Polymyxins: Basic lipopeptide antibiotic group obtained from Bacillus polymyxa. They affect the cell membrane by detergent action and may cause neuromuscular and kidney damage. At least eleven different members of the polymyxin group have been identified, each designated by a letter.Polymyxin B: A mixture of polymyxins B1 and B2, obtained from Bacillus polymyxa strains. They are basic polypeptides of about eight amino acids and have cationic detergent action on cell membranes. Polymyxin B is used for infections with gram-negative organisms, but may be neurotoxic and nephrotoxic.Colistin: Cyclic polypeptide antibiotic from Bacillus colistinus. It is composed of Polymyxins E1 and E2 (or Colistins A, B, and C) which act as detergents on cell membranes. Colistin is less toxic than Polymyxin B, but otherwise similar; the methanesulfonate is used orally.Anti-Bacterial Agents: Substances that reduce the growth or reproduction of BACTERIA.Hemoperfusion: Removal of toxins or metabolites from the circulation by the passing of blood, within a suitable extracorporeal circuit, over semipermeable microcapsules containing adsorbents (e.g., activated charcoal) or enzymes, other enzyme preparations (e.g., gel-entrapped microsomes, membrane-free enzymes bound to artificial carriers), or other adsorbents (e.g., various resins, albumin-conjugated agarose).Lipid A: Lipid A is the biologically active component of lipopolysaccharides. It shows strong endotoxic activity and exhibits immunogenic properties.Pseudomonas aeruginosa: A species of gram-negative, aerobic, rod-shaped bacteria commonly isolated from clinical specimens (wound, burn, and urinary tract infections). It is also found widely distributed in soil and water. P. aeruginosa is a major agent of nosocomial infection.Lipopolysaccharides: Lipid-containing polysaccharides which are endotoxins and important group-specific antigens. They are often derived from the cell wall of gram-negative bacteria and induce immunoglobulin secretion. The lipopolysaccharide molecule consists of three parts: LIPID A, core polysaccharide, and O-specific chains (O ANTIGENS). When derived from Escherichia coli, lipopolysaccharides serve as polyclonal B-cell mitogens commonly used in laboratory immunology. (From Dorland, 28th ed)Microbial Sensitivity Tests: Any tests that demonstrate the relative efficacy of different chemotherapeutic agents against specific microorganisms (i.e., bacteria, fungi, viruses).Gram-Negative Bacteria: Bacteria which lose crystal violet stain but are stained pink when treated by Gram's method.Drug Resistance, Bacterial: The ability of bacteria to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).Gram-Negative Bacterial Infections: Infections caused by bacteria that show up as pink (negative) when treated by the gram-staining method.Drug Resistance, Microbial: The ability of microorganisms, especially bacteria, to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).Burkholderia cenocepacia: A species of gram-negative bacteria that causes disease in plants. It is found commonly in the environment and is an opportunistic pathogen in humans.Acinetobacter baumannii: A species of gram-negative, aerobic bacteria, commonly found in the clinical laboratory, and frequently resistant to common antibiotics.Drug Resistance, Multiple, Bacterial: The ability of bacteria to resist or to become tolerant to several structurally and functionally distinct drugs simultaneously. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).Achromobacter denitrificans: The type species of gram negative, aerobic bacteria in the genus ACHROMOBACTER. Previously in the genus ALCALIGENES, the classification and nomenclature of this species has been frequently emended. The two subspecies, Achromobacter xylosoxidans subsp. denitrificans and Achromobacter xylosoxidans subsp. xylosoxidans are associated with infections.Endotoxins: Toxins closely associated with the living cytoplasm or cell wall of certain microorganisms, which do not readily diffuse into the culture medium, but are released upon lysis of the cells.Bacterial Proteins: Proteins found in any species of bacterium.Antimicrobial Cationic Peptides: Small cationic peptides that are an important component, in most species, of early innate and induced defenses against invading microbes. In animals they are found on mucosal surfaces, within phagocytic granules, and on the surface of the body. They are also found in insects and plants. Among others, this group includes the DEFENSINS, protegrins, tachyplesins, and thionins. They displace DIVALENT CATIONS from phosphate groups of MEMBRANE LIPIDS leading to disruption of the membrane.Uranyl Nitrate: Bis(nitrato-O)dioxouranium. A compound used in photography and the porcelain industry. It causes severe renal insufficiency and renal tubular necrosis in mammals and is an effective lymphocyte mitogen.Kidney Cortex Necrosis: Death of cells in the KIDNEY CORTEX, a common final result of various renal injuries including HYPOXIA; ISCHEMIA; and drug toxicity.Paenibacillus: A genus of GRAM-POSITIVE ENDOSPORE-FORMING RODS in the family Paenibacillaceae.Neomycin: Antibiotic complex produced by Streptomyces fradiae. It is composed of neomycins A, B, and C. It acts by inhibiting translation during protein synthesis.