Biomedical subjects

Ioannis Chatzinikolaou

Publications and source records attributed to Ioannis Chatzinikolaou.

9 recordsLinked to original sources

PubMed2006

Prospective study of the value of quantitative culture of organisms from blood collected through central venous catheters in differentiating between contamination and bloodstream infection.

Collection of blood through a central venous catheter for the diagnosis of bacteremia is a debated topic. Quantitative cultures of organisms from blood collected through central venous catheters were found to be highly sensitive, specific, and predictive of bacteremia, especially when a cutoff point of 15 colonies of skin organisms was used.

Adult↗

PubMed2004

Aspergillus terreus: an emerging amphotericin B-resistant opportunistic mold in patients with hematologic malignancies.

BACKGROUND: Invasive aspergillosis (IA) has emerged as a common cause of morbidity and mortality among immunocompromised patients. At The University of Texas M. D. Anderson Cancer Center (Houston, TX), Aspergillus terreus is second to A. fumigatus as the most common cause of IA. In the current study, the authors compared the risk factors and outcomes associated with IA caused by A. terreus and IA caused by A. fumigatus. METHODS: The authors retrospectively reviewed the medical records of 300 patients who received care at our institution between 1995 and 2001 and who had cultures that were positive for Aspergillus infection, including 90 patients whose cultures were positive for A. fumigatus and 70 patients whose cultures were positive for A. terreus. RESULTS: Thirty-two patients with IA caused by A. terreus and 33 patients with IA caused by A. fumigatus were evaluated. The two groups were comparable in terms of age, gender, and underlying disease. Leukemia was the most common underlying malignancy (84%). More than 40% of patients in each group had undergone bone marrow transplantation. There was a trend toward a higher frequency of neutropenia among patients with IA caused by A. terreus (P = 0.12). IA caused by A. terreus was considered to be nosocomial in origin significantly more frequently compared with IA caused by A. fumigatus (P = 0.03). In vitro, A. terreus was found to be more resistant to amphotericin B (minimal inhibitory concentration [MIC90], 4.0 microg/mL) than to antifungal therapy (MIC90, 1.0 Hg/mL) in the isolates that were tested (< 50% of all isolates). The overall rate of response to antifungal therapy was 39% for patients with A. fumigatus infection, compared with 28% for patients with A. terreus infection (P = 0.43). CONCLUSIONS: Despite the decreased in vitro susceptibility of A. terreus (relative to A. fumigatus) to amphotericin B, the two groups within the current patient population had comparably poor responses to amphotericin B preparation and somewhat improved responses to posaconazole.

Adult↗

PubMed2004

Long-term silicone central venous catheters impregnated with minocycline and rifampin decrease rates of catheter-related bloodstream infection in cancer patients: a prospective randomized clinical trial.

PURPOSE: To evaluate the efficacy of long-term nontunneled silicone catheters impregnated with minocycline and rifampin (M-R) in reducing catheter-related bloodstream infections. PATIENTS AND METHODS: This prospective, randomized, double-blind clinical trial was conducted at M.D. Anderson Cancer Center, a tertiary care hospital in Houston, TX. All patients in the trial had a malignancy. RESULTS: Between September 1999 and May 2002, 356 assessable catheters were used: 182 M-R and 174 nonimpregnated. The patients' characteristics were comparable between the two study groups. The mean (+/- standard deviation) duration of catheterization with M-R catheters was comparable to that of nonimpregnated catheters (66.21 +/- 30.88 v 63.01 +/- 30.80 days). A total of 17 catheter-related bloodstream infections occurred during the course of the study. Three were associated with the use of M-R catheters and 14 were associated with the nonimpregnated catheters, with a rate of catheter-related bloodstream infection of 0.25 and 1.28/1,000 catheter-days, respectively (P = .003). Gram-positive cocci accounted for the majority of the organisms causing the infections. There were no allergic reactions associated with M-R catheters. CONCLUSION: Long-term nontunneled central venous catheters impregnated with minocycline and rifampin are efficacious and safe in reducing catheter-related bloodstream infections in cancer patients.

Anti-Bacterial Agents↗

PubMed2004

Differential time to positivity: a useful method for diagnosing catheter-related bloodstream infections.

BACKGROUND: Catheter-related bloodstream infections are associated with recognized morbidity and mortality, especially in critically ill patients. Accurate diagnosis of such infections results in proper management of patients and in reducing unnecessary removal of catheters. OBJECTIVE: To evaluate differential time to positivity as a method for diagnosing catheter-related bacteremias caused by both short-term and long-term use of central venous catheters. DESIGN: Prospective study design. SETTING: M.D. Anderson Cancer Center, Houston, Texas, a tertiary care cancer center. PATIENTS: All patients, between September 1999 and November 2000, who had the same organism isolated from blood cultures drawn simultaneously through the central venous catheter and the peripheral vein. MEASUREMENTS: Time necessary for the blood cultures from the central venous catheter and the peripheral vein to become positive, as well as other relevant patient information. RESULTS: 191 bloodstream infections with positive simultaneous central venous catheter and peripheral vein blood cultures were included. One hundred eight patients had catheter-related bacteremias, and 83 had non-catheter-related bacteremias. Catheter-related bacteremias were more frequently caused by staphylococci and less likely to be associated with underlying hematologic malignant conditions, neutropenia, and longer duration of hospitalization. As a diagnostic tool for catheter-related bacteremia (using a composite definition reference standard according to the Infectious Diseases Society of America guidelines), differential time to positivity of 120 minutes or more was associated with 81% sensitivity and 92% specificity for short-term catheters and 93% sensitivity and 75% specificity for long-term catheters. CONCLUSION: Differential time to positivity of 120 minutes or more is highly sensitive and specific for catheter-related bacteremia in patients who have short- and long-term catheters.

Bacteremia↗

PubMed2004

Differential quantitative blood cultures for the diagnosis of catheter-related bloodstream infections associated with short- and long-term catheters: a prospective study.

We prospectively evaluated the value of two levels of differential quantitative blood culture (DQBC) ratio (> or =2:1 or > or =5:1) in diagnosing catheter-related bloodstream infections (CRBSIs) in patients with malignancy that have short-term and long-term central venous catheters (CVCs) (<30 and > or =30 days of placement). Diagnosis of CRBSIs was based on results of semiquantitative cultures of removed catheters. For short-term CVCs a 5:1 or greater DQBC ratio had an 18% sensitivity, 67% specificity, 18% positive predictive value (PPV) and 67% negative predictive value (NPV), whereas a 2:1 or greater cut-off point for the DQBC was associated with a 45% sensitivity, 48% specificity, 26% PPV, and 68% NPV for the diagnosis of CRBSIs. For long-term CVCs, a cut-off point of 5:1 or greater of the DQBC had an 81% sensitivity, 40% specificity, 36% PPV, and 83% NPV for the diagnosis of CRBSIa, whereas a 2:1 or greater cut-off point had a 90% sensitivity, 30% specificity, 35% PPV, and 88% NPV for the diagnosis of CRBSIs. In conclusion, DQBCs are not diagnostic of CRBSIs for short-term CVCs. In long-term CVCs, DQBCs at 2:1 or greater or 5:1 or greater are sensitive but associated with low specificity and positive predictive value.

Adult↗

PubMed2003

Antibiotic-coated hemodialysis catheters for the prevention of vascular catheter-related infections: a prospective, randomized study.

PURPOSE: To determine the efficacy of minocycline-rifampin-coated hemodialysis catheters in reducing catheter-related infections in patients requiring hemodialysis for acute renal failure. METHODS: Between May 2000 and March 2002, 66 patients were randomly assigned to receive a minocycline-rifampin-impregnated central venous catheter and 64 were randomly assigned to receive an unimpregnated catheter. Patients were followed prospectively until the catheter was removed. Catheter-related infection was determined through quantitative catheter cultures, quantitative blood cultures, or both. RESULTS: Both groups of patients were similar in age, sex, underlying disease, type of dialysis (continuous vs. intermittent), neutropenia during catheterization and its duration, catheter insertion difficulties, and administration of blood products or medication. The mean (+/- SD) catheter dwell time was the same in both groups (8 +/- 6 days, P = 0.7). There were seven catheter-related infections (11%), all associated with the use of unimpregnated catheters. Kaplan-Meier estimates for the risk of catheter-related infection showed that coated catheters were less likely to be associated with infection (P = 0.006). CONCLUSION: The use of polyurethane hemodialysis catheters impregnated with minocycline and rifampin decreases the risk of catheter-related infection in patients with acute renal failure.

Acute Kidney Injury↗

PubMed2003

Clinical experience with minocycline and rifampin-impregnated central venous catheters in bone marrow transplantation recipients: efficacy and low risk of developing staphylococcal resistance.

In this retrospective evaluation of the 4-year clinical use of minocycline and rifampin-impregnated catheters in bone marrow transplantation (BMT) patients, we report low risk of development of staphylococcal resistance to the antibiotics coating the catheters and efficacy in preventing primary staphylococcal bloodstream infections.

Adult↗

PubMed2003

In vitro and ex vivo activities of minocycline and EDTA against microorganisms embedded in biofilm on catheter surfaces.

Minocycline-EDTA (M-EDTA) flush solution has been shown to prevent catheter-related infection and colonization in a rabbit model and in hemodialysis patients. We undertook this study in order to determine the activities of M-EDTA against organisms embedded in fresh biofilm (in vitro) and mature biofilm (ex vivo). For the experiment with the in vitro model, a modified Robbin's device (MRD) was used whereby 25 catheter segments were flushed for 18 h with 10(6) CFU of biofilm-producing Staphylococcus epidermidis, Staphylococcus aureus, and Candida albicans per ml. Subsequently, each of the catheter segments was incubated in one of the following solutions: (i) streptokinase, (ii) heparin, (iii) broth alone, (iv) vancomycin, (v) vancomycin-heparin, (vi) EDTA, (vii) minocycline (high-dose alternating with low-dose), or (viii) M-EDTA (low-dose minocycline alternating with high-dose minocycline were used to study the additive and synergistic activities of M-EDTA). All segments were cultured quantitatively by scrape sonication. For the experiment with the ex vivo model, 54 catheter tip segments removed from patients and colonized with bacterial organisms by roll plate were longitudinally cut into two equal segments and exposed to either saline, heparin, EDTA, or M-EDTA (with high-dose minocycline). Subsequently, all segments were examined by confocal laser electron microscopy. In the in vitro MRD model, M-EDTA (with a low concentration of minocycline) was significantly more effective than any other agent in reducing colonization of S. epidermidis, S. aureus, and C. albicans (P < 0.01). M-EDTA (with a high concentration of minocycline) eradicated all staphylococcal and C. albicans organisms embedded in the biofilm. In the ex vivo model, M-EDTA (with a high concentration of minocycline) reduced bacterial colonization more frequently than EDTA or heparin (P < 0.01). We concluded that M-EDTA is highly active in eradicating microorganisms embedded in fresh and mature biofilm adhering to catheter surfaces.

Anti-Bacterial Agents↗

PubMed2002

Minocycline-ethylenediaminetetraacetate lock solution for the prevention of implantable port infections in children with cancer.

In this prospective cohort study, minocycline-ethylenediaminetetraacetate (M-EDTA) was used as a lock solution in indwelling ports inserted in 14 children with cancer. No port infections, thrombotic events, or other adverse events were observed, compared with 10 port infections that occurred in 48 control patients whose ports were flushed with heparin. M-EDTA is a promising lock solution in long-term catheters.

Anti-Bacterial Agents↗