Infectious Diseases
Lyle D. Broemeling in Bayesian Analysis of Infectious Diseases, 2021
Certain antibiotics such as penicillin, streptomycin, and tetracycline are very effective against bacterial infections. The designation “antibiotic” is based on the concept of antibiosis, or the use of substances made by one living thing to kill another. Antibiotics are made by bacteria and molds that are specially cultured by commercial drug laboratories. Antibiotics kill bacteria and other disease organisms in a variety of ways. For example, some destroy cell walls, while others interfere with the multiplication of bacteria or fatally alter the way the bacteria manufacture vital proteins. Still others mix up the genetic plan of the bacteria. Ordinarily, an antibiotic tricks bacteria into using the antibiotic’s chemicals instead of closely related ones that organisms really need for making the key enzymes required for their growth and reproduction. With the antibiotic assimilated into their systems, instead of vital chemicals, an essential activity or structure of the pathogens is lacking and they die.
The Role of Gut Microbiota in the Pathogenesis and Treatment of Obesity
Emmanuel C. Opara, Sam Dagogo-Jack in Nutrition and Diabetes, 2019
Antibiotic overuse and overexposure, as contributing factors to the development of obesity, are an important area of study right now. Farmers are using low doses of antibiotics to increase the weight of their livestock, and researchers believe that passive or active vulnerability to these antibiotics may be a key factor in the recent increase in the rate of obesity. Research in human infants and mice has indicated that premature antibiotic use may lead to eventual progression of obesity and adiposity [1]. Medically, antibiotics are used to treat infections by preventing unwanted bacterial colonization in the body. However, as most do not target specific species of bacteria and instead have broad-spectrum activity, even a brief exposure to antibiotics can affect the gut microbiota for years to come [7,8].
Human Rhinovirus Infections
Sunit K. Singh in Human Respiratory Viral Infections, 2014
Because there are currently no approved antiviral medications for HRV respiratory tract infections, symptomatic treatment should be considered.204 Anticholinergic medications could be used for the commonly reported symptom, rhinorrhea. Anticholinergic nasal sprays have been reported to reduce rhinorrhea by approximately 30%. Nasal congestion can be alleviated by nasal and systemic decongestants. Several studies have suggested that heated, humidified steam may reduce nasal congestion in common colds, but the data are not conclusive.205 Cough is a common accompanying problem in respiratory viral infections and can be suppressed with nonprescription cough suppressants. Other symptoms such as sore throat, myalgia, fever, or headache can be controlled with nonsteroidal anti-inflammatory drugs. Antibiotics are inappropriate for treating viral infections, although they are frequently prescribed by physicians.
Use of broad-spectrum antibiotics impacts outcome in patients treated with immune checkpoint inhibitors
Published in OncoImmunology, 2018
Jibran Ahmed, Arun Kumar, Kaushal Parikh, Asad Anwar, Bettina M Knoll, Carmelo Puccio, Hoo Chun, Michael Fanucchi, Seah H Lim
Antibiotics are effective for treating various infections. However, contingent on their antimicrobial spectrum and pharmacokinetics, they will also change the composition of the intestinal microbiota. A balanced intestinal microbiome is needed for the immune homeostasis, most notably on adaptive immunity.1 Perturbation of the balanced microbiome may, therefore, disrupt the homeostatic loop and induce detrimental health effects.2 Compositional and metabolic changes in the intestinal microbiota (dysbiosis) have been found in association with inflammatory bowel disease, where there are increases in Proteobacteria, Firmicutes bacillus, and Actinobacteria.3 Dysbiosis has also been implicated in the pathophysiology of colorectal cancer, multiple sclerosis, diabetes mellitus, obesity and allergies,4–8 and most recently by us in sickle cell disease.9 In addition to changing the intestinal microbiome, some antibiotics, like tetracyclines, fluoroquinolones and macrolides, also have intrinsic anti-inflammatory effects on the hosts.10–15 Antibiotics may, therefore, affect the outcome of patients treated with ICIs, through their influence on the intestinal microbiota composition or direct anti-inflammatory activities. In this study, we set out to determine whether antibiotic use during therapy with ICI affected the treatment outcome.
Bacteriophage endolysins as a potential weapon to combat Clostridioides difficile infection
Published in Gut Microbes, 2020
Shakhinur Islam Mondal, Lorraine A. Draper, R Paul Ross, Colin Hill
Bacteriophage endolysins have a unique attribute in comparison to intact phages and antibiotics, in that resistance development is an extremely rare event. Generally, antibiotics work by inhibiting essential metabolic pathways of bacteria leading to cell death.101 However, bacteria have found ways to overcome this adverse situation by using alternative metabolic pathways. It is difficult for bacteria to find means of resistance to endolysin as they bind to and degrade highly conserved peptidoglycan targets within the cell wall.102 Any mutations leading to endolysin resistance would be damaging to the integrity of the cell and thus a very rare event.103 Although no attempts have been made to study lysin-resistance development in C. difficile, there are some studies using other bacterial strains that have investigated repeated lysin exposure and revealed resistance did not develop to either native or engineered phage lysins.40,104-106 Some CWHs of C. difficile have more than one catalytic domain and this theoretically lowers the chance of mutation in multiple target sites in bacteria. Similar observations have been made with S. aureus endolysins.107
The war against bacteria, from the past to present and beyond
Published in Expert Review of Anti-infective Therapy, 2022
Lucrezia Bottalico, Ioannis Alexandros Charitos, Maria Assunta Potenza, Monica Montagnani, Luigi Santacroce
While definitive therapy depends on the microbiologic diagnosis by isolation, empirical therapy should be based on a clinical diagnosis combined with literature evidence and physician experience. Empirical use of antibiotics should be justified in patients with life threatening infections, in ICU settings and while awaiting results of culture. To optimize an accurate microbiological diagnosis, clinicians should ensure that properly obtained specimens are promptly submitted to the microbiology laboratory. Antibiotics work by eliminating the majority of bacteria while allowing the immune system to handle the remaining germs. Besides choosing the right antibiotics (based on their activity spectrum and mode of action), the proper duration of the correct antibiotic therapy is a priority, since not finishing the full course increases the likelihood of recurrence, and also promotes the development of drug resistance. This is particularly relevant when considering the bactericidal or bacteriostatic nature of the antimicrobial agent used. Concomitantly, factors affecting antibiotic activity such as poor bioavailability for incorrect route of administration, renal excretion, other drugs’ interactions, and allergy must be considered before prescribing the chosen antibiotic, to avoid or limit long-term toxicities in specific patients. Therefore, antibiotic therapy should be reevaluated in order to escalate or deescalate doses according to the efficacy achieved and to increased risk of side effects.
Related Knowledge Centers
- Antibiotic Prophylaxis
- Antiseptic
- Bacteria
- Bacteriostatic Agent
- Virus
- Common Cold
- Antimicrobial
- Pathogenic Bacteria
- Medication
- Antiprotozoal