Cholelithiasis and Nephrolithiasis
John K. DiBaise, Carol Rees Parrish, Jon S. Thompson in Short Bowel Syndrome Practical Approach to Management, 2017
The risk of nephrolithiasis increases as a result of enhanced absorption of enteric oxalate in those with colon remaining. Oxalate absorption in the colon is increased by high oxalate intake in the diet. Up to 40% of the daily excretion of oxalate in the urine is from a dietary source; however, oxalate absorption in the intestine depends linearly on the concomitant dietary intake of calcium and is influenced by the bacterial degradation by several bacterial species of intestinal microbiota. The gut-dwelling obligate anaerobe Oxalobacter formigenes has been an area of research interest because of its oxalate-degrading property [54]. A reduction in bacterial breakdown of oxalate due to decreased O. formigenes in the colon of SBS patients has been described [55]. By altering the intestinal bacterial population, probiotics may have the potential to lower oxalate absorption and urinary excretion and may be beneficial in the treatment or prevention of oxalate stones as shown in healthy subjects [56].
Arcobacter
Dongyou Liu in Handbook of Foodborne Diseases, 2018
As commented, Arcobacter spp. are gram-negative, non-spore-forming curved or helical rod-shaped cells (0.2–0.9 × 1–3 μm) that are motile via a single polar flagellum [14]. This morphology is similar to that of Campylobacter spp. However, growth requirements are somewhat less fastidious because most Arcobacter, depending upon species and/or strains, display aerotolerance of at least 5% O2 and grow at a broad range of temperatures (15°C, 25°C, 37°C–42°C). It has been stated that optimal growth can be obtained at 30°C under microaerobic conditions. However, using an incubation temperature of 25°C Van den Abeele et al. [21] detected a similar incidence of Arcobacter among patients with diarrhea (1.31%) than previous studies from India that employed 37°C [22 and references therein]. In addition, in a recent study performed by Levican et al. [23], there was no significant difference between the species recovered from wastewater when comparing results obtained after incubation under aerobic or microaerobic conditions. However, recently an obligate anaerobic species, Arcobacter anaerophilus has been described [24], but this is so far an atypical characteristic for the genus. An additional atypical member of the genus is an obligate halophile species, that is, Arcobacter halophilus that requires the presence of at least 2% NaCl in the culture media to grow [25]. Recently, six isolates of A. halophilus and 52 new isolates of Arcobacter marinus were recovered from water and shellfish using an enrichment step in Arcobacter-CAT (Cefoperazone, Amphotericin B, and Teicoplanin) liquid medium supplemented with 2.5% NaCl (w/v) followed by culturing on marine agar after passive filtration [26]. In the same study, several new species from shellfish and water, pending description, were discovered mainly from the medium containing salt [26].
Control of the Large Bowel Microflora
Michael J. Hill, Philip D. Marsh in Human Microbial Ecology, 2020
Numerically, the most important genus of intestinal bacteria in animals and humans are the Gram-negative Bacteroides. Among the Gram-positive, nonsporing rods several genera are numerically important in the gut. Obligate anaerobic types include Eubacterium sp. and Bifidobacterium sp., such as the B. bifidum and B. infantis found in the feces of breast-fed infants. The genus Lactobacillus contains many species occurring in the gut of most warmblooded animals. Although numerically important throughout the alimentary tract, their ecological significance has not been conclusively elucidated. Several types of spore-forming rods and cocci are normal inhabitants of the gut. The genus Clostridium is probably the most ubiquitous. C. perfringens, C. bifermentans, and C. tetani are found regularly, albeit in relatively low numbers, in the lower gut of animals and are of significance in human and veterinary medicine. The presence of the aerobic Bacillus genus is thought to be the result of contamination of the environment. Facultative and obligate anaerobic Gram-positive cocci are numerically important in the gut. The strict anaerobes include Peptostreptococcus, Ruminococcus, Megaspnaera elsdenii, and Sarcina ventriculi. The facultatively anaerobic streptococci are well represented by many species from Lancefield group D including Streptococcus faecalis, S. bovis, and S. equinus, and some from group K such as S. salivarius which is usually associated with the mouth. Gram-negative anaerobic cocci include Veillonela and Acidaminococcus. Although they are not numerically important, the Gram-negative facultative anaerobic rods include a number of very important pathogens. Members of the Enterobacteraceae, particularly E. coli, are usually thought of as the characteristic intestinal bacteria. Several types of spirochaete can be seen in the gut of healthy animals and their status in the human gut is uncertain.
Botulism Outbreak in a Regional Community Hospital: Lessons Learned in Transfer and Transport Considerations
Published in Prehospital Emergency Care, 2019
William Krebs, Terri Higgins, Martha Buckley, James J. Augustine, Bradley D. Raetzke, Howard A. Werman
Botulism is a potentially lethal condition caused by a neurotoxin released by Clostridium botulinum. This organism is a spore-forming obligate anaerobe and is ubiquitous, being isolated from variety of fruits and vegetables, soil, and marine environments. The organism produces a neurotoxin, which attacks the pre-synaptic nerve endings in affected muscles. Exposure to clostridal spores or direct exposure to toxin, via ingestion, contact with an infected wound, absorption by the lungs or parenteral injection can lead to botulism. The toxin causes various degrees of paralysis typically starting with the bulbar nerves but ultimately causing prolonged respiratory failure in its victims (1). For a comprehensive review on botulism, the reader is referred to the Centers for Disease Control (CDC) website at http://emergency.cdc.gov/agent/botulism/factsheet.asp.
Microbiome therapeutics for the treatment of recurrent Clostridioides difficile infection
Published in Expert Opinion on Biological Therapy, 2023
Patricia P Bloom, Vincent B Young
The gut microbiome is clearly implicated in the pathogenesis of CDI and its recurrence. By definition, all patients with rCDI have had a primary CDI episode, for which the first step is development of C. difficile colonization. When C. difficile, an obligate anaerobe, reaches the human colon, the anoxic colonic environment enables C. difficile to survive, proliferate, and produce toxins [8]. A normal, healthy microbiome mediates resistance to C. difficile colonization [9]. Disruption of a healthy microbiome with antibiotics can lead to loss of colonization resistance, and subsequent infection [10]. While antibiotics often precipitate CDI, antibiotics directed against C. difficile are also the standard treatment for CDI, albeit with the risk for further disruption of the indigenous gut microbiota. Antibiotics target the vegetative form of C. difficile, but not the spore form of the pathogen, which later germinate and produce new vegetative cells if colonization resistance is not restored [11]. C. difficile spores are resistant to heat, oxygen, and common disinfectants [12]. When antibiotics are administered to treat vegetative C. difficile in the setting of acute CDI they contribute to further disruption of the gut microbiota. For example vancomycin, a standard treatment for CDI, can extend the microbial disruption caused by the original antibiotic course that predisposed to CDI [13]. After treatment for CDI, if the microbiome does not normalize and restore colonization resistance, that individual is susceptible to rCDI.
Emerging drugs for the treatment of clostridium difficile
Published in Expert Opinion on Emerging Drugs, 2019
Giovanni Cammarota, Antonella Gallo, Gianluca Ianiro, Massimo Montalto
Clostridium difficile (C. difficile), or Clostridioides difficile, according to the new proposed reclassification [1], is a spore-forming gram-positive bacillus, usually spread by the fecal-oral route [2]. Since its obligate anaerobic nature, C. difficile has to produce highly resistant spore in order to survive in unfavorable environments. In susceptible patients, C. difficile spores may germinate in to the colon to the vegetative form, thus producing toxins and damaging the intestinal epithelium [2,3]. Toxin A and toxin B are the two virulence factors mainly involved in C. difficile infection (CDI), nowadays representing the most common cause of healthcare-associated infection [2,3]. The most relevant risk factors for CDI include previous antibiotic exposure, prolonged hospitalization, advanced age and gastrointestinal surgery [4].
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