1.5 Bacteriology structure classification

Staining spirochaetes.

There is no net gain or loss in the number of bacterial cells.

Using a single loop sterilized in flame and cooled, or using disposable loops.

They are involved in the attachment process and protection against phages.

Streptococcus bacteria are spherical and form chains.

Organelles are specialized structures within a cell, and they are found in eukaryotic cells.

Culturing equipment.

Gram-negative bacteria do not trap crystal violet in their peptidoglycan and are stained by counterstaining (red).

Because their peptidoglycan layer does not trap the crystal violet.

Bacteria from the genera Bacillus and Clostridium are known for producing endospores.

The presence of the enzyme catalase, which breaks down hydrogen peroxide into water and oxygen.

Enriched media.

Purple or violet.

A modified Giemsa/Romanowsky staining method for rapid staining of bacterial morphology.

With neutral red.

To help bacteria attach to surfaces and protect against phages.

Biochemical tests are used commercially to identify and differentiate bacteria, often through automated systems or test kits like API strips.

The coagulase test is used to distinguish Staphylococcus species.

Yes, hemolysis can be specific for blood from certain hosts.

Place the slide in solution 1 for a few seconds.

In reference laboratories.

Gram-positive bacteria have peptidoglycan that binds crystal violet, resulting in a dark purple stain.

Red, due to counterstaining.

Prokaryotic cells do not have a nucleus, whereas eukaryotic cells do.

Gammaproteobacteria.

Bile and crystal violet.

Enterobacteriaceae.

Streptococcus, Enterococcus.

The presence of bubbles.

The capsule helps protect bacteria from phagocytosis and can aid in adherence to surfaces.

Spherical.

Flagella, lipopolysaccharides (LPS/LOS), and capsules.

It determines the susceptibility or resistance of bacteria to specific antimicrobials.

To determine if a bacterium produces cytochrome c oxidase.

Teichoic acid is present in Gram-positive bacteria and contributes to their ability to bind crystal violet.

To identify bacteria that produce the enzyme urease, which hydrolyzes urea into ammonia and carbon dioxide.

Acid-fast bacteria have a waxy cell wall that is resistant to decolorization by acids during staining procedures.

Shape and configuration.

To perform multiple biochemical tests simultaneously for the identification of bacteria.

To wash away the crystal violet-iodine complex from Gram-negative bacteria, but not from Gram-positive bacteria.

Pink or red.

The conversion of H2O2 to H2O and O2, indicated by bubbles.

To prevent contamination.

Complete hemolysis, incomplete hemolysis, and no hemolysis.

Bacilli (rods), Cocci (spherical), Spirochaetes, Vibrios (comma).

Staphylococcus bacteria are spherical and form clusters.

Approximately 4 degrees Celsius.

Phage-typing is based on susceptibility to a panel of bacteriophages.

Bacterial morphology refers to the shape and arrangement of bacterial cells.

Domain: Bacteria, Phylum: Proteobacteria, Class: Gammaproteobacteria, Order: Enterobacterales, Family: Enterobacteriaceae, Genus: Escherichia, Species: Escherichia coli.

It helps classify and understand the evolutionary relationships between different organisms.

Yes, endospores can return to their vegetative state through a process called germination when conditions become favorable again.

Enterobacteriaceae.

Alcohol or acetone.

Bacterial cells grow exponentially in ideal conditions.

Pseudomonas, Neisseria, Moraxella, Campylobacter.

Prokaryotes and Eukaryotes.

Dilute the bacteria.

Microscope, staining, and Bunsen burner.

Rod-shaped.

No hemolysis indicates that there is no lysis of red blood cells around the bacterial colony.

Microscopy, culture, and antigen/molecular tests.

An endospore is a dormant, tough, and non-reproductive structure produced by certain bacteria.

Nutrient agar and Mueller Hinton.

Escherichia.

Nutrient availability, temperature, pH, and oxygen levels.

Escherichia coli.

Some bacteria require CO2 for optimal growth conditions.

Retaining crystal violet staining and counterstaining.

Staining Mycobacteria.

Carbon dioxide.

Staphylococcus, Listeria, Enterobacteriaceae.

Campylobacter bacteria are spiral-shaped.

Pili or fimbriae are involved in attachment to surfaces and other cells, and can play a role in conjugation.

S. epidermidis and S. hominis test negative in the coagulase test.

Place the slide in solution 2 for a few seconds.

42 degrees Celsius.

Yes, bacteria may have a limited temperature range for growth.

Dark purple.

Nutrient media.

Endospores have a tough outer coating made of keratin, dehydration, DNA-protecting proteins, and other protective layers that make them resistant to extreme conditions such as heat, radiation, and chemicals.

The presence of the enzyme coagulase, which causes blood plasma to clot.

It helps in understanding the evolutionary relationships and classification of bacteria.

Escherichia coli.

Structures like pili, flagella, and capsules that can be used for identification.

To differentiate bacterial species into Gram-positive and Gram-negative based on the characteristics of their cell walls.

Iodine acts as a mordant that forms a complex with crystal violet, trapping it in the cell wall.

To fix the bacteria to the slide.

It indicates that the culture has reached its carrying capacity, with limited resources and space.

To provide a common language for describing findings and to organize bacteria based on their structure, function, and genetic relationships.

The bacterial population decreases.

To obtain single colonies.

Flagella are used for motility, allowing bacteria to move.

No, prokaryotic cells do not have a nucleus.

Mastitis.

They are all quite small in size.

Comma-shaped.

Meningitis.

Examples include cocci (spherical), bacilli (rod-shaped), and spirilla (spiral-shaped).

Thick bacterial envelopes typically refer to Gram-positive bacteria with a thick peptidoglycan layer, while thin envelopes refer to Gram-negative bacteria with a thin peptidoglycan layer and an outer membrane.

The enzyme lysozyme can degrade peptidoglycan.

Microscopy.

Media that is supplemented with specific substances, such as antibiotics, to select for certain bacteria.

It can help in differentiating and identifying bacterial species.

Lag phase, log (exponential) phase, stationary phase, and death (decline) phase.

No, it is not usable with all bacteria.

Because their thinner peptidoglycan layer and outer membrane allow the crystal violet-iodine complex to be washed away during decolorization.

Capnophiles.

API strips are used to combine multiple biochemical tests for the identification and differentiation of bacteria.

The coagulase test converts fibrinogen to fibrin.

Place a drop on the slide and let it air dry briefly.

Place the slide in fixative for a few seconds.

Hemolysis can be specific for blood from certain hosts.

Spiral-shaped.

Because optimal growth temperature and gas conditions are often related to the host or environmental niche, and they can affect the viability of the samples.

The optimal growth temperature is often related to the host or environmental niche of the bacteria.

Peptidoglycan assists in preventing phagocytosis.

Endospores form through a process called sporulation, which occurs when the bacterium encounters unfavorable conditions.

Proteobacteria.

The Gram staining technique is a method used to differentiate bacteria into Gram-positive and Gram-negative based on the structure of their cell walls.

Supplemented plates with antibiotics for Campylobacter.

Colony morphology such as rough/smooth texture and round/edged shape.

To provide additional nutrients and growth factors for certain bacteria.

Fuchsine or safranin.

Because of their thick peptidoglycan layer, which traps the crystal violet-iodine complex.

Because the number of bacteria doubles at a constant rate, leading to exponential growth.

Lactose-fermenters.

To selectively grow and identify specific types of bacteria based on their growth requirements and characteristics.

Flagella, Pili/Fimbriae, and Capsule.

Eukaryotic cells have a nucleus and organelles, while prokaryotic cells do not.

S. aureus and S. intermedius test positive in the coagulase test.

Complete hemolysis indicates the total lysis of red blood cells around the bacterial colony.

Serology is based on antisera to surface structures such as flagella, lipopolysaccharides (LPS/LOS), and capsules.

Let the excess liquid drain.

Prokaryotes and Eukaryotes.

Prokaryotes lack a nucleus and membrane-bound organelles, while eukaryotes have both.

Peptidoglycan gives rigidity to bacterial cells.

The bacterial envelope provides structural integrity and protection, and it plays a role in the bacterium's interaction with its environment.

Peptidoglycan can cause fever.

Blood agar, serum agar (whole blood, lysed blood, serum).

Gram-positive rods are rod-shaped bacteria that retain the crystal violet stain used in the Gram staining procedure, indicating a thick peptidoglycan layer in their cell walls.

A visible mass of microorganisms all originating from a single mother cell.

MacConkey agar.

Crystal violet.

Rapid cell division and exponential increase in the number of bacteria.

The initial condition of the bacteria, the composition of the growth medium, and environmental conditions.

It is used to test for Gram-negative bacteria based on cytochrome C oxidase.

The type of bacteria (thebac).

Using a single loop sterilized in flame and cooled, or using disposable loops.

To identify characteristics such as whether the colonies are mixed, smooth, or rough.

Spirochaete bacteria are spiral-shaped.

Incomplete hemolysis indicates partial lysis of red blood cells around the bacterial colony.

Wash the slide with distilled water.

Yes, a lot more variety is possible, including hyphae and combinations.

Genomic data.

The primary function of an endospore is to ensure the survival of the bacterium through periods of environmental stress.

Bacteria.

By using media that contain lactose and a pH indicator to detect acid production from lactose fermentation.

Electron acceptors and energy sources.

Enterobacterales.

Gram staining.

Bacteria adapt to their environment and prepare for cell division, but do not yet divide.

Nutrient depletion and accumulation of waste products cause the rate of cell death to exceed the rate of cell division.

Wet fixation.

Aerobic, facultative anaerobic, and microaerobic.

To obtain single colonies.

Media that differentiates bacteria based on their use of nutrients, such as the fermentation of sugars.

Binary fission.

The rate of bacterial cell growth equals the rate of cell death, leading to a stable population size.

They do not appear as Gram-positive in the staining process.

It can help in identifying and classifying bacteria based on their resistance or sensitivity.

Gram-positive and Gram-negative bacteria.

The bacterial cell replicates its DNA, elongates, and divides into two identical daughter cells.

To understand bacterial population dynamics, optimize growth conditions, and evaluate the effects of antibiotics.