Bacteriology Anaerobes Quiz Part 2

Patients suspected of having antibiotic associated diarrhea or pseudomembranous colitis may have C. difficile identified by growth on CCFA agar or by detection of the toxin by EIA or latex agglutination. C. difficile is a bacterium that can cause inflammation of the colon and lead to diarrhea. It is commonly associated with antibiotic use, as antibiotics can disrupt the normal balance of bacteria in the gut, allowing C. difficile to overgrow. The presence of C. difficile can be confirmed by culturing it on CCFA agar or by detecting its toxin using EIA or latex agglutination tests.

A double zone of hemolysis on anaerobic blood agar is suggestive of C. perfringens. This bacterium is known for its ability to produce two distinct zones of hemolysis due to the presence of two different hemolytic toxins. The outer zone of complete hemolysis is caused by the alpha toxin, while the inner zone of partial hemolysis is caused by the theta toxin. This characteristic hemolytic pattern is a key diagnostic feature of C. perfringens.

An alternative to an anaerobic chamber or anaerobic jar is an anaerobic bag. This bag is specifically designed to create an oxygen-free environment, allowing for the growth and study of anaerobic organisms. The bag is usually made of a gas-impermeable material and has a gas-generating system inside, which produces an anaerobic atmosphere when activated. It provides a convenient and cost-effective solution for conducting anaerobic experiments without the need for specialized equipment like chambers or jars.

A catalase test using 15% H2O2 can be done to determine the presence of catalase enzyme in a sample. This test is useful for identifying the B. fragilis group, as they are known to produce catalase. Catalase is an enzyme that breaks down hydrogen peroxide into water and oxygen, and the production of catalase can be a characteristic feature of certain bacterial species. Therefore, performing a catalase test with 15% H2O2 can help in the identification of the B. fragilis group.

Bacteroides are gram-negative coccobacilli or bacilli. This means that they do not retain the crystal violet stain during the Gram staining process, indicating that their cell walls have a thin peptidoglycan layer. Bacteroides are commonly found in the human gut and are involved in various physiological processes, including digestion and immune system regulation.

Actinomyces should be suspected if Gram positive, irregular staining causing a beaded or banded appearance in addition to branching or filamentous rods. This is because Actinomyces is a genus of bacteria that are known for their filamentous growth pattern and irregular staining. They often appear as branching or beaded rods under the microscope. Perfringens and B. fragilis are not typically associated with this staining pattern, so they are not the correct answers.

The correct answer is Anaerobic Jar. Anaerobic jars are used to create an oxygen-free environment for the growth of anaerobic bacteria. However, a disadvantage of using anaerobic jars is that they need to be opened and the plates removed in order to be examined. This can introduce oxygen into the jar, disrupting the anaerobic conditions and potentially affecting the growth of anaerobic bacteria.

Labs using anaerobic jars usually wait for 48 hours before opening. This is because slower growing anaerobes will be too small and even a short exposure to oxygen may kill them. Waiting for 48 hours ensures that the slower growing anaerobes have had enough time to grow to a size where they can withstand exposure to oxygen without being killed.

Clostridium septicum is a bacterium that is commonly associated with colon cancer. It is known to cause infections in individuals with colon cancer, specifically in cases where the cancer has spread to other parts of the body. The presence of Clostridium septicum in a patient with colon cancer may indicate a more advanced stage of the disease. Therefore, the correct answer to the question is colon cancer.

The double zone produced by Clostridium perfringens is due to two different hemolysins. The outer zone is characterized by partial Beta hemolysis.

The double zone produced by Clostridium perfringens is due to two different hemolysins. The inner zone is complete Beta hemolysis.

Anaerobic Specimens are collected from a warm, moist environment so they must not be refrigerated.

Mobiluncus is a type of bacteria that is commonly found in cases of bacterial vaginosis. These bacteria are known to have a curved shape, which is why they are described as "curved" in the answer choice. Additionally, when performing a Gram staining test, Mobiluncus bacteria do not retain the crystal violet dye, further supporting the statement that they are "curved" and do not retain the dye.

The correct answer is "anaerobius". Sodium polyanethol sulfonate disk is a commonly used test to presumptively identify the most common anaerobic Gram-positive coccus, which in this case is P. anaerobius. This test is based on the ability of P. anaerobius to produce a black precipitate when it reacts with the disk. The other options, "cystics" and "aeruginos", are not relevant to the identification of P. anaerobius.

If the colony only grows anaerobically, it is an anaerobe; if the colony grows both aerobically and anaerobically, the colony is not a true anaerobe but a FACULTATIVE anaerobe.

Most of the genus Prevotella produce protoporphyrin, a dark pigment that causes the colonies to turn brown to black with age; are sensitive to bile.

Veillonella species is a very small pathogenic Gram negative cocci that inhabits the oral cavity. These bacteria are commonly found in dental plaque and can contribute to the development of dental caries and periodontal diseases. They thrive in the oral cavity due to the availability of nutrients and the presence of other bacteria that create a suitable environment for their growth. Therefore, the oral cavity is the most appropriate habitat for Veillonella species.

A boxcar shaped Gram positive anaerobic rod that produces a double zone of hemolysis on anaerobic blood agar can be presumptively identified as Clostridium perfringens.

The correct answer is Anaerobic Bag. Anaerobic bags are used in microbiology to create an anaerobic environment for the growth of bacteria. They are typically made of a gas-impermeable material and contain a gas-generating system that removes oxygen and creates an anaerobic atmosphere. By looking through the bag, one can examine if there is any growth of bacteria. If no growth is seen, it indicates that the anaerobic conditions have been maintained and there is no need to open the bag and expose it to oxygen.

The correct answer is Anaerobic bag. An anaerobic environment is achieved faster using an anaerobic bag because it creates a sealed chamber where oxygen is removed and replaced with a gas mixture that supports anaerobic conditions. The bag provides a more efficient and controlled method for creating anaerobic conditions compared to an anaerobic jar or chamber.

Prevotella are similar to Bacteroides on Gram stain, which means they both appear as gram-negative bacteria. When exposed to long-wave UV light, Prevotella bacteria will fluoresce brick-red. This fluorescence is a characteristic feature of Prevotella and can help in their identification and differentiation from other bacteria.

Veillonella is the correct answer because it is the only indigenous anaerobic Gram negative cocci that is considered a pathogen. Bacteroides fragilis and Porphyromonas gingivalis are both anaerobic Gram negative bacteria, but they are not cocci. Veillonella, on the other hand, is a cocci-shaped bacterium and is known to cause infections in humans, particularly in the oral cavity and respiratory tract.

Anaerobic cultures can be held anywhere from 3 to 7 days, particularly if a slow growing anaerobe is suspected. This time frame allows for the proper growth and identification of anaerobic bacteria, which can take longer compared to aerobic bacteria. Holding the culture for a longer period of time, such as 14-21 days, may not be necessary and could increase the risk of contamination or overgrowth of other organisms.

Porphyromonas are Gram negative rods that produce a brick-red fluorescence and are sensitive to bile. This means that when exposed to certain wavelengths of light, Porphyromonas bacteria will emit a brick-red color. Additionally, these bacteria are sensitive to bile, which means that they are affected or inhibited by the presence of bile.

In an anaerobic jar, the indicator starts off as blue. However, when an anaerobic environment is achieved, the indicator changes to white. This change in color indicates the absence of oxygen in the jar, which is characteristic of an anaerobic environment.

The major disadvantage of using the Anaerobic jar is that it takes 30-45 minutes for an anaerobic environment to be achieved. This means that it takes a significant amount of time for the jar to create the necessary conditions for anaerobic growth. This can be inconvenient for researchers who need to quickly establish an anaerobic environment for their experiments or studies.

The correct answer is blue or green. The spot indole test using p-dimethylaminocinnamaldehyde is a biochemical test used to detect the presence of indole, which is a byproduct of the metabolism of tryptophan by certain bacteria. When indole is present, it reacts with p-dimethylaminocinnamaldehyde to produce a blue or green color. Therefore, if a blue or green color is produced during the test, it indicates the presence of indole.

A swarming Gram positive anaerobic rod with subterminal spores is most likely C. septicum. This bacterium is known to exhibit swarming behavior, meaning it can move rapidly across a surface. It is also Gram positive, indicating that it retains the crystal violet stain in the Gram staining procedure. The presence of subterminal spores suggests that the spores are located near the end of the bacterial cell.