infection final - Sheet1 Flashcards
What is the difference between Gram-positive and Gram-negative bacteria?
Gram-positive bacteria have a thick peptidoglycan wall and retain the dye in the Gram staining process, while Gram-negative bacteria have a thin peptidoglycan wall, do not retain the dye, and have an outer LPS coat (endotoxin).
Why is it harder for antibiotics to penetrate Gram-negative bacteria?
Gram-negative bacteria are harder to treat with antibiotics because their thin cell wall and outer LPS coat make it more difficult for substances to penetrate.
What is the role of oxygen in aerobic bacteria?
Aerobic bacteria need oxygen for metabolism and live in areas with higher oxygen concentrations.
Where do aerobic bacteria live in a test tube?
In a test tube, aerobic bacteria live near the top, where oxygen is available.
What is the role of oxygen in anaerobic bacteria?
Anaerobic bacteria can survive and metabolize in environments with low or no oxygen.
Where do anaerobic bacteria live in a test tube?
In a test tube, anaerobic bacteria live near the bottom, where oxygen levels are low.
What type of bacteria is E. Coli?
E. Coli is a Gram-negative, extracellular bacteria that can grow in both aerobic and anaerobic environments.
Where is E. Coli normally found?
E. Coli is part of the normal human microbiome and aids in digestion.
How is pathogenic E. Coli contracted?
Pathogenic E. Coli strains are contracted through eating contaminated food or water, contact with animals or their feces, or contact with infected person’s feces.
What are common infections caused by E. Coli?
E. Coli is the most common cause of UTIs and GI infections. It can also cause bacteremia, prostatitis, pelvic inflammatory disease, cholecystitis, and wound infections.
What are common manifestations of E. Coli infection?
Symptoms include low-grade fever, fatigue, nausea/vomiting, dysuria, pyuria, flank pain, cramping abdominal pain, bloody/watery diarrhea.
How is E. Coli infection diagnosed?
Diagnosis is based on history and physical exam (H&P) and stool or urine cultures.
What can be a complication of E. Coli infection related to potassium?
E. Coli infections can lead to potassium loss, which is important for heart function.
What type of bacteria is MRSA?
MRSA is a Gram-positive, extracellular infection caused by antibiotic-resistant Staphylococcus aureus that can grow in both aerobic and anaerobic environments.
Where does MRSA typically cause infection?
MRSA causes severe infections in both community and healthcare settings.
What does methicillin resistance indicate in MRSA?
Methicillin is an antibiotic no longer used, but it is still used as a marker for resistance to beta-lactam antibiotics.
What are manifestations of HA-MRSA?
HA-MRSA causes invasive diseases like pneumonia, endocarditis, deep wound infections, and osteomyelitis in immunocompromised individuals.
What are manifestations of CA-MRSA?
CA-MRSA causes pyogenic skin and soft tissue infections, including boils, abscesses, and cellulitis, and can lead to necrotizing fasciitis, pneumonia, and bacteremia.
How is MRSA diagnosed?
MRSA is diagnosed through H&P and blood, sputum, or wound cultures.
What type of bacteria is Clostridium Difficile (C. Diff)?
C. Diff is a Gram-positive, extracellular bacterium that causes GI symptoms.
What is the main mechanism behind C. Diff infection?
C. Diff infections are linked to overuse of antibiotics, which destroys normal flora and allows overgrowth of antibiotic-resistant strains.
What are complications of C. Diff?
Complications include C. Diff colitis, low potassium and magnesium (leading to irregular heartbeats and cardiac arrest), renal failure.
What are common manifestations of C. Diff infection?
Symptoms include foul-smelling diarrhea, dehydration, GI pain, tachycardia, fever, leukocytosis, blood in stool, and nausea.
How is C. Diff diagnosed?
Diagnosis is based on history/physical exam and a C. Diff stool test.
