Cephalexin: A semisynthetic cephalosporin antibiotic with antimicrobial activity similar to that of CEPHALORIDINE or CEPHALOTHIN, but somewhat less potent. It is effective against both gram-positive and gram-negative organisms.Cephradine: A semi-synthetic cephalosporin antibiotic.Cefadroxil: Long-acting, broad-spectrum, water-soluble, CEPHALEXIN derivative.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.Cephaloridine: A cephalosporin antibiotic.Cefaclor: Semisynthetic, broad-spectrum antibiotic derivative of CEPHALEXIN.Cephalothin: A cephalosporin antibiotic.Cephaloglycin: A cephalorsporin antibiotic.Cefixime: A third-generation cephalosporin antibiotic that is stable to hydrolysis by beta-lactamases.Penicillin V: A broad-spectrum penicillin antibiotic used orally in the treatment of mild to moderate infections by susceptible gram-positive organisms.Skin Diseases, Infectious: Skin diseases caused by bacteria, fungi, parasites, or viruses.Ampicillin: Semi-synthetic derivative of penicillin that functions as an orally active broad-spectrum antibiotic.Rats, Hairless: Mutant strains of rats that produce little or no hair. Several different homozygous recessive mutations can cause hairlessness in rats including rnu/rnu (Rowett nude), fz/fz (fuzzy), shn/shn (shorn), and nznu/nznu (New Zealand nude). Note that while NUDE RATS are often hairless, they are most characteristically athymic.Ferula: A plant genus of the family APIACEAE. It contains pungent oils and resins. It is used to flavor curries, as a carminative, and as cat and dog repellent. The occasionally used common name of 'giant fennel' should not be confused with true fennel (FOENICULUM).Dicloxacillin: One of the PENICILLINS which is resistant to PENICILLINASE.Cefazolin: A semisynthetic cephalosporin analog with broad-spectrum antibiotic action due to inhibition of bacterial cell wall synthesis. It attains high serum levels and is excreted quickly via the urine.Amdinocillin: An amidinopenicillanic acid derivative with broad spectrum antibacterial action.Anti-Bacterial Agents: Substances that reduce the growth or reproduction of BACTERIA.Symporters: Membrane transporters that co-transport two or more dissimilar molecules in the same direction across a membrane. Usually the transport of one ion or molecule is against its electrochemical gradient and is "powered" by the movement of another ion or molecule with its electrochemical gradient.Microbial Sensitivity Tests: Any tests that demonstrate the relative efficacy of different chemotherapeutic agents against specific microorganisms (i.e., bacteria, fungi, viruses).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.Norethindrone: A synthetic progestational hormone with actions similar to those of PROGESTERONE but functioning as a more potent inhibitor of ovulation. It has weak estrogenic and androgenic properties. The hormone has been used in treating amenorrhea, functional uterine bleeding, endometriosis, and for contraception.