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Daniel Lew

Publications and source records attributed to Daniel Lew.

31 records · Page 2Linked to original sources
PubMed2004

A novel multiplex real-time PCR assay for rapid typing of major staphylococcal cassette chromosome mec elements.

We describe a novel procedure for rapid typing of the staphylococcal cassette chromosome mec element, a molecular marker allowing discrimination between community- and hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) strains. Oligonucleotides targeting the recombinase genes were type specific and used to type a collection of 399 MRSA isolates recovered during patient screening at admission. This novel assay constitutes a valuable tool for evaluating the molecular epidemiology of MRSA and adjusting infection control strategies against MRSA.

Bacterial Proteins↗
PubMed2004

First report of Arthroderma benhamiae in Switzerland.

BACKGROUND: Dermatophytes are usually identified on the basis of macroscopic characteristics and microscopic examination of the cultures. Identification of dermatophytes often remains difficult or uncertain because there are variations from one isolate to another and overlapping characteristics between species. OBJECTIVE: To identify dermatophyte species producing numerous microconidia and resembling Trichophyton mentagrophytes by DNA sequence analysis. METHODS: The complete ITS1 + 5.6s + ITS2 rDNA region of various dermatophytes isolated in culture was amplified by PCR and sequenced. RESULTS: Nine isolates of a fast-growing dermatophyte species were identified as Arthroderma benhamiae by DNA sequencing. Retrospective investigations revealed that the isolates were from 8 children and 1 adult suffering from inflammatory dermatophytosis. Eight of the 9 patients had had previous contact with rodents, mostly guinea pigs. CONCLUSION: It is the first time that A. benhamiae is reported in Switzerland. In cases of dermatophytosis attributed to A. benhamiae, a rodent is the most likely cause of infection.

Adolescent↗
PubMed2003

Trends in the treatment of orthopaedic prosthetic infections.

The most commonly used therapy for prosthetic joint infection is a two-stage prosthetic exchange separated by 6 weeks of intravenous antibiotic therapy. This often results in long periods of hospitalization, morbidity, severe functional impairment and sometimes increased mortality. Therefore novel and challenging therapeutic approaches have been attempted, particularly in hip prosthetic infection. This includes, whenever possible, according to the type of microorganism, antibacterial susceptibility and clinical presentation (including age and comorbidities): (i) less aggressive surgical techniques (debridement and prosthesis retention, or re-implantation with a single-stage exchange arthroplasty); and (ii) antibiotic combinations active against biofilm-associated bacteria, including rifampicin (particularly with quinolones) with excellent bio-availability which allow prolonged and efficient oral therapy.

Anti-Bacterial Agents↗
PubMed2003

Inappropriate initial antimicrobial therapy and its effect on survival in a clinical trial of immunomodulating therapy for severe sepsis.

PURPOSE: To examine the effect of inappropriate initial antimicrobial therapy on the prognosis of patients with sepsis who were enrolled in a clinical trial of an immunomodulating agent conducted in 108 hospitals in North America and Europe. METHODS: We assessed initial antimicrobial choice and results of microbiologic cultures in 904 patients who had microbiologically confirmed severe sepsis or early septic shock. If a patient did not receive at least one antimicrobial agent to which the causative microorganisms were susceptible within 24 hours from the diagnosis of severe sepsis, then the initial antimicrobial treatment was considered to be inappropriate. A propensity score that adjusted for factors associated with inappropriate antimicrobial treatment was calculated and included in multivariable models to adjust for confounding. RESULTS: A total of 468 patients (52%) had documented bloodstream infection, and 211 patients (23%) received inappropriate initial antimicrobial therapy. Characteristics associated with inappropriate treatment were study enrollment in Europe, admission to surgery, nosocomial infection, infection with multiresistant microorganisms, and fungal or polymicrobial infection (all P <0.05). The 28-day mortality was 24% (168/693) for patients in the adequately treated group versus 39% (82/211) for patients receiving inappropriate initial antimicrobial therapy (P <0.001). After adjusting for comorbid conditions, severity of illness, site of infection, and the propensity score, inappropriate antimicrobial therapy was independently associated with increased mortality (odds ratio = 1.8; 95% confidence interval: 1.2 to 2.6). CONCLUSION: In a large cohort of patients with microbiologically confirmed severe sepsis, appropriate initial antimicrobial therapy was an important determinant of survival. New approaches aimed at improving detection and treatment of early sepsis are needed.

Aged↗
PubMed2003

Antibiotic consumption, bacterial resistance and their correlation in a Swiss university hospital and its adult intensive care units.

Ecological surveys of high-antibiotic use areas in the hospital should be used to evaluate patterns and trends in order to optimise antibiotic consumption and minimise resistance. We conducted a retrospective cohort study with the aim to examine trends in antimicrobial consumption and bacterial susceptibility at the Geneva University Hospital and its adult ICUs between 1996 and 2000. The average annual consumption of antimicrobials was 400 d-defined doses (DDD)/1000 patient-d in the entire hospital, 462 in the surgical ICU and 683 in the medical ICU. In the medical ICU, we observed a steady decrease of intravenous antimicrobial use, whereas a 25% increase in the total antimicrobial consumption was noted in 1999 and 2000 for the entire hospital. The proportion of different bacterial species, resistance rates and antibiotic consumption rates differed between the entire hospital and the ICUs, with moderate variation between y. Possible relationships between antibiotic consumption and resistance rates, expressed as DDD and as number of resistant isolates per 1000 patient-d respectively, were calculated for of the most frequently isolated bacteria (total 71 correlations). Statistically significant positive correlations between antibiotic consumption and resistance were found in Escherichia coli for piperacillin, in Pseudomonas aeruginosa for piperacillin, cephalosporins and aminoglycosides, in Klebsiella spp. for cephalosporin, in coagulase-negative staphylococci for gentamicin and in Streptococcus pneumoniae for penicillin.

Anti-Bacterial Agents↗
PubMed2003

Rapid detection of methicillin-resistant Staphylococcus aureus directly from sterile or nonsterile clinical samples by a new molecular assay.

A rapid procedure was developed for detection and identification of methicillin-resistant Staphylococcus aureus (MRSA) directly from sterile sites or mixed flora samples (e.g., nose or inguinal swabs). After a rapid conditioning of samples, the method consists of two main steps: (i) immunomagnetic enrichment in S. aureus and (ii) amplification-detection profile on DNA extracts using multiplex quantitative PCR (5'-exonuclease qPCR, TaqMan). The triplex qPCR assay measures simultaneously the following targets: (i) mecA gene, conferring methicillin resistance, common to both S. aureus and Staphylococcus epidermidis; (ii) femA gene from S. aureus; and (iii) femA gene from S. epidermidis. This quantitative approach allows discrimination of the origin of the measured mecA signal. qPCR data were calibrated using two reference strains (MRSA and methicillin-resistant S. epidermidis) processed in parallel to clinical samples. This 96-well format assay allowed analysis of 30 swab samples per run and detection of the presence of MRSA with exquisite sensitivity compared to optimal culture-based techniques. The complete protocol may provide results in less than 6 h (while standard procedure needs 2 to 3 days), thus allowing prompt and cost-effective implementation of contact precautions.

Bacterial Proteins↗
PubMed2002

Synaptotagmin II could confer Ca(2+) sensitivity to phagocytosis in human neutrophils.

Phagolysosome fusion and granule exocytosis in neutrophils are calcium-dependent processes. The calcium requirements vary between granule types, suggesting the presence of different calcium sensors. The synaptotagmins, a family of calcium-binding proteins, previously shown to participate in vesicle fusion and vesicle recycling in excitable cells, are putative calcium-sensors of exocytosis in excitable cells. In this study, we show that synaptotagmin II is present in human neutrophils and may participate in phagocytic and in exocytotic processes. In protein extracts from human neutrophils, we identified synaptotagmin II by Western blot as an 80 kDa protein. Subcellular fractionation revealed that synaptotagmin II was associated with the specific granules. In fMLP-stimulated cells, synaptotagmin II translocated to the plasma membrane. This correlated with the upregulation of complement receptor 3 (CR 3), reflecting the translocation of specific granules to the cell surface. Synaptotagmin II also translocated to the phagosome after complement-mediated phagocytosis in the presence of calcium. LAMP-1 translocated in parallel but probably was located to another subcellular compartment than synaptotagmin II. Under calcium-reduced conditions, neither synaptotagmin II nor LAMP-1 translocated to the phagosome. We therefore suggest a role for synaptotagmin II as calcium-sensor during phagocytosis and secretion in neutrophils.

Animals↗
PubMed2002

Symptoms and clinical and radiological signs predicting the presence of pathogenic bacteria in acute rhinosinusitis.

A minority of patients with upper respiratory tract infections (URTI) have a bacterial infection and may benefit from antibiotherapy. In previous investigations we showed that in patients suffering from acute rhinosinusitis associated with the presence of Streptococcus pneumoniae, Haemophilus influenzae or Moraxella catarrhalis in their nasopharygeal secretions, resolution of symptoms was significantly improved by antibiotic treatment. The present analysis was performed to determine whether specific clinical symptoms or signs observed during careful endoscopic examination of the nasal cavities could help the clinician to identify a subset of patients with moderate forms of acute rhinosinusitis infected with pathogenic bacteria. Detailed clinical histories were obtained and medical examinations performed in 265 patients (138 females, 127 males; mean age 35 years) presenting with a < 4-week history of URTI symptoms but who did not require immediate antibiotic therapy for severe rhinosinusitis. The presence of three pathogenic bacteria (S. pneumoniae, H. influenzae and M. catarrhalis) was determined in all patients by culture of nasopharyngeal secretions. Azithromycin (500 mg/day for 3 days; n = 133) or placebo (n = 132) were randomly given to all patients in a double-blind manner. Pathogenic bacteria were found in 77 patients (29%). The clinical signs and symptoms significantly associated in a multivariate model with the presence of bacteria included colored nasal discharge (p < 0.003), facial pain (p < 0.032) and radiologically determined maxillary sinusitis (complete opacity, air-fluid level or mucosal thickening > 10 mm) (p < 0.001). This best predictive model had a sensitivity of 69% and a specificity of 64% and therefore could not be used either as a screening tool or as a diagnostic criterion for bacterial rhinosinusitis. In the group of patients with positive bacterial cultures, resolution of symptoms at Day 7 was observed in 73% of patients treated with azithromycin and in 47% of patients in the placebo group (p < 0.007). We conclude that signs and symptoms of acute rhinosinusitis in patients with mild-to-moderate clinical presentations are poor predictors of the presence of bacteria.

Acute Disease↗
PubMed2002

Successful treatment of Paecilomyces lilacinus endophthalmitis with voriconazole.

Paecilomyces lilacinus is a rare cause of endophthalmitis and there are few reports of it in the literature. Herein we report a patient with P. lilacinus endophthalmitis who was treated with the new triazole, voriconazole, for 4 months, with a good clinical evolution. This treatment appears to be a valuable new therapeutic option but requires further clinical confirmation.

Adolescent↗
PubMed2002

Secular trends of candidemia over 12 years in adult patients at a tertiary care hospital.

The incidence of fungal infections has been increasing for the last 3 decades, especially among neutropenic, cancer, and critically ill patients. These infections are associated with high mortality rates. We retrospectively reviewed medical charts of adult patients with fungemia from 1989 to 2000 at our institution. The characteristics of the population groups served by the hospital were described. Of 328 patients with fungemia, we reviewed 315 (96%) medical records, and focused on those with candidemia (n = 294). The species distribution in patients with candidemia showed that the most commonly identified species were Candida albicans (66%), followed by C. glabrata (17%), and C. parapsilosis (6%). The incidence of candidemia ranged from 0.2 to 0.46 per 10,000 patient-days with the highest incidence in 1993 and the lowest in 1997. Although most studies show an increased incidence of candidemia, we observed a reduction over the study period. Furthermore, we observed no shift from C. albicans to non-albicans Candida species despite a significant increase in the use of fluconazole. The overall mortality among patients with candidemia was 44%, with the highest rate in patients over 65 years (52%). Factors independently associated with higher mortality were patient age greater than 65 years, intensive care unit admission, and underlying cancer.

Adolescent↗
PubMed2002

Short-term bone responses to hydroxyapatite cement.

PURPOSE: The purpose of this study was to evaluate the short-term wound healing and repair at the tissue/cement interface with different hydroxyapatite cement formulations. MATERIALS AND METHODS: Three groups of Sprague-Dawley rats were implanted with HAC for 3, 7, or 14 days. The medial femur-tibia sites on each leg of the animals were used to create four separate 1.5-mm defects, which were filled with HAC (Bone-Source, Howmedica-Leibinger, Inc.) mixed with either water (W) as a control, an accelerant (0.1 M sodium phosphate, SP), or a stabilizer (1% hydroxypropylmethyl cellulose, HPMC) as diluents. At the appropriate postimplantation times, the animals were euthanized and tissue-implant blocks were prepared for qualitative histopathologic evaluations. RESULTS: Osseoconduction around and into the HAC was observed with all three cement formulations and the control (unfilled) site by day 7 and continued through day 14. The histologic staining did not reveal resorption lacunae or other cellular activities characteristic of osteoclast degradation of HAC. These results suggests that other processes, perhaps physical-chemical in nature, contributed to the initial degradation of the HAC following surgical placement. Structural stability of HAC was noted when using HPMC as the diluent. However, when either W or SP were employed, dissociation (washout) of the HAC into the surrounding tissue was noted. CONCLUSION: HAC is prone to in situ physical-chemical breakdown before the completion of the setting reaction. Diluents designed to stabilize or accelerate the HAC mixture appeared to improve the handling properties of the HAC without compromising the biological characteristics of the cement.

Absorbable Implants↗