| Which type of streptococcus is the most pathogenic? | Strep pyogene is the most aggressive one since it spreads to all tissues |
| Give properties of streptococci. | Facultative anaerobes
Fastidious (need certain conditions to grow, studied only in vivo we cant study them in vitro) |
| Talk about streptococcus pyogenes. | Have a hyaluronic acid capsule (works different from other capsules)
Have a M protein which is a functional protein found also in heart cells thus making more invasiveness.
They release pyrogenic exotoxins (Streptolysin S (structural - not very significant) and O (can be found by Antistreptolysine O test) |
| What molecules are secreted by strep pyogene destroying blood clots? | Streptodornase (nuclease which destroys DNA leading to spread of the bacteria) and Streptokinase (destroys fibrin clots- was originally used to destroy any clot type)
In addition, they secrete hyaluronidase (but these only destroy tissue hyaluronan, not capsule) |
| What do we call having 2 infections at once? | Coinfection (for example by strep pyogene and staph aureus) |
| What are the types of skin infections that occur for streptococcus pyogene? | Impetigo, Erysipelas, Cellulitis, Necrotizing Fasciitis, Myoitis. |
| What is Erysipelas? | Superficial redness in an area of the skin, appears all in the same color, doesn't spread to inner fascia. |
| What is cellulitis? | Deeper skin infection than erysipelas, appears as a spectrum of colors from yellow to red, may reach the inner perineal area where it becomes necrotizing fasciitis. |
| Talk about necrotizing fasciitis. | Fournier's Gangrene, flesh eating bacteria, spreading very widely in fascia of perineal region, mostly would lead to death |
| What are the causes of myositis? | May be infection, or auto immune |
| What symptoms present during strep pyogene that are not skin infections? | Pharyngitis (doesn't include coughing like the viral one, white dots, red tonsils and swollen uvula)
Otitis
Sinusitis
May cause acute endocarditis due to strep endotoxins (SPEs which are TSST1-like)
Cause toxic shock syndrome due to bacteremia (unlike staph which is caused by toxemia
As well as scarlet fever. |
| Talk about the post-streptococcal disease. | These may include:
hematuria (red urine which may be micro or macroscopic resolves on its own)
proteinuria
Acute glomerulonephritis (which happens on the level of the glomeruli of the nephrons where they become inflamed)
We may have granulomas in the heart (Aschoff) which may cause heart failure
Increasing ASO
Nodules |
| Talk about streptococcus agalactiae. | gBs (group B strep), beta hemolytic (like pyogene), causes disease for elderly and neonatal (fetal) babies and pregnant women. |
| What are the consequences of catching strep agalactiae on babies? | We will have premature labor, we may have stillbirth (death post-delivery) or abortion
It all depends on whether we get early onset or late onset of the bacteria. |
| How to test for strep agalactaie acquisition for babies? | If they are delivered we get a swab of vaginal tissue, and test it on agalactiae agar (which contains an inoculum of staph aureus thus making a diamond shape whenever they are coupled with strep agalactiae.)
Another way is screening after 8 months.
CAMP test |
| How do we treat agalactiae infections? | By giving ampicillin (prophylaxis IV) |
| Talk about the early onset and the late onset. | Early onset is caused before delivery, it leads to septicemia of the baby, and leads to stillbirth/ floppy baby/ lethargy/ cyanosis)
Late onset occurs post delivery and it is infection by interaction with mom, drs, nurses... Causes meningitis (encephalitis) and it is not septic |
| What is pleurisy? | New name for pleuritis (inflammation of the pleura, which is very painful due to the presence of pain receptors)
Lobar |
| Talk about streptococcus pneumonia. | Many strains/ types, usually are present as diplococci which are lancet shaped (infinity like)
The different strains are detected by typing of the capsules.
They release pneumolysins O (which are toxins)
They attack and cause disease post-viral infection (like staph aureus) or alcohol consumption or smoking onset.
Mostly aerobic bacteria and carried by most human beings |
| Talk about the Quellung reaction test. | We swell the capsules of the bacteria by using antiserums in order to detect the diplococci shape |
| When do we have community acquired disease? | When carriers of the disease transmit it to a carrier |
| What are the consequences of strep pneumonia infection? | Bacteremia (leads to meningitis, septic arthritis, and endocarditis)
Mucosal infection leads to Sinusitis, otitis media, and empyema
Rusty sputum and consolidation occurs in the lungs as well |
| What is consolidation? | Consolidation refers to an area of homogeneous increase in lung parenchymal attenuation that obscures the margins of vessels and airway walls |
| What are the vaccines of strep pneumonia? | PPV23
PCV13 (pneumococcal conjugated vaccine 13(type of capsule with no boost) |
| Describe the otitis media condition caused by strep pneumonia. | It appears as a buldging in the middle ear |
| Talk about viridians streptococcus. | alpha hemolytic, URT and GI NF, green, diseased people may need mitral valve replacement because of vegetations occuring in them targeting healthy tissues close to heart causing subacute endocarditis due to bacteremia
S. mutans is very common for dental extractions
These are optochin resistant, and we just need prophylactic antibiotics to get rid of them (amoxicillin for 1 day) |
| Talk about the enterococcus. | G+ catalse- GI NF optochin resistant.
UTIs in hospitals, they are also called strep D and normal flora of tract
make adhesions and biofilms, some are vancomycin resistant (VRE)
Cause meningitis and endocarditis
treated by beta lactams + aminoglycosides |
