Biomedical subjects

I Raad

Publications and source records attributed to I Raad.

At least 55 records · Page 3Linked to original sources

PubMed1997

The epidemiology of hematogenous candidiasis caused by different Candida species.

The medical records of patients with hematogenous candidiasis at M. D. Anderson Cancer Center (Houston) between 1988 and 1992 were retrospectively reviewed. There were 491 episodes of infection (6 per 1,000 admissions), 79% of which occurred outside the intensive care unit setting. A significant decrease in incidence was observed among patients with leukemia over the study period, together with a relative decrease in Candida albicans and Candida tropicalis infections and an increase in Candida krusei and possibly Candida glabrata infections. In the multivariate analysis, fluconazole prophylaxis provided strong protection against the development of C. tropicalis infection (odds ratio [OR] = 0.08) and C. albicans infection (OR = 0.15), in comparison with protection against infections due to other species, but it was the single most important determinant for the relative increase in C. krusei (OR = 27.07) and C. glabrata (OR = 5.08) infections. In conclusion, there has been a substantial shift in the epidemiology of hematogenous candidiasis caused by different Candida species in recent years. Fluconazole appears to be playing a major role in this observed shift.

Adult↗

PubMed1997

Minocycline and ethylenediaminetetraacetate for the prevention of recurrent vascular catheter infections.

Three patients with recurrent vascular catheter-related bacteremia were successfully treated by allowing a solution of minocycline and ethylenediaminetetraacetate (EDTA) to dwell in the lumen of the indwelling catheter or by coating polyurethane catheters with minocycline/EDTA and flushing the lumen daily with the same solution. In vitro and in vivo experiments showed that minocycline/EDTA may have broad-spectrum antimicrobial activity, may have optimal anticoagulant activity, and may be highly efficacious in preventing catheter colonization.

Adult↗

PubMed1997

Nosocomial respiratory syncytial virus infections: prevention and control in bone marrow transplant patients.

OBJECTIVE: To assess the effectiveness of a multifaceted infection control strategy in limiting the nosocomial transmission of respiratory syncytial virus (RSV) infection to patients in a bone marrow transplant (BMT) unit. DESIGN: Before/after trial. SETTING: University-affiliated tertiary cancer center. PATIENTS: Adult BMT recipients hospitalized during two consecutive wintertime community outbreaks of RSV infection. INTERVENTIONS: An infection control strategy against nosocomial RSV infection was implemented in the BMT unit in February 1993. The strategy involved prompt identification, isolation, and cohorting of RSV-infected patients; prompt therapy with aerosolized ribavirin; use of masks and gloves by anyone entering an infected BMT patient's room; screening visitors for respiratory symptoms; restricting visitation by all children under 12 years of age and all family members and other visitors with RSV symptoms; and restricting symptomatic hospital staff from working in the BMT unit. RESULTS: After implementation of the multifaceted infection-control strategy, there were four cases of nosocomial RSV infection in 3,870 patient days (incidence density, 1.0 case/1,000 patient days) compared with 14 cases of nosocomial RSV infection in 3,152 patient days (incidence density, 4.4 cases/1,000 patient days) during the 1992-1993 RSV season (rate ratio, 4.4; 95% confidence interval [CI95]. 1.4-17.9: P < .01). This decrease in incidence occurred despite a comparable prevalence of community-acquired RSV cases between the two seasons (2.2% vs 3.2% in 1992-1993 and 1993-1994, respectively; prevalence ratio, 0.7; CI95, 0.2-2.1; P = 0.5). CONCLUSION: Institution of a multifaceted infection control strategy significantly reduced the frequency of nosocomial RSV infection in a high-risk group of adult BMT recipients.

Adult↗

PubMed1996

In vitro study of the potential role of quinupristin/dalfopristin in the treatment of catheter-related staphylococcal infections.

The susceptibility of clinical isolates of methicillin-susceptible and -resistant staphylococci from cancer patients with central venous catheter bacteremia to quinupristin/dalfopristin, a semisynthetic streptogramin, was determined in vitro. Susceptibility of these isolates to nine other antistaphylococcal antibiotics was also determined for comparison. A total of 197 staphylococcal strains were tested from 1983 to 1992. Quinupristin/dalfopristin was bactericidal against all isolates, independent of their resistance to methicillin. Its activity was similar to that of vancomycin but superior to that of teicoplanin. Quinupristin/dalfopristin may prove to be an important addition to our armamentarium against catheter-related staphylococcal infections.

Anti-Bacterial Agents↗

PubMed1996

Imipenem or cefoperazone-sulbactam combined with vancomycin for therapy of presumed or proven infection in neutropenic cancer patients.

The purpose of this prospective randomized study was to compare the efficacy and safety of imipenem and cefoperazone-sulbactam combined with vancomycin for the treatment of fever in neutropenic cancer patients. Patients were assigned to either imipenem 500 mg/m2 (500 mg for bone marrow transplant recipients) every 6 h or cefoperazone (2 g)-sulbactam (1 g) every 8 h All patients received vancomycin 1 g every 12 h. A total of 457 febrile or infectious episodes occurring in 407 patients were entered in the study. The response rate was 73% for imipenem plus vancomycin and 74% for cefoperazone-sulbactam plus vancomycin among the 369 episodes that could be evaluated. Response rates were comparable for the two regimens with regard to infecting organism, administration of antimicrobial prophylaxis, and neutrophil count and trend. The frequency of side-effects was significantly higher for imipenem plus vancomycin (11% vs.5%, p = 0.02), due to therapy-associated nausea and vomiting (5.3% vs. 0%, p = 0.0004). The overall frequency of superinfections was similar with both regimens, but Clostridium difficile colitis occurred significantly more often in patients receiving imipenem plus vancomycin (5 vs. 0, p = 0.02). In this study cefoperazone-sulbactam plus vancomycin was an effective alternative to imipenem plus vancomycin for initial therapy of fever in neutropenic patients.

Adolescent↗

PubMed1996

In vitro antimicrobial efficacy of silver iontophoretic catheter.

A silver iontophoretic catheter was designed consisting of two silver wires connected to an electric power source and disposed in a parallel and helical manner around the proximal subcutaneous segment of a silicone catheter. In an in vitro tunnelled bridge model the silver iontophoretic catheter prevented the migration of Staphylococcus epidermidis from the highly contaminated hub to the sterile tip over a 40-d period. The silver impregnated cuff and electrically charged wires made of aluminium or iron delayed migration for only 72 h. A modified Kirby-Bauer technique, used to test the inhibitory activity of antimicrobial catheters, showed that the silver iontophoretic catheter has a broad spectrum inhibitory activity against Gram-positive bacteria, Gram-negative bacteria and Candida albicans. The silver iontophoretic catheter provides a long-term electrochemical barrier against the migration of organisms from the external contaminated environment into the sterile intravascular compartment.

Catheterization↗

PubMed1996

Use of adjunctive treatment with interferon-gamma in an immunocompromised patient who had refractory multidrug-resistant tuberculosis of the brain.

We describe a patient with acute lymphocytic leukemia and multidrug-resistant tuberculosis of the brain and spinal cord. Despite treatment with six antituberculous drugs and a steroid medication for 11 months, there was no appreciable clinical or radiological improvement in the patient's condition. Within 5 months of initiating adjunctive therapy with IFN-gamma and granulocyte colony stimulating factors, substantial neurological and radiological improvement was noted. Therapy with IFN-gamma was continued for 12 months, resulting in complete resolution of the lesions in the brain and spinal cord.

Adult↗

PubMed1996

Community respiratory virus infections among hospitalized adult bone marrow transplant recipients.

From 1 November 1992 through 1 May 1993 and from 1 November 1993 through 1 May 1994, we conducted a prospective surveillance study at the University of Texas M.D. Anderson Cancer Center (Houston) to evaluate the role of community respiratory virus infections in hospitalized adult bone marrow transplant (BMT) recipients, Respiratory secretions were obtained from all adult BMT recipients with acute respiratory illnesses. During these two winters, a community respiratory virus was isolated from 37 (36%) of 102 patients and 30 (26%) of 115 patients, respectively. Approximately half (49%) of these infections were due to respiratory syncytial virus (RSV); the remainder were due to influenza virus (18%), picornaviruses (18%), parainfluenza virus (9%), or adenovirus (6%). Fifty-eight percent of these infections were complicated by pneumonia, with an associated mortality of 51%. The pneumonias that complicated RSV infection were almost exclusively viral in origin and were associated with a mortality of 100% if not treated promptly with antiviral agents. In contrast, many of the pneumonias that complicated the other viral infections, such as influenza, appeared to be either self-limited viral pneumonias or secondary bacterial or fungal pneumonias. Community respiratory viruses are frequent causes of acute respiratory illnesses in adult BMT recipients hospitalized during the winter and are associated with substantial morbidity and mortality.

Adenovirus Infections, Human↗

PubMed1996

Cutaneous and pulmonary infections caused by Mycobacterium vaccae.

Mycobacterium vaccae is a rapidly growing mycobacterial species that was previously not considered a human pathogen. We report four cases of M. vaccae infection that occurred in the southern United States; one patient had cutaneous disease, and three patients had cavitary lung disease. Two of the three patients with pulmonary disease had a history of exposure to cattle. The conditions of all patients improved with therapy: the cutaneous infection responded to therapy with minocycline and trimethoprim-sulfamethoxazole, and the pulmonary infections responded to therapy with ciprofloxacin.

Aged↗

PubMed1996

The broad-spectrum activity and efficacy of catheters coated with minocycline and rifampin.

The in vitro and in vivo activities of catheters coated with minocycline and rifampin and with chlorhexidine gluconate and silver sulfadiazine were evaluated. When incubated in serum at 37 degrees C, the half-life of the inhibitory activity of catheters coated with minocycline and rifampin was 25 days compared with 3 days for catheters coated with chlorhexidine gluconate and silver sulfadiazine. In a rabbit model, catheters coated with minocycline and rifampin were significantly more efficacious than catheters coated with chlorhexidine and silver sulfadiazine in preventing colonization and infection with Staphylococcus aureus (P < .05). Catheters coated with minocycline and rifampin demonstrated broad-spectrum in vitro inhibitory activity against gram-positive bacteria, gram-negative bacteria, and Candida albicans that was significantly superior to the inhibitory activity of catheters coated with chlorhexidine gluconate and silver sulfadiazine (P < .01). Minocycline and rifampin were also highly efficacious in preventing colonization and infection in vivo.

Animals↗

PubMed1996

Silver iontophoretic catheter: a prototype of a long-term antiinfective vascular access device.

A silver iontophoretic catheter (SIC) was developed consisting of two electrically charged parallel silver wires helically wrapped around the proximal segment of a vascular catheter. In vitro and in vivo activities of this catheter were compared with those of an aseptic catheter coated with chlorhexidine and silver sulfadiazine (CH/SS). The SIC demonstrated broad-spectrum in vitro inhibitory activity against bacteria and Candida albicans comparable to that of the CH/SS-coated catheter. The durability of activity was determined by incubating catheters in serum at 37 degrees C for various time intervals. After 30 days, the antimicrobial activity of the SIC did not change significantly, while that of the CH/SS-coated catheter was reduced to a suboptimal level. In a rabbit model, the SIC was safe and significantly more efficacious than the CH/SS-coated catheter in preventing colonization with Staphylococcus aureus (P < .05). The SIC has broad-spectrum inhibitory activity of long durability and is highly efficacious in preventing colonization in vivo.

Animals↗

PubMed1995

Role of catheter colonization and infrequent hematogenous seeding in catheter-related infections.

Adult cancer patients were prospectively studied to determine the relationship between ultrastructural and microbiologic catheter colonization and clinical catheter-related infections. Participants included 38 patients whose central venous catheters were removed because of suspected catheter infection (16 patients) or other noninfectious causes (22 controls). The presence of clinical infection was determined. Catheters were examined by microbiologic methods (sonication and roll-plate culture) and by scanning and transmission electron microscopy. Ultrastructural microbial colonization and biofilm formation were universal and occurred as early as one day after catheter insertion. The extent of biofilm formation was unrelated to the clinical status of patient or the catheter microbiological findings. Secondary seeding of catheters was rarely seen. Catheter microbial biofilm formation occurs early, is universal and does not necessarily represent an infectious condition.

Adult↗

PubMed1995

Treatment of central venous catheter-related fungemia due to Fusarium oxysporum.

We report a case of Fusarium oxysporum fungemia that was related to the presence of a central venous catheter and was confirmed by quantitative cultures and scanning electron microscopy of the catheter hub, subcutaneous segment and cuff, and tip. Despite progressive neutropenia, the infection responded to antifungal therapy within 1 day after the catheter was removed. The removal of the catheter could have contributed to the patient's early favorable response.

Catheterization, Central Venous↗

PubMed1995

Antibiotics and prevention of microbial colonization of catheters.

Slime-producing staphylococci frequently colonize catheters, and when they are embedded in biofilm, they become resistant to various antibiotics. In the study that is described, the comparative efficacies of vancomycin, clindamycin, novobiocin, and minocycline, alone or in combination with rifampin, were tested in an in vitro model of colonization. The model consisted of the modified Robbins device with antibiotic-impregnated cement filling the lumen of catheter segments. The synergistic combination of minocycline and rifampin was the most efficacious in preventing bacterial colonization of slime-producing strains of Staphylococcus epidermidis and Staphylococcus aureus to catheter surfaces. A similar trend was observed when the inhibitory activities of polyurethane catheters coated with minocycline and rifampin were compared with the inhibitory activities of catheters coated with other antimicrobial agents. The inhibitory activities of catheters coated with minocycline and rifampin against S. epidermidis, S. aureus, and Enterococcus faecalis strains, for example, were significantly better than those of catheters coated with vancomycin (P < 0.05). The inhibitory activities of catheters coated with minocycline and rifampin against gram-negative bacilli and Candida albicans were comparable to those of catheters coated with ceftazidime and amphotericin B, respectively. We found that the combination of minocycline and rifampin is unique and highly effective in preventing the colonization of catheters with slime-producing staphylococci and that it also displays a broad-spectrum inhibitory activity against gram-negative bacteria and yeast cells.

Anti-Bacterial Agents↗

PubMed1993

Low infection rate and long durability of nontunneled silastic catheters. A safe and cost-effective alternative for long-term venous access.

BACKGROUND: Tunneled central venous catheters (CVCs) and infusion ports have often been considered as the only safe alternative for long-term venous access. The objective of this study was to assess the durability, cost, and infection rate of nontunneled, noncuffed Silastic CVCs. METHODS: We studied a representative cohort of 340 consecutive cancer patients with 359 nontunneled Silastic CVCs inserted and followed up at our center. All patients were evaluated clinically and microbiologically at the time of CVC removal. RESULTS: The mean in-place duration of the catheter for the 359 nontunneled CVCs studied was 109 days (total, 39,147 days of catheter use), and the infection rate was 0.13 per 100 catheter days. When compared with the tunneled Hickman catheter, the insertion cost saving was at least $2322 per CVC. At our institution, the use of nontunneled Silastic catheters with the support of an expert infusion team has resulted in an annual cost saving of at least $7,692,000. Long peripheral CVCs (in the basilic/cephalic vein) had a 26% rate of inflammation at the insertion site compared with only 2.6% for the short subclavian CVCs (P < .01). Most of the exit-site inflammations were sterile, with negative skin and catheter cultures. Neutropenia, bone marrow transplantation, high-dose steroids, and use of vesicant chemotherapeutic agents through the CVC did not predispose the patients to catheter infection. By univariate analysis, acute leukemia was the only risk factor for catheter infection. CONCLUSIONS: Given the low infection rate and long durability of nontunneled silicone CVCs, these catheters could offer a cost-effective and safe alternative to surgically implantable tunneled catheters.

Adult↗

PubMed1993

The duration of placement as a predictor of peripheral and pulmonary arterial catheter infections.

To determine the appropriate time for removal or replacement of peripheral and pulmonary arterial catheters in critically ill cancer patients, we prospectively studied 71 peripheral arterial catheters and 71 pulmonary artery (Swan-Ganz) catheters from 110 consecutive cancer patients. All catheters were cultured semiquantitatively, by the roll-plate culture technique. Of the 71 peripheral arterial catheters, 11 (15%) produced local infections (> or = 15 colonies) and four (5.5%) produced catheter-related septicaemia. Ten of the 11 local infections and all four septicaemias occurred after 4 days of catheter placement (P < 0.05). Likewise, of the 71 Swan-Ganz catheters, 12 (17%) produced local infection and four (5.6%) led to septicaemia. Swan-Ganz catheter-related septicaemia occurred at rates of 2% and 16%, before and after 7 days of catheter placement, respectively (P = 0.056). Duration of placement was a risk factor for the development of catheter infections, independent of the patient's neutropenic status, administration of antibiotics such as vancomycin during catheterization, and the presence of concurrent central venous catheters. Life-table analysis showed that the cumulative risks of developing a catheter infection increased from 7% to 17% after 6 days of peripheral arterial catheter placement and from 9% to 18% after 4 days of placement of the Swan-Ganz catheter. We conclude that in the critically ill cancer patient in our unit, peripheral arterial catheters should be changed to a new site every 4-6 days and pulmonary artery catheters every 4-7 days.

Adolescent↗

PubMed1993

Ultrastructural analysis of indwelling vascular catheters: a quantitative relationship between luminal colonization and duration of placement.

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.

Bacteria↗

PubMed1993

Nonwound infections following head and neck oncologic surgery.

Little information exists regarding the comorbidity of postoperative nonwound infections (NWIs) in patients with head and neck cancer. Prospectively, 225 patients were randomized in a double-blind fashion to receive either clindamycin or ampicillin sodium/sulbactam sodium for prevention of postoperative wound infection. Of the 113 patients receiving clindamycin, 14 developed nonwound infections, compared with 10 of 112 patients receiving ampicillin/sulbactam. A single site of nonwound infection occurred in 21 patients, and 2 sites occurred in 3 patients. The majority of infections were pulmonary (22), followed by urinary tract (3), septic phlebitis (1), and acute sinusitis (1). Gram-negative organisms were isolated more frequently among patients on clindamycin (18) versus ampicillin/sulbactam (6) (P = .014). Risk factors for pulmonary nonwound infection included: longer surgery, a greater than 70 packs per year smoking history, blood transfusion, and hypoalbuminemia (P < .05). Nonwound infections produce significant postoperative morbidity and the predominance of gram-negative organisms isolated from these infections has therapeutic implications.

Adolescent↗