scholarly journals Promising Anti-MRSA Activity of Brevibacillus sp. Isolated from Soil and Strain Improvement by UV Mutagenesis

2020 ◽  
Vol 89 (1) ◽  
pp. 1
Author(s):  
Nuttapon Songnaka ◽  
Monthon Lertcanawanichakul ◽  
Apichart Atipairin

Antibiotic-resistant infection is a major health problem, and a limited number of drugs are currently approved as antibiotics. Soil bacteria are promising sources in the search for novel antibiotics. The aim of the present study is to isolate and assess soil bacteria with anti-MRSA activity and improve their capabilities by UV mutagenesis. Soil samples from the upper south of Thailand were screened for antibacterial activity using the cross-streak method. Agar well diffusion was used to examine the activity of isolates against a spectrum of human pathogens. The most active isolate was identified by 16S rRNA sequencing, and the production kinetics and stability were investigated. The most promising isolate was mutated by UV radiation, and the resulting activity and strain stability were studied. The results show that isolates from the cross-streak method could inhibit Staphylococcus aureus TISTR 517 (94 isolates) and Escherichia coli TISTR 887 (67 isolates). Nine isolates remained active against S. aureus TISTR 517 and MRSA, and eight isolates inhibited the growth of E. coli TISTR 887 as assessed using agar well diffusion. The most active strain was Brevibacillus sp. SPR-20, which had the highest activity at 24 h of incubation. The active substances in culture supernatants exhibited more than 90% activity when subjected to treatments involving various heat, enzymes, surfactants, and pH conditions. The mutant M201 showed significantly higher activity (109.88–120.22%) and strain stability compared to the wild-type strain. In conclusion, we demonstrate that soil Brevibacillus sp. is a potential resource that can be subjected to UV mutagenesis as a useful approach for improving the production of anti-MRSA in the era of antibiotic resistance.

2009 ◽  
Vol 7 (S1) ◽  
pp. S75-S93 ◽  
Author(s):  
Mark D. Sobsey ◽  
Suresh D. Pillai

A consideration of available evidence for some known and well-characterized waterborne pathogens suggests that the diversity of pathogen virulence mechanisms and properties is too great to specifically predict the emergence and future human health impacts of new waterborne pathogens. However, some future emerging pathogens are existing microbes that will be discovered to cause disease. Some will arise from existing ones by either predictable evolutionary and adaptation changes or by unpredictable changes involving a variety of biotic and abiotic mechanisms. Many, and perhaps most, emerging waterborne human pathogens will be zoonotic agents or come from other non-human reservoirs. The emergence of some waterborne pathogens will be related to antibiotic use, resulting in emerging antibiotic-resistant waterborne pathogens. Reliably predicting pathogen emergence and human health effects based on VFARs or other properties of microbes and their hosts is not possible at this time. This is because of (1) the diversity of microbes and their virulence and pathogenicity properties, (2) their ability to change unpredictably, (3) their intimate and diverse interrelationships with a myriad of hosts and dynamic natural and anthropogenic environments and (4) the subtle variations in the immune status of individuals. The best available approach to predicting waterborne pathogen emergence is through vigilant use of microbial, infectious disease and epidemiological surveillance. Understanding the microbial metagenome of the human body can also lead to a better understanding of how we define and characterize pathogens, commensals and opportunists.


2020 ◽  
Author(s):  
Lucas A. Meirelles ◽  
Elena K. Perry ◽  
Megan Bergkessel ◽  
Dianne K. Newman

SummaryAs antibiotic-resistant infections become increasingly prevalent worldwide, understanding the factors that lead to antimicrobial treatment failure is essential to optimizing the use of existing drugs. Opportunistic human pathogens in particular typically exhibit high levels of intrinsic antibiotic resistance and tolerance1, leading to chronic infections that can be nearly impossible to eradicate2. We asked whether the recalcitrance of these organisms to antibiotic treatment could be driven in part by their evolutionary history as environmental microbes, which frequently produce or encounter natural antibiotics3,4. Using the opportunistic pathogen Pseudomonas aeruginosa as a model, we demonstrate that the self-produced natural antibiotic pyocyanin (PYO) activates bacterial defenses that confer collateral tolerance to certain synthetic antibiotics, including in a clinically-relevant growth medium. Non-PYO-producing opportunistic pathogens isolated from lung infections similarly display increased antibiotic tolerance when they are co-cultured with PYO-producing P. aeruginosa. Furthermore, we show that beyond promoting bacterial survival in the presence of antibiotics, PYO can increase the apparent rate of mutation to antibiotic resistance by up to two orders of magnitude. Our work thus suggests that bacterial production of natural antibiotics in infections could play an important role in modulating not only the immediate efficacy of clinical antibiotics, but also the rate at which antibiotic resistance arises in multispecies bacterial communities.


2013 ◽  
Vol 57 (2) ◽  
pp. 254-262 ◽  
Author(s):  
Abel N. Kho ◽  
Bradley N. Doebbeling ◽  
John P. Cashy ◽  
Marc B. Rosenman ◽  
Paul R. Dexter ◽  
...  

2008 ◽  
Vol 105 (10) ◽  
pp. 3957-3962 ◽  
Author(s):  
S. Demaneche ◽  
H. Sanguin ◽  
J. Pote ◽  
E. Navarro ◽  
D. Bernillon ◽  
...  

2004 ◽  
Vol 186 (14) ◽  
pp. 4808-4812 ◽  
Author(s):  
Pauline Yoong ◽  
Raymond Schuch ◽  
Daniel Nelson ◽  
Vincent A. Fischetti

ABSTRACT Enterococcus faecalis and Enterococcus faecium infections are increasingly difficult to treat due to high levels of resistance to antibiotics. PlyV12, a bacteriophage lytic enzyme, was isolated and shown to effectively kill both E. faecalis and E. faecium (including vancomycin-resistant strains), as well as other human pathogens. We propose its development and use as an alternative therapeutic tool.


2016 ◽  
Vol 75 (s2) ◽  
Author(s):  
Andrea Di Cesare ◽  
Ester Eckert ◽  
Gianluca Corno

<p class="p1">Antibiotic resistant bacteria are found in most environments, especially in highly anthropized waters. A direct correlation between human activities (<em><span class="s1">e.g., </span></em>pollution) and spread and persistence of antibiotic resistant bacteria (ARB) and resistance genes (ARGs) within the resident bacterial communities appears more and more obvious. Furthermore, the threat posed for human health by the presence of ARB and ARGs in these environments is enhanced by the risk of horizontal gene transfer of resistance genes to human pathogens. Although the knowledge on the spread of antibiotic resistances in waters is increasing, the understanding of the driving factors determining the selection for antibiotic resistance in the environment is still scarce. Antibiotic pollution is generally coupled with contamination by heavy metals (HMs) and other chemicals, which can also promote the development of resistance mechanisms, often through co-selecting for multiple resistances. The co-selection of heavy metal resistance genes and ARGs in waters, sediments, and soils, increases the complexity of the ecological role of ARGs, and reduces the effectiveness of control actions. In this mini-review we present the state-of-the-art of the research on antibiotic- and HM-resistance and their connection in the environment, with a focus on HM pollution and aquatic environments. We review the spread and the persistence of HMs and/or ARB, and how it influences their respective gene co-selection. In the last chapter, we propose Lake Orta, a system characterized by an intensive HM pollution followed by a successful restoration of the chemistry of the water column, as a study-site to evaluate the spread and selection of HMs and antibiotic resistances in heavily disturbed environments.</p>


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