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Embelia ribes (False Black Pepper) and Gymnema sylvestre (Sugar Destroyer)
Published in Azamal Husen, Herbs, Shrubs, and Trees of Potential Medicinal Benefits, 2022
Chandrabose Selvaraj, Chandrabose Yogeswari, Sanjeev Kumar Singh
Researchers have found that the antimicrobial properties of E. ribes have only moderate activity against bacteria that are resistant to multiple drugs, such as Salmonella typhi (Ansari and Bhandari, 2008). Researchers found that the main bioactive component of E. ribes had significant antibacterial effects on the populations of Shigella flexneri, Streptococcus pyogenes, and Pseudomonas aeruginosa (Chitra et al., 2003). There is effective growth inhibition on Enterobacter aerogenes, Staphylococcus aureus, and Klebsiella pneumonia caused by the ethanol extract of E. ribes seeds (Gajjar et al., 2009). According to Feresin et al., (2003), embelin of E. ribes effectively inhibits the growth of methicillin-sensitive and methicillin-resistant Staphylococcus aureus with MICs of 250 and 62 µg/ml, respectively and also shows 50 µg/ml of MIC for E. coli. Schrader (2010) described the antimicrobial activity of E. ribes extract against Edwardsiella ictaluri, an effective causative organism of enteric septicemia, with a MIC value of 294.4 µg/ml. The ethanolic extract of E. ribes has significant inhibitory activity against Staphylococcus aureus, E. coli, Streptococcus faecalis, and B. subtilis at MBC concentrations ranging from 16 to 18.5 mg/ml (Khan et al., 2010). In 2011, a study by Rathakrishnan et al. found that embelin had a significant antibacterial effect against gram-positive bacteria and bacteriostatic activity against gram-negative strains of bacteria.
Potential of Piper Germplasm Against Pathogenic Bacteria: Tropical Bay Islands in India
Published in Megh R. Goyal, Durgesh Nandini Chauhan, Assessment of Medicinal Plants for Human Health, 2020
Chinthamani Jayavel, Ajit Arun Waman, Saravanan Kandasamy, Pooja Bohra
Studies with Edwardsiella tarda showed that Pipergenotypes could inhibit the growth of pathogen to some extent, whereas it remained lower than the inhibition observed for streptomycin (Table 5.5). In P. colubrinum-2, no inhibitory activity was seen, while P. colubrinum-1 showed inhibition zone at 100 µL. Contradictory reports are available for P. betle against the pathogen as some reports suggested its antibacterial activity,2,21 while poor response was observed in other,27 These variations could be attributed to the variation in the genotypes used and the strains/virulence of the pathogens employed.
Imipenem–Cilastatin and Imipenem–Relebactam
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
Yoshiro Hayashi, David L. Paterson
The Enterobacteriaceae, such as Escherichia coli, Enterobacter spp., Klebsiella spp., Proteus spp., Salmonella spp., Shigella spp., Providencia spp., Serratia spp., Citrobacter spp., Hafnia alvei, Edwardsiella spp., and Yersinia spp. are generally imipenem sensitive (Stock and Wiedemann, 2001a; Stock et al., 2002; Stock et al., 2005; Abdel-Haq et al., 2006; Deshpande et al., 2006b; Reinert et al., 2007; Turner, 2008). In recent years, carbapenem-resistant Enterobacteriaceae (and by definition, resistant to imipenem) have been increasingly observed (Paterson, 2006; Queenan and Bush, 2007). This issue will be discussed in section 2b, Emerging resistance and cross-resistance. Chromosomally mediated beta-lactamases produced by Morganella morganii, Proteus rettgeri, Serratia marcescens, and Enterobacter spp. are inducible. Imipenem acts as an inducer of these enzymes, but it is not hydrolyzed by them. So these organisms, when the enzymes are induced, remain sensitive to imipenem, but they are resistant to most third-generation cephalosporins (Labia et al., 1986; Ashby et al., 1987). Enterobacteriaceae, in particular E. coli and Klebsiella spp., which produce extended-spectrum beta-lactamases (ESBLs), may be resistant to a wide range of cephalosporins and cephamycins, but imipenem is typically effective against ESBL producers (Paterson and Bonomo, 2005) because imipenem is highly stable to beta-lactamase hydrolysis, and porin penetration is facilitated by their general size and structure. Their susceptibility to most strains of Enterobacteriaceae makes them generally useful as treatment for multidrug-resistant organisms.
Antibacterial activity of essential oils for combating colistin-resistant bacteria
Published in Expert Review of Anti-infective Therapy, 2022
Abdullah M. Foda, Mohamed H. Kalaba, Gamal M. El-Sherbiny, Saad A. Moghannem, Esmail M. El-Fakharany
The results obtained from the antibiotics susceptibility test of the five bacterial isolates referred to as these isolates are considered to be multidrug-resistant (MDR) bacteria, except E. coli AB-7. According to (CLSI) [28], the bacterial strain resistant to one antibiotic of three or more antibiotic classes is considered to be multidrug-resistant (MDR). Many studies have stated that there are various genera of Gram-negative bacteria that have acquired or natural resistance to colistin, such as Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, Escherichia coli, Proteus spp., Morganella morganii, Serratia spp., Providencia spp., Edwardsiella tarda, and Burkholderia cepacia. Most of the above-mentioned resistant bacteria have several mechanisms to defend themselves against polymyxins, such as the alteration of lipopolysaccharide (LPS) of the cell envelope, modifications of lipid A with phosphoethanolamine and 4-amino-4-deoxy-L-arabinose, furthermore, the use of efflux pumps, the development of capsules and overexpression of the outer membrane protein OprH, which are all efficiently controlled at the molecular level. All these strategies are thought to be responsible for the acquired and intrinsic resistance of polymyxins in these bacteria [30–33]. Gram-negative bacteria are resistant to colistin through intrinsic, adaptation, or mutation, in addition to horizontally acquired resistance via the mcr-1 gene and its variants [7].
The role of chitosan on oral delivery of peptide-loaded nanoparticle formulation
Published in Journal of Drug Targeting, 2018
Chun Y. Wong, Hani Al-Salami, Crispin R. Dass
Edwardsiella tarda can infect fish species, such as Japanese flounder, which causes emphysematous putrefactive disease, enteric septicaemia, gangrene and red disease [100]. The recombinant outer membrane protein A (rOmpA) of E. tarda was encapsulated in chitosan-based nanoparticles for oral vaccination of an endangered fish species called Labeo fimbriatus [101]. When compared to inactivated whole cell E. tarda vaccine, the rOmpA-loaded nanoparticles in oral vaccine produced higher level of antibodies, slower antigen release and superior protection against the pathogen. Therefore, oral vaccine can potentially be an effective immunisation strategy and increase the population of this fish species. Nevertheless, future studies should optimise the encapsulation efficiency.
Transposon mutagenesis in oral streptococcus
Published in Journal of Oral Microbiology, 2022
Yixin Zhang, Zhengyi Li, Xin Xu, Xian Peng
Transposon mutagenesis is an effective forward genetic strategy for studying gene function by observing the phenotypic changes in mutated genes. Random mutants in a variety of prokaryotes have been created by using different transposon genes such as Tn3 derivatives, IS (insertion sequence) elements, Tn7, Tn5, and mariner. Since the advent of genome sequencing, techniques such as genetic footprinting, signature-tagged Mutagenesis (STM), transposon site hybridization (TraSH), and scanning Linker mutagenesis (SLM) have been developed [17]. And with the advent of next-generation sequencing (NGS), transposon insertion sequencing (TIS) combines it with large-scale transposon insertion mutations to evaluate the essentiality of genetic features and fitness contribution in the bacterial genome in the saturated random mutant libraries. The four TIS techniques published in 2009 include insertion sequencing (INSeq) in Bacteroides thetaiotaomicron [18], high-throughput insertion tracking by deep sequencing (HITS) in Haemophilus influenzae [19], transposon sequencing (Tn-Seq) in S. pneumoniae [20], and transposon-directed insertion site sequencing (TraDIS) in S. Typhi [21]. Those techniques have been widely used in various bacteria to study fitness and virulence, including Enterococcus faecalis [22], Vibrio parahaemolyticus [23], Salmonella enteritidis [24], Edwardsiella piscicida [25], Ralstonia solanacearum [26] and Pantoea [27]. Ultimately, TIS is a key tool for interpreting the rapidly increasing amount of genome sequencing data and is expected to shed light on the function of individual genome features. With the development of transposon technology, TIS has been reviewed from the perspectives of design and analysis [28,29]. Cain et al. discussed recent applications of TIS in answering general biological questions [30]. The present review focuses on oral microorganisms and highlights the application of transposon mutagenesis, including TIS, to oral streptococci, as well as research progress, aiming to better understand the relationship between oral streptococcal phenotype and genotype, which can help clarify the processes of colonization, virulence, and persistence and provides a more reliable basis for investigating relationships with host ecology and disease status. Table 1 and Figure 1 show some articles and conclusions regarding transposon mutagenesis applied to oral streptococci.