Infections caused by Gram-negative bacteria

2017 ◽  
Author(s):  
Philippa C. Matthews
Keyword(s):  
Escherichia Coli ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Treatment And Prevention ◽  
Clinical Syndromes ◽  
Causes Of Disease ◽  
Gram Negative Organisms ◽  
The Tropics

This chapter consists of short notes, diagrams, and tables to summarize Gram-negative organisms that are significant causes of disease in the tropics and subtropics. This includes Escherichia coli, Shigella, and Salmonella species (including typhoid and paratyphoid), Brucella, melioid, Campylobacter, and meningococci. For ease of reference, each topic is broken down into sections, including classification, epidemiology, microbiology, pathophysiology, clinical syndromes, diagnosis, treatment, and prevention.

Infections caused by RNA viruses

2017 ◽  
Author(s):  
Philippa C. Matthews
Keyword(s):  
Hepatitis A ◽  
Rna Viruses ◽  
T Lymphotropic Virus ◽  
Treatment And Prevention ◽  
Clinical Syndromes ◽  
Causes Of Disease ◽  
The Tropics

This chapter consists of short notes, diagrams, maps, and tables to summarize RNA viruses that are significant causes of disease in the tropics and subtropics. This includes measles, polio, hepatitis A, C, and E viruses, rabies, arboviruses, and viral haemorrhagic fevers. The chapter also includes sections on important retroviruses, HIV, and human T-lymphotropic virus. For ease of reference, each topic is broken down into sections, including classification, epidemiology, microbiology, pathophysiology, clinical syndromes, diagnosis, treatment, and prevention.

Infections caused by DNA viruses

2017 ◽  
Author(s):  
Philippa C. Matthews
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Dna Viruses ◽  
Treatment And Prevention ◽  
Clinical Syndromes ◽  
B Virus ◽  
Causes Of Disease ◽  
The Tropics

This chapter consists of short notes, diagrams, and tables to summarize DNA viruses that are significant causes of disease in the tropics and subtropics. This includes pox viruses and hepatitis B virus. For ease of reference, each topic is broken down into sections, including classification, epidemiology, microbiology, pathophysiology, clinical syndromes, diagnosis, treatment, and prevention

Infections caused by Gram-positive bacteria

2017 ◽  
Author(s):  
Philippa C. Matthews
Keyword(s):  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Treatment And Prevention ◽  
Clinical Syndromes ◽  
Causes Of Disease ◽  
The Tropics

This chapter consists of short notes, diagrams, and tables to summarize Gram-positive organisms that are significant causes of disease in the tropics and subtropics. This includes anthrax, tetanus, clostridial infections, diphtheria, and streptococci. For ease of reference, each topic is broken down into sections, including classification, epidemiology, microbiology, pathophysiology, clinical syndromes, diagnosis, treatment, and prevention.

Fungal infections

2017 ◽  
Author(s):  
Philippa C. Matthews
Keyword(s):  
Fungal Infections ◽  
Dimorphic Fungi ◽  
Cryptococcal Infection ◽  
Treatment And Prevention ◽  
Clinical Syndromes ◽  
Causes Of Disease ◽  
Madura Foot ◽  
Primary Focus ◽  
The Tropics

This chapter consists of short notes, diagrams, maps, and tables to summarize fungal infections that are significant causes of disease in the tropics and subtropics, with a primary focus on dimorphic fungi (Histoplasma, Blastomyces, Coccidioides, Paracoccidioides, and Penicillium species). The chapter also includes cryptococcal infection and Madura foot. For ease of reference, each topic is broken down into sections, including classification, epidemiology, microbiology, pathophysiology, clinical syndromes, diagnosis, treatment and prevention.

scholarly journals ROLE OF MENINGOCOCCAL ENDOTOXIN IN MENINGOCOCCAL PURPURA

1974 ◽  
Vol 140 (1) ◽  
pp. 159-171 ◽  
Author(s):  
Charles E. Davis ◽  
Karen Arnold
Keyword(s):  
Escherichia Coli ◽  
Gas Chromatography ◽  
Salmonella Typhimurium ◽  
Skin Lesions ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Clinical Syndromes ◽  
Shwartzman Reaction ◽  
Phenol Water

Enteric bacilli and meningococci (MGC) both contain potent endotoxins, but purpuric skin lesions indistinguishable from the experimental dermal Shwartzman reaction are much more common during meningococcal bacteremia than during bacteremia with enteric organisms. Highly purified lipopolysaccharides (LPS), virtually free of contamination by protein, RNA, and capsule, were extracted by a modification of the phenol-water technique from MGC (serogroups A, B, and C) and enteric bacilli (Escherichia coli 04 and 0:111, and Salmonella typhimurium). Polysaccharides in these LPS were similar by gas chromatography except for one galactose-deficient strain of MGC (135B). LPS from MGC and enterics were equally potent for the general Shwartzman reaction and mouse lethality, but LPS from MGC was 5–10 times more potent in inducing the dermal Shwartzman reaction. The greater skin potency of LPS from MGC explains the prominence of purpura in meningococcemia. Comparison of the properties of LPS may explain other differences in clinical syndromes caused by gram-negative bacteria.

Antimicrobial and cytotoxic activity of Macrophomina phaseolina isolated from gummosis infected citrus reticulata

2013 ◽  
pp. 125-133
Author(s):  
Rubal C Das ◽  
Rajib Banik ◽  
Robiul Hasan Bhuiyan ◽  
Md Golam Kabir
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Brine Shrimp ◽  
Inhibitory Concentration ◽  
Lethal Dose ◽  
Macrophomina Phaseolina ◽  
Chloroform Extract ◽  
Citrus Reticulata ◽  
Gram Negative Bacteria ◽  
Gram Negative

Macrophomina phaseolina is one of the pathogenic organisms of gummosis disease of orange tree (Citrus reticulata). The pathogen was identified from the observation of their colony size, shape, colour, mycelium, conidiophore, conidia, hyaline, spore, and appressoria in the PDA culture. The crude chloroform extracts from the organism showed antibacterial activity against a number of Gram positive and Gram-negative bacteria. The crude chloroform extract also showed promising antifungal activity against three species of the genus Aspergillus. The minimum inhibitory concentration (MIC) of the crude chloroform extract from M. phaseolina against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Shigella sonnie were 128 ?gm, 256 ?gm, 128 ?gm and 64 ?gm/ml respectively. The LD50 (lethal dose) values of the cytotoxicity assay over brine shrimp of the crude chloroform extract from M. phaseolina was found to be 51.79 ?gm/ml. DOI: http://dx.doi.org/10.3329/cujbs.v5i1.13378 The Chittagong Univ. J. B. Sci.,Vol. 5(1 &2):125-133, 2010

scholarly journals Proteomic response of Escherichia coli to a membrane lytic and iron chelating truncated Amaranthus tricolor defensin

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tessa B. Moyer ◽  
Ashleigh L. Purvis ◽  
Andrew J. Wommack ◽  
Leslie M. Hicks
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Antimicrobial Peptides ◽  
Mechanism Of Action ◽  
Gram Negative Bacteria ◽  
Amaranthus Tricolor ◽  
Core Motif ◽  
Gram Negative ◽  
E Coli ◽  
Membrane Lysis

Abstract Background Plant defensins are a broadly distributed family of antimicrobial peptides which have been primarily studied for agriculturally relevant antifungal activity. Recent studies have probed defensins against Gram-negative bacteria revealing evidence for multiple mechanisms of action including membrane lysis and ribosomal inhibition. Herein, a truncated synthetic analog containing the γ-core motif of Amaranthus tricolor DEF2 (Atr-DEF2) reveals Gram-negative antibacterial activity and its mechanism of action is probed via proteomics, outer membrane permeability studies, and iron reduction/chelation assays. Results Atr-DEF2(G39-C54) demonstrated activity against two Gram-negative human bacterial pathogens, Escherichia coli and Klebsiella pneumoniae. Quantitative proteomics revealed changes in the E. coli proteome in response to treatment of sub-lethal concentrations of the truncated defensin, including bacterial outer membrane (OM) and iron acquisition/processing related proteins. Modification of OM charge is a common response of Gram-negative bacteria to membrane lytic antimicrobial peptides (AMPs) to reduce electrostatic interactions, and this mechanism of action was confirmed for Atr-DEF2(G39-C54) via an N-phenylnaphthalen-1-amine uptake assay. Additionally, in vitro assays confirmed the capacity of Atr-DEF2(G39-C54) to reduce Fe3+ and chelate Fe2+ at cell culture relevant concentrations, thus limiting the availability of essential enzymatic cofactors. Conclusions This study highlights the utility of plant defensin γ-core motif synthetic analogs for characterization of novel defensin activity. Proteomic changes in E. coli after treatment with Atr-DEF2(G39-C54) supported the hypothesis that membrane lysis is an important component of γ-core motif mediated antibacterial activity but also emphasized that other properties, such as metal sequestration, may contribute to a multifaceted mechanism of action.

scholarly journals MexAB-OprM Efflux Pump Interaction with the Peptidoglycan of Escherichia coli and Pseudomonas aeruginosa

2021 ◽  
Vol 22 (10) ◽  
pp. 5328
Author(s):  
Miao Ma ◽  
Margaux Lustig ◽  
Michèle Salem ◽  
Dominique Mengin-Lecreulx ◽  
Gilles Phan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Cell Division ◽  
Membrane Proteins ◽  
Outer Membrane ◽  
Efflux Pump ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Active Efflux

One of the major families of membrane proteins found in prokaryote genome corresponds to the transporters. Among them, the resistance-nodulation-cell division (RND) transporters are highly studied, as being responsible for one of the most problematic mechanisms used by bacteria to resist to antibiotics, i.e., the active efflux of drugs. In Gram-negative bacteria, these proteins are inserted in the inner membrane and form a tripartite assembly with an outer membrane factor and a periplasmic linker in order to cross the two membranes to expulse molecules outside of the cell. A lot of information has been collected to understand the functional mechanism of these pumps, especially with AcrAB-TolC from Escherichia coli, but one missing piece from all the suggested models is the role of peptidoglycan in the assembly. Here, by pull-down experiments with purified peptidoglycans, we precise the MexAB-OprM interaction with the peptidoglycan from Escherichia coli and Pseudomonas aeruginosa, highlighting a role of the peptidoglycan in stabilizing the MexA-OprM complex and also differences between the two Gram-negative bacteria peptidoglycans.

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