scholarly journals Chemistry and Biology of Siderophores from Marine Microbes

Marine Drugs ◽  
2019 ◽  
Vol 17 (10) ◽  
pp. 562 ◽  
Author(s):  
Jianwei Chen ◽  
Yuqi Guo ◽  
Yaojia Lu ◽  
Bixia Wang ◽  
Jiadong Sun ◽  
...  

Microbial siderophores are multidentate Fe(III) chelators used by microbes during siderophore-mediated assimilation. They possess high affinity and selectivity for Fe(III). Among them, marine siderophore-mediated microbial iron uptake allows marine microbes to proliferate and survive in the iron-deficient marine environments. Due to their unique iron(III)-chelating properties, delivery system, structural diversity, and therapeutic potential, marine microbial siderophores have great potential for further development of various drug conjugates for antibiotic-resistant bacteria therapy or as a target for inhibiting siderophore virulence factors to develop novel broad-spectrum antibiotics. This review covers siderophores derived from marine microbes.

Antibiotics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 732
Author(s):  
Nikolay V. Volozhantsev ◽  
Anna M. Shpirt ◽  
Alexander I. Borzilov ◽  
Ekaterina V. Komisarova ◽  
Valentina M. Krasilnikova ◽  
...  

Bacteriophages and phage enzymes are considered as possible alternatives to antibiotics in the treatment of infections caused by antibiotic-resistant bacteria. Due to the ability to cleave the capsular polysaccharides (CPS), one of the main virulence factors of Klebsiella pneumoniae, phage depolymerases, has potential in the treatment of K. pneumoniae infections. Here, we characterized in vivo two novel phage-encoded polysaccharide depolymerases as therapeutics against clinical isolates of K. pneumoniae. The depolymerases Dep_kpv79 and Dep_kpv767 encoded by Klebsiella phages KpV79 (Myoviridae; Jedunavirus) and KpV767 (Autographiviridae, Studiervirinae, Przondovirus), respectively, were identified as specific β-galactosidases that cleave the K. pneumoniae K57 type CPS by the hydrolytic mechanism. They were found to be highly effective at combating sepsis and hip infection caused by K. pneumoniae in lethal mouse models. Here, 80–100% of animals were protected against death by a single dose (e.g., 50 μg/mouse) of the enzyme injected 0.5 h after infection by K. pneumoniae strains of the K57 capsular type. The therapeutic effect of the depolymerases is because they strip the capsule and expose the underlying bacterium to the immune attack such as complement-mediated killing. These data provide one more confirmation that phage polysaccharide depolymerases represent a promising tool for antimicrobial therapy.


Toxins ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 255 ◽  
Author(s):  
Clara Pérez-Peinado ◽  
Sira Defaus ◽  
David Andreu

For decades, natural products in general and snake venoms (SV) in particular have been a rich source of bioactive compounds for drug discovery, and they remain a promising substrate for therapeutic development. Currently, a handful of SV-based drugs for diagnosis and treatment of various cardiovascular disorders and blood abnormalities are on the market. Likewise, far more SV compounds and their mimetics are under investigation today for diverse therapeutic applications, including antibiotic-resistant bacteria and cancer. In this review, we analyze the state of the art regarding SV-derived compounds with therapeutic potential, focusing on the development of antimicrobial and anticancer drugs. Specifically, information about SV peptides experimentally validated or predicted to act as antimicrobial and anticancer peptides (AMPs and ACPs, respectively) has been collected and analyzed. Their principal activities both in vitro and in vivo, structures, mechanisms of action, and attempts at sequence optimization are discussed in order to highlight their potential as drug leads.


2019 ◽  
pp. 48-54
Author(s):  
Duy Binh Nguyen ◽  
Trung Tien Phan ◽  
Trong Hanh Hoang ◽  
Van Tuan Mai ◽  
Xuan Chuong Tran

Sepsis is a serious bacterial infection. The main treatment is using antibiotics. However, the rate of antibiotic resistance is very high and this resistance is related to the outcome of treatment. Objectives: To evaluate the situation of antibiotic resistance of some isolated bacteria in sepsis patients treated at Hue Central Hospital; to evaluate the relationship of antibiotic resistance to the treatment results in patients with sepsis. Subjects and methods: prospective study of 60 sepsis patients diagnosed according to the criteria of the 3rd International Consensus-Sepsis 3 and its susceptibility patterns from April 2017 to August 2018. Results and Conclusions: The current agents of sepsis are mainly S. suis, Burkhoderiae spp. and E. coli. E. coli is resistant to cephalosporins 3rd, 4th generation and quinolone group is over 75%; resistance to imipenem 11.1%; the ESBL rate is 60%. S. suis resistant to ampicilline 11.1%; no resistance has been recorded to ceftriaxone and vancomycine. Resistance of Burkholderiae spp. to cefepime and amoxicillin/clavulanic acid was 42.9% and 55.6%, resistant to imipenem and meropenem is 20%, resistance to ceftazidime was not recorded. The deaths were mostly dued to E. coli and K. pneumoniae. The mortality for patients infected with antibiotic-resistant bacteria are higher than for sensitive groups. Key words: Sepsis, bacterial infection, antibiotics


Antibiotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 466
Author(s):  
Herbert Galler ◽  
Josefa Luxner ◽  
Christian Petternel ◽  
Franz F. Reinthaler ◽  
Juliana Habib ◽  
...  

In recent years, antibiotic-resistant bacteria with an impact on human health, such as extended spectrum β-lactamase (ESBL)-containing Enterobacteriaceae, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE), have become more common in food. This is due to the use of antibiotics in animal husbandry, which leads to the promotion of antibiotic resistance and thus also makes food a source of such resistant bacteria. Most studies dealing with this issue usually focus on the animals or processed food products to examine the antibiotic resistant bacteria. This study investigated the intestine as another main habitat besides the skin for multiresistant bacteria. For this purpose, faeces samples were taken directly from the intestines of swine (n = 71) and broiler (n = 100) during the slaughter process and analysed. All samples were from animals fed in Austria and slaughtered in Austrian slaughterhouses for food production. The samples were examined for the presence of ESBL-producing Enterobacteriaceae, MRSA, MRCoNS and VRE. The resistance genes of the isolated bacteria were detected and sequenced by PCR. Phenotypic ESBL-producing Escherichia coli could be isolated in 10% of broiler casings (10 out of 100) and 43.6% of swine casings (31 out of 71). In line with previous studies, the results of this study showed that CTX-M-1 was the dominant ESBL produced by E. coli from swine (n = 25, 83.3%) and SHV-12 from broilers (n = 13, 81.3%). Overall, the frequency of positive samples with multidrug-resistant bacteria was lower than in most comparable studies focusing on meat products.


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