Monobactams: Monocyclic, bacterially produced or semisynthetic beta-lactam antibiotics. They lack the double ring construction of the traditional beta-lactam antibiotics and can be easily synthesized.Anti-Bacterial Agents: Substances that reduce the growth or reproduction of BACTERIA.beta-Lactamases: Enzymes found in many bacteria which catalyze the hydrolysis of the amide bond in the beta-lactam ring. Well known antibiotics destroyed by these enzymes are penicillins and cephalosporins.Ceftazidime: Semisynthetic, broad-spectrum antibacterial derived from CEPHALORIDINE and used especially for Pseudomonas and other gram-negative infections in debilitated patients.Microbial Sensitivity Tests: Any tests that demonstrate the relative efficacy of different chemotherapeutic agents against specific microorganisms (i.e., bacteria, fungi, viruses).beta-Lactams: Four-membered cyclic AMIDES, best known for the PENICILLINS based on a bicyclo-thiazolidine, as well as the CEPHALOSPORINS based on a bicyclo-thiazine, and including monocyclic MONOBACTAMS. The BETA-LACTAMASES hydrolyze the beta lactam ring, accounting for BETA-LACTAM RESISTANCE of infective bacteria.Cephalosporins: A group of broad-spectrum antibiotics first isolated from the Mediterranean fungus ACREMONIUM. They contain the beta-lactam moiety thia-azabicyclo-octenecarboxylic acid also called 7-aminocephalosporanic acid.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.Pseudomonas Infections: Infections with bacteria of the genus PSEUDOMONAS.beta-Lactam Resistance: Nonsusceptibility of bacteria to the action of the beta-lactam antibiotics. Mechanisms responsible for beta-lactam resistance may be degradation of antibiotics by BETA-LACTAMASES, failure of antibiotics to penetrate, or low-affinity binding of antibiotics to targets.Cefoperazone: Semisynthetic broad-spectrum cephalosporin with a tetrazolyl moiety that is resistant to beta-lactamase. It has been proposed especially against Pseudomonas infections.Gram-Negative Bacteria: Bacteria which lose crystal violet stain but are stained pink when treated by Gram's method.Klebsiella pneumoniae: Gram-negative, non-motile, capsulated, gas-producing rods found widely in nature and associated with urinary and respiratory infections in humans.Enterobacter: Gram-negative gas-producing rods found in feces of humans and other animals, sewage, soil, water, and dairy products.Amikacin: A broad-spectrum antibiotic derived from KANAMYCIN. It is reno- and oto-toxic like the other aminoglycoside antibiotics.Azlocillin: A semisynthetic ampicillin-derived acylureido penicillin.Imipenem: Semisynthetic thienamycin that has a wide spectrum of antibacterial activity against gram-negative and gram-positive aerobic and anaerobic bacteria, including many multiresistant strains. It is stable to beta-lactamases. Clinical studies have demonstrated high efficacy in the treatment of infections of various body systems. Its effectiveness is enhanced when it is administered in combination with CILASTATIN, a renal dipeptidase inhibitor.Enterobacteriaceae: A family of gram-negative, facultatively anaerobic, rod-shaped bacteria that do not form endospores. Its organisms are distributed worldwide with some being saprophytes and others being plant and animal parasites. Many species are of considerable economic importance due to their pathogenic effects on agriculture and livestock.Enterobacteriaceae Infections: Infections with bacteria of the family ENTEROBACTERIACEAE.CephalosporinaseTobramycin: An aminoglycoside, broad-spectrum antibiotic produced by Streptomyces tenebrarius. It is effective against gram-negative bacteria, especially the PSEUDOMONAS species. It is a 10% component of the antibiotic complex, NEBRAMYCIN, produced by the same species.Piperacillin: Semisynthetic, broad-spectrum, AMPICILLIN derived ureidopenicillin antibiotic proposed for PSEUDOMONAS infections. It is also used in combination with other antibiotics.Isoelectric Focusing: Electrophoresis in which a pH gradient is established in a gel medium and proteins migrate until they reach the site (or focus) at which the pH is equal to their isoelectric point.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).Cefotaxime: Semisynthetic broad-spectrum cephalosporin.Clavulanic Acid: Clavulanic acid and its salts and esters. The acid is a suicide inhibitor of bacterial beta-lactamase enzymes from Streptomyces clavuligerus. Administered alone, it has only weak antibacterial activity against most organisms, but given in combination with other beta-lactam antibiotics it prevents antibiotic inactivation by microbial lactamase.Skin Diseases, Bacterial: Skin diseases caused by bacteria.Klebsiella Infections: Infections with bacteria of the genus KLEBSIELLA.Carbapenems: A group of beta-lactam antibiotics in which the sulfur atom in the thiazolidine ring of the penicillin molecule is replaced by a carbon atom. THIENAMYCINS are a subgroup of carbapenems which have a sulfur atom as the first constituent of the side chain.Thienamycins: Beta-lactam antibiotics that differ from PENICILLINS in having the thiazolidine sulfur atom replaced by carbon, the sulfur then becoming the first atom in the side chain. They are unstable chemically, but have a very broad antibacterial spectrum. Thienamycin and its more stable derivatives are proposed for use in combinations with enzyme inhibitors.Klebsiella: A genus of gram-negative, facultatively anaerobic, rod-shaped bacteria whose organisms arrange singly, in pairs, or short chains. This genus is commonly found in the intestinal tract and is an opportunistic pathogen that can give rise to bacteremia, pneumonia, urinary tract and several other types of human infection.Citrobacter: A genus of gram-negative, rod-shaped enterobacteria that can use citrate as the sole source of carbon.Azabicyclo Compounds: Bicyclic bridged compounds that contain a nitrogen which has three bonds. The nomenclature indicates the number of atoms in each path around the rings, such as [2.2.2] for three equal length paths. Some members are TROPANES and BETA LACTAMS.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Amdinocillin: An amidinopenicillanic acid derivative with broad spectrum antibacterial action.Serratia marcescens: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria found in soil, water, food, and clinical specimens. It is a prominent opportunistic pathogen for hospitalized patients.Cephalosporin Resistance: Non-susceptibility of an organism to the action of the cephalosporins.Cefoxitin: A semisynthetic cephamycin antibiotic resistant to beta-lactamase.Serratia Infections: Infections with bacteria of the genus SERRATIA.Gentamicins: A complex of closely related aminoglycosides obtained from MICROMONOSPORA purpurea and related species. They are broad-spectrum antibiotics, but may cause ear and kidney damage. They act to inhibit PROTEIN BIOSYNTHESIS.Enterobacter cloacae: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria that occurs in water, sewage, soil, meat, hospital environments, and on the skin and in the intestinal tract of man and animals as a commensal.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).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).Bacterial Infections: Infections by bacteria, general or unspecified.Ticarcillin: An antibiotic derived from penicillin similar to CARBENICILLIN in action.Kinetics: The rate dynamics in chemical or physical systems.Cystic Fibrosis: An autosomal recessive genetic disease of the EXOCRINE GLANDS. It is caused by mutations in the gene encoding the CYSTIC FIBROSIS TRANSMEMBRANE CONDUCTANCE REGULATOR expressed in several organs including the LUNG, the PANCREAS, the BILIARY SYSTEM, and the SWEAT GLANDS. Cystic fibrosis is characterized by epithelial secretory dysfunction associated with ductal obstruction resulting in AIRWAY OBSTRUCTION; chronic RESPIRATORY INFECTIONS; PANCREATIC INSUFFICIENCY; maldigestion; salt depletion; and HEAT PROSTRATION.Half-Life: The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacologic, physiologic, or radiologic activity.Cefuroxime: Broad-spectrum cephalosporin antibiotic resistant to beta-lactamase. It has been proposed for infections with gram-negative and gram-positive organisms, GONORRHEA, and HAEMOPHILUS.Drug Therapy, Combination: Therapy with two or more separate preparations given for a combined effect.Proteus vulgaris: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria that occurs in soil, fecal matter, and sewage. It is an opportunistic pathogen and causes cystitis and pyelonephritis.Gram-Negative Aerobic Bacteria: A large group of aerobic bacteria which show up as pink (negative) when treated by the gram-staining method. This is because the cell walls of gram-negative bacteria are low in peptidoglycan and thus have low affinity for violet stain and high affinity for the pink dye safranine.Penicillins: A group of antibiotics that contain 6-aminopenicillanic acid with a side chain attached to the 6-amino group. The penicillin nucleus is the chief structural requirement for biological activity. The side-chain structure determines many of the antibacterial and pharmacological characteristics. (Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed, p1065)Bacteria: One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.Gram-Positive Bacteria: Bacteria which retain the crystal violet stain when treated by Gram's method.Vancomycin: Antibacterial obtained from Streptomyces orientalis. It is a glycopeptide related to RISTOCETIN that inhibits bacterial cell wall assembly and is toxic to kidneys and the inner ear.Clavulanic Acids: Acids, salts, and derivatives of clavulanic acid (C8H9O5N). They consist of those beta-lactam compounds that differ from penicillin in having the sulfur of the thiazolidine ring replaced by an oxygen. They have limited antibacterial action, but block bacterial beta-lactamase irreversibly, so that similar antibiotics are not broken down by the bacterial enzymes and therefore can exert their antibacterial effects.Acinetobacter: A genus of gram-negative bacteria of the family MORAXELLACEAE, found in soil and water and of uncertain pathogenicity.Aminoglycosides: Glycosylated compounds in which there is an amino substituent on the glycoside. Some of them are clinically important ANTIBIOTICS.Kanamycin: Antibiotic complex produced by Streptomyces kanamyceticus from Japanese soil. Comprises 3 components: kanamycin A, the major component, and kanamycins B and C, the minor components.Conjugation, Genetic: A parasexual process in BACTERIA; ALGAE; FUNGI; and ciliate EUKARYOTA for achieving exchange of chromosome material during fusion of two cells. In bacteria, this is a uni-directional transfer of genetic material; in protozoa it is a bi-directional exchange. In algae and fungi, it is a form of sexual reproduction, with the union of male and female gametes.Proteus mirabilis: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria that is frequently isolated from clinical specimens. Its most common site of infection is the urinary tract.Lactams: Cyclic AMIDES formed from aminocarboxylic acids by the elimination of water. Lactims are the enol forms of lactams.Salmonella paratyphi A: A serotype of SALMONELLA ENTERICA that causes mild PARATYPHOID FEVER in humans.Plasmids: Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.Hydrolysis: The process of cleaving a chemical compound by the addition of a molecule of water.Muramoylpentapeptide Carboxypeptidase: Enzyme which catalyzes the peptide cross-linking of nascent CELL WALL; PEPTIDOGLYCAN.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Penicillanic Acid: A building block of penicillin, devoid of significant antibacterial activity. (From Merck Index, 11th ed)Gram-Negative Bacterial Infections: Infections caused by bacteria that show up as pink (negative) when treated by the gram-staining method.Penicillin-Binding Proteins: Bacterial proteins that share the property of binding irreversibly to PENICILLINS and other ANTIBACTERIAL AGENTS derived from LACTAMS. The penicillin-binding proteins are primarily enzymes involved in CELL WALL biosynthesis including MURAMOYLPENTAPEPTIDE CARBOXYPEPTIDASE; PEPTIDE SYNTHASES; TRANSPEPTIDASES; and HEXOSYLTRANSFERASES.Bacteria, AerobicChromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.Ciprofloxacin: A broad-spectrum antimicrobial carboxyfluoroquinoline.Hexosyltransferases: Enzymes that catalyze the transfer of hexose groups. EC 2.4.1.-.Paratyphoid Fever: A prolonged febrile illness commonly caused by several Paratyphi serotypes of SALMONELLA ENTERICA. It is similar to TYPHOID FEVER but less severe.Sulbactam: A beta-lactamase inhibitor with very weak antibacterial action. The compound prevents antibiotic destruction of beta-lactam antibiotics by inhibiting beta-lactamases, thus extending their spectrum activity. Combinations of sulbactam with beta-lactam antibiotics have been used successfully for the therapy of infections caused by organisms resistant to the antibiotic alone.Feces: Excrement from the INTESTINES, containing unabsorbed solids, waste products, secretions, and BACTERIA of the DIGESTIVE SYSTEM.Bile: An emulsifying agent produced in the LIVER and secreted into the DUODENUM. Its composition includes BILE ACIDS AND SALTS; CHOLESTEROL; and ELECTROLYTES. It aids DIGESTION of fats in the duodenum.Bacterial Proteins: Proteins found in any species of bacterium.Acinetobacter baumannii: A species of gram-negative, aerobic bacteria, commonly found in the clinical laboratory, and frequently resistant to common antibiotics.Infusions, Parenteral: The administration of liquid medication, nutrient, or other fluid through some other route than the alimentary canal, usually over minutes or hours, either by gravity flow or often by infusion pumping.Peptidyl Transferases: Acyltransferases that use AMINO ACYL TRNA as the amino acid donor in formation of a peptide bond. There are ribosomal and non-ribosomal peptidyltransferases.Escherichia coli Infections: Infections with bacteria of the species ESCHERICHIA COLI.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.Drug Synergism: The action of a drug in promoting or enhancing the effectiveness of another drug.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Meningitis, Haemophilus: Infections of the nervous system caused by bacteria of the genus HAEMOPHILUS, and marked by prominent inflammation of the MENINGES. HAEMOPHILUS INFLUENZAE TYPE B is the most common causative organism. The condition primarily affects children under 6 years of age but may occur in adults.Bacteria, AnaerobicInjections, Intramuscular: Forceful administration into a muscle of liquid medication, nutrient, or other fluid through a hollow needle piercing the muscle and any tissue covering it.Aztreonam: A monocyclic beta-lactam antibiotic originally isolated from Chromobacterium violaceum. It is resistant to beta-lactamases and is used in gram-negative infections, especially of the meninges, bladder, and kidneys. It may cause a superinfection with gram-positive organisms.Ampicillin: Semi-synthetic derivative of penicillin that functions as an orally active broad-spectrum antibiotic.Macaca fascicularis: A species of the genus MACACA which typically lives near the coast in tidal creeks and mangrove swamps primarily on the islands of the Malay peninsula.Minocycline: A TETRACYCLINE analog, having a 7-dimethylamino and lacking the 5 methyl and hydroxyl groups, which is effective against tetracycline-resistant STAPHYLOCOCCUS infections.Integrons: DNA elements that include the component genes and insertion site for a site-specific recombination system that enables them to capture mobile gene cassettes.Drug Stability: The chemical and physical integrity of a pharmaceutical product.Penicillinase: A beta-lactamase preferentially cleaving penicillins. (Dorland, 28th ed) EC 3.5.2.-.Administration, Inhalation: The administration of drugs by the respiratory route. It includes insufflation into the respiratory tract.Endocarditis, Bacterial: Inflammation of the ENDOCARDIUM caused by BACTERIA that entered the bloodstream. The strains of bacteria vary with predisposing factors, such as CONGENITAL HEART DEFECTS; HEART VALVE DISEASES; HEART VALVE PROSTHESIS IMPLANTATION; or intravenous drug use.Cross Infection: Any infection which a patient contracts in a health-care institution.Blood Proteins: Proteins that are present in blood serum, including SERUM ALBUMIN; BLOOD COAGULATION FACTORS; and many other types of proteins.Culture Media: Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.Drug Resistance, Multiple: Simultaneous resistance to several structurally and functionally distinct drugs.Electrophoresis, Gel, Pulsed-Field: Gel electrophoresis in which the direction of the electric field is changed periodically. This technique is similar to other electrophoretic methods normally used to separate double-stranded DNA molecules ranging in size up to tens of thousands of base-pairs. However, by alternating the electric field direction one is able to separate DNA molecules up to several million base-pairs in length.Neisseria gonorrhoeae: A species of gram-negative, aerobic bacteria primarily found in purulent venereal discharges. It is the causative agent of GONORRHEA.Penicillin Resistance: Nonsusceptibility of an organism to the action of penicillins.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Injections, Intravenous: Injections made into a vein for therapeutic or experimental purposes.Drug Combinations: Single preparations containing two or more active agents, for the purpose of their concurrent administration as a fixed dose mixture.Double-Blind Method: A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.Bacteriological Techniques: Techniques used in studying bacteria.Genes, Bacterial: The functional hereditary units of BACTERIA.Biological Availability: The extent to which the active ingredient of a drug dosage form becomes available at the site of drug action or in a biological medium believed to reflect accessibility to a site of action.Enzyme Induction: An increase in the rate of synthesis of an enzyme due to the presence of an inducer which acts to derepress the gene responsible for enzyme synthesis.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Mice, Inbred ICRChromatography, Thin Layer: Chromatography on thin layers of adsorbents rather than in columns. The adsorbent can be alumina, silica gel, silicates, charcoals, or cellulose. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Amino Acid Substitution: The naturally occurring or experimentally induced replacement of one or more AMINO ACIDS in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish, enhance, or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Tissue Distribution: Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.Kidney Diseases: Pathological processes of the KIDNEY or its component tissues.Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Dogs: The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)