Medline ® Abstracts for References 7-10
of 'Antibiotic lock therapy for treatment of catheter-related bloodstream infections'
Impact of central venous catheter removal on the recurrence of catheter-related coagulase-negative staphylococcal bacteremia.
Raad I, Davis S, Khan A, Tarrand J, Elting L, Bodey GP
Infect Control Hosp Epidemiol. 1992;13(4):215.
OBJECTIVE: To determine the impact of catheter management on the acute and long-term outcome of catheter-related coagulase-negative staphylococcal bacteremia.
DESIGN: Retrospective surveillance of catheter-related sepsis using quantitative blood and catheter cultures.
SETTING: University-affiliated tertiary cancer center.
PATIENTS AND METHODS: Seventy patients with catheter-related coagulase-negative staphylococcal bacteremia were studied by retrospective chart review. The clinical characteristics of the patients and the management of the bacteremias were determined. The impact of immunosuppressive risk factors, antibiotic therapy, and catheter management on the recurrence of the bacteremia was investigated.
RESULTS: Acute sepsis-related morbidity and mortality were not related to catheter management. However, during a 12-week followup period, the bacteremia recurred in 20% of the patients whose catheters remained in place, compared with only 3% of those whose catheters were removed (p less than .05). By multivariate analysis, patients whose catheters remained in place were 2.9 times more likely to experience a recurrence than those whose catheters were removed (odds ratio = 2.9, 95% confidence interval = 1.2-8.8, p = .03). All other potential risk factors were equally distributed between patients, with and without a recurrence.
CONCLUSIONS: Although patients with catheter-related coagulase-negative staphylococcal bacteremia could be treated successfully while the catheter remains in place with the majority remaining free of recurrence, catheter retention results in a significantly higher risk for the recurrence of the bacteremia.
Department of Medical Specialties, University of Texas MD Anderson Cancer Center, Houston 77030.
Conventional and nonconventional modes of vancomycin administration to decontaminate the internal surface of catheters colonized with coagulase-negative staphylococci.
Gaillard JL, Merlino R, Pajot N, Goulet O, Fauchere JL, Ricour C, Veron M
JPEN J Parenter Enteral Nutr. 1990;14(6):593.
Using a quantitative in vitro model simulating clinical conditions, we studied the efficacy of conventional and nonconventional 3-day therapies involving vancomycin for treating the internal surface of catheters colonized with a slime-producing strain of Staphylococcus epidermidis. When infused for 1 hr every 8 hr through the catheter at the daily dose recommended for a 10-kg child (450 mg), vancomycin alone reduced bacterial colonization but failed to sterilize the inserts. Vancomycin was more active in combination with netilmicin (25 mg for 1 hr every 8 hr), rifampin (150 mg for 90 min every 12 hr), or fosfomycin (500 mg for 4 hr every 6 hr), but the catheters were inconsistently decontaminated after 3 days of treatment. Two nonconventional modes of antibiotic administration were tested for their capacity to ensure high levels of vancomycin in the catheter lumen over a prolonged time. Vancomycin infused continuously through the catheter at a daily dose of 450 mg had the same poor sterilizing effect as vancomycin administered intermittently. On the contrary, catheters were totally decontaminated when 2.5 mg of vancomycin in a volume of 0.5 ml were injected twice daily into noninfused catheters, confirming that the antibiotic-lock technique is an approach of great interest to sterilize the internal surface of catheters colonized with staphylococci.
Laboratoire Central de Microbiologie, Hôpital Necker-Enfants Malades, Paris, France.
Effect of polyurethane catheters and bacterial biofilms on the in-vitro activity of antimicrobials against Staphylococcus epidermidis.
Pascual A, Ramirez de Arellano E, Martínez Martínez L, Perea EJ
J Hosp Infect. 1993;24(3):211.
The effect of two polyurethane ['Cavafix Certo' (CAV); 'Viacath' (VIA)]catheters on the in-vitro activity of amikacin (AN), clindamycin (CM), cloxacillin (CX), ciprofloxacin (CIP), vancomycin (VA), teicoplanin (TEI) and daptomycin (DAP) against slime producing and non-producing Staphylococcus epidermidis strains was determined using a microdilution assay. None of the antimicrobial agents was significantly affected in the presence of the catheters. The susceptibility of S. epidermidis attached to CAV and VIA catheters was also evaluated. Minimum inhibitory concentration (MIC) values were similar when planktonic and attached bacteria were compared. Minimum bactericidal concentrations (MBCs) markedly increased in the presence of 6 and 48 h bacterial biofilms. These increases in MBC values occurred when either slime producing or non-producing strains were used, and in most cases were higher for CAV catheters than for VIA catheters. This phenomenon was shown not to be due to differences in bacterial adherence. It is concluded that the in-vitro bactericidal activity of certain antimicrobials markedly decreased when bacteria adhered to plastic catheters, but this effect could have been dependent partially on the nature of the catheters.
Department of Microbiology, University of Sevilla Medical School, Spain.
Ultrastructural analysis of indwelling vascular catheters: a quantitative relationship between luminal colonization and duration of placement.
Raad I, Costerton W, Sabharwal U, Sacilowski M, Anaissie E, Bodey GP
J Infect Dis. 1993;168(2):400.
To assess the degree of luminal and extraluminal colonization of long-term central venous catheters (CVC), 359 indwelling silicone CVC from 340 consecutive cancer patients were examined. All CVC were cultured by the roll-plate and sonication quantitative culture techniques. Semiquantitative electron microscopy was done on 39 CVC associated with catheter infections and on 26 culture-negative controls. An additional 10 culture-negative CVC obtained after death were also studied by electron microscopy. Ultrastructural colonization and biofilm formation was universal and quantitatively independent of clinical catheter-related infections. Ultrastructural colonization and biofilm formation was predominantly luminal in long-term CVC (>30 days). Based on a composite definition, the sensitivity of the roll-plate catheter tip culture was 42%-45% compared with 65%-72% for the sonication of the tip. Colonization of indwelling catheters is universal regardless of culture results. For long-term CVC, colonization becomes predominantly luminal and extraluminal quantitative catheter cultures are of limited diagnostic sensitivity.
Department of Medical Specialties, University of Texas M. D. Anderson Cancer Center, Houston 77030.