Clinical Management

Antibiotic therapy for catheter-related infection is often initiated empirically. The initial choice of antibiotics depends on the severity of the patient's clinical disease, risk factors for infection, and likely pathogens associated with the specific intra-vascular device (Fig. 5) (120). Although there are no data supporting the use of specific empiric antibiotic therapy for device-related BSIs, vancomycin is usually recommended in those hospitals or countries with an increased incidence of methicillin-resistant staphylococci, because of its activity against coagulase-nega-tive staphylococci and S. aureus. In the absence of MRSA, penicillinase-resistant penicillins, such as nafcillin or oxacillin, should be used. Additional empiric coverage for enteric Gram-negative bacilli and P. aeruginosa, with a third- or fourth-generation cephalosporin, such as ceftazidime or cefepime, may be indicated in severely ill or immunocompromised patients with suspected CR-BSI. Antimicrobial therapy should be given intravenously initially, but once the patient has stabilized and antibiotic sensitivities are known, an oral quinolone, such as ciprofloxacin, TMP-SMX, or linezolid could be administered, because of their excellent oral bioavailability and tissue penetration.

There are no compelling data to support specific recommendations for the duration of therapy for device-related infections. Patients with catheter-related bacteremia should be separated from those with complicated infections in which there is septic thrombosis, endocarditis, osteomyelitis, or possible metastatic seeding, and those with uncomplicated bacteremia in which there is no evidence of such complications (Fig. 5). If there is a prompt response to initial antibiotic therapy, most patients who are not immunocompromised, or lack underlying heart disease or a prosthetic device, should receive 10 to 14 days of antimicrobial therapy for pathogens other than coagulase-negative staphylococci. A more prolonged antibiotic course of 4 to 6 weeks should be considered for complicated infections due to S. aureus. Predictors of complicated S. aureus bacteremia include community acquisition, skin findings suggestive of acute systemic infection, persistent fever > 72 hr and a positive follow-up blood culture at 48 to 96 hr (121). Also, if there is evidence of endocarditis, septic thrombosis, or osteomyelitis, a longer course of antibiotic therapy is recommended (120).

Surgically implantable vascular devices consist of either a surgically implantable catheter, such as tunneled silicone catheters (Hickman, Broviac, or Groshong), or implantable devices, such as Port-A-Cath (120). Because removal of a surgically-implantable vascular device is often a management challenge, it is important to be sure that one is dealing with a true CR-BSI rather than skin contamination, catheter colonization, or infection from another source. Patients with complicated device infections, such as tunnel infection or port abscess, require removal of the catheter and 7 to 10 days of antibiotic therapy. Septic thrombosis or endocarditis requires removal of the catheter or device and antibiotic treatment for 4 to 6 weeks. In cases complicated by osteomyelitis, the

FIGURE 5 Summary of the duration of antibiotic therapy recommended for therapy of catheter-related bloodstream infections. Note the difference in duration of therapy for the different pathogens. Abbreviations: ALT, alanine aminotransferase test; CoNS, coagulase negative streptococci; CVC, central venous catheter; ID, implantable device. Source: From Ref. 120.

FIGURE 5 Summary of the duration of antibiotic therapy recommended for therapy of catheter-related bloodstream infections. Note the difference in duration of therapy for the different pathogens. Abbreviations: ALT, alanine aminotransferase test; CoNS, coagulase negative streptococci; CVC, central venous catheter; ID, implantable device. Source: From Ref. 120.

catheter should be removed and patients treated for 6 to 8 weeks. In the presence of uncomplicated infection due to coagulase-negative staphylococci, the tunneled CVC may be retained, if there is no evidence of persisting or relapsing bacteremia. Antibiotic lock therapy, using high concentrations of antibiotics locked into the catheter or implantable device, should be considered for salvage therapy in selected patients where there are compelling reasons why the catheter cannot be removed (120).

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