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Bacteria
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
During aerobic respiration (electron transport), some highly toxic by-products of oxygen are produced which inhibit any organisms that are not equipped to detoxify them. Two of these by-products of metabolism, superoxide and hydrogen peroxide, can be produced when oxygen reacts with flavoprotein during oxygen respiration. Aerobic organisms contain the enzymes superoxide dismutase, which converts water and superoxide to hydrogen peroxide, and catalase, which converts hydrogen peroxide to water and oxygen; thereby detoxifying the superoxide and hydrogen peroxide. Strict (obligate) anaerobes, i.e., those that are killed or inhibited by traces of oxygen, contain neither superoxide dismutase nor catalase. Some obligate anaerobes, e.g., several species of Clostridium, produce superoxide dismutase but not catalase and can tolerate a small amount of oxygen, usually less than one percent partial pressure. Still others, e.g., Lactobacillus species, that must derive their energy from fermentation reactions are relatively insensitive to oxygen and are called aerotolerant anaerobes. Oxygen tolerant anaerobes are usually fermenters that possess superoxide dismutase but not catalase. Facultative anaerobes such as the enteric bacteria, e.g., Escherichia, Salmonella, and Shigella species, have the facility to derive energy from either aerobic respiration if oxygen is present or from fermentation in the absence of oxygen.
The immune and lymphatic systems, infection and sepsis
Published in Peate Ian, Dutton Helen, Acute Nursing Care, 2020
Michelle Treacy, Caroline Smales, Helen Dutton
Lactate is a normal product of anaerobic metabolism that is released into the bloodstream and metabolised by the liver. Aerobic metabolism produces energy from glucose in the form of adenosine triphosphate (ATP) in the presence of oxygen. Pyruvate (which is the end product of glycolysis), formed as part of this process, can also be metabolised without oxygen if it is not available in sufficient quantities. The end-product of anaerobic pyruvate metabolism is lactate, and this pathway is helpful in health, in terms of meeting a short-term oxygen deficit. Serum lactate, though, may be raised in a number of clinical circumstances, such as in hyperthermia, seizures, liver problems and cardiac arrest. A normal serum lactate level is less than 1mmol/L in both arterial and venous blood.
Chemical and Biological Threats to Public Safety
Published in Frank A. Barile, Barile’s Clinical Toxicology, 2019
Anthrax is an infectious disease caused by the spore-forming bacterium Bacillus anthracis. The organism is an obligate aerobe and facultative anaerobe. The highly resistant, prominent polypeptide capsule of the endospore renders B. anthracis immune to most methods of disinfection or natural processes of inactivation.† Thus the organism may be present in the soil for decades, occasionally infecting grazing goats, sheep, and cattle. When ingested, the hibernating, dehydrated, protected spores release viable bacteria on contact with gastrointestinal (GI) fluids. Human infection occurs by three routes of exposure to anthrax spores: cutaneous, GI, and inhalation. Although human cases of anthrax are infrequent in North America, the U.S. military views anthrax as a potential biological terrorist threat because of its high resistance and ease of communicability through the air.
Bacterial effluxome as a barrier against antimicrobial agents: structural biology aspects and drug targeting
Published in Tissue Barriers, 2022
Pownraj Brindangnanam, Ajit Ramesh Sawant, K. Prashanth, Mohane Selvaraj Coumar
In the beginning, single cells were the only living being on earth. By the process of natural selection, from a single cell to anaerobes, anaerobes to aerobes, aerobes to multicellular organisms emerged slowly.27–30 Between anaerobes to aerobes era, various races, for instance, aerotolerant, facultative, obligate bacteria, and so on have emerged.30,31 In the race for “survival of the fittest” or in the “war of defence”, microbes start competing with each other including multicellular organisms (animals including humans). Microbes use various armaments in their defense for survival. To propagate within the host, microbes first use only a few knacks like colonization, adherence and drug-metabolizing enzymes. Later on, they use other tricks such as lenience, frameshift mutations, rapid reproduction to attain the power of “resistance”, leading to better survival.
The prediction of surgical intervention in patients with tubo-ovarian abscess
Published in Journal of Obstetrics and Gynaecology, 2022
Jong Ha Hwang, Bo Wook Kim, Soo Rim Kim, Jang Heub Kim
To diagnosis TOA in patients with suspected PID, imaging methods such as ultrasound, CT, and MRI are used. Gynaecologic ultrasound is the most common imaging modality for differentiating between haemorrhagic ovarian cysts, endometriosis, and TOA in patients with clinically suspected TOA. Treatment of TOA includes broad spectrum antibiotics or surgical interventions such as drainage or more invasive procedures. Broad spectrum antibiotics targeting anaerobes and gram-negative aerobes is the first line treatment and is effective in 70% of TOA patients (Wiesenfeld and Sweet 1993; McNeeley et al. 1998). Surgical intervention is needed in approximately 30% of TOA patients who do not respond to antibiotics or whose abscesses rupture. In patients diagnosed with TOA, prediction of antibiotic treatment failure may help in the early identification of patients with a high likelihood of needing surgical treatment. Body temperature, white blood count (WBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) are useful in determining the severity of the inflammation. Dewitt J et al (Dewitt et al. 2010) reported that high WBC counts or high CRP was associated with risk of surgical intervention. However, the inconsistency exists among these studies (Akkurt et al. 2015; Alay et al. 2019). The aim of this study was to determine the clinical characteristics including inflammation marker associated with the need for surgical intervention.
Prevalence of Acb and non-Acb complex in elderly population with urinary tract infection (UTI)
Published in Acta Clinica Belgica, 2021
Smiline Girija AS, Vijayashree Priyadharsini J, Paramasivam A
Acinetobacter calcoaceticus–baumannii complex [Acb complex] with A. calcoaceticus and A. baumannii and the other species of Acinetobacter genus constituting A. lwoffii, A. hemolyticus, A. jhonsonii, A. pitti, A. radioresistens and A. nosocomialis are reported as priority pathogens causing nosocomial infections and various other recalcitrant infections [1]. Acinetobacter species has been genotyped into various groups by DNA–DNA hybridisation studies [2]. Most of the species are considered as saprophytic pathogens habituating the soil and environment, and its role as a nosocomial pathogen is recently an explorable fact [3]. Acinetobacter sp., is a gram negative coccobacilli and a strict aerobe and has been implicated in hospital-acquired infections [HAI], community-acquired pneumonia [CAP], ventilator- associated pneumonia, septicaemia and meningitis [4]. Of the Acinetobacter, A. baumannii has been recognised as a potent pathogen either as mono-microbial or as poly-microbial pathogen in urinary tract infections (UTIs), secondary meningitis, infective endocarditis and wound and burn infections [5].