Biomedical subjects

Hend Hanna

Publications and source records attributed to Hend Hanna.

At least 19 recordsLinked to original sources

PubMed2006

Optimal antimicrobial catheter lock solution, using different combinations of minocycline, EDTA, and 25-percent ethanol, rapidly eradicates organisms embedded in biofilm.

Antimicrobial lock solutions may be needed to salvage indwelling catheters in patients requiring continuous intravenous therapy. We determined the activity of minocycline, EDTA, and 25% ethanol, alone or in combination, against methicillin-resistant Staphylococcus aureus and Candida parapsilosis catheter-related bloodstream infection strains in two established models of biofilm colonization. Biofilm-colonized catheter segments from a modified Robbins device and a silicone disk biofilm colonization model were exposed to these antimicrobial agents for 15 or 60 min, respectively. After exposure, segments were sonicated and cultured. To determine regrowth after incubation at 37 degrees C, following the brief exposure to the antimicrobial agents, an equal number of segments were washed, reincubated for 24 h, and then sonicated and cultured. The triple combination of minocycline-EDTA (M-EDTA) in 25% ethanol was the only antimicrobial lock solution that completely eradicated S. aureus and C. parapsilosis in biofilm of all segments tested in the two models, and it completely prevented regrowth. In addition, M-EDTA in 25% ethanol was significantly more effective in rapidly eradicating the growth or regrowth of methicillin-resistant S. aureus and C. parapsilosis biofilm colonization in the two models than the other solutions--minocycline, EDTA, M-EDTA, 25% ethanol, and EDTA in ethanol. We conclude that M-EDTA in 25% ethanol is highly effective at rapidly eradicating S. aureus and C. parapsilosis embedded in biofilm adhering to catheter segments.

Anti-Bacterial Agents↗

PubMed2006

Central venous catheter and Stenotrophomonas maltophilia bacteremia in cancer patients.

BACKGROUND: Stenotrophomonas maltophilia bacteremia is frequently found in cancer patients. This study attempted to determine how often the catheters were the source of this infection and the risk factors associated with catheter-related bacteremias. METHODS: The microbiology records were retrospectively reviewed of all cancer patients having S. maltophilia bacteremia and indwelling central venous catheters seen between January 1998 and January 2004. In a multivariate analysis the patients' clinical characteristics, antimicrobial therapy, outcome, and source of bacteremia that were significantly associated with definite catheter-related S. maltophilia bacteremia as opposed to secondary bacteremia were identified. RESULTS: A total of 217 bacteremias were identified in 207 patients: 159 (73%) were primary catheter-related (53 definite, 89 probable, and 17 possible), 11 (5%) were primary noncatheter-related, and 47 (22%) were secondary. Multivariate analysis showed the following factors to be independently associated with definite catheter-related bacteremias: 1) polymicrobial bacteremia (odds ratio [OR], 7.6; 95% confidence interval [95% CI], 1.3-45.5); 2) no prior intensive care unit admission (OR, 0.06; 95% CI, 0.005-0.578); and 3) nonneutropenic status at onset (OR, 0.07; 95% CI, 0.013-0.419). The response rate to appropriate antibiotics and catheter removal was 95% in the patients with definite catheter-related bloodstream infections, compared with only 56% in the patients with secondary bacteremias (P = .001). CONCLUSIONS: The majority of the S. maltophilia bacteremias occurring in cancer patients with indwelling central venous catheters appear to be catheter-related and are often polymicrobial. Catheter-related S. maltophilia bacteremias occurred more frequently in noncritically ill, nonneutropenic patients, and prompt removal of the catheter was found to be associated with a better prognosis.

Adult↗

PubMed2006

Clinical and radiologic predictors of invasive pulmonary aspergillosis in cancer patients: should the European Organization for Research and Treatment of Cancer/Mycosis Study Group (EORTC/MSG) criteria be revised?

BACKGROUND: Invasive pulmonary aspergillosis (IPA) is a life-threatening infection in immunocompromised patients. The outcome of such infections depends on early diagnosis and prompt initiation of therapy. The objective of the current study was to determine the significant predictive factors that characterize IPA in patients with cancer. METHODS: The clinical characteristics and computed tomography (CT) findings for 47 cases with IPA were retrospectively reviewed and compared with 49 controls (patients diagnosed on autopsy with nonfungal pneumonias). Data from all 96 patients were modeled using multivariate logistic regression. Subgroups of patients with common characteristics and outcomes were identified. RESULTS: Leukemia, neutropenia, cavitation, and nodular lesions occurred significantly more often among cases than controls (P = 0.04, 0.004, 0.04, and 0.02, respectively). A quantitative scoring system was developed that could be used to identify patients as being at low, medium, and high risk for IPA. CONCLUSIONS: IPA should be highly suspected in leukemia patients with profound neutropenia, pleuritic chest pain, and cavitary or nodular lesions detected on CT scan. These predictive factors can be used to indicate when early prophylactic and therapeutic antifungal interventions should be initiated.

Adult↗

PubMed2006

Comparative in vitro efficacies and antimicrobial durabilities of novel antimicrobial central venous catheters.

We investigated the efficacies and durability of novel antimicrobial central venous catheters (CVCs) in preventing the adherence of microbial organisms to the surfaces of the CVCs. Novel antimicrobial CVCs investigated in this in vitro study were impregnated with antibiotics (minocycline and rifampin), with Oligon agent (silver, platinum, and carbon black), with approved antiseptics (chlorhexidine and silver sulfadiazine), or with a novel antiseptic agent, gendine, which contains gentian violet and chlorhexidine. When tested against methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, gendine-coated CVC segments provided protection against bacterial adherence significantly more than all other types of tested CVCs (P < 0.05). Gendine-coated CVCs also provided better protection against Candida albicans and Candida parapsilosis than CVCs impregnated with antibiotics or with silver, platinum, and carbon (P < 0.02). After 28 days of being soaked in serum, the CVCs impregnated with chlorhexidine and silver sulfadiazine and the CVCs impregnated with silver, platinum, and carbon had lost antimicrobial activity against MRSA, P. aeruginosa, and C. parapsilosis, and the CVCs impregnated with minocycline and rifampin had lost activity against P. aeruginosa and C. parapsilosis. The CVCs impregnated with gendine maintained antimicrobial activities against MRSA, P. aeruginosa, and C. parapsilosis after 28 days of being soaked in serum. Central venous catheters impregnated with the novel investigational antiseptic gendine showed in vitro efficacy and provided protection against bacterial adherence more than other approved novel antimicrobial-coated CVCs.

Anti-Bacterial Agents↗

PubMed2006

EDTA as an adjunct antifungal agent for invasive pulmonary aspergillosis in a rodent model.

Rats immunosuppressed by the administration of cyclophosphamide and cortisone acetate and then infected with Aspergillus fumigatus were treated with an antifungal drug, EDTA, or a combination of one of the antifungal agents, amphotericin B lipid complex (ABLC; 5 mg/kg of body weight/day for 7 days), and EDTA (30 mg/kg/day for 7 days). The mortality rate was reduced, the duration of survival was increased, fewer A. fumigatus organisms were recovered from the lungs, and less-severe lung lesions were seen histopathologically in the rats receiving the combination treatment than in the rats receiving either an antifungal agent or EDTA alone. Further studies regarding the mechanisms of EDTA and its interactions with ABLC are warranted, and further studies are needed to more fully examine the safety, tolerance, and optimal dosing of EDTA in the treatment of this and other fungal infections.

Amphotericin B↗

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↗

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↗

PubMed2005

Itraconazole added to a lipid formulation of amphotericin B does not improve outcome of primary treatment of invasive aspergillosis.

BACKGROUND: Invasive aspergillosis (IA) is associated with poor outcome in patients with hematologic malignancy treated with amphotericin B (AMB)-based therapy. Itraconazole (ITC), a triazole with activity against Aspergillus, has been used in combination with AMB or lipid formulations of AMB (LipoAMB) in the treatment of IA, although the efficacy of this strategy is uncertain. METHODS: To determine whether the addition of ITC to LipoAMB improves outcome of IA, the authors retrospectively studied 179 consecutive patients with hematologic malignancies and definite or probable IA who received primary antifungal therapy with either LipoAMB (n = 146), or lipoAMB plus ITC (n = 33) between June 1993 and June 2003. In view of the erratic absorption of ITC tablets, only patients who received either intravenous or liquid ITC were analyzed. Patients who received < 1 week of treatment were excluded. RESULTS: Evaluable patients in both groups (LipoAMB: n =101; ITC and LipoAMB: n = 11) had comparable distribution of risk factors of poor outcome such as neutropenia at onset of IA, persistent neutropenia, systemic steroids, previous antifungal prophylaxis, admission to the intensive care unit, disseminated IA, previous bone marrow transplant, and IA due to infection by a non-fumigatus Aspergillus species. Response to primary antifungal therapy was equally poor in both groups (LipoAMB group: 10%; ITC and LipoAMB group: 0%; P = not significant). CONCLUSIONS: In the authors' 10-year study of patients with hematologic malignancy and IA, the response rate to LipoAMB given as primary therapy was very poor. In a comparable group of patients, the addition of ITC did not result in a therapeutic benefit.

Amphotericin B↗

PubMed2005

Efficacy and safety of weekly dalbavancin therapy for catheter-related bloodstream infection caused by gram-positive pathogens.

BACKGROUND: Catheter-related bloodstream infections (CR-BSIs) are associated with substantial mortality, prolongation of hospital stay, and increased cost of care. Dalbavancin, a new glycopeptide antibiotic with unique pharmacokinetic properties that have allowed clinical development of a weekly dosing regimen, possesses excellent activity against clinically important gram-positive bacteria, suggesting utility in the treatment of patients with CR-BSIs. METHODS: A phase 2, open-label, randomized, controlled, multicenter study of 75 adult patients with CR-BSIs compared treatment with intravenous dalbavancin, administered as a single 1000-mg dose followed by a 500-mg dose 1 week later, with intravenous vancomycin, administered twice daily for 14 days. Gram-positive bacteria isolated in this study included coagulase-negative staphylococci (CoNS) and Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA). RESULTS: Infected patients who received weekly dalbavancin (n=33) had an overall success rate (87.0%; 95% confidence interval [CI], 73.2%-100.0%) that was significantly higher than that of those who received vancomycin (n=34) (50.0%; 95% CI, 31.5%-68.5%). Adverse events and laboratory abnormalities were generally mild and were comparable for the 2 drugs. CONCLUSIONS: Dalbavancin thus appears to be an effective and well-tolerated treatment option for adult patients with CR-BSIs caused by CoNS and S. aureus, including MRSA.

Adult↗

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

Relationship between myalgias/arthralgias occurring in patients receiving quinupristin/dalfopristin and biliary dysfunction.

OBJECTIVES: To determine whether myalgias/arthralgias occurring in cancer patients who receive quinupristin/dalfopristin are associated with biliary tract dysfunction. METHODS: We studied 56 patients with vancomycin-resistant enterococcal infections who were treated with quinupristin/dalfopristin 7.5 mg/kg every 8 h for a mean duration of 12 days (range 2-52 days). Liver function tests, including a test for alkaline phosphatase, were performed before, during and after the end of therapy. All patients were followed for 1 month after completion of therapy. RESULTS: Thirty-eight (68%) of the 56 patients responded. Myalgias/arthralgias were the leading adverse events occurring in 20 (36%) of the patients. Patients with myalgias/arthralgias had significantly higher levels of alkaline phosphatase (mean 318.7 IU/L) during the mid-term therapy cycle compared with patients without any joint or muscular pain (mean 216.3 IU/L, P = 0.05). In addition, 3/18 (16.6%) patients with myalgias/arthralgias had more than five-fold the normal levels of alkaline phosphatase, which did not occur in any of the other patients who did not develop myalgias/arthralgias (P = 0.04). All myalgias/arthralgias resolved after the discontinuation of quinupristin/dalfopristin. By univariate analysis, other factors associated with myalgias/arthralgias were relapse of haematological malignancy (P = 0.01), receiving tacrolimus within 1 month prior to treatment (P = 0.04) and receiving methotrexate during antimicrobial therapy (P = 0.05). CONCLUSIONS: Myalgias/arthralgias occur frequently in cancer patients receiving quinupristin/dalfopristin and may be associated with biliary tract dysfunction, as measured by alkaline phosphatase or other factors that could lead to intra-hepatic cholestasis, such as relapse of haematological malignancy or treatment with tacrolimus or methotrexate.

Aged↗

PubMed2004

Management of central venous catheters in patients with cancer and candidemia.

To determine the need and appropriate timing of catheter removal in patients with candidemia, the records for 404 patients with cancer and central venous catheters (CVCs) who developed candidemia during the period of 1993-1998 were retrospectively reviewed. Of the total 404 cases of candidemia, 241 (60%) were due to a primary source, 111 (27%) were catheter related, and 52 (13%) were secondary cases of candidemia caused by a source other than the catheter. Multivariate analysis showed that catheter removal < or =72 h after onset improved response to antifungal therapy exclusively in patients with catheter-related candidemia (P=.04). Clinical characteristics that suggested a noncatheter source for the candidemia were disseminated infection (P<.01), previous chemotherapy (P<.01), previous corticosteroid therapy (P=.02), and poor response to antifungal therapy (P<.03). CVC removal < or =72 h after onset should be considered in patients with suspected catheter-related candidemia who have no evidence of dissemination, recent corticosteroid therapy, or chemotherapy.

Candidiasis↗

PubMed2004

Prospective, randomized study comparing quinupristin-dalfopristin with linezolid in the treatment of vancomycin-resistant Enterococcus faecium infections.

OBJECTIVES: Quinupristin-dalfopristin and linezolid have been shown to be efficacious in the treatment of vancomycin-resistant Enterococcus faecium (VREF) infections. However, the two antibiotics have not been compared in terms of safety and efficacy in a prospective randomized study. The objective of this study was to compare the safety and efficacy of the two drugs in the treatment of VREF infections in cancer patients. PATIENTS AND METHODS: Forty cancer patients with VREF infection were randomized to receive linezolid 600 mg every 12 h or quinupristin-dalfopristin 7.5 mg/kg every 8 h. All patients were followed up for 30 days after discontinuation of study drugs. RESULTS: Linezolid and quinupristin-dalfopristin had comparable clinical responses (58% and 43%, respectively, P = 0.6). Myalgias and/or arthralgias occurred at a frequency of 33% in patients who received quinupristin-dalfopristin, but were not observed in the linezolid group (P = 0.03). In contrast, drug-related thrombocytopenia occurred in 11% of patients who received linezolid, but was not observed in the quinupristin-dalfopristin group (P = 0.2). CONCLUSION: In cancer patients, quinupristin-dalfopristin treatment is associated with a relatively high frequency of myalgias/arthralgias; however, profound thrombocytopenia might limit the choice of linezolid in a subpopulation of cancer patients.

Acetamides↗

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↗

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

Smallpox vaccine: "non-take" responses in previously vaccinated adults.

This small, retrospective study of laboratory workers who received smallpox vaccine showed a strong correlation between "non-take" reactions and the presence of prior vaccination scars. Although we cannot exclude technique and vaccine potency as causes, the association we observed may indicate that these workers are displaying residual immunity to smallpox.

Adult↗

PubMed2004

Central venous catheter-related bacteremia due to gram-negative bacilli: significance of catheter removal in preventing relapse.

OBJECTIVE: To study the characteristics of catheter-related, gram-negative bacteremia (GNB) and the role of central venous catheter (CVC) removal. DESIGN: This retrospective study involved a search of the microbiological department records of CVC and blood cultures and patients' medical records. SETTING: University of Texas M. D. Anderson Cancer Center, a tertiary-care hospital in Houston, Texas. PATIENTS: Patients with cancer who had catheter-related GNB, defined as (1) a positive catheter tip culture with at least 15 colony-forming units semiquantitatively, (2) isolation of the same organism from the tip and peripheral blood cultures, (3) no other source for bacteremia except the CVC, and (4) clinical manifestations of infection (fever or chills). RESULTS: Between January 1990 and December 1996, 72 cases of catheter-related GNB were available for review. Most of the patients (67; 93%) had their CVCs removed in response to the bacteremia. Few patients (5; 7%) retained their CVCs and were treated with appropriate antibiotics. When CVCs were removed, only 1 patient (1%) relapsed with the same organism, whereas all 5 patients with retained CVCs relapsed after having responded (P < .001). The most commonly isolated organisms were Enterobacter, Klebsiella, Stenotrophomonas, Pseudomonas, and Acinetobacter species. Catheter removal within 72 hours of the onset of the catheter-related GNB was the only independent protective factor against relapse of the infection (odds ratio, 0.13; 95% confidence interval, 0.02-0.75; P = .02). CONCLUSION: In patients with documented catheter-related GNB, CVCs should be removed within 48 to 72 hours to prevent relapse.

Anti-Bacterial Agents↗