BLOOD STREAM INFECTIONS

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BLOOD STREAM INFECTIONS

• Joseph G. Timpone, M.D.
• Georgetown University Hospital

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Case one

• A 56 y.o. male with a Hx/o HTN, DM, was admitted
  4 days ago with hyperglycemia and dehydration. A
  CVC was placed in the right subclavian vein at
  the time of admission. Blood cultures were
  obtained in the ER after the line was placed.

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• The pt received IV hydration and his
  hyperglycemia was managed with intensive insulin
  therapy and glucose monitoring. On hospital day
  4 you are called by the lab with the following
  blood culture results 1/4 bottles with
  Corynebacterium. 1/4 bottles with alpha hemolytic
  Streptococci. The pt is currently afebrile and is
  ready for discharge.

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The most appropriate management would be

• A) Cancel discharge, repeat blood cultures and
  begin vancomycin
• B) Cancel discharge, repeat blood cultures and
  begin vancomycin and obtain Echocardiogram
• C) Remove line, repeat blood cultures, and
  observe pt on Vancomycin
• D) Remove line, and discharge pt
• E) Call for an ID consult

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Blood Cultures The Basics

• Only 5-15 of blood cultures are () in febrile
  patients
• Types of bacteremia
• Extravascular via the lymphatics
• Intravascular i.e. CVC infections

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Bacteremia Types

• Transient Disruption of mucosal surfaces (dental
  or surgical procedures)
• Intermittent Associated with abscesses
• Continuous Infective endocarditis (I.E.,P.V.E.)

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Bacteremia Pathogens

• S. Aureus
• S. Pyogenes
• S. Pneumoniae
• H. Influenzae
• Enterobacteriaceae
• Bacteroides
• Pseudomonas Aeruginosa
• Candida species

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Blood Cultures Methods

• 2 blood cultures for separate venipuncture sites
  is adequate
• 3 sets of blood cultures for I.E.
• At least 10ml/ venipuncture
• BLD CX gt 5ml blood 92 yield
• BLD CX lt 5 ml blood 69 yield
• Diagnostic yield increased by 3 for every 1 ml
  of blood drawn

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Blood Cultures Methods

• Avoid contamination
• Contamination rate
• Povidone Iodine 3.8
• Tincture of Iodine 2.4
• Estimated 4100 increase in hospital costs for
  contaminated blood cultures

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Blood Cultures Methods

• Blood cultures from a recently inserted CVC site
  had a higher rate of contamination than a
  separate venipuncture site (9.1 vs. 2.8)
• Peripheral venipuncture are preferred

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Blood Cultures Laboratory Methods

• Blood culture incubator (BACTEC) Has space for
  240 blood culture bottles.
• BACTEC is triggered by CO2 production from
  bacteria
• CO2 production causes fluorescence which triggers
  BACTEC
• Blood cultures are Gram stained (e.g. Gram ()
  cocci in clusters)
• Blood cultures are plated
• Colony growth Prepare for VITEK for final
  identification and susceptibility

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Blood Cultures Interpretation

• Organisms isolated gt 72 hours are often
  contaminants
• () BLD cultures not compatible with a clinical
  syndrome are usually contaminants
• A single BLD CX with coagulase (-) staphylococci
  is often a contaminant
• A single () BLD CX with S. Aureus, gm (-)
  bacillie or candida is always a pathogen and
  requires therapy.

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Bacteremia Contaminants

• Coagulase (-) Staphylococci
• Propionibacterium acnes
• Corynebacterium species
• Bacillus species
• If multiple isolated from separate sites are
  obtained, the organisms could be pathogenic
• IVC infections and I.E. or P.V.E
• Viridans Streptococci can be a contaminant

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Case Two

• A 75 y.o. male NH resident was admitted 10 days
  ago with new onset (R) CVA and a UTI. Urine
  culture was () for E. coli and IV Ciprofloxacin
  was given via a PICC line. The pt developed fever
  to 103, and a work-up revealed blood cultures ¾
  with S. epidermidis.

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The most appropriate management would be

• A) Begin vancomycin treat for 14 days
• B) Remove line and treat with vancomycin for 5-7
  days
• C) Remove line treat with vancomycin for 7 days
  and obtain an echocardiogram
• D) Maintain line offer no therapy because blood
  cultures are contaminants
• E) A or B

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Bacteremia Contaminants

• Coagulase (-) Staphylococci
• Propionibacterium acnes
• Corynebacterium species
• Bacillus species
• If multiple isolated from separate sites are
  obtained, the organisms could be pathogenic
• IVC infections and I.E.P.V.E
• Viridans Streptococci can be a contaminant

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Causes of CVC infections

• Coagulase (-) staphylococci
• S. aureus, MRSA
• E. Faecalis, VRE
• Candida species
• Gram negative E. coli, Klebsiella sp.,
  Enterobacter sp, S. marcescens, Acinetobacter
  sp., S. maltophilia, and P. aeruginosa.

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CVC infections

• Uncommon pathogens Corynebacterium sp., B.
  cepacia, Flavobacterium sp., O. anthropi, T.
  beigelii, M. furfur, Mycobacterium sp. (M.
  fortuitum, M. mucogenicum)

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Coagulase-negative staphylococci

• Treat empirically with vancomycin.
• Combination therapy with vancomycin plus
  gentamicin or rifampin is not recommended for
  routine therapy
• If the CVC is removed, appropriate systemic
  antibiotic therapy is recommended for 5-7 days
• If nontunneled CVC is retained and intraluminal
  infection is suspected, systemic antibiotic
  therapy for 10-14 days and antibiotic lock
  therapy are recommended
• A tunneled CVC or an ID can be retained, if
  necessary, in pts with uncomplicated,
  catheter-related, bloodstream infection if the
  CVC or the ID is retained, pts should be treated
  with systemic antibiotic therapy for 7 days and
  with antibiotic lock therapy for 14 days
• Treatment failure that manifests as persistent
  fever, persistent positive blood culture results,
  or relapse of infection after antibiotics have
  been discontinued is a clear indication for
  removal of the catheter.

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Case Three

• A 50 y.o. male with HTN, DM, hyperlipidemia was
  admitted to the CCU with an acute M.I. A CVC is
  placed in the right subclavian vein for
  hemodynamic monitoring. On H.D. 3 the pt
  developed fevers to 39.5. On the following day,
  blood cultures 4/4 are () for S. aureus

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The most appropriate management is

• A) Begin nafcillin
• B) Begin vancomycin
• C) Remove CVC and begin nafcillin
• D) Remove CVC and begin vancomycin
• E) Remove CVC begin vancomycin and obtain TEE

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S. Aureus Bacteremia

• 8/132 pts receiving short course therapy (6.1)
  developed endocarditis or deep tissue infections
• 16/69 (23) of pts with S. aureus CVC infections
  had endocarditis on TEE. (TTE was found to be 27
  sensitive)
• For CVC-Associated S. aureus bacteremia
• -Remove CVC
• -Initiate antibiotics (Nafcillin, Vancomycin)
• -TEE is indicated

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S. Aureus Bacteremia Treatment

• TEE (-) 14 days duration
• TEE () 4-6 wks duration
• MSSA Nafcillin 2 gm IV Q 4
• MRSA Vancomycin 15mg/kg IV Q 12 (maintain
  trough at 15)
• MRSA Alternatives
• -Daptomycin
• -Trimethoprim/Sulfamethoxazole
• -Linezolid
• -Quinupristin/Daltopristin

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Case Four

• A 45 y.o. male with AML is status post induction
  chemotherapy. He has developed fever and
  neutropenia (ANC 100) and was placed on imipenem
  and vancomycin. The pt has a Hickman catheter in
  place. There is no erythma. Blood cultures ¼ are
  positive for candida tropicalis.

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The most appropriate management is

• A) Begin Amphotericin B
• B) Begin caspofungin
• C) Remove line, begin Amphotericin B, and obtain
  TEE
• D) Remove line, begin Amphotericin B, and obtain
  ophthalmology consult
• E) Remove line begin Caspofungin and call ID
  consult

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Candidemia CVC Infection

• Remove CVC
• Treatment duration At least 14 days after last
  () blood cultures
• Ophthalmology evaluation to rule out
  endophthalmitis (risk of endophthalmitis is
  26-45)
• No role for CVC salvage therapy

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Case Five

• A 50 y.o. male with a chronic SBO is receiving
  TPN. The pt develops a transient fever to 38.5
  associated with the TPN infusion. Blood cultures
  ¼ become () for S. maltophilia 2 days later.

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The most appropriate management would be

• A) Observe pt
• B) Repeat blood cultures
• C) Repeat blood cultures, begin Bactrim, and
  remove line
• D) Begin Bactrim, remove line, and obtain
  Echocardiogram

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Indications for CVC Removal

• Tunnel infection (gt2cm of erythema from exit
  site)
• Site abscess
• Hypotension
• Septic thrombosis
• Metastatic focus of infection Endocarditis,
  Endophthalmitis, Osteomyelitis)
• Persistent bacteremia despite appropriate
  antibiotics
• Pathogens S. Aureus, Gm (-) bacilli and Candida
  species
• Other pathogens A typical mycobacteria

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GM (-) Bacilli Bacteremia CVC Infection

• Remove CVC
• Treatment Duration 10-14 days
• Can consider tunneled CVC salvage
• -Systemic antibiotics X14 days
• -Antibiotic lock therapy X14 days
• -No response Remove CVC and treat for 14
  days