Bacteriology Random Questions Question

Bacillus cereus is a type of bacteria commonly found in soil and food. It can produce toxins that cause food poisoning when ingested. This bacterium is often associated with fried rice dishes from Chinese restaurants, as it can survive and multiply in cooked rice that is left at room temperature for too long. Symptoms of Bacillus cereus food poisoning include nausea, vomiting, abdominal cramps, and diarrhea. Therefore, Bacillus cereus is the most likely cause of food poisoning in this scenario.

Enterohemorrhagic E. coli O157:H7 is capable of causing hemolytic uremic syndrome (HUS). HUS is a condition characterized by the destruction of red blood cells, low platelet count, and kidney failure. Enterohemorrhagic E. coli O157:H7 produces a toxin called Shiga toxin, which damages the cells lining the blood vessels and can lead to HUS. This strain of E. coli is commonly associated with foodborne outbreaks, particularly from contaminated ground beef or raw milk. It is important to note that other strains of E. coli may also cause HUS, but in this case, enterohemorrhagic E. coli O157:H7 is specifically mentioned as the correct answer.

Splenectomised patients more prone to infection with CAPSULATED organism.

The bacterial capsule is an important protective mechanism for bacteria. It is a layer of polysaccharides or glycoproteins that surrounds the bacterial cell wall. The capsule helps bacteria to evade the host immune system by preventing phagocytosis, as well as providing protection against desiccation, antimicrobial agents, and environmental stresses. It also plays a role in the adherence of bacteria to surfaces and the formation of biofilms. The composition of the capsule can vary among different bacterial species, and it is not always composed of peptidoglycan. The gram stain reaction, on the other hand, is determined by the structure of the bacterial cell wall, not the capsule.

T for T

Buruli ulcer is caused by Mycobacterium ulcerans. This bacterium is known to produce a toxin called mycolactone, which damages the skin and subcutaneous tissues, leading to the development of ulcers. Peptostreptococcus and S. aureus are not associated with Buruli ulcer. Therefore, the correct answer is Mycobacterium ulcerans.

Both Helicobacter pylori and Campylobacter are microaerophilic organisms. Microaerophiles are organisms that require low levels of oxygen to survive and grow. They cannot tolerate high levels of oxygen like aerobes, but also cannot survive in the absence of oxygen like anaerobes. Helicobacter pylori is a bacterium that colonizes the human stomach and is associated with various gastrointestinal diseases. Campylobacter is a genus of bacteria that can cause foodborne illnesses in humans. Both of these organisms have adapted to survive in environments with low oxygen levels, making them microaerophilic.

The 'O' in O157:H7 indicates the presence of cell wall lipopolysaccharide. Lipopolysaccharide is a major component of the outer membrane of Gram-negative bacteria, including Escherichia coli O157:H7. It plays a crucial role in maintaining the structural integrity of the cell wall and also acts as an endotoxin, triggering an immune response in the host. Therefore, the presence of cell wall lipopolysaccharide is indicated by the 'O' in the O157:H7 strain.

Y. pseudotuberculosis can cause reactive arthritis, mesenteric adenitis, and an appendicitis-like clinical picture. This means that it can lead to any of these conditions. Reactive arthritis is an inflammatory joint condition that can occur after an infection, mesenteric adenitis is inflammation of the lymph nodes in the abdomen, and an appendicitis-like clinical picture refers to symptoms similar to those of appendicitis. Therefore, Y. pseudotuberculosis can cause any of these conditions.

Satellitism is a phenomenon where a bacterium requires the presence of another bacterium for its growth. In the case of H.influenzae, it requires the presence of Staphylococcus aureus for its growth. This is because H.influenzae lacks the ability to produce certain essential growth factors, such as NAD (nicotinamide adenine dinucleotide), on its own. Staphylococcus aureus can produce and release NAD into the surrounding environment, which H.influenzae can then utilize for its growth. This relationship between the two bacteria is an example of satellitism.

The most common cause of acute osteomyelitis is Staphylococcus aureus. Staphylococcus aureus is a type of bacteria that commonly resides on the skin and can enter the body through a cut or wound, leading to infection in the bones. It is known to be a major cause of osteomyelitis, especially in children. Other bacteria such as Streptococcus, Salmonella, and Pseudomonas can also cause osteomyelitis, but they are less common compared to Staphylococcus aureus.

Tetanospasmin is the toxin responsible for tetanus. Tetanolysin is hemolytic.

alpha or Lecithinase

Bacillus anthracis is the correct answer because its capsule is made up of amino acids. The bacterial capsule is a protective layer outside the cell wall, and it is composed of various substances including polysaccharides, proteins, and amino acids. In the case of Bacillus anthracis, its capsule is primarily composed of amino acids. This capsule helps the bacterium evade the host's immune system and contributes to its pathogenicity.

The false statement regarding chlamydia is that the reticulate body is the infectious form. In reality, the elementary body is the infectious form of chlamydia. The elementary body is the extracellular form and is responsible for infecting host cells. The reticulate body, on the other hand, is the intracellular form of chlamydia and is involved in replication within the host cells.

Vibrio parahaemolyticus directly invade the epithelium.

The Castaneda method is used for Brucella. This method involves the use of selective media, such as Farrell's medium or Castaneda's medium, which provide optimal conditions for the growth and isolation of Brucella bacteria. These media contain specific nutrients and inhibitors that suppress the growth of other bacteria and allow for the selective growth of Brucella. By using this method, Brucella can be successfully isolated and identified from clinical samples, aiding in the diagnosis and treatment of brucellosis, a bacterial infection caused by Brucella species.

The correct answer is "Any of the above". Siderophilic bacteria are those that have an affinity for iron and can cause infections in individuals with hemochromatosis, a condition characterized by excessive iron absorption. Listeria monocytogenes, Vibrio vulnificus, and Yersinia enterocolitica are all examples of siderophilic bacteria that can potentially cause infections in people with hemochromatosis.

The Ames test is a widely used method to determine the mutagenic nature of chemicals or substances. It involves exposing a strain of Salmonella bacteria to a potential mutagen and observing whether it causes genetic mutations in the bacteria. If the substance being tested is mutagenic, it will cause mutations in the bacteria's DNA, which can be detected through various genetic markers. The Ames test is an important tool in assessing the potential carcinogenicity of substances and is commonly used in toxicology and cancer research.

The correct answer is 1. ampicillin & clindamycin, 2. C.difficle, 3. Metronidazole & Vancomycin. Pseudomembranous colitis is caused by the overgrowth of Clostridium difficile (C.difficle) in the colon, often as a result of antibiotic use. Ampicillin and clindamycin are antibiotics that can disrupt the normal gut flora and allow C.difficle to flourish. Metronidazole and Vancomycin are commonly used to treat C.difficle infections. Therefore, the correct answer includes the drugs responsible for causing the condition, the organism responsible, and the appropriate treatment options.

Acenetobacter boumani is not a member of the HACEK group of organisms. The HACEK group is a group of bacteria that are commonly associated with infective endocarditis, a serious infection of the heart valves. The HACEK group includes Haemophilus aphrophilus, Cardiobacterium hominis, and Eikenella corrodens, but not Acenetobacter boumani.

Frequently asked question !!

The correct answer is Adenylate cyclase. Oedema factor is a component of anthrax toxin that acts as an adenylate cyclase enzyme. It catalyzes the conversion of ATP to cyclic AMP (cAMP) within the host cell, leading to an increase in cAMP levels. This increase in cAMP disrupts cellular signaling pathways and impairs the immune response, contributing to the pathogenicity of anthrax.

GM1 ganglioside is the receptor for Cholera Toxin on epithelial cells. Cholera toxin binds to GM1 ganglioside on the cell surface, allowing the toxin to enter the cell. Once inside, the toxin activates adenylate cyclase, leading to increased cyclic AMP levels and subsequent secretion of chloride ions and water into the intestinal lumen, resulting in the characteristic watery diarrhea seen in cholera infection.

The Sereny test is performed to determine the invasiveness of enteroinvasive E. coli (EIEC) strains. EIEC is known to invade and multiply within the intestinal epithelial cells, causing invasive diarrhea. The Sereny test involves inoculating the bacteria onto the conjunctiva of guinea pigs and observing for the development of keratoconjunctivitis, which is characteristic of EIEC infection. This test helps in differentiating EIEC from other pathogenic E. coli strains that do not exhibit invasiveness.

Gas gangrene is a severe and potentially life-threatening infection caused by certain species of Clostridium bacteria. These bacteria are known to produce toxins that destroy tissue and create gas bubbles in the infected area. Cl. perfringens, Cl. novyi, Cl. septicum, and Cl. histolyticum are all species of Clostridium that can cause gas gangrene. Therefore, the correct answer is "All of the above" as all of these species can lead to the development of gas gangrene.

LCL (Levinthal-Cole-Lillie) bodies are seen in infection with Chlamydophila psittaci.