Microbiology Chapter 5 Medical Bacteriology Part 3

H. pylori is the correct answer because it is a bacterium that is known to cause peptic ulcer disease. It is estimated that H. pylori infection is responsible for the majority of peptic ulcers. This bacterium can colonize the stomach lining and cause inflammation, leading to the development of ulcers. It is a common and important cause of peptic ulcer disease and is often treated with antibiotics to eradicate the infection and promote healing of the ulcers.

Patients with compromised immune systems are more susceptible to opportunistic infections. Opportunistic infections are caused by organisms that do not normally cause disease in individuals with healthy immune systems but can take advantage of a weakened immune system to cause infection. These infections can range from mild to severe and can be caused by various bacteria, viruses, fungi, or parasites. Therefore, the correct answer is "opportunistic infection."

The correct answer is B. pertussis because it is the bacterium that causes whooping cough, also known as pertussis. Whooping cough is a highly contagious respiratory infection that causes severe coughing fits, followed by a "whooping" sound when the person tries to breathe in. B. pertussis infects the respiratory tract and spreads through droplets when an infected person coughs or sneezes. Vaccination is an effective way to prevent whooping cough, but it can still occur in individuals who are not vaccinated or have waning immunity.

Venereal syphilis is caused by the bacterium T. pallidum. This bacterium is transmitted through sexual contact, including vaginal, anal, and oral sex. It can also be transmitted from mother to child during pregnancy or childbirth. T. pallidum enters the body through small breaks or tears in the skin or mucous membranes. It then multiplies and spreads throughout the body, causing various symptoms and complications if left untreated. Therefore, T. pallidum is the correct answer as it is the specific bacterium responsible for causing venereal syphilis.

A bacteria that induces the fermentation of a pus-like discharge containing polymorphonuclear leukocytes is referred to as pyogenic. Pyogenic bacteria are capable of causing the formation of pus, which is a thick fluid containing dead tissue, white blood cells, and bacteria. This type of bacterial infection often results in the characteristic symptoms of inflammation, such as redness, swelling, and pain.

A syphilitic lesion is called a chancre. A chancre is a painless ulcer that appears at the site of infection in the early stages of syphilis. It is typically round, firm, and often accompanied by swollen lymph nodes. The presence of a chancre is a primary symptom of syphilis and is highly contagious.

During the paroxysmal phase of Bordetella pertussis infections, cyanosis occurs. Cyanosis is the bluish discoloration of the skin or mucous membranes due to a lack of oxygen in the blood. This phase is characterized by severe coughing fits followed by a high-pitched intake of breath, known as the "whooping" sound. Cyanosis occurs during these coughing fits when the airways become narrowed, leading to a decrease in oxygen intake and subsequent cyanosis. The catarrhal phase, on the other hand, is characterized by mild respiratory symptoms and does not typically involve cyanosis.

During the catarrhal phase of Bordetella pertussis infections, the patient is highly infectious but not very ill. This phase is characterized by symptoms similar to the common cold, such as a runny nose, sneezing, and a mild cough. The bacteria can easily spread to others during this phase, making the patient highly contagious. However, the severity of the illness is not as pronounced as in the paroxysmal phase, where the patient experiences severe coughing fits. Therefore, the correct answer is catarrhal phase only.

Ischemic necrosis is caused by the presence of dermonecrotic toxin. This toxin is known to cause tissue death by damaging the cells and blood vessels in the affected area. It leads to a lack of blood supply and oxygen to the tissues, resulting in necrosis. Agglutinogens, filamentous hemagglutin, tracheal cytotoxin, and pertussis toxin do not directly cause ischemic necrosis, making them incorrect options.

H. pylori produces urease. Urease is an enzyme that breaks down urea into ammonia and carbon dioxide. H. pylori uses urease to neutralize the acidic environment of the stomach, allowing it to survive and colonize the gastric mucosa. This enzyme also contributes to the development of peptic ulcers and gastric cancer, as the ammonia produced by urease damages the gastric epithelium.

Filamentous hemagglutin facilitates the attachment to ciliated epithelial cells in the respiratory tract.

Tracheal cytotoxin causes an accumulation of mucus, bacteria, and inflammatory debris in the lungs. This toxin damages the cells lining the trachea, leading to increased mucus production and impaired clearance of bacteria and debris. This accumulation can result in respiratory infections and inflammation in the lungs.

A patient on a contraceptive pill is more likely to contract gonorrhea because some types of contraceptives can alter the vaginal pH balance and decrease the natural defenses against infections. This can create an environment that is more favorable for the growth and transmission of gonorrhea bacteria. Additionally, contraceptives may also reduce the use of barrier methods such as condoms, which can further increase the risk of contracting sexually transmitted infections like gonorrhea.

Gummas are localized dermal cancer-like lesions. They are a characteristic manifestation of tertiary syphilis, a late stage of the sexually transmitted infection caused by the bacterium Treponema pallidum. Gummas are soft, tumor-like growths that can occur in various parts of the body, including the skin, bones, and internal organs. These lesions can be destructive and cause significant damage if left untreated.

N. meningitidis is the correct answer because it is the only option that is capsulated. Capsulation refers to the presence of a protective capsule around the bacteria, which helps them evade the immune system and cause disease. N. gonorrhoeae does not have a capsule, making it incorrect. The option "both N. gonorrhoeae and N. meningitidis" is also incorrect as only N. meningitidis is capsulated. The option "none of the above" is also incorrect as N. meningitidis is capsulated.

L. pneumophila causes Pontiac fever. Pontiac fever is a mild respiratory illness that is similar to a flu-like illness. It is caused by the bacterium Legionella pneumophila, which is commonly found in water sources such as hot tubs, cooling towers, and plumbing systems. When people inhale aerosolized droplets containing the bacteria, they can develop Pontiac fever. Symptoms include fever, headache, muscle aches, and fatigue. Unlike Legionnaires' disease, which is a more severe form of infection caused by the same bacteria, Pontiac fever does not cause pneumonia.

Fibrotic walling-off is a process where fibrous tissue forms around an area of infection or inflammation in order to contain it and prevent its spread. In the case of primary lesion of Treponema pallidum, the fibrotic walling-off helps to contain the initial site of infection caused by the bacteria. This prevents the bacteria from spreading to other parts of the body and causing further damage. Therefore, fibrotic walling-off is resolved by the primary lesion of Treponema pallidum.

V. cholerae has an O-polysaccharide side chain of LPS. LPS, or lipopolysaccharide, is a molecule found on the outer membrane of Gram-negative bacteria. It consists of three components - lipid A, core polysaccharide, and O-polysaccharide. The O-polysaccharide side chain is variable among different bacterial species and can play a role in virulence and immune response. In the case of V. cholerae, the O-polysaccharide side chain is a characteristic feature of its LPS structure.

Hib stands for Haemophilus influenzae type b, which is a bacterium that can cause severe upper respiratory tract infections, such as pneumonia and meningitis. To prevent these infections, a vaccine called Hib vaccine is given. Therefore, the correct answer is Hib.

Pertussis toxin can lead to lymphocytosis and hypoglycemia. Pertussis toxin is produced by the bacteria Bordetella pertussis, which causes whooping cough. This toxin affects the immune system by inhibiting the function of lymphocytes, leading to an increase in their numbers in the blood (lymphocytosis). Additionally, pertussis toxin affects glucose metabolism in the body, leading to low blood sugar levels (hypoglycemia).