Week 4 Flashcards
What is the standard media to grow Haemophilus influenzae?
chocolate agar
Haemophilus influenzae requires chocolate agar to grow. This medium has the necessary elements such as factor V (NAD) and factor X (hematin).
What are some infections caused by Haemophilus influenzae?
Haemophilus influenzae can cause epiglottitis, otitis media, and meningitis. While the other diseases listed can be bacteria-related, they are not typically associated with this bacteria.
Which strains of Haemophilus influenzae are commonly associated with causing meningitis?
Type B
When is the most appropriate time to vaccinate children against Haemophilus influenzae?
2 and 18 months
What type of bacteria is Haemophilus influenzae?
Gram-negative
The filamentous hemagglutinin in Bordetella pertussis is responsible for which function?
attachment to the respiratory epithelium
What is the primary method of transmission for Bordetella pertussis?
respiratory droplets
Legionnaires’ disease (caused by Legionella pneumophila) may present with low levels of what in the blood?
hyponatremia
What laboratory test might be performed for a rapid diagnosis of Legionnaires’ disease?
urine antigen test
What are the primary components found in the growth media agar for Legionella pneumophila?
cysteine, iron, buffered charcoal
Which stain is necessary in order to visualize Legionella pneumophila?
silver stain
What kind of bacteria is Brucella?
gram-negative
Which of the following is the most common reservoir for Brucella?
farm animals
What is a common reservoir for Francisella tularensis?
rabbits
Which of the following does Yersinia pestis cause when it establishes infection in humans?
Yersinia pestis, the bacterium responsible for causing bubonic and pneumonic plague, causes lymphadenopathy in humans. Lymphadenopathy refers to the swelling of lymph nodes, which is a characteristic feature of bubonic plague. The bacteria enter the lymphatic system and cause inflammation of the lymph nodes, leading to painful, enlarged buboes.
Bacillary angiomatosis is a disease caused by Bartonella henselae. This condition typically affects people who:
Bacillary angiomatosis, caused by Bartonella henselae, predominantly affects immunocompromised individuals, particularly those living with HIV/AIDS.
Besides fever and a history of a cat scratch, what is a common presentation of cat scratch disease?
Cat-scratch disease frequently presents with swollen regional lymph nodes, especially in the axilla. This is in addition to fever and usually a history of a cat scratch or bite.
What effect does severely low magnesium (Mg2+) levels have on PTH secretion?
Severely low levels of magnesium (Mg2+) inhibit PTH secretion. While magnesium plays less of a role in the regulation of PTH than calcium (Ca2+), its levels still influence PTH release. Normally, low Mg2+ results in increased PTH release; however, when Mg2+ levels are extremely low, it paradoxically inhibits PTH secretion. This inhibition can exacerbate hypocalcemia, as PTH is necessary for maintaining normal blood calcium levels.
How does PTH influence vitamin D metabolism?
Parathyroid hormone (PTH) promotes the conversion of vitamin D into its active form, calcitriol (1,25-dihydroxyvitamin D3), in the kidneys. This active form then facilitates increased calcium absorption in the intestines, contributing to the regulation of blood calcium levels.
How does parathyroid hormone (PTH) affect phosphate homeostasis in the body?
PTH regulates phosphate homeostasis primarily by increasing its excretion in the urine. It achieves this by inhibiting the reabsorption of phosphate in the proximal convoluted tubule of the kidney. This action, known as phosphaturia, helps to prevent hyperphosphatemia, which can occur when phosphate levels are too high and complex with calcium, potentially leading to decreased serum calcium levels.
What is the space called that is between the inner and outer membrane of a gram-negative bacteria?
periplasmic space
Protein A is a virulence factor found on which bacteria?
S. aureus
A 22-year-old female presents with dysuria and increased urinary frequency. Urinalysis shows hematuria. Urine culture identifies bacteria that grow as pink colonies on MacConkey’s agar. Which of the following best describes this growth medium?
selective and differential
It suppresses the growth of gram-positives through the addition of bile salts and crystal violet (so its selective)
It can differentiate between those bacteria which can ferment lactose (which turn red/pink) and those that cannot (which are clear)
The O, H, and K antigens are used for serotyping certain bacteria. What does each stand for?
O= outer polysaccharide portion of LPS
H= flagellar protein
K= capsule