Microbiology - Marrow Edition 8 Lecture Review

Comprehensive vocabulary flashcards covering general microbiology, bacteriology, immunology, virology, parasitology, and mycology based on the Marrow Edition 8 lecture notes.

Light Microscope Resolution

The ability to distinguish two separate points, which for this type of microscope is $0.2\,\mu\text{m}$.

Dark Field Microscope Modification

A type of microscope where the condenser lens has a central opaque light stop, illuminating the specimen with a hollow cone of light resulting in a bright organism against a dark background.

Calcofluor White

A fluorophore used in fluorescent microscopy that binds specifically to chitin in fungal cell walls.

Secondary Electrons

Particles released in a Scanning Electron Microscope when a specimen is stained with vaporized gold or palladium to create an image of the topography.

Gram Stain Mordant

Iodine, which functions to fix the primary stain (Crystal violet) to the bacterial structures.

Acid Fastness Principle

A staining property typically seen in mycobacteria due to a lipid-rich cell wall that prevents reagents from penetrating unless heat or high concentrations of phenol are applied.

Kinyoun Stain

Also known as the cold stain or Gabbet stain, it is a modification of the Ziehl-Neelson stain that omits the heating step post-primary stain.

Metachromatic Granules

Also known as volutin or Babes Ernst granules, these act as energy stores and are seen in species like Corynebacterium and Yersinia pestis.

Mycoplasma

The only prokaryote lacking a cell wall and containing sterols in its cell membrane.

Capsular Polypeptide

A unique capsule composed of a polymer of $\text{D-glutamic}$ acid found only in Bacillus anthracis.

Quellung Reaction

A biochemical reaction where the capsule swells upon the addition of specific anticapsular antibodies.

Peptidoglycan Composition

The structural component of the cell wall made of a murein backbone linked by $\text{N-acetyl muramic acid (NAM)}$ and $\text{N-acetyl glucosamine (NAG)}$.

Lipid A

The innermost layer of Lipopolysaccharide (LPS) in gram-negative bacteria that features the actual endotoxic activity.

L-forms

Cell wall-deficient bacteria formed spontaneously or due to cell wall inhibitors like penicillin, which are pleomorphic and contribute to persistence of infections.

Dipicolinic Acid

A chemical substance present in the spore core that is responsible for the heat resistance of bacterial spores.

MIC ($\text{Minimum Inhibitory Concentration}$)

The lowest concentration of an antibiotic that just inhibits the visible growth of a bacterium.

Autotrophs

Chemotrophs that synthesize energy by using atmospheric gases such as $N_2$ and $CO_2$.

Enriched Media

Simple media supplemented with serum, egg, or blood to support the growth of fastidious bacteria.

TCBS ($\text{Thiosulphate Citrate Bile Salt Sucrose}$) Medium

A selective and differential medium specific for sucrose-fermenting Vibrio, where bromothymol blue is used as the indicator.

Generation Time

The population doubling time required for one binary fission, which is $20\,\text{mins}$ for E. coli but $20\,\text{days}$ for M. leprae.

Lag Phase

The stage of adaptation in the bacterial growth curve where bacteria are metabolically active but there is no multiplication and the bacterial size is maximum.

Hfr ($\text{High frequency recombinant}$) Conjugation

A gene transfer process where the F plasmid is integrated into the bacterial chromosome.

BSL-IV ($\text{Biosafety Level 4}$)

The highest safety level reserved for serious hazards with a high risk of aerosol transmission of life-threatening diseases for which no vaccine is available, such as Ebola or Lassa fever.

Sterilization

The process of destruction of all forms of life, including bacterial spores.

Autoclave Parameters

Standard sterilization requires $121\,^\circ\text{C}$ for $15-20\,\text{minutes}$ under pressure of $15\,\text{psi}$.

Spaulding Classification: Critical Devices

Medical devices that enter sterile tissue or the vasculature, such as surgical instruments or implants, requiring heat sterilization or high-level disinfection.

Protein A

A cell wall-associated factor in S. aureus that is antiphagocytic and binds to the Fc portion of IgG.

Panton-Valentine Leukocidin ($\text{PVL}$) Toxin

A synergohymenotropic toxin secreted by S. aureus with strong leucocidal activity, often associated with community-acquired MRSA.

Optochin Sensitivity

A biochemical test used to identify Streptococcus pneumoniae, which shows a zone of inhibition around the disk.

M Protein

A filamentous protein in the cell wall of Streptococcus pyogenes that is antiphagocytic, anticomplementary, and used for Griffith typing.

Diphtheria Toxin Mechanism

Inhibition of protein synthesis by the ADP ribosylation of elongation factor-2 ($EF-2$).

McFadyean's Reaction

A staining reaction for Bacillus anthracis using polychrome methylene blue that reveals pink amorphous material around blue bamboo-stick bacilli.

Listeriolysin O ($\text{LLO}$)

A virulence factor of Listeria monocytogenes that causes the lysis of the endosome to allow replication in the cytosol.

Nagler Reaction

An identification test for Clostridium perfringens on egg yolk agar that demonstrates opacification due to lecithinase ($\alpha\text{-toxin}$) activity.

Botulinum Toxin Mechanism

Proteolysis of SNARE proteins, which inhibits the release of Acetylcholine ($Ach$) at the neuromuscular junction, leading to flaccid paralysis.

Tetanospasmin

A plasmid-mediated toxin that cleaves synaptobrevin to inhibit the release of GABA and Glycine, resulting in spastic paralysis.

Mantoux Test

A screening test for TB involving the intradermal injection of Purified Protein Derivative ($\text{PPD}$) to look for an induration after $48-72\,\text{hrs}$.

Thayer Martin Media

A selective medium used for the growth of pathogenic Neisseria, containing Vancomycin, Colistin, and Nystatin.

Shiga Toxin Mechanism

The toxin inhibits protein synthesis through the proteolysis of the $60S$ ribosome.

HRP-II ($\text{Histidine-rich protein-II}$)

A specific antigen detected in Malaria Rapid Diagnostic Tests ($\text{mRDTs}$) to identify Plasmodium falciparum.

Negri Bodies

Eosinophilic, cytoplasmic inclusion bodies seen diagnostic of Rabies, typically found in the hippocampus and cerebellum.

Thermal Dimorphism

A property of certain fungi where they exist as yeast at $37\,^\circ\text{C}$ (body temperature) and hyaline septate mould at room temperature.

Jones Criteria

A set of clinical markers (major and minor) used for the diagnosis of Acute Rheumatic Fever following a Group A Streptococcal infection.

Kass Definition

The criteria for 'Significant Bacteriuria,' typically defined as $\ge 10^5\,\text{CFU/mL}$ in a clean catch mid-stream urine sample from an asymptomatic individual.