Clinical Bacteriology – Lesson 2 Vocabulary

Vocabulary flashcards covering historical milestones, cell structure, physiology, genetics, control, specimen handling, and culture media from Clinical Bacteriology Lesson 2.

Compound microscope

First multi-lens microscope, developed by Hans Jansen (1590-1595).

Animalcules

Microscopic life forms first observed by Antonie van Leeuwenhoek in 1676.

Smallpox immunization

Protection produced by Edward Jenner (1798) through cowpox inoculation.

Cell theory

Concept by Schwann & Schleiden (1838-1839) that all living things are composed of cells.

Theory of biogenesis

Rudolf Virchow’s 1858 idea that life arises only from pre-existing life.

Aerobic organism

Microbe that requires oxygen for metabolism (term popularized by Pasteur, 1861).

Anaerobic organism

Microbe that grows without oxygen (term popularized by Pasteur, 1861).

Attenuated strain

Weakened microbe used in vaccine development (Pasteur, 1880).

Anthrax vaccine

First bacterial vaccine, created by Louis Pasteur in 1881.

Rabies vaccine

Vaccine produced by Louis Pasteur in 1885.

Antiseptic surgery

Joseph Lister’s 1867 technique using phenol to prevent surgical infection.

Germ theory

Robert Koch’s 1882 proposal that specific microbes cause specific diseases.

Koch’s postulates

Four criteria published in 1882 for linking a microbe to a disease.

Phagocytosis

Process of cell ‘eating’ described by Elie Metchnikoff in 1884.

Gram stain

Differential stain introduced by Hans Christian Gram in 1884.

Petri dish

Glass plate for culturing microbes, devised by Julius Richard Petri (1887).

Antitoxin

Serum factors against diphtheria and tetanus prepared by Emil von Behring (1890).

Complement

Heat-labile serum factor discovered by Jules Bordet (1895) that aids antibody action.

Autoclave

Steam under pressure device (developed 1884) for sterilization at 121 °C, 15 psi.

Blood group system

ABO typing discovered by Karl Landsteiner in 1901.

Treponema pallidum

Spirochete identified by Schaudinn & Hoffmann (1906) as the cause of syphilis.

Chemotherapeutic agent for syphilis

Paul Ehrlich’s 1910 arsenical drug, Salvarsan (arsphenamine).

Prokaryote

Cell lacking membrane-bounded nucleus; term formalized by Chatton (1937).

Eukaryote

Cell with a true nucleus and organelles; counterpart to prokaryote.

Archaeobacteria

Ancient prokaryotic group recognized as separate domain in 1976.

Streptomycin

First aminoglycoside antibiotic, discovered by Selman Waksman in 1944.

Penicillin

β-lactam antibiotic from Penicillium mold, discovered by Alexander Fleming (1945 award).

DNA structure

Double-helix model described by Watson & Crick in 1953.

Radioimmunoassay

Sensitive hormone/antigen detection method by Yalow & Berson (1954).

Polymerase Chain Reaction (PCR)

DNA amplification technique invented by Kary Mullis (1983-1984).

Bacterial taxonomy

Formal system for organizing and naming bacteria.

Binomial nomenclature

Linnaean two-name system (Genus species) governed by the Bacteriological Code.

Genus

First, capitalized part of a bacterial scientific name (e.g., Staphylococcus).

Species epithet

Second, lower-case part of a bacterial name (e.g., aureus).

Prokaryotic cell

Cell with nucleoid DNA, 70 S ribosomes, and no membrane-bound organelles.

Eukaryotic cell

Cell containing nucleus, 80 S ribosomes, mitochondria, ER, etc.

Nucleoid

Diffuse, membrane-free DNA region in prokaryotes; usually a single circular chromosome.

70 S ribosome

Prokaryotic ribosome (50 S + 30 S subunits) free in cytoplasm.

Endospore

Dormant, highly resistant bacterial structure formed under stress (e.g., Bacillus).

Peptidoglycan

Main rigid polymer of Gram-positive cell wall (also in Gram-negatives thinner).

Teichoic acid

Polymers in Gram-positive walls contributing to charge and antigenicity.

Lipopolysaccharide (LPS)

Outer-membrane molecule unique to Gram-negative bacteria; contains lipid A, core, O antigen.

Lipid A

Endotoxic component of LPS responsible for fever and shock.

Autotroph

Organism that uses CO₂ as sole carbon source.

Heterotroph

Organism requiring organic carbon (e.g., glucose) for growth.

Fastidious organism

Bacterium needing extra nutrients such as vitamins or blood factors.

Psychrophile

Bacterium that grows best at 10-20 °C.

Mesophile

Bacterium thriving at 20-40 °C; includes most human pathogens (37 °C).

Thermophile

Organism growing optimally at 50-60 °C.

Obligate aerobe

Requires oxygen for growth.

Facultative anaerobe

Can grow with or without oxygen, switching metabolism accordingly.

Capnophilic organism

Requires increased CO₂ (e.g., 5-10 %) for optimal growth.

Binary fission

Asexual bacterial reproduction where one cell divides into two.

Lag phase

Adaptation period with little division after inoculation into fresh medium.

Log phase

Exponential bacterial growth and constant generation time.

Stationary phase

Growth rate equals death rate; nutrients deplete, toxins accumulate.

Plasmid

Extrachromosomal circular DNA carrying optional traits (e.g., drug resistance).

Transposon

Mobile DNA element that can move within or between genomes.

Point mutation

Single-base change in DNA; includes missense or nonsense types.

Missense mutation

Base substitution leading to a different amino acid in a protein.

Nonsense mutation

Base substitution creating a stop codon, truncating protein synthesis.

Transformation

Uptake of naked DNA by a bacterial cell.

Transduction

Bacteriophage-mediated transfer of bacterial genes.

Conjugation

Plasmid or chromosomal gene transfer requiring cell-to-cell contact via sex pilus.

Sterilization

Complete destruction/removal of all microbial life, including spores.

Disinfection

Reduction/elimination of pathogenic microbes, not necessarily spores.

Antiseptic

Disinfectant safe for application to living tissue.

Incineration

Dry-heat sterilization by burning material to ash at 870-980 °C.

Pasteurization

Heat treatment (63 °C 30 min or 72 °C 15 s) to kill pathogens in fluids.

HEPA filter

High-Efficiency Particulate Air filter removing ≥99.97 % of 0.3 µm particles.

Biosafety Level 2 (BSL-2)

Containment for moderate-risk pathogens (HBV, HIV); requires Class I/II BSC and PPE.

Gram-positive cell wall

Thick peptidoglycan with teichoic acids; stains purple with Gram stain.

Gram-negative cell wall

Thin peptidoglycan plus outer membrane containing LPS; stains pink.

Crystal violet

Primary dye in Gram stain that initially colors all cells purple.

Acid-fast stain

Carbolfuchsin-based method to detect mycolic-acid-rich bacteria like Mycobacterium.

Kinyoun method

Cold acid-fast staining procedure using high detergent concentration.

Ziehl-Neelsen method

Hot acid-fast staining procedure employing heat to drive dye in.

Auramine-rhodamine stain

Fluorochrome acid-fast stain; positive cells fluoresce yellow-orange.

Pure culture

Culture containing a single microbial species.

Selective media

Contains inhibitors allowing only certain microbes to grow.

Differential media

Shows visible differences among organisms (e.g., hemolysis on blood agar).

Enriched media

Base medium with added growth enhancers for fastidious bacteria.

Blood agar (BA)

Non-selective enriched differential medium showing hemolysis patterns.

Chocolate agar

Heated blood agar supporting Haemophilus and Neisseria; not differential.

Thayer-Martin agar

Chocolate agar with vancomycin, colistin, nystatin (and trimethoprim in MTM) selective for Neisseria.

Martin Lewis agar

Selective medium with vancomycin, colistin, anisomycin for Neisseria species.