽  
Flavia Camila Maia ◽  
Simone Busato de Feiria ◽  
Felipe Joia ◽  
...  

Medicinal plants play a major role as an alternative therapeutic agents for various disease conditions including cardiac and hepatic diseases, microbial infections and non-communicable disease such as diabetes mellitus. With the excessive use of synthetic antimicrobial drugs, micro-organisms become more virulent and resistant to available antimicrobial therapeutic agents. Further majority (around 60%-80%) of human microbial infections are biofilm associated infections and various resistance mechanisms of biofilms make it more difficult to eradicate or treat biofilm infections using available antimicrobial therapeutics. Further, biofilm structure acts as a physical barrier and prevent penetration of antimicrobial agents towards the biofilm core. Currently, scientists pay their attention to invent novel effective antimicrobial agents with less side effects for these biofilm infections. Phytochemicals have identified as a potential alternative antimicrobial strategy in biofilm control and eradication. Cinnamomum verum is a native Sri Lankan medicinal plant that has been widely used as a culinary spice, exhibits many medicinal benefits especially activity against microbial infectious diseases. Essential oils extracted from leaf and bark of C. verum have been used as a safe and effective antimicrobial agents against various infections for centuries. This review analyses the available scientific literature evidences on appositeness of true cinnamon leaf essential oil as an alternative antimicrobial strategy to control microbial biofilm infections with medical importance.


2021 ◽  
Vol 12 (4) ◽  
pp. 15-25
Author(s):  
D. P. Gladin ◽  
A. R. Khairullina ◽  
A. M. Korolyuk ◽  
N. S. Kozlova ◽  
O. V. Ananyeva ◽  
...  

Background. Staphylocci are the leading pus-forming Gram-positive bacteria in the childrens hospitals. The prevalence of the antibiotic resistant strains among them limits therapeutic effects of infections in children. Aim. The research is aimed at characterizing the species of staphylococcus, which are isolated from the different clinical specimens of the patients at the clinics of Saint Petersburg State Pediatric Medical University in 2019, and analysis of their susceptibility to antimicrobial agents. Materials and metods. According to the clinical recommendations of 2018, susceptibility to antimicrobial drugs (AMD) was revealed in 860 strains of staphylococci determined by the disc diffusion method, which were identified by the automated analyser Vitek-2 compact. Results. Six species of staphylococci were represented at the hospital departments, among which Staphylococcus epidermidis prevailed in the departments of the neonate pathology department and intensive care units (63.0% and 46.2% respectively), Staphylococcus aureus is commonly found at the departments of surgery and the departments of the therapeutic profiles (61.7% and 46.2% respectively). More than a half of the staphylococci strains (63.0%) were resistant to at least one of the antimicrobial drugs. Vancomycin and line solid showed the highest activity to these staphylococci. High specific weight of multidrug resistant (MDR) bacteria (37.8%) and extensively drug resistant (XDR) strains of the phenotype (33.0%) was revealed. The level of antibiotic resistant strains was the highest in Staphylococcus haemolyticus (98.1%) and S. epidermidis (82.0%), while the specific weight of the resistant ones, MDR and XDR strains was extremely low among S. aureus (16.2%, 1.5% and 0.4 respectively), as well as in methicillin-resistant isolates (0.8%). Conclusions. A great variety of antibiotic resistance was revealed among the staphylococci. The prevalence of these strains in the pediatric hospitals requires constant local monitoring of the antibiotic resistant staphylococci.


Biomedicines ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 405 ◽  
Author(s):  
Francisco Javier Álvarez-Martínez ◽  
Enrique Barrajón-Catalán ◽  
Vicente Micol

Drug-resistant bacteria pose a serious threat to human health worldwide. Current antibiotics are losing efficacy and new antimicrobial agents are urgently needed. Living organisms are an invaluable source of antimicrobial compounds. The antimicrobial activity of the most representative natural products of animal, bacterial, fungal and plant origin are reviewed in this paper. Their activity against drug-resistant bacteria, their mechanisms of action, the possible development of resistance against them, their role in current medicine and their future perspectives are discussed. Electronic databases such as PubMed, Scopus and ScienceDirect were used to search scientific contributions until September 2020, using relevant keywords. Natural compounds of heterogeneous origins have been shown to possess antimicrobial capabilities, including against antibiotic-resistant bacteria. The most commonly found mechanisms of antimicrobial action are related to protein biosynthesis and alteration of cell walls and membranes. Various natural compounds, especially phytochemicals, have shown synergistic capacity with antibiotics. There is little literature on the development of specific resistance mechanisms against natural antimicrobial compounds. New technologies such as -omics, network pharmacology and informatics have the potential to identify and characterize new natural antimicrobial compounds in the future. This knowledge may be useful for the development of future therapeutic strategies.


2020 ◽  
Vol 21 (13) ◽  
pp. 1333-1341
Author(s):  
Mohammed A. Almalki

Background: Streptomyces sp. produces various antibiotic agents and the number of lead molecules from the genus Streptomyces increased rapidly in recent years. Drug resistance against various commercially available antibiotics is one of the important problems throughout the world. Streptomyces spp. produce various antimicrobials with potent activity against drug-resistant bacteria. Methods: Streptomyces sp. SA1 was isolated from the marine environment for the biosynthesis of antibiotics. The important variables influencing secondary metabolite biosynthesis were optimized to increase the biosynthesis of antimicrobial agents using the traditional method and statistical approach. Results: Streptomyces sp. SA1 produced novel antibiotics and the process variables were optimized by the traditional method (One-variable-at-a-time approach). Maltose showed maximum antimicrobial activity (220 U/mL). Analysis of the nitrogen, the effect of nitrogen sources revealed that beef extract incorporated culture medium showed rich antibacterial activity (188/mL). Among the ionic sources, KCl significantly influenced antibiotic production. Maltose, beef extract and KCl were considered as the most influencing medium components. Antimicrobial agent biosynthesis was achieved with maltose 1.22 g/L, beef extract 0.93 g/L and KCl 0.27 g/L in response surface methodology. Conclusion: Actinomycetes, especially Streptomyces, play an important role as a source for bioactive compounds that are used to treat infections, and many other diseases. The isolated Streptomyces sp. was a good producer of antibacterial agent, which required various nutritional supplements in the culture medium. The optimized medium components investigated in this study will be useful for future studies with the mass production of secondary metabolites.


2021 ◽  
Vol 18 (4) ◽  
pp. 719-732
Author(s):  
Najwa Menwer Alharbi ◽  
Amjad Khalid Alharthi ◽  
Alsamadani Alsamadani ◽  
Raneem Ahmed Almihmadi ◽  
Bothaina Ali Alaidaroos

This study aimed to investigate a method to manage antimicrobial resistance (AMR) issues by exploring soil microorganisms that are capable of producing bioactive compounds. Eight different types of soil were selected from three locations to screen, isolate, and identify microorganisms that are capable of producing antimicrobial compounds. The multi-drug resistant strains are Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans were selected for primary and secondary screening using the crowded plate method and the agar well diffusion method. Inhibition zones were measured, and data were assessed using statistical tests to check for normality and differences between parametric variables and nonparametric data. This was followed by biochemical characterization, DNA isolation, and polymerase chain reaction (PCR). Molecular identification was performed using 16S rRNA amplification and sequencing. Here, 86 isolates containing bacteria and fungi were successfully extracted from soil samples. Further, 49 of 86 microbes showed possible antimicrobial activity, but only 12 isolates resulted in distinct inhibition zones with the selected multi-drug resistant strains. The following different taxa were identified: Firmicutes (nine strains), Proteobacteria (one strain), Actinobacteria (one strain), and Azotobacter (one strain). Species are represented in a phylogenetic tree, which was constructed using the unweighted pair-group method with arithmetic mean (UPGMA) method. The evolutionary distances were computed using the Maximum Composite Likelihood method. The identified microorganisms showed antimicrobial activity, confirming that soil microorganisms have great potential to address AMR issues.


1999 ◽  
Vol 5 (4) ◽  
pp. 265-270 ◽  
Author(s):  
LANFRANCO FATTORINI ◽  
ELISABETTA IONA ◽  
MARIA LUISA RICCI ◽  
OVE FREDRIK THORESEN ◽  
GERMANO ORRÚ ◽  
...  

2019 ◽  
Vol 2 (1) ◽  
pp. 170-180
Author(s):  
O. O. Oludairo

Multiple drug resistant (MDR) strains of Salmonella are frequently encountered with increased rates in recent years. Many variants of the organism have developed MDR genes which they retain even when antimicrobial drugs are no more in use, limiting the choice of drugs for therapy of Salmonella infections resulting in morbidity and mortality in both man and animals and raising more public health questions. The objective of this study was to evaluate the susceptibility of Salmonella spp. to twelve antimicrobial agents using the disk diffusion method. Eight Salmonella spp. isolated from wildlife were tested. All the isolates exhibited MDR, showing resistance to at least four and up to nine antimicrobial agents. They were all highly resistant (100%) to ceftazidime, cephazoline, cefuroxidine and ampicillin but were susceptible to nalidixic acid and ciprofloxacin. Six resistant patterns were observed, with ampicillin-cefuroxime sodiumcephazolin-ceftazidime and streptomycin-ampicillin-cefuroxime sodium-cephazolin-ceftazidime resistant patterns exhibited by two isolates each. The substantial multiple resistance pointed to the fact that limitations could be faced in choosing drugs for the treatment of Salmonella infections and that mortality and economic losses could be experienced especially if sensitivity tests are not carried out before antimicrobial choice is made for treatments in both man and animals.


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