The Short Textbook of Medical Microbiology Satish Gupte
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1General Bacteriology
  1. Glossary of Microbiology
  2. History and Scop
  3. Morphology of Bacteria
  4. Nutritional Requirements of Bacteria
  5. Bacterial Metabolism
  6. Media for Bacterial Growth
  7. Classification and Identification of Bacteria
  8. Sterilization and Disinfection
  9. Infection
  10. Antimicrobial Therapy
    2

Glossary of Microbiology1

Readers may find it useful to go through the following definitions, or at least indications of their meanings.
A
Abscess:
A localized collection of pus.
Acid fast:
Resistant to decolorization by acid after staining with hot carbol fuchsin and hence retaining a red color when stained by Ziehl-Neelsen method.
Accessory:
Something added which helps.
Active immunity:
Dependent upon stimulation of person's own immunological mechanisms.
Active:
To make something work.
Adenine:
A purine constituent of nucleic acid.
Adenosine triphosphate (ATP):
Compound in which energy is stored in high energy phosphate bonds; its components are the purine adenine, D-ribose and three phosphoric acid groups.
Adjuvant:
Insoluble materials which act to keep antigens in tissues for longer period, thus cause a longer stimulation of antibody production.
Aerobe:
An organism which requires oxygen to live and reproduce.
Agglutinate:
To join together to form clump.
Allele:
One of a group of genes which can occupy a given place on a pair of identical chromosomes.
Allergy:
An abnormal sensitive reaction.
Anaerobe:
A microorganism not requiring oxygen to live or reproduce.
Anamnestic reaction:
A rise of an existing antibody level in response to irrelevant stimulus.
Anhydrous:
Containing no water.
Anode:
A positive electrode.
Antagonism:
Impairment of the efficacy of drug in the presence of the other.
Antibiotic:
A substance used to kill microorganisms. It is a product of microorganism
Antibody:
A globulin produced in the body in response to the antigen or foreign bodies.
Antigen:
Any substance which can cause the production of antibodies.
Antiserum:
A serum containing antibodies against particular organism.
Antitoxin:
An antibody against particular toxin.
Asepsis:
Without infection.
Atmospheric pressure:
The pressure of air on earth.
Attenuated:
Reduced virulence but retaining antigenecity for host.
Atypical:
Unusual.
4Autoinfection:
Infection of oneself.
Automatic:
Doing something by itself.
B
Bacilli:
Stick-like or rod-like bacteria.
Bacteria:
Single celled organisms containing both RNA and DNA which reproduce by binary fission.
Bacteriology:
The study of bacteria.
Bacteremia:
Presence of bacteria in bloodstream.
Bacteriocide:
A chemical used to kill bacteria.
Balantidium coli:
A protozoan ciliate causative agent of balantidiasis, a type of dysentry.
Beaded:
Staining at intervals along the length of bacillus.
Binary fission:
Simple cell division by which the nucleus and cytoplasm divides into two.
Biologic oxidation:
Any chemical reaction occurring within a cell that results in the release of energy respiration.
Biologic oxygen demand (BOD):
A measurement of the amount of oxygen required for the microbial decomposition of the organic matter present in water.
Biopsy:
The removal of small piece of tissue during life for examination.
Bio-type:
A classification or a group of genetically similar organisms.
Bi-polar:
The staining of bacillus at both ends.
Blister:
A small swelling in the skin filled with serum.
Bovine:
Associated with cattle.
Booster dose:
Additional infection of antigen to maintain antibody production at its peak.
Brittle:
Easily broken.
Brownian movement:
Passive to and fro movement of bacteria suspended in a fluid, due to irregular bombardment of molecules in fluid.
Budding:
An asexual form of reproduction of unicellular organisms, e.g. yeast cells.
Buffer:
A solution, the reaction of which is not easily altered by adding an acid or alkali.
C
Candling:
Inspection of an unbroken egg by holding it in front of bright light source to know whether embryo is alive or dead.
Capsid:
The protein coat surrounding the genome of virus.
Capsomere:
One of the units of which virus capsid is composed.
Capsule:
A coating outside cell walls of some bacteria and fungi.
Carrier:
One who is harboring but not currently suffering any ill-effect from pathogenic organism.
Cathode:
A negative electrode.
Cell:
A microscopic mass of protoplasm containing nucleus.
Cell line:
An in vitro culture of cells of known origin.
Cellulitis:
The result of a spreading infection of pyogenic bacteria in the subcutaneous tissues.
Characteristic:
A quality which distinguishes something, i.e. typical.
Chemotherapeutic agent:
A synthetic chemical suitable for systemic administration and effective in treatment of microbial infections.
Chitin:
Polysaccharide containing glucosamine, characteristic of cell walls of some fungi and also found in insects.
Chromatin:
Darkly staining nuclear material.
5Chromosomes:
Thread-like structure in the cell nucleus which contains genes carrying inherited characteristics.
Chronic:
Slowly developing.
Clone:
Cell derived from single cell.
Clinical disease:
The ways by which a disease shows itself in a patient.
Clue cells:
These are epithelial cells covered with large clumps of coccobacilli. They are good markers of infection.
Coccus:
A rounded or ovoid bacterium.
Colony:
A number of organisms living or multiplying together on culture media and they result from multiplication of a single organism.
Commensal:
Deriving nourishment from a host without causing any harm or benefit to host.
Complement:
A group of substances present in fresh serum and necessary for completion of some processes like lysis that result from anti-antibody interactions.
Control:
A check.
Constitutive
Produced under all circumstan-
enzyme:
ces, not dependent upon the presence of appropriate substrate.
Conjugation:
Exchange of genetic material between bacteria.
Culture:
The growth and multiplication of microorganism.
Culture media:
The material used in a culture to nourish the growth of microorganism.
Cytopathic effect:
Degenerative changes occurring in tissue culture cells as a result of microorganism infection.
Cytoplasmic streaming:
Continuous movement of cytoplasm within the cell which results in constant distribution of intracellular contents. It provides amoebic motility to some types of cells.
D
Darting:
A fast jerky movement.
Decolorize:
To remove color.
Deaminase:
An enzyme which catalyzes the removal of an amino group from a molecule with liberation of ammonia, the process is called deamination.
Delicate:
Fragile, which can be damaged easily.
Deposit:
The sediment at the bottom of tube.
Desiccation:
Drying or removal of water.
Detergent:
A surface active agent used in cleaning.
Diplococci:
Cocci which occur in pairs.
Disinfectant:
A substance of chemical nature used for destroying pathogenic microorganisms.
Distorted:
Altered or changed.
E
Effective:
Producing a result.
Electrolyte:
A chemical which helps to keep correct water balance between the fluid in the cell and that which surrounds it.
Elementary bodies:
Single chlamydiae particle visible by ordinary microscope after staining.
Embed:
To penetrate into tissue.
Emergency:
A serious situation requiring immediate attention.
Encapsulate:
To surround with a capsule.
Endemic:
A disease constantly present in an area.
Endogenous:
Originated by organisms or factors already present in the patient's body before onset of disease.
6Endotoxin:
A toxic component of microorganism (Gram negative), largely dependent on the death or disruption of the organism for its release.
Enriched medium:
A culture medium to which an extra nourishing substance is added.
Enrichment medium:
A liquid medium used to encourage preliminary growth of an organism so as to enhance the chances of growing it on subsequent plate culture.
Enzyme:
A chemical produced by living organism to help some particular reaction.
Epidemic:
A disease that temporarily has a high frequency in a given community.
Eradicate:
To get rid of.
Excision repair:
An enzyme system which can repair DNA by the elimination of ultraviolet light induced thymine dimers.
Exogenous:
Originated by organisms or factors from outside the patient's body.
Exotoxin:
A toxin released by living microorganisms into the surrounding medium or tissues.
Exudate:
A fluid, often from formed elements of blood, discharged from tissue to a surface or cavity.
F
Factor:
A substance with a special purpose, e.g. blood clotting factor.
Facultative:
Able to behave in a specified way, with the implication that is not, however, the usual behaviour.
Fermentation:
The slow decomposition, for example by microorganisms, of organic material such as the decomposition of a sugar solution by yeast to form alcohol.
Filament:
A fine thread-like structure.
Fimbria:
Hair-like protrusion from bacterial cells.
Flagellum:
Whip-like organ of motion.
Flocculant:
A mass of cells floating or settled to the bottom in a liquid medium.
Flocculation:
Precipitation in small cloudy mass.
Fluctuation test:
It is to determine the development of mutants in culture. The test is based on the concept that mutation is a completely random event, and spontaneous mutation would result in the number of mutants in a series of identical cultures.
Fluorosis:
Mottling of tooth enamel due to excessive amount of fluoride in water.
Fomites:
Objects contaminated with pathogenic microorganisms.
Fragment:
A piece broken off.
Fungus:
A simple unicellular or multicellular structure which reproduces by forming spores.
Fusiform:
Spindle shaped.
G
Gel:
To become solid, to set.
Gene:
A unit of inheritance found on chromosomes.
Genetic:
The study of inheritance.
Genome:
The total genetic material of an organism.
Genotype:
The inherited characters of a particular individual.
Genus:
A group of closely related species of plant, animal or microorganism.
Globulin:
A plasma protein divided into the alpha, beta and gamma fraction.
7Gram negative:
Staining red by Gram's method.
Gram positive:
Staining violet by Gram's method.
Growth factor:
An ingredient of which at least small amount must be present in a culture medium so that it supports the growth of given organism.
Granules:
Small grains or particles, e.g. metachromatic granules of diphtheria bacilli.
H
Halophilic:
Salt loving.
Hapten:
A substance which acts as an antigenic stimulus only when combined with protein but capable of reacting with resultant antibody in uncombined state even.
Hemolysis:
The destruction of red cells with the release of hemoglobulin.
Hereditary:
Transmitted from one generation to the other.
Hetero:
Different.
Heterologous:
Related to different kind of organism.
Hfr strain:
A high frequency mating strain.
Homologous:
Related to same kind of organism.
Host:
The organism from which a parasite takes its nourishment.
Hypertonic:
A condition in which the fluid surrounding a cell is more concentrated than that within it.
Hypotonic:
A condition in which the fluid surrounding a cell is less concentrated than that within it.
I
Identical:
Exactly same.
Immune:
Protected from disease by the presence of antibodies.
Immunoglobulin:
Globulins which act as antibodies.
Inactive:
The heating of serum at 56°C to destroy its complement and inhibitory factors.
Inclusion:
Something which is enclosed.
Incubate:
To keep at the same temperature for a given length of time.
Infection:
The entry and multiplication of pathogenic organisms within the body.
Inoculate:
To introduce a living organism into a culture medium.
Intra:
Inside.
In vitro:
In laboratory apparatus.
In vivo:
In a living animal or human being.
L
L-form:
Cell wall deficient mutant.
Ligases:
Enzymes that catalyze the linking together of two molecules.
Locus:
The definite place of a gene on a chromosome.
Lyophilization:
Combined freezing and desiccation (freeze drying).
Lysis:
Disruption.
Lysogenic conversion:
Alteration of the property of bacterium as a result of lysogeny.
Lysogeny:
A temporary stable relationship between bacteriophage and its bacterial host, in which the phage is reproduced in step with the bacterium and, thus, handed on to succeeding generation of bacteria.
M
Macrophage:
A large mononuclear phagocytic cell.
Medium:
A nutrient substance used to grow microorganisms.
8Metabolism:
The process of building up chemical compounds in the body and their breaking down during activity.
Microaerophile:
An organism which grows best in subconcentration of oxygen.
Misense mutation:
A change in cell's DNA with the effect that a wrong amino acid has been put into essential protein.
Molecule:
The smallest part of an element or compound which can exist in normal way.
Monolayer:
A sheet of tissue culture cells one cell thick.
Morphology:
A study of the form of cells and organisms.
Motile:
Capable of movement.
Moult:
The shedding of skin.
Mutation:
An alteration in genetic material.
N
Neutral:
Neither acidic or alkaline with pH of 7.0.
Nodule:
A small rounded swelling.
Normal:
Usual or ordinary.
Normal solution:
A solution in which the equivalent weight in grams of a chemical is dissolved in one litre of solution.
Nucleoid:
Genome.
Nucleocap:
The genome and capsid.
Nucleus:
An essential part of the living cell, containing the chromosomes and controlling cell activity.
Nutrition:
Food.
O
Obligatory anaerobe:
An organism which cannot live in oxygen.
Occult:
Hidden.
Opaque:
Not allowing light to pass.
Optimum:
The most suitable.
Oxidation:
Combination with oxygen.
P
Pandemic:
World-wide epidemic.
Parasite:
An organism which takes its food from another organism without giving anything in return.
Passage:
Administration of microorganism to a host and its subsequent recovery from the host. This way pathogenicity of organism is modified.
Passive immunity:
Dependent upon injection of readymade antibodies and not upon the subject's own immunological mechanisms.
Pathogen:
An organism which can cause disease.
Petri dish:
A shallow circular flat bottomed glass or plastic dish used as a container for solid media.
Phage type:
The identity of a bacterial strain as indicated by its sensitivity or resistance to the lytic action of bacteriophages.
pH:
The symbol that indicates the acidity or alkalinity of a solution. pH less than 7 is acid and more than 7 is alkali.
Phagocyte:
A cell which ingests microorganisms.
Phenotype:
The expression of genotype.
Pigment:
A coloring substance.
Pilus:
Fimbria.
Plasmid:
An extrachromosomal portion of genetic material.
Polymerase:
General name of enzymes concerned with synthesis of nucleic acid.
Prophage:
Bacteriophage in a lysogenic relationship with its host.
Prophylactic:
A medicine to prevent disease.
Prozone:
The occurrence of an antigen-antibody reaction only when serum is adequately diluted but 9not when it is used at higher concentration.
Protoplast:
A bacterium deprived of its cell wall.
Puerperal fever:
Acute infection following child birth due to introduction of infectious agent into the uterus.
Purulent:
Containing pus.
Pus:
A thick yellowish green fluid containing phagocytic cells collecting in tissues infected with pyogenic bacteria.
Pyogenic:
Pus forming.
R
Rack:
A stand for holding tubes.
Rash:
A skin reaction, usually seen as small reddened or raised area.
Reaction:
An action which takes place in response to something.
Reagin:
Antibodies associated with certain types of hypersensitivity reactions. It may be contained in serum causing Wassermann reaction and related reactions.
Recombinant:
A cell or clone of cells resulting from conjugation.
Reduction:
The removal of oxygen from a chemical compound.
Replication:
Virus reproduction.
Reticuloendothelial system:
The system of phagocytic cells in the body.
Retraction:
Shrinking.
Ribonucleo protein:
Material in the cytoplasm and nucleus of cell.
Rodent:
A gnawing animal, e.g. rat, mouse.
Room temperature:
Usually 18 to 20°C.
Routine:
Carried out regularly.
S
Sanitize:
To reduce microbial number to safe levels.
Saprophytic:
Living on dead organic matter.
Saturated solution:
A solution which has dissolved as much as it can of a substance.
Satellitism:
Enhancement of bacterial growth on a solid medium around a source of growth factor.
Selective medium:
A solid culture medium on which all but the desired organisms are wholly or largely inhibited.
Septicemia:
Presence and multiplication of bacteria in blood stream resulting severe disease.
Serology:
The study of serum especially antibody contents.
Serotype:
Antigenic type.
Specific antibody:
An antibody which react with one particular antigen only.
Spheroplast:
Similar to protoplast with the difference that cell wall damage is partial and reversible.
Spirochete:
Genera of spiral bacteria.
Sterilization:
The process of killing all living microorganisms.
Symbiotic:
Living in mutually with the host.
T
Technique:
The method by which something is done.
Temperate phage:
A phage capable of a lysogenic relationship with its bacterial host.
Thermostat:
An instrument to control the temperature.
Tissue:
A group of similar cells.
Titer:
The highest dilution of antibody in a serum which will react with its specific antigen.
Tolerogen:
An antigen that induces tolerance.
Toxoid:
Toxin rendered harmless but retaining antigenicity.
10Transduction:
Transfer of genetic material from bacterial strain to another by means of bacteriophage.
Transformation:
Acquisition of genetic characters of one bacterial strain by a related strain grown in presence of DNA from the first strain.
Transport medium:
A medium which increases the chances of survival of microorganism during transportation from patient to laboratory.
Turbid:
Cloudy.
Typical:
Showing usual features.
U
Undulating:
Up and down, i.e. wavy.
Unicellular:
Single celled.
Unstable:
Easily changed.
Urticaria:
A skin rash caused by allergy.
V
Vaccinate:
To introduce into the body killed or mildly pathogenic organisms to produce resistance against disease.
Vaccine:
Material used in vaccination.
Variation:
A change from the usual.
Vector:
An insect which carries microorganism or parasite and is capable of transmitting this.
Viable:
Able to live.
Vibrio:
A comma shaped microorganism.
Viremia:
Presence of viruses in the bloodstream.
Virion:
A virus particle.
Virulent:
Harmful.
W
Working solution:
A solution used in a test, made up from concentrated stock solution.
Y
Yeast:
A unicellular fungus.
Z
Zygote:
The cell formed by the fertilization of a female cell by a male cell.