Module 9: Bacterial & Protozoan Pathogens Flashcards
What is special about chlamydia? Most infections are _________. Chlamydia can cause ________ or ________, but cannot be transferred ____________.
Chlamydia is the most common STI worldwide. Asymptomatic, conjunctivitis, pneumonia, in-utero
What are the two sub-species of Neisseria spp, and what do they cause?
Meningococcus - meningitis & throat infection
Gonococcus - gonorrhea
What are the 3 common features of the Neisseria species, and how do they assist the species?
Polysaccharide capsule (enhances virulence)
Endotoxin (causes fever & shock)
IgA protease (helps attachment to resp tract)
What are the 4 potential outcomes of gonorrhea in pregnancy? How can mothers and infants be treated?
- premature membrane rupture
- inflammation of fetal membranes
- preterm labor
- newborn conjunctivitis
Mothers: systemic antibiotics
Infants: Ceftriaxone or ciprofloxacin post-birth
What are the two important antigens of the beta-hemolytic streptococci?
C carbohydrate: located in cell wall
M protein: virulence factor, interferes with phagocytosis
What are the 5 clinical findings of group A strep?
- acute rheumatic fever
- strep throat
- scarlet fever
- impetigo
- kidney inflammation
Which two severe pathologies can S. pyogenes cause?
Puerperal sepsis
Necrotizing fasciitis
What percentage of pregnant women harbor GBS in their lower vaginal tract? What can it cause in infants?
20%. Congenital pneumonia, sepsis, meningitis.
What are the three staphylococcus spp species? How can they be identified in the lab and why?
Staphylococcus aureus
Staphylococcus epidermidis
Staphylococcus saprophyticus
All catalase positive, so species produce bubbles when H2O2 applied to colonies.
Which enzyme does S-aureus contain? What type of hemolytic, and what type of metabolism does it have? Where does it mostly colonize on humans?
Coagulase. Beta, anaerobic OR aerobic. Nose.
Which two pathologies do S. aureus cause? What is a recent adaptation of S. aureus?
- toxic shock syndrome
- scalded skin syndrome
Most S. aureus strains are not resistant to penicillin and/or methicillin.
What does S. epidermidis cause? S. saprophyticus?
Epidermitis: sepsis in neonates, resistant to penicillin and/or methicillin.
Saprophyticus: UTI
What type of bacteria is E. coli? Where does it adhere in the gut, and what do they synthesize? What do they cause in pregnancy?
Facultative anaerobe. Adheres to pili in jejunum & ileum, synthesize enterotoxins. Can cause enterohemorrhagic (EHEC), UTI.
What do clostridium spp. produce, and what do they cause? Name the 4 types/what they cause.
Exotoxins which cause tetanus, botulism, gangrene.
C. tetani (tetanus)
C. botulinum (botulism)
C. perfringens (gangrene)
C. difficile (nosocomial diarrhea)
What is special about C. difficile? What does it cause, and which two medicines treat it?
Nosocomial, meaning it originates in hospitals/targets immunocompromised. Causes pseudomembranosus colitis, which is treated by vancomycin, metronidazole.
What type of bacteria are mycoplasma/ureaplasma, what is it similar to, what does it cause? What are the three types?
Facultative anaerobes. Similar to chlamydia, causes urethral inflammation.
M. hominis
M. genitalium
U. urealyticum
How does one contract listeria? What does infection of the fetus/newborn cause?
Contact with infected animals/feces, unpasteurized milk.
Can cause sepsis, pneumonia, meningitis.
Where does trichomoniasis live? What are its symptoms and treatment? Is it severe for fetuses?
Vaginal lumen. Foul smelling discharge, heightened pH, treated by metronidazole. Only risks are minor (preterm birth, low birth weight).
How is toxoplasmosis contracted, and is it severe?
Ingesting cysts in cat feces or poorly cooked meat. Not really.
What are implications for toxoplasmosis in fetuses?
Can be transferred in-utero, can lead to convulsions, microcephaly, jaundice, conjunctivitis.
Is it easy for microbes to spread in the female urogenital tract? Describe the vaginal cleansing mechanism.
Yes, it is a continuous surface. No particular mechanism, but repetitive microtrauma increases risk of infection.
What do vaginal epithelial cells secrete and why?
Contain and secrete glycogen due to circulating estrogens, facilitating lactobacilli (good!) to colonize vagina.
Normal vaginal secretions contain lots of _____ bacteria. What might microbes take advantage of in order to colonize the vaginal tract?
Commensal. Altered immune function in menstrual cycle, contraceptive hormones.
What are the two pre-disposing factors of UTIs during pregnancy?
- significant urethral dilation
- residual urine in bladder
What can asymptomatic bacteriuria lead to, and what type of bacteria causes ti?
Acute pyelonephritis (bacterial infection of kidney), caused by E-coli.
What can acute pyelonephritis cause in mother/fetus?
Fever, sepsis, preterm labor, meningitis in newborn
Which bacteria is referred to as GBS?
Streptococcus agalactiae
Which condition causes the most common serious medical complication in pregnancy?
Acute pyelonphritis.
What occurs during a hypersensitivity reaction?
GBA antigens exist in BV, antibodies form a complex that passes through blood. Complex can be deposited into kidney, causes inflammation.
