Journal of Analytical & Pharmaceutical Research Antimicrobial Agents Abstract Mini Review The word antimicrobial was derived from the Greek words anti (against), micro (little) and bios (life) and refers to all agents that act against microbial organisms. Antimicrobial agent is a general term that is mainly concerned with antibiotics, Volume 4 Issue 3 - 2017 antibacterials, antifungals, antivirals and antiprotozoans. Antimicrobial agents Department of Pharmacy, Uttarakhand Technical University, are drugs, chemicals or other substances that are capable of acting by two modes India either kill (microbiocidal) or slow the growth of microbes (microbiostatic). Antimicrobial medicines can be classified according to the microorganisms they *Corresponding author: Mohammad Asif, Department of act primarily against. For example, antibacterials are used against bacteria and Pharmacy, Uttarakhand Technical University, GRD(PG)IMT, antifungals are used against fungi. Dehradun, 248009, Uttarakhand, India, Email: Keywords: Antimicrobial; Antibacterials; Antifungals; Microbiostatic; Microbiocidal; Bacteria; Fungi; Antivirals; Antiprotozoans; Penicillium Received: | Published: February 13, 2017 March 20, 2017 Introduction Use of substances with antimicrobial properties is known to have been common practice for at least 2000 years. Ancient extracts to treat infection. More recently, microbiologists such as LouisEgyptians Pasteur and andancient Jules GreeksFrancois used Joubert specific observed molds antagonism and plant for some bacteria and discussed the merits of controlling these interactions in medicine. In 1928, Alexander Fleming became the as Penicillium Rubens. The substance extracted from the fungus hefirst named to discover Penicillin a natural and in powerful 1942 it was antimicrobial successfully fungus used toknown treat a Streptococcus infections [1,2]. But nowadays, all over the world treatment of using antimicrobial agents is currently facing its own limitation, due to the development of resistance by the microbes over the period of time. Bacteria are involved in many aspects of and suffer from interactions with bacteria. For example we use bacteriaecology andfor makinghealth. Ityoghurt, seems likelycurd, cheesethat all andspecies other both fermented benefit foods and also large number of bacteria lives on the skin and Bacterial Cell Structure. in the digestive tract. The human gut contains more than 1000 Figure 1: bacterial species bacteria synthesize vitamins such as Folic Acid, Vitamin K and biotin and they ferment Cell Wall the complex, indigestible which are carbohydrates. beneficial [3]. OtherGut useful bacteria in Protects the cell and maintains its shape, bacteria can be sugar into Lactic Acid. Also bacteria play very important role in categorized according to their cell wall type: the medicinegut flora suchinclude as vaccine Lactobacillus component species, and whichin the productionconvert milk of a. Gram positive walls are thick with little lipid. antibiotics, drugs, hormones, and antibodies. On the other hand walls are much thinner, with two layers. a pathogenic bacterium causes an enormous level of spoilage, b. Gram negative Some have a slimy layer of polysaccharides and suffering and death through the infection. The bacterial cells differs bacteria polypeptides, allowing them to attach to objects and providing dramatically in structure and function compared to mammalian protection. cells. The bacterial cytoplasm is separated from the external environment by a cytoplasmic membrane, as shown in Figure 70s ribosomes 1. The bacterial cell wall is chemically distinct from mammalian cell [4] walls and so is constructed by enzymes that often have no These are for performing protein synthesis. They are smaller direct counterpart in mammalian cell construction. The following than the 80s ribosomes in eukaryotic cells. Flagellum another are the functions of the various parts of the bacterial cell. optional feature is a projection that moves around to allow the cell to move. A cell may have multiple flagella arranged around it. Submit Manuscript | http://medcraveonline.com J Anal Pharm Res 2017, 4(3): 00104 Copyright: Antimicrobial Agents ©2017 Asif 2/6 Nuclear material Gram (–) bacteria. Schematic view of cell wall after Gram staining A folded mass of DNA and RNA, also called the nuclear zone have been classified into two main categories viz., Gram (+) and additional rings of genetic material that aren’t essential to the cell, is shown in Figure 3 [6]. often-containing contain all genes the genes for antibiotic required resistance. for vital functions. Plasmid are Mesosome An infolding of the membrane that is the site of respiration existence of the mesosome is disputed and most scientists believe (like a mitochondrion) - it’s shape improves surface area. The it isIn a mistakeaddition, in bacteria electron possess microscope a crucial technique. structure surrounding the entire cell, the Peptidoglycan (PG), which forms a sacculus around the bacterial cell, is an essential cell wall polymer since interference with its synthesis or structure leads to loss of cell shape and integrity followed by bacterial death. The peptidoglycan [5] layer as shown in Figure 2 consists of a matrix of polysaccharide chains composed of alternating (italics) N N -acetylmuramic acid (MurNAc) -acetylglucosamine (GlcNAc) sugarClassification moieties cross-linked through pentapeptide sidechains. Hans christian gram: A Danish microbiologist, had developed the Gram stains in order to visualize bacteria more easily under Figure 2: Peptidoglycan layer. microscope. Based upon the staining pattern pathogenic bacteria Figure 3: Gram+Ve and Gram-Ve Cell Wall. The cell wall of gram (+): Bacteria although complex enough, Microorganisms are a group of organisms which include living (ex. (b) Bacteria, fungi, protozoans, algae of the cell is set of antigenic determinants which assists to organisms (ex. (v) Virus). adhereis simpler to particularthan that oftarget Gram cell. (-) The organisms. next barrier On the is thevery cell outside wall, etc.) as well as non-living Bacteria: Bacteria are unicellular organisms found in nature on cytoplasmic membrane and accounts for 50% of the dry weight of zero (psychrophiles) to up to 1000C (thermophilic). thespongy, bacterium. gel-forming Beneath layer, this i.e.layer peptidoglycan is the lipoidal layer cytoplasmic external cell to Bacteria all living and non-living things at temperature range from below membrane e.g. Staphylococci aureus, Streptococci pneumoniae, which they grow, on the basis of group of cells, depending on Bacillus subtilis . patogenecityare classified andaccording on staining. to the shapeOn the of ground cell, on of temperature staining they in With the gram[7] (-): Bacteria, the cell wall is more complex and Gram positive (Gram+ve) and Gram more lipoidal. These cells usually contain an additional, outer negative (Gram-ve). Gram positive bacteria shows violet color and membrane, which contains complex lipopolysaccharides that Gramare further negative classified bacteria asshows pink colour in a procedure called encode antigenic responses. Below this lies, less impressive, Gram Staining developed by C. Gram. Based on pathogenicity, layer of peptidoglycan this is followed by a phospholipid rich cytoplasmic membrane. e.g. Escherichia Coli, Haemophilus influenzae, Pseudomonas aeruginosa the classification is pathogenic disease/infection causing i.e. infectious and non-pathogenic-non infectious. In medicinal [7]. chemistry, this classification is important. Citation: Asif M (2017) Antimicrobial Agents. J Anal Pharm Res 4(3): 00104. DOI: 10.15406/japlr.2017.04.00104 Copyright: Antimicrobial Agents ©2017 Asif 3/6 Fungi: Fungi are universal in distribution. Many are terrestrial found on the skin, hair and nails. The fungus is a eukaryotic and thrive best in soil. Some live in tissues of plants and animals fungi grow animals and bacteria. Fungi contain unicellular, multinucleate on food stuffs such as bread, jams, pickles, fruits, and vegetables. organism which is classified as a separate kingdom from plants, Fungiwhile theare remaindersaprophytic is and found parasitic in aquatic in nature. places. Saprophytes Many grow reproductive spores and the nature of hyphae. They divide on dead organic matter, while parasites live on living bodies of sexuallyand multicellular or asexually forms or bythey both are ways. classified Fungi on are the almost basis entirelyof their other animals. Parasitic fungi include Candida albicans which is multicellular with exception of yeast Saccharomyces cerviseae the causative agent of Candiditis. which is prominent unicellular fungus. Fungi are heterotrophic, deriving their energy from another organism, whether alive or Protozoans: Protozoa are minute and acellular animalcules dead. Fungi are eukaryotic protista differing from bacteria in many without tissues and organs having one or more nuclei. They are ways, as they posses rigid cell wall containing chitin, mannan, free living or they remain in association with animals and plants. other polysaccharides and their cytoplasmic membrane contains Some which are parasitic in nature include protozoans Amoeba sterol. The major difference between fungal cells and plant cell is causing amoebiasis and causing Malaria. Plasmodium that fungal cell walls contain chitin, while plants contain cellulose Viruses: intracellular obligate parasites. They occupy position in between Viruses are acellular, micro-organisms which are [11-13]. interfering