Skip to Main Content

We have a new app!

Take the Access library with you wherever you go—easy access to books, videos, images, podcasts, personalized features, and more.

Download the Access App here: iOS and Android


Epidemiology and Microbiology

|Download (.pdf)|Print
Epidemiology and Microbiology

Most Common Organisms1

Organism Frequency Antimicrobial Resistance
Coagulase-negative staphylococci 31%  
Enterococci 9% Dramatic rise in enterococcal isolates resistant to vancomycin—from 0.5% in 1989 to 25.9% in 1999
Staphylococcus aureus 20% >50% of all S. aureus nosocomial isolates are oxacillin resistant1
Gram-negative bacilli 20% Increasing prevalence of Enterobacteriaceae with extended-spectrum β-lactamases (ESBLs), and carbapenemase-producing organisms particularly Klebsiella pneumoniae. Such organisms may be resistant to many commonly used cephalosporins and carbapenems
Candida infections   Growing resistance of Candida albicans to antifungals; 50% of Candida bloodstream infections are caused by non-albicans species including Candida glabrata and Candida krusei, which are more likely than C. albicans to demonstrate resistance to fluconazole and itraconazole. Resistance to voriconazole has not been reported thus far, although continued surveillance is need


  • Catheter colonization: Significant growth of a microorganism in a quantitative or semiquantitative culture of the catheter tip, subcutaneous catheter segment, or catheter hub

  • Exit-site infection: Erythema, induration, and/or tenderness within 2 cm of the catheter exit site; may be associated with other signs and symptoms of infection, such as fever or pus emerging from the exit site with or without concomitant bloodstream infections

  • Tunnel infection: Tenderness, erythema, and/or induration within 12 cm from the catheter exit site along the subcutaneous tract of a tunneled catheter (eg, Hickman or Broviac) with or without concomitant bloodstream infections

  • Pocket infection: Infected fluid in the subcutaneous pocket of a totally implanted intravascular device; often associated with tenderness, erythema, and/or induration over the pocket; spontaneous rupture and drainage, or necrosis of the overlying skin, with or without concomitant bloodstream infection, may also occur

  • Catheter-related bloodstream infection: Bacteremia or fungemia in a patient who has an intravascular device and 1 positive result from culture of blood samples from the peripheral vein, clinical manifestations of infection (eg, fever, chills, and/or hypotension), and no apparent source for bloodstream infection (except for the catheter). One of the following should be present: a positive result of semiquantitative (>15 CFU per catheter segment) or quantitative (>102 CFU per catheter segment) catheter culture, whereby the same organism (species and antibiogram) is isolated from a catheter segment and a peripheral blood sample; simultaneous quantitative cultures of blood samples with a ratio of >5:1 (central venous catheter [CVC] versus peripheral catheter); differential time to positivity (ie, a positive result of culture from a CVC is obtained at least 2 hours earlier than a positive result from a culture from peripheral blood)


  1. Blood cultures

    • Clinical findings for establishing the diagnosis of catheter-related infection are unreliable because of poor sensitivity and specificity

    • When catheter infection is suspected, 2 sets of blood cultures should be sent with at least 1 drawn percutaneously2

    • Paired quantitative or qualitative blood cultures with continuously monitored differential time to positivity are recommended when long-term catheters cannot be removed...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.