Clostridium difficile: A common inhabitant of the colon flora in human infants and sometimes in adults. It produces a toxin that causes pseudomembranous enterocolitis (ENTEROCOLITIS, PSEUDOMEMBRANOUS) in patients receiving antibiotic therapy.Clostridium Infections: Infections with bacteria of the genus CLOSTRIDIUM.Clostridium: A genus of motile or nonmotile gram-positive bacteria of the family Clostridiaceae. Many species have been identified with some being pathogenic. They occur in water, soil, and in the intestinal tract of humans and lower animals.Enterocolitis, Pseudomembranous: An acute inflammation of the INTESTINAL MUCOSA that is characterized by the presence of pseudomembranes or plaques in the SMALL INTESTINE (pseudomembranous enteritis) and the LARGE INTESTINE (pseudomembranous colitis). It is commonly associated with antibiotic therapy and CLOSTRIDIUM DIFFICILE colonization.Bacterial Toxins: Toxic substances formed in or elaborated by bacteria; they are usually proteins with high molecular weight and antigenicity; some are used as antibiotics and some to skin test for the presence of or susceptibility to certain diseases.Ribotyping: RESTRICTION FRAGMENT LENGTH POLYMORPHISM analysis of rRNA genes that is used for differentiating between species or strains.Enterotoxins: Substances that are toxic to the intestinal tract causing vomiting, diarrhea, etc.; most common enterotoxins are produced by bacteria.Feces: Excrement from the INTESTINES, containing unabsorbed solids, waste products, secretions, and BACTERIA of the DIGESTIVE SYSTEM.Clostridium botulinum: A species of anaerobic, gram-positive, rod-shaped bacteria in the family Clostridiaceae that produces proteins with characteristic neurotoxicity. It is the etiologic agent of BOTULISM in humans, wild fowl, HORSES; and CATTLE. Seven subtypes (sometimes called antigenic types, or strains) exist, each producing a different botulinum toxin (BOTULINUM TOXINS). The organism and its spores are widely distributed in nature.Diarrhea: An increased liquidity or decreased consistency of FECES, such as running stool. Fecal consistency is related to the ratio of water-holding capacity of insoluble solids to total water, rather than the amount of water present. Diarrhea is not hyperdefecation or increased fecal weight.Cytotoxins: Substances that are toxic to cells; they may be involved in immunity or may be contained in venoms. These are distinguished from CYTOSTATIC AGENTS in degree of effect. Some of them are used as CYTOTOXIC ANTIBIOTICS. The mechanism of action of many of these are as ALKYLATING AGENTS or MITOSIS MODULATORS.Bacterial Proteins: Proteins found in any species of bacterium.Metronidazole: A nitroimidazole used to treat AMEBIASIS; VAGINITIS; TRICHOMONAS INFECTIONS; GIARDIASIS; ANAEROBIC BACTERIA; and TREPONEMAL INFECTIONS. It has also been proposed as a radiation sensitizer for hypoxic cells. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985, p133), this substance may reasonably be anticipated to be a carcinogen (Merck, 11th ed).Cross Infection: Any infection which a patient contracts in a health-care institution.Anti-Bacterial Agents: Substances that reduce the growth or reproduction of BACTERIA.Spores, Bacterial: Heat and stain resistant, metabolically inactive bodies formed within the vegetative cells of bacteria of the genera Bacillus and Clostridium.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.Clostridium sordellii: A species of gram-positive bacteria in the family Clostridiaceae, found in INTESTINES and SOIL.Clostridium acetobutylicum: A species of gram-positive bacteria in the family Clostridiaceae, used for the industrial production of SOLVENTS.Antitoxins: Antisera from immunized animals that is purified and used as a passive immunizing agent against specific BACTERIAL TOXINS.Clostridium tetani: The cause of TETANUS in humans and domestic animals. It is a common inhabitant of human and horse intestines as well as soil. Two components make up its potent exotoxin activity, a neurotoxin and a hemolytic toxin.Clindamycin: An antibacterial agent that is a semisynthetic analog of LINCOMYCIN.Clostridium thermocellum: A species of gram-positive, thermophilic, cellulolytic bacteria in the family Clostridaceae. It degrades and ferments CELLOBIOSE and CELLULOSE to ETHANOL in the CELLULOSOME.Botulinum Toxins: Toxic proteins produced from the species CLOSTRIDIUM BOTULINUM. The toxins are synthesized as a single peptide chain which is processed into a mature protein consisting of a heavy chain and light chain joined via a disulfide bond. The botulinum toxin light chain is a zinc-dependent protease which is released from the heavy chain upon ENDOCYTOSIS into PRESYNAPTIC NERVE ENDINGS. Once inside the cell the botulinum toxin light chain cleaves specific SNARE proteins which are essential for secretion of ACETYLCHOLINE by SYNAPTIC VESICLES. This inhibition of acetylcholine release results in muscular PARALYSIS.Cecum: The blind sac or outpouching area of the LARGE INTESTINE that is below the entrance of the SMALL INTESTINE. It has a worm-like extension, the vermiform APPENDIX.Bacteriological Techniques: Techniques used in studying bacteria.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.ADP Ribose Transferases: Enzymes that transfer the ADP-RIBOSE group of NAD or NADP to proteins or other small molecules. Transfer of ADP-ribose to water (i.e., hydrolysis) is catalyzed by the NADASES. The mono(ADP-ribose)transferases transfer a single ADP-ribose. POLY(ADP-RIBOSE) POLYMERASES transfer multiple units of ADP-ribose to protein targets, building POLY ADENOSINE DIPHOSPHATE RIBOSE in linear or branched chains.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Bacterial Typing Techniques: Procedures for identifying types and strains of bacteria. The most frequently employed typing systems are BACTERIOPHAGE TYPING and SEROTYPING as well as bacteriocin typing and biotyping.Cecal Diseases: Pathological developments in the CECUM.Enteritis: Inflammation of any segment of the SMALL INTESTINE.Bacteria, AnaerobicClostridium butyricum: Type species of the genus CLOSTRIDIUM, a gram-positive bacteria in the family Clostridiaceae. It is used as a source of PROBIOTICS.Mesocricetus: A genus of the family Muridae having three species. The present domesticated strains were developed from individuals brought from Syria. They are widely used in biomedical research.Microbial Sensitivity Tests: Any tests that demonstrate the relative efficacy of different chemotherapeutic agents against specific microorganisms (i.e., bacteria, fungi, viruses).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.Caproates: Derivatives of caproic acid. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain a carboxy terminated six carbon aliphatic structure.Toxoids: Preparations of pathogenic organisms or their derivatives made nontoxic and intended for active immunologic prophylaxis. They include deactivated toxins. Anatoxin toxoids are distinct from anatoxins that are TROPANES found in CYANOBACTERIA.Germ-Free Life: Animals not contaminated by or associated with any foreign organisms.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).Hospitals, AnimalAza CompoundsMolecular 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.Clostridium septicum: A species of gram-positive bacteria in the family Clostridiaceae. Infections have a strong association with malignancies and also with GAS GANGRENE.Aminoglycosides: Glycosylated compounds in which there is an amino substituent on the glycoside. Some of them are clinically important ANTIBIOTICS.Disease Outbreaks: Sudden increase in the incidence of a disease. The concept includes EPIDEMICS and PANDEMICS.Intestines: The section of the alimentary canal from the STOMACH to the ANAL CANAL. It includes the LARGE INTESTINE and SMALL INTESTINE.Enterocolitis: Inflammation of the MUCOSA of both the SMALL INTESTINE and the LARGE INTESTINE. Etiology includes ISCHEMIA, infections, allergic, and immune responses.Glutamate Dehydrogenase: An enzyme that catalyzes the conversion of L-glutamate and water to 2-oxoglutarate and NH3 in the presence of NAD+. (From Enzyme Nomenclature, 1992) EC 1.4.1.2.Gastrointestinal Tract: Generally refers to the digestive structures stretching from the MOUTH to ANUS, but does not include the accessory glandular organs (LIVER; BILIARY TRACT; PANCREAS).Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.CresolsClostridium beijerinckii: A species of gram-positive bacteria in the family Clostridiaceae, capable of solventogenesis, and isolated from SOIL, infected WOUNDS, fermenting OLIVES, and spoiled CANDY.Rifamycins: A group of ANTI-BACTERIAL AGENTS characterized by a chromophoric naphthohydroquinone group spanned by an aliphatic bridge not previously found in other known ANTI-BACTERIAL AGENTS. They have been isolated from fermentation broths of Streptomyces mediterranei.Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)Clostridium perfringens: The most common etiologic agent of GAS GANGRENE. It is differentiable into several distinct types based on the distribution of twelve different toxins.Botulism: A disease caused by potent protein NEUROTOXINS produced by CLOSTRIDIUM BOTULINUM which interfere with the presynaptic release of ACETYLCHOLINE at the NEUROMUSCULAR JUNCTION. Clinical features include abdominal pain, vomiting, acute PARALYSIS (including respiratory paralysis), blurred vision, and DIPLOPIA. Botulism may be classified into several subtypes (e.g., food-borne, infant, wound, and others). (From Adams et al., Principles of Neurology, 6th ed, p1208)rho GTP-Binding Proteins: A large family of MONOMERIC GTP-BINDING PROTEINS that are involved in regulation of actin organization, gene expression and cell cycle progression. This enzyme was formerly listed as EC 3.6.1.47.Probiotics: Live microbial DIETARY SUPPLEMENTS which beneficially affect the host animal by improving its intestinal microbial balance. Antibiotics and other related compounds are not included in this definition. In humans, lactobacilli are commonly used as probiotics, either as single species or in mixed culture with other bacteria. Other genera that have been used are bifidobacteria and streptococci. (J. Nutr. 1995;125:1401-12)Hospitals: Institutions with an organized medical staff which provide medical care to patients.Enterococcus: A genus of gram-positive, coccoid bacteria consisting of organisms causing variable hemolysis that are normal flora of the intestinal tract. Previously thought to be a member of the genus STREPTOCOCCUS, it is now recognized as a separate genus.Environmental Microbiology: The study of microorganisms living in a variety of environments (air, soil, water, etc.) and their pathogenic relationship to other organisms including man.Colony Count, Microbial: Enumeration by direct count of viable, isolated bacterial, archaeal, or fungal CELLS or SPORES capable of growth on solid CULTURE MEDIA. The method is used routinely by environmental microbiologists for quantifying organisms in AIR; FOOD; and WATER; by clinicians for measuring patients' microbial load; and in antimicrobial drug testing.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Tenuazonic Acid: 3-Acetyl-5-sec-butyl-4-hydroxy-3-pyrrolin-2-one. A metabolite found in a strain of the fungus Alternaria tenuis Auct. which functions as an antibiotic with antiviral and antineoplastic properties, and may also act as a mycotoxin.Latex Fixation Tests: Passive agglutination tests in which antigen is adsorbed onto latex particles which then clump in the presence of antibody specific for the adsorbed antigen. (From Stedman, 26th ed)Gene Expression Regulation, Bacterial: Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.Streptogramin B: A specific streptogramin group B antibiotic produced by Streptomyces graminofaciens and other bacteria.Genes, Bacterial: The functional hereditary units of BACTERIA.Molecular Epidemiology: The application of molecular biology to the answering of epidemiological questions. The examination of patterns of changes in DNA to implicate particular carcinogens and the use of molecular markers to predict which individuals are at highest risk for a disease are common examples.Molecular Diagnostic Techniques: MOLECULAR BIOLOGY techniques used in the diagnosis of disease.Clostridium botulinum type A: Subtype of CLOSTRIDIUM BOTULINUM that produces BOTULINUM TOXINS, TYPE A which is neurotoxic to humans and animals.Anti-Infective Agents: Substances that prevent infectious agents or organisms from spreading or kill infectious agents in order to prevent the spread of infection.Bacterial Load: Measurable quantity of bacteria in an object, organism, or organism compartment.Infection Control: Programs of disease surveillance, generally within health care facilities, designed to investigate, prevent, and control the spread of infections and their causative microorganisms.Virulence: The degree of pathogenicity within a group or species of microorganisms or viruses as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenic capacity of an organism is determined by its VIRULENCE FACTORS.Bacterial Shedding: The expelling of bacteria from the body. Important routes include the respiratory tract, genital tract, and intestinal tract.Ileitis: Inflammation of any segment of the ILEUM and the ILEOCECAL VALVE.Ileum: The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.Clostridium cellulolyticum: A species of gram-positive bacteria in the family Clostridiaceae. It is a cellulolytic, mesophilic species isolated from decayed GRASS.Carrier State: The condition of harboring an infective organism without manifesting symptoms of infection. The organism must be readily transmissible to another susceptible host.Prophages: Genomes of temperate BACTERIOPHAGES integrated into the DNA of their bacterial host cell. The prophages can be duplicated for many cell generations until some stimulus induces its activation and virulence.Recurrence: The return of a sign, symptom, or disease after a remission.Vero Cells: A CELL LINE derived from the kidney of the African green (vervet) monkey, (CERCOPITHECUS AETHIOPS) used primarily in virus replication studies and plaque assays.Intestinal Mucosa: Lining of the INTESTINES, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. In the SMALL INTESTINE, the mucosa is characterized by a series of folds and abundance of absorptive cells (ENTEROCYTES) with MICROVILLI.Colon: The segment of LARGE INTESTINE between the CECUM and the RECTUM. It includes the ASCENDING COLON; the TRANSVERSE COLON; the DESCENDING COLON; and the SIGMOID COLON.Clostridium cellulovorans: A species of gram-positive, cellulolytic bacteria in the family Clostridiaceae. It produces CELLULOSOMES which are involved in plant CELL WALL degradation.Clostridium chauvoei: A species of gram-positive bacteria in the family Clostridiaceae isolated from infected CATTLE; SHEEP; and other animals. It causes blackleg in cattle and sheep and is transmitted through soil-borne spores.Caco-2 Cells: Human colonic ADENOCARCINOMA cells that are able to express differentiation features characteristic of mature intestinal cells, such as ENTEROCYTES. These cells are valuable in vitro tools for studies related to intestinal cell function and differentiation.QuinolinesColitis: Inflammation of the COLON section of the large intestine (INTESTINE, LARGE), usually with symptoms such as DIARRHEA (often with blood and mucus), ABDOMINAL PAIN, and FEVER.Fluoroquinolones: A group of QUINOLONES with at least one fluorine atom and a piperazinyl group.