China
Africa
Explore chapters and articles related to this topic
Bacteria
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Legionnaires′ disease was first described in 1976 and eventually the etiologic agent was identified as Legionella pneumophila, an inhabitant of contaminated water that may become airborne in aerosols from cooling towers, air conditioners, and plumbing systems where water has previously been heated followed by a prolonged period of stagnation. Apparently sufficient nutrients accumulate in water lines from valve gaskets, etc. to support growth of the organisms. When contaminated aerosols are inhaled, infection may result. The bacteria are probably not free-living in the water, but infect free-living amoebae and ciliated protozoa; where, if they infect amoebae cysts, can survive environmental extremes such as insufficient chlorination, desiccation, and elevated temperature. A second species, L. micdadei is also implicated in the disease in immunocompromised patients. Both species are facultative intracellular pathogens which multiply within mononuclear phagocytes following ingestion or inhalation. They have also been observed to multiply in vacuoles of amoebae. Disease production is related to impairment of host defense mechanisms. A heat stable cytotoxin that blocks the oxidative metabolism of monocytes and neutrophils and production of a phosphatase enzyme that blocks superoxide production by neutrophils are implicated in the pathogenesis of the disease. Legionella are quite susceptible to erythromycin.
Paper 2
Published in Aalia Khan, Ramsey Jabbour, Almas Rehman, nMRCGP Applied Knowledge Test Study Guide, 2021
Aalia Khan, Ramsey Jabbour, Almas Rehman
Legionella pneumophila must be considered in patients who have recently travelled abroad as the pathogen tends to breed in warm stag nant water such as is found in air conditioning systems. The patient may present with extra-pulmonary signs initially such as diarrhoea, vomiting, confusion and delirium. The patient may be very unwell. Diagnosis is with serology and treatment with erythromycin is effective.
The Chemistry of O-Polysaccharide Chains in Bacterial Lipopolysaccharides
Published in Helmut Brade, Steven M. Opal, Stefanie N. Vogel, David C. Morrison, Endotoxin in Health and Disease, 2020
Legionella pneumophila, the etiological agent of legionellosis, causes severe respiratory tract infections in humans, which may be lethal. The O-chain of type 1 (105) is a homopolymer of 5,7-diamino-3,5,7,9-tetmdeoxy-glycero-galacto-nonulosonic acid (Table 9). The absolute configuration was not determined but is most probably l-glycero-d-galacto, which is the configuration demonstrated for several other O-antigens (59).
High rate of bacterial respiratory tract co-infections upon admission amongst moderate to severe COVID-19 patients
Published in Infectious Diseases, 2022
Regev Cohen, Talya Finn, Frida Babushkin, Keren Geller, Hanna Alexander, Maurice Shapiro, Martina Uda, Abdol R. Mostrchy, Rabia Amash, Zvi Shimoni, Svetlana Paikin, Adi Ilani, Jonathan Lellouche
Of the 198 COVID-19 patients, 115 (58%) had FA results. One patient had two FA tests performed within 3 days, hence altogether 116 FA results were analyzed. Most FA tests (89%) were ordered and obtained during hospitalization days 2 and 3 (Table 2). In 46/116 (40%), the FA test was negative for all the targets tested, and a positive result was found in 70 cases (60%) – all were bacterial targets. In one case, a viral (Rhinovirus/Enterovirus) pathogen and in another case an atypical bacterial spp. (Legionella pneumophila) were detected in addition to the bacteria. In 27/116 cases (23%), there was one bacterial species and in 43 (37%) two or more bacterial species were detected. The detailed FA results are depicted in Table 3. The positive FA results according to the source of sampling (sputa versus lower respiratory tract samples) are presented in Figure 2.
Natural compounds and extracts as novel antimicrobial agents
Published in Expert Opinion on Therapeutic Patents, 2020
Paolo Guglielmi, Virginia Pontecorvi, Giulia Rotondi
The effectiveness of various compositions has been evaluated against different targets and the concentrations of each extract changed accordingly. For example, the composition Com1 (Table 3), was evaluated against pathogenic bacteria and yeasts like Acinetobacter baumannii, E. coli, Candida albicans and Pseudomonas aeruginosa through the antibiogram test, exhibiting good antimicrobial effects. A more complex composition (Com2, Table 3) displayed the ability to fight Legionella pneumophila, a Gram-negative bacterium found usually in the water and causing Legionnaire’s disease in humans [12]. In particular, the experiments demonstrated the ability of this mixture to inhibit Legionella pneumophila growth (Colony-Forming Unit, CFU = 0) after the addition of 1.5 grams of that composition in water, previously spiked with the bacterium. Moreover, the efficiency of the Com3 (Table 3) was evaluated against Salmonella enterica and E. coli bacteria, through a time-kill evaluation test detected at the intervals of 30 seconds, 60 seconds and 5 minutes after the inoculation (Table 4). The data reported in the Table 4 referred to a treatment performed with 2% solution of the composition, displaying as the total number of surviving bacteria at each time point was very low, with an overall log reduction >5.7 and >5 for S. enterica and E. coli, respectively.
Of coccus, Rocco and scores: pneumococcal disease, Rocky Graziano and pneumonia severity scoring systems
Published in Infectious Diseases, 2020
Only a couple of decades ago, sputum and blood cultures represented the main routine diagnostic tests for CAP. Interestingly, several studies found that these conventional diagnostic tests did not contribute significantly to the overall patient disease management [7–9]. More recently, urinary antigen tests to diagnose pneumonia caused by Legionella pneumophila (serotype 1) or Streptococcus pneumoniae have been introduced. An immunochromatographic assay has been developed to detect C polysaccharide cell wall antigens that are present in all pneumococci, a very useful rapid test for the diagnosis of CAP, with sensitivities and positive predictive values in the 50–80% range, while specificity and negative predictive values have been in the 90%s. The test sensitivity is higher in patients with bacteremic pneumonia, and the test does not appear to be influenced by prior use of antibiotics. The performance of this diagnostic test is occasionally affected by other, non-pneumococcal species (false positive tests), recent pneumococcal disease (with persistently positive results) or nasopharyngeal carrier status (especially in children). It is important to know that no organism is effectively isolated, hence no antibiotic sensitivities are obtained in these cases [10,11].