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Resident Version Staphylococcus aureus bacteremia module Created by Dr. Wendy Gerstein updated 10/2010 Objectives: 1) Recognize two clinical differences and implications between spontaneous and catheter related S. aureus bacteremia. 2) List the criteria for type and duration of therapy for S. aureus bacteremia. 3) Recognize three common complications associated with S. aureus bacteremia. References: 1) Mermel LA, Farr BM, Sheretz RJ et al. Guidelines for the Management of Intravascular Catheter-Related Infections. CID 2001:32 (1 May) 1249-1272. 2) Rosen AB, Fowler VG Jr, Corey GR et al. Cost-effectiveness of transesophageal echocardiography to determine the duration of therapy for intravascular catheterassociated Staphylococcus aureus bacteremia. Ann Intern Med. 1999; 130:810-20 Case: HPI: Mr. T is a 56 yo male with a history of severe COPD (on home O2 and chronic steroids), DM, HTN, DVT/PE, who come to the ED complaining of dysuria, hematuria, left sided back pain, suprapubic abdominal pain, and fever/chills for the past 2 days. He was seen in ED the day prior to admission, given IV ciprofloxacin for presumed UTI/pyelonephritis, and sent home with oral ciprofloxacin. He took one dose but was unable to tolerate it because of emesis. He has had emesis x 7 the day of admission. Mr. T has just finished a steroid taper 5 days ago and feels like he is more SOB and has more productive cough with yellowish sputum. PMH Severe COPD--(FEV1 1.36, 35% predicted, on home O2, on chronic steroids) HTN DM--hga1c 5.5 GERD PE 5 years ago and DVT 12 years ago--on chronic coumadin therapy BPH GI bleed 2 years ago: friable nodule found at GE junction by EGD, negative biopsy. MRSA UTI 10 months prior SH Lives in Portales with his wife. Denies tobacco or drug use; h/o heavy ETOH abuse and quit 7 years ago. Used to drink a 5th of vodka every day for 7 years. FMH Mother: died age 65 lung ca Dad: died age 65 of CAD CHF in siblings ALLERGIES NKDA OUTPATIENT MEDICATIONS Inhaler for COPD Ciprofloxacin 500 mg po bid Citalopram 40 mg 1 po q day Insulin NPH 5 units q bedtime, insulin ss before meals. Irbesartan 150 mg 1 po q day Lovastatin 10 mg 1 po q day Oxycodone 5 mg 1 po tid for pain Pantoprazole 40 mg 1 po bid Prednisone 10 mg 1 po q day Spironalactone 25 mg 1 po bid Warfarin PE: BP 104/54, P 108, RR 14, T 102.8, O2 94% 3L NC General: AAO x 3, NAD HEENT: PERRLA, EOMI, pharynx w/ post nasal drainage, no LAD, neck supple, thyroid normal. Lungs: scattered crackles, prolonged expiratory phase, and few scattered wheezes. CV: RRR no m/r/g, no JVD, no s3/4, equal dp/radial pulses Abd: soft, non-distended, mild suprapubic tenderness, +bs Back: L CVA tenderness Ext: No C/C/E Neuro: CN 2-12 grossly intact, motor/strength in 4 extremities grossly intact LABS WBC/H/H/Plt:18.8/16/48/96-->plt 145 in 2/06 Na/K/Cl/CO2/BUN/Cr/Glc:130/3.8/98/25/12/1.1/139 Ca/Mg:8.3/1.7 TP/Alb/AST/ALT/AP/TB:6.1/3.1/29/47/61/0.9 CXR: poor quality portable, hypoventilation, B basilar atelectasis blood/urine cultures pending UA (initial ED visit): nitrite +, mod LCE, 102 wbc, 18 rbc UA day of admission: nitrite -, trace LCE, 25 WBC, 150 ketones What is your initial impression or diagnosis based on presentation and above data? Hospital Course: Patient admitted with diagnosis of pyelonephritis, and inability to tolerate PO antibiotics. Patient was started on IV ciprofloxacin, and also treated for a COPD exacerbation with steroids and nebulizers. By hospital day 2, patient was improved, and urine and blood cultures were still negative. Approximately 5 hours after his discharge, the medical team was notified that 1/4 blood cultures were growing gram positive cocci in clusters. Medical team was concerned due to h/o MRSA UTI, but was unable to contact patient at home. The next morning 4/4 blood cultures were growing S. aureus with sensitivities pending. Team reached patient and wife as they were traveling home. Wife stated that her husband was still doing OK, but he felt a little weaker than yesterday, and patient returned to be readmitted. What is the next step in managing this patient? What is the most likely source of the MRSA bacteremia? What further evaluation is warranted? Outline for discussion Community-acquired (spontaneous) S. aureus bacteremia: (Of note, there is a separate module for endocarditis) A) Epidemiology Leading cause of community-acquired bacteremia. It is a marker for complicated disease: >40% of patients have metastatic disease and in one study 60% had endocarditis. It has significant mortality associated with it: 20-40% depending upon underlying comorbities. B) Risk factors: IVDU Indwelling foreign body/prosthesis Underlying medical conditions (HIV, hemodialysis patients, diabetes, malignancy, nasal carriers). C) Management/workup: Look for deep focus of infection (osteomyelitis, abscess, endocarditis, prosthetic infection), and drain or debride if possible. Repeat blood cultures until documented clearance of bacteremia. Remove any associated hardware or prosthesis if feasible. All patients with S. aureus bacteremia should have a transthoracic echocardiogram (TTE). Transesophageal echocardiogram (TEE) to rule out vegetation has been proven to be cost effective; perform if feasible unless 6 weeks of therapy is already going to be given for other known deep focus of infection. If signs of endocarditis are present, TEE helps evaluate for complications (embolic phenomenon, chf, size of vegetation). D) Treatment: Methicillin sensitive S. aureus (MSSA) o nafcillin 2 grams iv q 4 hours is drug of choice. o Cefazolin 2 grams iv q 8 hours if patient with h/o type 4 beta-lactam allergy. o Vancomycin 30mg/kg per day divided over 8-12 hour dosing if patient with type 1 beta-lactam allergy (follow troughs aiming for level of 1520). o Linezolid is 3rd line therapy if patient refuses IV (600mg po bid). You can also use oral dicloxacillin if patient leaves AMA (linezolid needs monitoring). Methicillin resistant S. aureus (MRSA) o Vancomycin 30mg/kg per day divided over 8-12 hour dosing, follow troughs aiming for level of 15-20. o Daptomycin 6mg/kg q 24 hours is an alternative treatment for MRSA, need to monitor for elevated CPK. E) Duration of therapy: Duration (minimum is 14 days) depends on presence or absence of the following: o Removable focus o Response to initial therapy (blood culture results at three days) o Presence of prosthesis, deep focus, or endocarditis. F) Complications of bacteremia: o Relapse rate of bacteremia is 9.4% with endocarditis, or if vancomycin used. o Septic thrombosis, endocarditis, purulent pericarditis (seen in HIV patients), deep abscesses, prosthetic infection, vertebral osteomyelitis, septic arthritis (RA), septic pulmonary emboli, bacteriuria (look for source of S. aureus bacteriuria such as endocarditis, renal abscess, prostatitis). G) Catheter-related S. aureus bacteremia: o Diagnosis: catheter tip culture positive (quantitative or semi-quantitative) and blood culture positive for same organism, or peripheral blood culture and blood culture from catheter positive with same organism. Clinical findings tend to be unreliable. o Mortality rate for catheter associated S. aureus bacteremia is lower than for community-acquired: 8.2%. Much fewer develop endocarditis compared to community-acquired S. aureus bacteremia o Central venous catheters accounts for >90% of catheter infections (less common with tunneled/implantable catheters). o Treatment: o If CVC, remove and treat with antibiotic (vancomycin or nafcillin depending on organism and allergies) for 14 days minimum (assuming TTE/TEE negative for vegetation, and no clinical evidence of deep infection or embolic phenomenon). If unable to get TEE, base duration on clinical picture and TTE results. o If TEE positive, treat as endocarditis with 6 weeks of appropriate therapy o Tunneled/implantable catheter infection: if complicated, remove catheter. If non-complicated, can attempt salvage therapy (<50% success) with antibiotic lock therapy for 2 weeks in addition to systemic antibiotics, although guidelines always recommend removing due to high failure rate. o Complications are similar to community-acquired S. aureus bacteremia: endocarditis, osteomyelitis, septic thrombosis, deep tissue space infection (liver, kidney, spleen), epidural abscess. Review questions 1) 38 yo male with past medical history significant for end stage renal disease, on dialysis, who had a permacatheter placed 2 weeks prior to admission due to failure of his fistula (it clotted off). Two days prior to admission patient noted fevers/chills/diarrhea and pus coming out of permacath site. 2 sets of blood cultures are drawn, patient is dialyzed, one dose of vancomycin is given, and permacatheter is removed. The patient improves, but blood cultures from admission grow Staphylococcus aureus that is methicillin resistant. Patient has a new permacatheter placed, and repeat blood cultures are negative. Physical exam is negative for any signs of endocarditis, patient is afebrile with normal exam, normal wbc, old permacath site has healed well, and he is anxious to go home. Which of the following is the most appropriate management of this patient? A. With negative blood cultures and a new permacatheter placed, patient does not need any more studies or therapy and is safe to discharge home. B. Patient is safe to go home with no further diagnostic studies, but will need the IV vancomycin for 2 weeks with dialysis. C. Obtain a transthoracic echocardiogram – if negative, patient does not need any more therapy. D. Obtain a transesophageal echocardiogram. If negative for endocarditis, continue the IV vancomycin for 2 weeks. E. Obtain a transesophageal echocardiogram. If negative for endocarditis can discontinue antibiotics. 2) An IVDU presents with right-sided endocarditis and is growing methicillin sensitive S. aureus in their blood cultures. Standard of care treatment is: A) 4 weeks of IV vancomycin and low-dose (q 8 hour) gentamicin B) 2 weeks of IV vancomycin C) 4 weeks of IV nafcillin D) 2 weeks of IV nafcillin plus low-dose (q 8 hour) gentamicin E) 4 weeks of oral ciprofloxacin plus rifampin 3) A 45 yo male had a right knee prosthesis placed 6 weeks ago, and now presents with increasing knee pain for two weeks, swelling, purulent drainage from wound, fevers/rigors, and malaise. Physical exam is notable for temperature of 39 C, bp 90/50, p 110, RR 16. R knee wound has dehisced with greenish discharge, and surrounding edema and erythema is present, with pain with palpation or any movement. Patient was started empirically on IV vancomycin at time of admission. Blood cultures drawn prior to antibiotics are now growing methicillin-sensitive S. aureus. The next most appropriate management is: A) Continue IV vancomycin, contact orthopedics for removal of hardware, and treat for 6 week with vancomycin. B) Switch to IV nafcillin, contact orthopedics for removal of hardware, and treat for 6 weeks with nafcillin. C) Switch to IV nafcillin, contact orthopedics for irrigation and debridement of knee, continue antibiotics for 6-8 weeks. D) Switch to IV nafcillin for duration of hospitalization, contact orthopedics for irrigation and debridement of knee, and send home on oral suppressive therapy with ciprofloxacin and rifampin indefinitely. E) Continue IV vancomycin, add rifampin, contact orthopedics for irrigation and debridement of knee, and treat for 6-8 weeks with vancomycin and rifampin. Post Module Evaluation Please place completed evaluation in an interdepartmental mail envelope and address to Dr. Wendy Gerstein, Department of Medicine, VAMC (111). 1) Topic of module:__________________________ 2) On a scale of 1-5, how effective was this module for learning this topic? _________ (1= not effective at all, 5 = extremely effective) 3) Were there any obvious errors, confusing data, or omissions? Please list/comment below: ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ 4) Was the attending involved in the teaching of this module? Yes/no (please circle). 5) Please provide any further comments/feedback about this module, or the inpatient curriculum in general: 6) Please circle one: Attending Resident (R2/R3) Intern Medical student