Enterococcus Notes

NOTES NOTES ENTEROCOCCUS ENTEROCOCCUS osms.it/enterococcus PATHOLOGY & CAUSES ▪ Gram-positive spherical-shaped bacteria (cocci) ▪ Grow in pairs (diplococci)/short chains ▪ Non-spore forming ▪ Optimal growing conditions: 45ºC/113°F, can withstand up to 60ºC/140°F ▫ Facultatively anaerobic bacteria ▫ 6.5% NaCl, bile-containing media ▪ Characteristics ▫ Catalase negative, pyrrolidonyl arylamidase (PYR) positive ▫ Variable hemolytic activity on blood agar plates; most commonly gamma hemolytic ▪ Common human pathogens: E. faecalis, E. faecium ▪ Important cause of hospital-acquired infections, esp. infective endocarditis, urinary tract infections (UTIs), infections of prosthetic devices (e.g. venus/urinary catheters) ▫ Surface carbohydrates → adherence to cardiac valves → fibrinogen synthesis → valve vegetations → infective endocarditis ▫ Adherence to renal epithelial cells → UTI ▪ Less common associations ▫ Wound, bloodstream, biliary tract, pelvic infections; intraabdominal abscesses RISK FACTORS ▪ Indwelling medical devices (e.g. central venous, urinary catheterization) ▪ Cardiovascular abnormalities 380 OSMOSIS.ORG ▪ Prolonged hospitalization, mechanical ventilation ▪ Prior antibiotic use, immunodeficiency COMPLICATIONS ▪ Bacteremia ▫ Immunocompromised individuals SIGNS & SYMPTOMS ▪ UTIs ▫ Cystitis, pyelonephritis; dysuria, frequency, urgency, suprapubic/flank tenderness ▪ Infective endocarditis ▫ Subacute onset of fever, malaise, peripheral signs (e.g. Janeway lesions, Osler’s nodes), cardiac murmurs (usually left-sided), splenomegaly ▪ Infection of prosthetic devices, wounds ▫ Erythema, swelling, tenderness, warmth DIAGNOSIS DIAGNOSTIC IMAGING Transthoracic echocardiography; abdominal CT scan; ultrasound ▪ Identify organ involvement LAB RESULTS ▪ Cultures from infected sites (e.g. blood, urine) ▪ Susceptibility testing ▫ Detect antibiotic resistance

Chapter 70 Enterococcus ▪ Complete blood count (CBC) ▫ ↑ polymorphonuclear cells ▪ Urinalysis ▫ UTI → pyuria, proteinuria, hematuria TREATMENT MEDICATIONS Antimicrobial therapy ▪ Localized infections ▫ Ampicillin/beta lactamase inhibitors (clavulanate/sulbactam) ▫ Alternative: nitrofurantoin ▪ Serious infections with bacteremia, meningitis, endocarditis ▫ Penicillin/ampicillin + aminoglycoside ▫ Alternative: vancomycin, aminoglycoside ▪ Vancomycin-resistant enterococcal (VRE) infection ▫ Linezolid/daptomycin SURGERY ▪ Drain abscess ▪ Valve replacement OTHER INTERVENTIONS ▪ Remove venous/urinary catheters OSMOSIS.ORG 381