Surgical infection
Professor Sir Norman Williams, Professor P. Ronan O’Connell, Professor Andrew W. McCaskie in Bailey & Love's Short Practice of Surgery, 2018
Gas gangrene is caused by C. perfringens. These gram-positive, anaerobic, spore-bearing bacilli are widely found in nature, particularly in soil and faeces. This infection is particularly relevant to military and trauma surgery. Patients who are immunocompromised, diabetic or have malignant disease are at greater risk, particularly if they have wounds containing necrotic or foreign material, resulting in anaerobic conditions. Military wounds provide an ideal environment as the kinetic energy of high-velocity missiles or shrapnel causes extensive tissue damage. The cavitation which follows passage of a missile through the tissues causes a ‘sucking' entry wound, leaving clothing and environmental soiling in the wound in addition to devascularised tissue. Gas gangrene wound infections are associated with severe local wound pain and crepitus (gas in the tissues, which may also be visible on plain radiographs). The wound produces a thin, brown, sweet-smelling exudate, in which Gram staining will reveal bacteria. Oedema and spreading gangrene follow the release of collagenase, hyaluro- nidase, other proteases and alpha toxin. Early systemic complications with circulatory collapse and organ failure follow if prompt action is not taken.
Mycobacterium tuberculosis – The Organism
Peter D O Davies, Stephen B Gordon, Geraint Davies in Clinical Tuberculosis, 2014
The alternative theory that persisting bacilli are not strictly dormant but are in a balanced state of replication and destruction by immune mechanisms, would explain why lowered immune responses lead to reactivation of disease and why there is a continued production of gamma-interferon in those with latent tuberculosis [93]. The morphological nature of the persisting bacilli and their location in the host tissues also remain a mystery. Although they may well be ‘normal’ acid-fast bacilli, a range of alternative morphological forms have been postulated, but none have been isolated and characterised [99]. Under conditions conducive to dormancy depletion of a mycobacterial protein, Wag31 (one of a class of proteins present in all Gram-positive bacteria, which – by a regulatory effect on peptidoglycan synthesis – determines cell morphology and division) causes a weakening of the cell wall, initially at one pole but with the eventual formation of circular cells [98]. This could well be the initiating phase in formation of the postulated cell-wall-free, non-acid-fast persisting bacilli.
The Tubercle Bacillus
Arthur Newsholme in The Prevention of Tuberculosis, 2015
Range of Temperature.—The tubercle bacillus of mammalian tuberculosis ceases to grow below 29°C. and over 42°C., of avian tuberculosis below 25°C. and over 45°C. The best temperature for the growth of the mammalian tubercle bacillus is 37°–38°C. As these temperatures are not common in the external world, it is important to note that, as Cornet (p. 42) remarks, the tubercle bacillus does not meet with the conditions of growth “except solely and exclusively within the animal organism with its constant and equable temperature of 37°–39°C.” Or as Dr. Moxon (1885) put it : “The life of the bacillar parasite is difficult, easily discouraged by unfavourable circumstance, like an aphis by an eastern wind.” Beevor, Delépine, and Kanthack have succeeded in obtaining growths of the tubercle bacillus on potato at room temperature; but this is difficult, and there is no evidence that it occurs frequently. Extreme cold does not kill the bacillus. There is considerable discrepancy in the evidence as to the thermal death-point of the tubercle bacillus. Probably different strains of bacilli vary in this respect, and much will depend on the medium surrounding them. Further details on this point will be found on page 409. Generally the tubercle bacillus is destroyed after 4 to 6 hours’ exposure to a temperature of 55°C.; after 15 minutes at 65°C.; after 5 minutes at 80°C.; after 2 minutes at 90°C.; and in a less time at the temperature of boiling water. In a dried condition its vitality may survive higher temperatures than the above.
Multispecies biofilm formation by the contaminating microbiota in raw milk
Published in Biofouling, 2019
G. S. Oliveira, D. R. G. Lopes, C. Andre, C. C. Silva, F. Baglinière, M. C. D. Vanetti
Many bacteria belonging to the class Gammaproteobacteria are described in the literature as biofilm formers, such as Hafnia alvei, Pseudomonas spp., Serratia spp., Enterococcus faecalis and Staphylococcus aureus (Viana et al. 2009; Cleto et al. 2012; Fabres-Klein et al. 2015; Cherif-Antar et al. 2016). Some of these bacteria are also predominant proteolytic spoilage bacteria found in refrigerated raw milk, such as Serratia liquefaciens, Pseudomonas fluorescens, and Pseudomonas lundensis (Machado et al. 2015). Members of the class Bacilli are commonly found in dairy farms and processing plants, and it has been demonstrated that Bacillus spp. (Flint et al. 2001; Parkar et al. 2001; Faille et al. 2014) and Anoxybacillus flavithermus (Palmer et al. 2010) are capable of adhering strongly to SS. These bacteria also have great potential to spoil dairy products due to the production of proteolytic and lipolytic enzymes (Molva et al. 2009; Faille et al. 2014).
The Sporobiota of the Human Gut
Published in Gut Microbes, 2021
Muireann Egan, Eugene Dempsey, C. Anthony Ryan, R. Paul Ross, Catherine Stanton
Aerobic spore-formers found in the gut microbiota include members of the Bacillaceae family.23 Spore-forming bacilli are more commonly associated with the soil microbiome and their presence in the gut is associated with ingestion of food and water. However, despite it not being their natural habitat, Bacillus species are well adapted to survive the GIT and reports suggest that describing Bacillus as merely a “transient” member of the gut microbiome is incorrect and that they may be gut colonizers.66,67 A number of facultative anaerobic Bacillus spore-formers have been isolated from human fecal samples.66,68,69 In a murine model, it was shown that Bacillus spore-formers can undergo a complete life-cycle within the GIT, including germination, vegetative growth and re-sporulation.68
Advances in preventing adverse events during monoclonal antibody management of multiple sclerosis
Published in Expert Review of Neurotherapeutics, 2019
Laura De Giglio, Alessandro E. Grimaldi, Federica Fubelli, Fabiana Marinelli, Carlo Pozzilli
Except for PML, no other opportunistic infections were detected during the clinical trials in NTZ-treated MS patients [49]. ALZ treatment in patients with hematological diseases resulted in a rate of infection with Pneumocystis jirovecii pneumonia of 3%, but no case was detected during clinical trials for MS and only one case was described in post-marketing surveillance [50]. Nocardia spp. are gram-positive bacilli ubiquitous in soil, decaying organic matter and water. Two cases of nocardiosis have been reported in literature in MS patients treated with ALZ [50], even though diagnosis is often missed. Rare cases of spirochetal gingivitis, Legionella longbeachae pneumonia, Pasteurella spp. and Blastocystis hominis infection have been reported [50]. Despite the high rates of opportunistic infections in rheumatoid arthritis trials [16], there has been no report in OCR-treated MS patients during clinical trials [24].
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