Micro Block 2 Pt. 2

ptheodore's version from 2015-06-29 01:03

Infective Endocarditis

Question Answer
MC overall cause of Infective EndocarditisStreptococcus Viridans
2nd MC overall cause of Infective Endocarditis.Staph.aureus
MCC of Acute Infective Endocarditis in Intravenous Drug Abusers (IVDA)Staph.aureus
MC cause of Infective Endocarditis after prosthetic valve.Staph.epidermidis
MC cause of Infective Endocarditis from intravenous cathetersStaph.epidermidis:
MC cause of Infective Endocarditis in ulcerative colitis or colorectal cancerStrep.bovis
MC cause of subacute bacterial endocarditisStreptococcus Viridans

Streptococcus agalactiae (Group B Strep = GBS)

Question Answer
Meningitis in newborns; High fever, Bulging fontanelle (soft spot on top of head), Irritability, poor feeding, stiffness in body or neckStreptococcus agalactiae
Treatment – penicillin/ampicillin plus aminoglycoside, or cephalosporin (cefotaxime). Prevention – screen and treat pregnant carriersStreptococcus agalactiae
In Human vagina (15-20% women). Neonate infected during birth (increased risk with prolonged labor after premature rupture of membranes)Streptococcus agalactiae
Treat Pregnant woman with: positive vaginal/rectal culture of GBS, History of recent infection with GBS, Prolonged rupture of membranes, Intrapartum prophylaxis of group B strep carriers Streptococcus agalactiae

Streptococcus pneumoniae

Question Answer
Gram positive diplococcus with capsuleStreptococcus pneumoniae
What is the basis for Streptococcus pneumoniae vaccinesPolysaccharide capsule
Bile soluble, Optochin sensitive, Positive quellung reaction (Detects capsule), alpha-hemolyticStreptococcus pneumoniae
Antecedent viral resp. infection (influenza or measles infection), Chronic obstructive pulmonary disease (COPD), Asplenia (spleen not working properly) predisposes to septicemia are predisposing factors toStreptococcus pneumoniae
A cytotoxin that binds to host cell membranes → pores → destroys host cells: Ciliated epithelial cells, Phagocytic cells. Suppresses phagocytic cell oxidative burst (required for intracellular killing)Pneumolysin
Pneumonia, Meningitis, Otitis media & SinusitisStreptococcus pneumoniae
Most common cause of community-acquired lobar pneumoniaStreptococcus pneumoniae
Abrupt onset – shaking chills, high fever. Productive cough with blood-tinged sputum (“rusty sputum”)Streptococcus pneumoniae
Most common cause of adult meningitis (High fever, Nuchal rigidity, Photophobia (increased sensitivity to light), Altered mental status (confusion), Nausea, vomiting)Streptococcus pneumoniae
Lab findings: CSF (cerebrospinal fluid); High neutrophils, Low glucose. Gram stain (Numerous neutrophils + GPC pairs). Capsular antigen detected in CSFStreptococcus pneumoniae - Meningitis
One of the most common causes of sinusitis and middle ear infectionsStreptococcus pneumoniae
Treatment for Streptococcus pneumoniae that causes otitis media and sinusitis in childrenErythromycin
Treatment for Streptococcus pneumoniaeQuinolone (e.g., ciprofloxacin), or cephalosporin, macrolide (e.g., azithromycin), or vancomycin *
Empiric therapy for serious pneumococcal infections from Streptococcus pneumoniaeVancomycin + ceftriaxone

Viridans Streptococci

Question Answer
GPC chains, Not bile soluble, Optochin resistant, Alpha-hemolytic, part of normal flora in OropharynxViridans Streptococci
Part of normal microflora in Anterior naresStaphylococcus aureus
Transmitted via sneezing, contaminated hands, MCC of Hospital-acquired (nosocomial) infectionsStaphylococcus aureus
Plaque & dental caries/cavities Streptococcus mutans
MC cause of subacute bacterial endocarditis. Enters the bloodstream during dental surgery and infect previously damaged heart valvesViridans Streptococci
Streptococcus pneumoniae and Nontypeable Haemophilus influenzae (no capsule) can be found as normal microflora in theThroat (oropharynx)
MC cause of subacute endocarditis. Infects damaged / prosthetic heart valves. Important predisposing factors: Dental work without prophylactic antibiotics. Very poor oral hygieneViridans Streptococci
Treatment for Viridans streptococci causing endocarditisPenicillin G + Aminoglycoside
To prevent viridans streptococci infection during dental work, patients with damaged heart valves must be administered withProphylactic antibiotics (antibiotics to prevent infections)


Question Answer
Located in human colon,& urethra. Catalase negative, Grow in presence of 6.5%NaCl, Hydrolyze esculin in 40% bile (bile esculin agar turns black)Enterococcus
Patients receiving broad-spectrum antibiotics are likely to get Urinary tract infections, Peritonitis, biliary tract infections, & Subacute endocarditisEnterococcus
Treatment for Vancomycin resistant Enterococci (VRE) & multi-drug resistant strainsLinezolid, Quinupristin/daflopristin, Selected fluoroquinolones

Streptococcus bovis – Group D

Question Answer
MC cause of endocarditis in those with gastro-intestinal malignancies (cancer colon)Streptococcus bovis
Subacute Endocarditis, strongly associated with underlying malignancy or premalignant lesions of the colonStreptococcus bovis
Treatment for Streptococcus bovisMostly sensitive to penicillins and other antibiotics

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