Biomedical subjects

Ray Hachem

Publications and source records attributed to Ray Hachem.

33 records · Page 2Linked to original sources

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

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↗

PubMed2003

Efficacy and toxicity of caspofungin in combination with liposomal amphotericin B as primary or salvage treatment of invasive aspergillosis in patients with hematologic malignancies.

BACKGROUND: Caspofungin (CAS) as salvage therapy for refractory invasive aspergillosis (IA) had a response rate of 45% among a heterogeneous group of patients. The use of CAS with other agents is appealing given its unique mechanism of action. Therefore, the authors retrospectively evaluated the efficacy and toxicity of CAS plus liposomal amphotericin B (LipoAMB) in patients with documented (definite or probable) or possible IA. METHODS: Patients were evaluable for outcome if they received CAS/LipoAMB for at least 7 days. Patients who received CAS and LipoAMB sequentially were excluded. All patients were evaluable for toxicity. Outcome was assessed weekly and at the end of therapy. Stable disease and progression were considered treatment failures. RESULTS: Forty-eight patients with documented (n=23) or possible (n=25) IA were identified between March 2001 and December 2001. The majority of the patients (65%) received CAS/LipoAMB as salvage therapy for progressive IA despite 7 or more days of previous LipoAMB monotherapy. The overall response rate was 42%. No significant toxic effects were seen. Factors associated with failure at the end of therapy were documented IA (P=0.03), significant steroid use before the study (P=0.02), and duration of combination therapy for less than 14 days (P=0.01). The response rate in patients with progressive documented IA was low (18%). CONCLUSIONS: The CAS/LipoAMB combination is a promising preemptive therapy for IA and was generally well tolerated. This combination might have limited benefit as salvage therapy for documented IA.

Adolescent↗

PubMed2003

Aspergillosis caused by non-fumigatus Aspergillus species: risk factors and in vitro susceptibility compared with Aspergillus fumigatus.

Invasive aspergillosis (IA) caused by inherently more antifungal-resistant non-fumigatus Aspergillus species has become an important life-threatening complication in severely immunocompromised patients with cancer. The purpose of this study was to compare the relative incidence of, risk factors for, and in vitro correlation of amphotericin B and itraconazole with the clinical outcome of IA caused by Aspergillus fumigatus with those of IA caused by non-fumigatus Aspergillus spp. in patients with cancer. A retrospective search of our tertiary care cancer center's microbiology laboratory reports from 1998-2001 revealed 40 patients with cancer and IA. A non-fumigatus Aspergillus species caused IA in 28 (70%) of those patients. A. fumigatus was the predominant cause of late-onset IA after bone marrow transplantation (p = 0.05), whereas IA due to non-fumigatus Aspergillus spp. was more common in patients with neutropenia (p = 0.01). The minimum inhibitory concentration (50/90) and minimum fungicidal concentration (50/90) for amphotericin B were higher in the non-fumigatus Aspergillus spp. group than in the A. fumigatus one. The Aspergillus species distribution in IA cases in our institution shows a predominance of the more antifungal-resistant or -tolerant non-fumigatus Aspergillus spp.

Adult↗

PubMed2003

Fungal sinusitis in the immunocompetent patient: risk factors and surgical management.

BACKGROUND: Fungal sinusitis has been reported increasingly in immunocompetent patients. However, the most effective, appropriate mode of therapy has not been determined. MATERIALS AND METHODS: In this retrospective study, we examined the records of 110 immunocompetent patients with chronic sinusitis who had undergone sinus surgery at our institution between 1983 and 1994. Five patients (4.5%) with fungal sinusitis were identified. Information on those patients was compared with that of the 105 patients with nonfungal sinusitis. RESULTS: Prolonged use of topical steroids was no more common in patients with fungal sinusitis (20%) than it was in patients with nonfungal sinusitis (4.8%) (p = 0.25). Differentiating features of fungal sinusitis were the presence of a metallic density and areas of high- and low-density on radiologic examination (p < 0.01). All five of the patients with fungal sinusitis were cured by surgical intervention, primarily endoscopic sinus surgery, without undergoing anti-mycotic therapy. Four of the five patients were followed up for at least 3 years without any recurrence. CONCLUSION: Endoscopic sinus surgery is and should remain the mainstay of treatment for fungal sinusitis in immunocompetent patients. Adjunctive anti-mycotic therapy may not be necessary.

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↗

PubMed2002

Skin lesions associated with Fusarium infection.

Infections caused by Fusarium species are increasing in frequency among immunocompromised hosts. We identified 35 patients with cancer who had Fusarium skin lesions. Twenty patients had disseminated infection, 6 had primary localized skin infections, 4 had skin lesions associated with sinus infections, and 5 had onychomycosis. All patients (except 3 with onychomycosis) had hematologic malignancies and neutropenia. Skin lesions associated with disseminated infection included red or gray macules, papules (some with central necrosis or eschar), pustules, and subcutaneous nodules. Most patients had a variety of lesions simultaneously. Multiple red or gray macules with central ulceration or black eschar are characteristic of Fusarium infection. Disseminated infection may originate from skin lesions or onychomycosis. Most infections fail to respond to antifungal therapy unless there is resolution of the patient's neutropenia.

Adult↗

PubMed2002

Prevention and management of long-term catheter related infections in cancer patients.

Long-term central venous catheters (CVC) are necessary in the care of cancer patients. However, catheter-related bloodstream infection (CRBSI) is commonly associated with serious complications resulting in considerable morbidity and mortality. The diagnosis of CRBSI frequently requires catheter removal to confirm the diagnosis by either quantitative or semiquantitative catheter culture method. Differential time to positivity, whereby a nonquantitative blood culture drawn from the CVC that becomes positive at least 2 hr earlier than the peripheral blood culture, is a new method for the diagnosis of CRBSI without removing the catheter. Prevention of CRBSI may be accomplished with the use of strict infection control measures, antimicrobial-impregnated catheters; and antibiotic-lock technique, as well as other methods. Once infection develops, management of long-term CRBSI is dictated by the type of organism, the severity of the infection, and availability of other venous access sites. If the infection is caused by Staphylococcus aureus, gram-negative bacilli, or Candida, the catheter should be removed and systemic antimicrobial therapy given for 10-14 days or longer in cases of complicated or deep-seated infection. In some cases, where there is no other venous access site, the catheter can remain in place, but a combination of systemic antimicrobials and antibiotic-lock therapy should be used.

Antibiotic Prophylaxis↗

PubMed2002

Masking of neutropenic patients on transport from hospital rooms is associated with a decrease in nosocomial aspergillosis during construction.

To prevent nosocomial pulmonary aspergillosis during hospital construction, neutropenic patients with hematologic malignancy were required to wear high-efficiency masks when leaving their rooms. The rate of nosocomial aspergillosis decreased from 0.73 per 1,000 hospital patient-days during fiscal years 1993 to 1996 to 0.24 per 1,000 hospital patient-days during fiscal years 1996 to 1999 (P < .001). High-efficiency masks reduced nosocomial aspergillosis during hospital construction.

Air Pollutants↗

PubMed2002

Failure of oral antimicrobial agents in eradicating gastrointestinal colonization with vancomycin-resistant enterococci.

Eradication of gastrointestinal colonization with vancomycin-resistant enterococci (VRE) using a combination of oral bacitracin and gentamicin was evaluated. Twenty-eight evaluable treated patients were matched with 28 control patients. After 3 months of follow-up, 5 patients (18%) in the treatment group versus 1 patient (4%) in the control group (P = .2) had negative results on stool cultures, with a similar frequency of VRE bacteremia (P = .8). The use of oral bacitracin plus gentamicin did not reduce VRE colonization or bacteremia.

Administration, Oral↗

PubMed2002

Risk factors for vancomycin-resistant Enterococcus (VRE) infection in colonized patients with cancer.

To determine the risk factors for vancomycin-resistant Enterococcus (VRE) infection in colonized patients with cancer, we conducted a case-control study. According to multivariate analysis, the only significant factors were neutropenia (< 500 cells/mm3) for more than 1 week and the use of oral vancomycin. Therefore, colonized neutropenic patients with cancer who have previously used oral vancomycin are most prone to VRE infection.

Adolescent↗

PubMed2002

Epidemiology, molecular mycology, and environmental sources of Fusarium infection in patients with cancer.

OBJECTIVE: To investigate the epidemiology and environmental sources of Fusarium infections in patients with cancer. DESIGN: Retrospective case-control study conducted following surveillance environmental cultures and DNA analysis of isolated organisms. SETTING: A tertiary-care, university cancer center. METHODS: In 1996 and 1997, environmental cultures were performed on air samples and water systems. A retrospective chart review was performed for 70 patients with cancer identified with fusariosis between 1987 and 1997. Patients with fusariosis were compared with 49 uninfected control patients who occupied hospital rooms with positive environmental cultures for Fusarium. With the use of random amplification of polymorphic DNA, organisms isolated from infected patients were compared with environmental organisms. RESULTS: Most of the patients with Fusarium (40, 57%) were infected on or within 3 days of admission, indicating community rather than nosocomial acquisition. Patients were comparable in terms of underlying immunocompromised status to 49 uninfected control patients. However, the duration from admission to infection in the patients with fusariosis tended to be shorter than the duration from admission to discharge in the exposed control patients (P = .06). Water cultured from the hospital tanks and from sinks and water fountains was negative for Fusarium. With the use of polymerase chain reaction, environmental isolates did not match clinical ones. Quantitative air sampling showed that the quantitative outdoor Fusarium levels were eightfold higher than the indoor levels. During the rainy summer season, outdoor air concentrations of Fusarium were at their highest, coinciding with the peak incidence of fusariosis at our center. CONCLUSION: The most likely source of fusariosis was the external environment rather than nosocomial sources, such as water.

Adolescent↗

PubMed2002

Efficacy of minocycline and EDTA lock solution in preventing catheter-related bacteremia, septic phlebitis, and endocarditis in rabbits.

To determine the efficacy of antibiotic catheter lock solution in preventing catheter-related infections, silicone catheters were tunneled and inserted into the jugular veins of 18 rabbits. The catheters were challenged with an intraluminal injection of 10(5) CFU of slime-producing Staphylococcus epidermidis in 0.1 ml of water. The catheters were maintained on heparin (100 IU/ml) flush for the first 3 days. On day 3, quantitative blood samples for culture were obtained from the catheters and ear veins, which documented catheter-related bacteremia, and the rabbits were randomized to have their catheters flushed as follows: five animals were continued on heparin (100 IU/ml), five animals received vancomycin (3 mg/ml) with heparin (100 IU/ml), and eight animals received 3 mg of minocycline per ml with 30 mg of EDTA per ml (M-EDTA). All animals were killed at day 7. Blood, catheters, jugular veins, and heart valves were cultured quantitatively. Animals maintained on heparin developed catheter-related colonization, bacteremia, septic phlebitis, and endocarditis. Vancomycin-heparin partially prevented catheter colonization, bacteremia, and phlebitis (P = 0.2). M-EDTA completely prevented catheter colonization, catheter-related bacteremia, and phlebitis in all of the animals (P < 0.01). Tricuspid endocarditis was equally prevented by vancomycin-heparin and M-EDTA (P < or = 0.06). In conclusion, the M-EDTA catheter flush solution was highly efficacious in preventing catheter-related colonization, bacteremia, septic phlebitis, and endocarditis in rabbits.

Animals↗

PubMed2002

Diagnosis of invasive pulmonary aspergillosis using polymerase chain reaction-based detection of aspergillus in BAL.

STUDY OBJECTIVE: To assess the value of Aspergillus polymerase chain reaction (PCR) test performed on the BAL in diagnosing invasive pulmonary aspergillosis (IPA). DESIGN: Between January 1996 and 1997, we prospectively followed up 249 cancer patients with pulmonary infiltrates suggestive of pneumonia. Bronchoscopy with fungal stains, cultures, and PCR was performed on all patients. PCR was used for the detection of Aspergillus mitochondrial and alkaline protease gene DNA. The PCR products were visualized either directly on polyacrylamide gel or after Southern transfer and probing with specific probes for mitochondrial and alkaline protease DNA. RESULTS: The 249 patients consisted of 10 patients with proven IPA (tissue invasion), 22 patients with probable IPA (microbiologic culture), 18 patients with possible IPA (consistent clinical and radiologic findings), and 199 control patients with no evidence of IPA. PCR positivity was strongly associated with all forms of IPA (p < 0.002). The sensitivity, specificity, positive predictive value, and negative predictive value of PCR were 80%, 93%, 38%, and 99%, respectively, for proven IPA, and 64%, 93%, 52%, and 96%, respectively, for probable IPA. Southern blotting analysis did not improve the diagnostic yield of the PCR test. CONCLUSION: PCR performed on BAL is associated with high specificity and negative predictive value for IPA. The low positive predictive value could be related to the transient colonizing presence of aspergilli in the respiratory tract. The sensitivity correlates with the certainty of the diagnosis based on tissue invasion.

Adolescent↗