Biomedical subjects

Tanya Dvorak

Publications and source records attributed to Tanya Dvorak.

6 recordsLinked to original sources

PubMed2005

Risk factors for infections with multidrug-resistant Pseudomonas aeruginosa in patients with cancer.

BACKGROUND: Pseudomonas aeruginosa is responsible for a wide range of infections. In immunocompromised patients with cancer, the emergence of multidrug resistant P. aeruginosa may have grave consequences. METHODS: Patients with cancer who were infected with multidrug-resistant P. aeruginosa with polyclonal DNA restriction patterns were used as the case group. Two control groups were used: one group of cancer patients who were infected with multidrug-susceptible P. aeruginosa and another group of cancer patients who had the same underlying disease and the same intensive care unit exposure as patients in the case group but who were not infected or colonized by P. aeruginosa. RESULTS: Risk factors that were associated significantly with multidrug-resistant P. aeruginosa infection were the use of carbapenem for > or = 7 days, a history of P. aeruginosa infection during the preceding year, and a history of chronic obstructive pulmonary disease (P < 0.01). CONCLUSIONS: Carbapenems may need to be used more judiciously as first-line empirical therapy for cancer patients with prior pseudomonal infection or chronic obstructive pulmonary disease who require hospitalization, and alternative, antipseudomonal antibiotic regimens may need to be considered, especially in this patient population.

Aged↗

PubMed2004

A rapid method of impregnating endotracheal tubes and urinary catheters with gendine: a novel antiseptic agent.

OBJECTIVES: To test the efficacy of gendine, a novel antiseptic, containing Gentian Violet and chlorhexidine, in coating different medical devices, including endotracheal tubes (ETT) and urinary catheters (UC). METHODS: We determined the antimicrobial efficacy and cytotoxicity of ETT and UC segments coated, through an instant dip method, with gendine. Using the modified Kirby-Bauer method, gendine-coated devices showed zones of inhibition of >/=15 mm against methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, Escherichia coli and Candida parapsilosis. RESULTS: Gendine-coated endotracheal tubes (GND-ETT) soaked in bronchoalveolar fluid (BAL) and incubated at 37 degrees C maintained a zone of inhibition of >/=15 mm against MRSA and P. aeruginosa for at least 3 weeks. Similarly, gendine-coated urinary catheters (GND-UC), soaked in urine, maintained a zone of inhibition of >/=15 mm against E. coli for 8 weeks. Using the minimum essential media elution method in mouse fibroblast cells, GND-ETT and GND-UC were found to be non-cytotoxic. Gendine-coated UC significantly reduced the amount of viable MRSA, E. coli or C. parapsilosis organisms adhering to their surfaces when compared with silver/hydrogel-coated urinary catheters or control uncoated catheters (P < 0.01). Similarly GND-ETT significantly reduced the adherence of the same organisms as well as P. aeruginosa when compared with control (P </= 0.02). CONCLUSIONS: GND-ETT and GND-UC impregnated using an instantaneous dip method, were shown to have broad-spectrum activity, prolonged antimicrobial durability and high efficacy in inhibiting adherence of organisms commonly causing nosocomial pneumonia and urinary tract infection. Furthermore, these coated devices were shown to be non-cytotoxic.

Animals↗

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

Impact of surveillance for vancomycin-resistant enterococci on controlling a bloodstream outbreak among patients with hematologic malignancy.

OBJECTIVE: To determine the impact of stool surveillance cultures of critically ill patients on controlling vancomycin-resistant enterococci (VRE) outbreak bacteremia. DESIGN: Stool surveillance cultures were performed on patients who had hematologic malignancy or were critically ill at the time of hospital admission to identify those colonized with VRE. Hence, contact isolation was initiated. SETTING: A tertiary-care cancer center with a high prevalence of VRE. PARTICIPANTS: All patients with hematologic malignancy who were admitted to the hospital as well as all of those admitted to the intensive care unit were eligible. RESULTS: Active stool surveillance cultures performed between 1997 and 2001 decreased the incidence density of VRE bacteremias eightfold while vancomycin use remained constant. In fiscal year (FY) 1997 and FY 1998, there were five and three VRE outbreak bacteremias, respectively. The outbreak clones were responsible for infection in 69% of those patients with VRE bacteremia. However, the stool surveillance program resulted in the complete control of VRE bacteremia by FY 1999 until the end of the study. CONCLUSION: Despite the steady use of vancomycin, the active surveillance program among high-risk patients with hematologic malignancy and those who were critically ill resulted in the complete control of VRE outbreak bacteremia at our institution.

Bacteremia↗

PubMed2004

Clinical-use-associated decrease in susceptibility of vancomycin-resistant Enterococcus faecium to linezolid: a comparison with quinupristin-dalfopristin.

The susceptibility of 135 vancomycin-resistant Enterococcus faecium bacteremic isolates to linezolid and quinupristin-dalfopristin was determined. All were susceptible to linezolid, while 88% were susceptible to quinupristin-dalfopristin prior to the clinical use of the drugs at our hospital. More than 6 months after their clinical use, a decrease in susceptibility was noted for only linezolid at 83%. This was related in part to a single G2576U gene mutation in domain V of the 23S rRNA gene.

Acetamides↗

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↗