colistin and Necrosis

Despite of proven LPS neutralizing activity, intravenous polymyxin use was waned due to experience of associated nephrotoxicity. But, increasing resistance to all available antibiotics has necessitated their resurgence and the prodrug of colistin sulfate (CS), known as colistin-methanesulfonate (CMS), is increasingly used as the only therapeutic option in many infections. Currently available CMS employ very different dose definitions and thus because of complex pharmacokinetics/pharmacodynamics information and short half-life, this drug use remains confusing. We aimed to expose CS in endotoxic shock models by micro-osmotic pump and evaluated its effectiveness.. We used micro-osmotic pumps to deliver either sterile saline or CS at different dosages ranging from 0.25mg/day to 7mg/day for consecutive 3days in LPS (8mg/kg body weight) induced endotoxic mice and observed their outcome twice daily for a week to determine the survival rate. Serum pro-inflammatory cytokine levels and apoptosis in renal tissues in these models were evaluated.. We showed endotoxic shock was reversed and all mice survived with a CS administration at a dosage of 2mg/day for 3 days, in comparison to survival rate with saline administration (p≤0.0001) in endotoxic models. CS infusion in shock models using micro-osmotic pump ameliorated rising of serum TNF-α, IL-12p70 and IL-6 levels. Nephrotoxicity was evident only with a higher dosage, but not with a lower dosage which was optimum to control endotoxic shock in models.. These results highlighted that an optimal dosage of CS effectively improved outcome in endotoxic shock models without causing nephrotoxicity when administered at a slow and sustained manner. And a higher CS dosage administration was nephrotoxic and fatal. Thus this study bought an opportunity to consider future investigations with CS administration in murine Gram-negative bacterial infections in a novel way.

Topics: Animals; Apoptosis; Colistin; Cytokines; Disease Models, Animal; Dose-Response Relationship, Drug; Endotoxins; Gram-Negative Bacterial Infections; Kidney; Lipopolysaccharides; Male; Mice; Mice, Inbred BALB C; Necrosis; Polymyxins; Shock, Septic; Survival Rate

Colistin (polymixin E) is an antibiotic prescribed with resurging frequency for multidrug resistant gram negative bacterial infections. It is associated with nephrotoxicity in humans in up to 55% of cases. Little is known regarding genes involved in colistin nephrotoxicity. A murine model of colistin-mediated kidney injury was developed. C57/BL6 mice were administered saline or colistin at a dose of 16 mg/kg/day in 2 divided intraperitoneal doses and killed after either 3 or 15 days of colistin. After 15 days, mice exposed to colistin had elevated blood urea nitrogen (BUN), creatinine, and pathologic evidence of acute tubular necrosis and apoptosis. After 3 days, mice had neither BUN elevation nor substantial pathologic injury; however, urinary neutrophil gelatinase-associated lipocalin was elevated (P = 0.017). An Illumina gene expression array was performed on kidney RNA harvested 72 h after first colistin dose to identify differentially expressed genes early in drug treatment. Array data revealed 21 differentially expressed genes (false discovery rate < 0.1) between control and colistin-exposed mice, including LGALS3 and CCNB1. The gene signature was significantly enriched for genes involved in cell cycle proliferation. RT-PCR, immunoblot, and immunostaining validated the relevance of key genes and proteins. This murine model offers insights into the potential mechanism of colistin-mediated nephrotoxicity. Further studies will determine whether the identified genes play a causative or protective role in colistin-induced nephrotoxicity.

Topics: Animals; Body Weight; Cell Cycle Checkpoints; Cluster Analysis; Colistin; Disease Models, Animal; Galectin 3; Gene Expression Profiling; In Situ Nick-End Labeling; Kidney; Kidney Tubules; Male; Mice; Mice, Inbred C57BL; Necrosis; Proliferating Cell Nuclear Antigen; Reproducibility of Results

Necrotizing external otitis (NEO) is a fulminant Pseudomonas infection of the external auditory canal affecting mainly elderly diabetic patients. Since the early descriptions, many authors have related cases of NEO in non diabetic patients. We report eight cases of NEO in young children. They are less than two years old, they are undernourished and non diabetics. We get a good evolution in spite of our modest therapeutic ways. Emphasis is placed on efficiency of local remedy with colistine.

Topics: Anti-Bacterial Agents; Colistin; Cote d'Ivoire; Female; Humans; Infant; Infant, Newborn; Male; Necrosis; Nutrition Disorders; Otitis Externa; Pseudomonas Infections

The authors test antibiotic strategies aimed at either mitigating bacterial translocation from the gut or delivering antibiotics specifically concentrated by the pancreas for prevention of early secondary infection after acute necrotizing pancreatitis.. Infection currently is the principal cause of death after severe pancreatitis. The authors have shown that the risk of bacterial infection correlates directly with the degree of tissue injury in a rodent model of pancreatitis. Bacteria most likely arrive by translocation from the colon.. Severe acute necrotizing pancreatitis was induced in rats by a combination of low-dose controlled intraductal infusion of glycodeoxycholic acid superimposed on intravenous cerulein hyperstimulation. At 6 hours, animals were randomly allocated to five treatment groups: controls, selective gut decontamination (oral antibiotics and cefotaxime), oral antibiotics alone, cefotaxime alone, or imipenem. At 96 hours, surviving animals were killed for quantitative bacterial study of the cecum, pancreas, and kidney.. The 96-hour mortality (35%) was unaffected by any treatment regimen. Cecal gram-negative bacteria were significantly reduced only by the oral antibiotics. Pancreatic infection was significantly reduced by full-gut decontamination and by imipenem, but not by oral antibiotics or by cefotaxime alone. Renal infection was reduced by both intravenous antibiotics.. Early pancreatic infection after acute necrotizing pancreatitis can be reduced with a full-gut decontamination regimen or with an antibiotic concentrated by the pancreas (imipenem) but not by unconcentrated antibiotics of similar spectrum (cefotaxime) or by oral antibiotics alone. These findings suggest that 1) both direct bacterial translocation from the gut and hematogenous seeding interplay in pancreatic infection while hematogenous seeding is dominant at extrapancreatic sites and 2) imipenem may be useful in clinical pancreatitis.

Topics: Acute Disease; Administration, Oral; Amphotericin B; Animals; Bacteria; Bacterial Infections; Bacterial Physiological Phenomena; Cecal Diseases; Cefotaxime; Colistin; Disease Models, Animal; Drug Therapy, Combination; Imipenem; Injections, Intravenous; Kidney Diseases; Male; Necrosis; Pancreas; Pancreatic Diseases; Pancreatitis; Rats; Rats, Sprague-Dawley; Survival Rate; Tobramycin

Topics: Animals; Anti-Bacterial Agents; Cephaloridine; Cephalothin; Colistin; Female; Furosemide; Glycerol; Kanamycin; Kidney; Kidney Tubules, Proximal; Necrosis; Organ Size; Rats; Time Factors; Urea