Untitled Quiz

Bacterial Susceptibility and Antibiotics

• A bacterial strain is considered susceptible to an antibiotic if MIC: TC is 8:4 or 8:32.
• Rifampicin inhibits the synthesis of nucleic acid.

Anaerobic Conditions

• Anaerobic conditions are created by mechanical, physical, chemical, and biological methods.

Bacteriological Methods

• At the third step of bacteriological method, the workload includes study of culture character and susceptibility test (antibiotic).
• At the second step of isolation of aerobic culture, the workload includes study of morphotinctorial character and study of culture features.

Bacterial Shapes

• Bacteria with elongated shapes include E. coli, Bacillus subtilis, Clostridium tetani, Mycobacterium tuberculosis, Salmonella enterica, Listeria monocytogenes, and Corynebacterium diphtheriae.

Bacteriophages

• Bacteriophages attach to specific receptors on the cellular wall of bacteria, cytoplasmic membrane, or pilus.

Culture Media

• Culture media must be sterile, nutritious, and have a certain potential redox.
• The concentration of agar to obtain semi-solid media is around 0.5-1.5%.

Sterilization

• Autoclaving is performed at temperatures of 121°C for 15-30 minutes or 134°C for 5-10 minutes.
• Sterilization is indispensable for instruments that penetrate the outer layers of the organism and tissues.

Microbial Aggression

• Structural factors that provide microbial aggression include pili, glycocalyx, and surface antigens.

Bacterial Cell Wall

• The cell wall contains peptidoglycan and is essential for the bacterial cell.
• Bacteria with defective cell walls include protoplasts, spheroplasts, and L-forms.

Bacterial Motility

• Methods of studying bacterial motility include dark field microscopy, phase-contrast microscopy, and electron microscopy.

Prokaryotic Cells

• Prokaryotic cells have 70S ribosomes, no nuclear membrane, and contain mesosomes.
• The genetic system is located in the prokaryotes in the nucleoid.

Bacterial Spores

• The arrangement of bacterial spores in the cell can be terminal, bipolar, subterminal, or central.

Antibody Production

• IgM immunoglobulins are the first to appear after antigenic stimulus, opsonize for phagocytosis, and are sensitive to cysteine.
• IgA immunoglobulins protect the mucosal layer against microbial aggression and are produced by plasmocytes.

Virulence

• Virulence is the ability of an organism to infect the host and cause disease.
• Virulence factors are molecules that assist the bacterium in colonizing the host at the cellular level.