For people who are critically ill that require a feeding tube, there is evidence suggesting that the risk of aspiration pneumonia may be reduced by inserting the feeding tube into the duodenum or the jejunum (post-pyloric feeding), when compared to inserting the feeding tube into the stomach (gastric feeding). Enhanced swallow
Many people at risk for aspiration pneumonia have an impaired swallowing mechanism, which may increase the chance of aspiration of food particles with meals. There is some evidence to indicate that training of various parts of the body involved in the act of swallowing, including the tongue and lips, may reduce episodes of aspiration and aspiration pneumonia; however, further research is required to confirm this benefit. Other simple actions during feeding can improve the swallowing capability of a person and thus reduce the risk of aspiration, including changes in position and feeding assistance. After surgery
Many instances of aspiration occur during surgical operations, especially during anesthesia induction. The administration of anesthesia causes suppression of protective reflexes, most importantly the gag reflex. As a result, stomach particles can easily enter the lungs. Certain risk factors predispose individuals to aspiration, especially conditions causing dysfunction of the upper gastrointestinal system. Identifying these conditions before the operation begins is essential for proper preparation during the procedure. It is recommended that patients fast prior to procedures as well. Other practices that may be beneficial but have not been well-studied include medication that reduce the acidity of gastric contents and rapid sequence induction.
It is derived from bacteria of the genus Paenibacillus. Medical uses
Antibacterial spectrum
Colistin has been effective in treating infections caused by Pseudomonas, Escherichia, and Klebsiella species. The following represents minimum inhibitory concentration (MIC) susceptibility data for a few medically significant microorganisms:
Escherichia coli: 0.12–128 μg/mL
Klebsiella pneumoniae: 0.25–128 μg/mL
Pseudomonas aeruginosa: ≤0.06–16 μg/mLFor example, colistin in combination with other drugs is used to attack P. aeruginosa biofilm infection in lungs of patients with cystic fibrosis. Biofilms have a low-oxygen environment below the surface where bacteria are metabolically inactive, and colistin is highly effective in this environment. However, P. aeruginosa reside in the top layers of the biofilm, where they remain metabolically active. This is because surviving tolerant cells migrate to the top of the biofilm via pili and form new aggregates via quorum sensing. Administration and dosage
Forms
Two forms of colistin are available commercially: colistin sulfate and colistimethate sodium (colistin methanesulfonate sodium, colistin sulfomethate sodium). Colistin sulfate is cationic; colistimethate sodium is anionic. Colistin sulfate is stable, whereas colistimethate sodium is readily hydrolysed to a variety of methanesulfonated derivatives. Colistin sulfate and colistimethate sodium are eliminated from the body by different routes. With respect to Pseudomonas aeruginosa, colistimethate is the inactive prodrug of colistin. The two drugs are not interchangeable. Colistimethate sodium may be used to treat Pseudomonas aeruginosa infections in patients with cystic fibrosis, and it has come into recent use for treating multidrug-resistant Acinetobacter infection, although resistant forms have been reported.