Biomedical subjects

Zmira Samra

Publications and source records attributed to Zmira Samra.

13 recordsLinked to original sources

PubMed2003

Use of the NOW Streptococcus pneumoniae urinary antigen test in cerebrospinal fluid for rapid diagnosis of pneumococcal meningitis.

Streptococcus pneumoniae is one of the most common pathogens in bacterial meningitis. Rapid diagnosis is critical for effective treatment. The aim of this study was to assess the accuracy of the NOW S. pneumoniae Urinary Antigen Test, (Binax, Portland, ME, USA) originally developed for urine testing, in detecting the S. pneumoniae antigen in cerebrospinal fluid (CSF). The study included 519 patients with suspected meningitis. CSF, blood and urine samples were cultured according to standard methods. CSF viral culture was also performed. CSF and urine specimens were tested for pneumococcal antigen with the NOW S. pneumoniae test.S. pneumoniae was isolated from the CSF of 22 patients. The direct antigen test was positive in CSF in 21/22 patients (95.4% sensitivity), and in urine, in 12/21 (57.1% sensitivity). Direct CSF smear was positive in 15/22 (68% sensitivity). CSF samples that cultured negative for S. pneumoniae (n = 470) or positive for other bacteria (n = 27) were also negative on the NOW test (100% specificity). By contrast, urine samples of 63/470 of patients with negative CSF culture were positive on the NOW test, as were 5/27 urine samples of patients with CSF culture positive for other bacteria (p = 0.45). The NOW S. pneumoniae antigen test in CSF yields a rapid and very reliable diagnosis of pneumococcal meningitis, enabling prompt and adequate treatment. Its low sensitivity in urine indicates that this mode of testing is not useful for the diagnosis of pneumococcal meningitis. These data have been included in the FDA application for approval of the NOW test for use in the CSF for the diagnosis of pneumococcal meningitis.

Adolescent↗

PubMed2003

Ill from eel?

Explore the source record for details and available documents.

Adult↗

PubMed2003

Seven-year study of bacteremia in hospitalized patients on chronic hemodialysis in a single tertiary hospital.

Sixty-seven hospitalized bacteremic patients on chronic hemodialysis were matched with 134 bacteremic controls. Mortality (25% and 28% respectively) was unrelated to dialysis. Predictors of mortality were: advanced age, decreased functional capacity, and malignancies. Most common organisms recovered were Staphylococcus aureus (30%), coagulase negative Staphylococcus (15%), and polymicrobial agents (15%).

Adolescent↗

PubMed2003

Growing antimicrobial resistance of Shigella isolates.

Appropriate antibiotic treatment of shigellosis depends on identifying resistance patterns. By studying Shigella isolates in central Israel from 1998 to 2000, and comparing with the period 1991-1992, we identified a significantly increased resistance to tetracycline (from 23% to 87%, P < 0.00001), high resistance to trimethoprim-sulfamethoxazole (94%) and ampicillin (85%) and emerging resistance to quinolones (0.5-2%). These data mandate local monitoring of resistance and its consideration in empirical therapy.

Adult↗

PubMed2003

Genotypic and phenotypic resistance: longitudinal and sequential analysis of hepatitis B virus polymerase mutations in patients with lamivudine resistance after liver transplantation.

OBJECTIVE: Lamivudine-resistant strains appear in 27-62.5% of liver transplant recipients treated with lamivudine for hepatitis B virus (HBV) recurrence, and may lead to failure of antiviral therapy. In an extension of our previous study, we investigated the molecular events associated with the emergence of lamivudine-resistant mutants in this population. METHODS: Sequential serum samples from 10 consecutive patients with lamivudine resistance after liver transplantation were analyzed for viral genotype, precore mutants, and viral polymerase gene mutants (L528M, M552V, M552I) using restriction fragment length polymorphism. Quantitative analysis of HBV DNA was performed using hybridization assay and polymerase chain reaction. RESULTS: Eight patients (80%) were infected with genotype D and two (20%) with genotype C. Polymerase mutants (genotypic resistance) were identified in all the patients. Phenotypic resistance (rise in serum HBV DNA titers above the detection limit of the hybridization assay) developed in five patients (50%); of the remainder, three (30%) did not have phenotypic resistance, and two were primary nonresponders. Genotypic resistance was detected earlier than phenotypic resistance (median 285 days [range 42-510] vs median 387 days [range 320-420], p = 0.055). In five patients (50%), the emergence of the YMDD mutants took over the wild type; in three (30%), the YMDD mutant took over the wild type, but the wild type re-emerged during lamivudine therapy; and in two (20%), the YMDD mutants were detected in a mixture with the wild type (in different percentages). The mean pretreatment serum ALT level was significantly lower in the patients who did not develop phenotypic resistance (p = 0.0002). The M552I pure viral population was found mainly in these patients, and all retained stable graft function (median follow-up 33 months). A high pretreatment HBV DNA level (>50 x 10(6) copies/ml) was highly statistically significantly correlated with the rapid occurrence of phenotypic resistance (r = -0.90, p = 0.04). CONCLUSIONS: We reached the following conclusions: 1) In our area, liver transplant recipients who develop resistance to lamivudine given for recurrent HBV infection seem to be mainly infected with genotype D. 2) Re-emergence of the wild type can occur during lamivudine therapy. 3) Genotypic resistance precedes phenotypic resistance, although phenotypic resistance does not always follow genotypic resistance. 4) Quantitative determination of viremia and analysis of polymerase gene mutants are recommended for monitoring antiviral therapy of liver transplant patients with HBV reinfection in the graft.

Adult↗

PubMed2003

In vitro synergy of caspofungin and itraconazole against Aspergillus spp.: MIC versus minimal effective concentration end points.

Caspofungin and itraconazole were studied alone and in combination against 31 clinical isolates of Aspergillus spp. according to NCCLS M38-P guidelines. MICs and microscopic minimal effective concentrations (MECs) were recorded, and synergy was calculated by using both end points. Synergy or synergy to additivity was found in 30 of 31 isolates by using MIC end points. With MEC end points no synergy was found and indifference was detected in 26 of 31 strains.

Anti-Bacterial Agents↗

PubMed2002

High prevalence of toxin A-negative toxin B-positive Clostridium difficile in hospitalized patients with gastrointestinal disease.

The incidence of Clostridium difficile toxin A-negative toxin B-positive in hospitalized patients with severe gastrointestinal disease was evaluated. Of 530 stool specimens tested in parallel by two immunoassay tests, Tox A and Tox A/B (TechLab, Inc., Blacksburg, VA), 422 produced negative results on both tests. One hundred eight specimens (20.4%) tested positive by Tox A/B assay, and only 47 of them were also positive by Tox A. The 61 specimens with discrepant results were confirmed to be positive for toxin B by tissue culture cytotoxicity assay. Furthermore, 3 of the 422 specimens that were negative by enzyme immunoassay tested positive by cytotoxicity assay. The sensitivity and specificity of the Tox A/B test were 95.3% and 100%, respectively, with negative and positive predictive values of 99.3% and 100%, respectively, and a correlation rate of 99.4%. The high prevalence (56.5%) of specimens from symptomatic patients having detectable toxin B, but undetectable toxin A emphasizes the importance of using diagnostic tests that include toxin B. Furthermore, our data support the potential role of toxin B in the pathogenesis of toxigenic Clostridium difficile.

Bacterial Proteins↗

PubMed2002

In vitro susceptibility of Mycoplasma hominis clinical isolates to tetracyclines, quinolones and macrolides.

We tested the in vitro activity of levofloxacin, ciprofloxacin, doxycycline, tetracycline, erythromycin, roxithromycin, clarithromycin and azithromycin against 110 clinical isolates of Mycoplasma hominis. The minimal inhibitory concentrations (MICs) were determined with the Etest. The minimal concentrations at which 90% of the isolates were inhibited (MIC(90)) were 0.064 microg/ml doxycycline and 0.19 microg/ml tetracycline. In 9 isolates (8.1%), the MIC for doxycycline was 4-12 microg/ml. These isolates were also resistant to tetracycline with a MIC of 32-128 microg/ml. No significant difference was found between doxycycline and tetracycline (p = 0.076). Comparison of the two quinolones revealed that the MIC(90) for levofloxacin was 0.19 microg/ml and for ciprofloxacin, 0.5 microg/ml. A significant difference was found between doxycycline/tetracycline and levofloxacin or ciprofloxacin (p = 0.0001), and between levofloxacin and ciprofloxacin (p = 0.001). All the isolates were highly resistant to the macrolides with MIC > or = 256 microg/ml. This finding has important implications for cases in which Mycoplasma infection is suspected and culture and/or in vitro susceptibility tests are not available.

4-Quinolones↗

PubMed2002

Once-daily versus twice-daily intravenous administration of vancomycin for infections in hospitalized patients.

The efficacy and toxicity of once-daily (od) versus twice-daily (bd) dosing of vancomycin was compared in 121 hospitalized patients. Eighteen patients were then withdrawn from the study. Clinical and bacteriological responses were evaluated in all patients (n = 103). Nephrotoxicity was assessed in patients who did not receive nephrotoxic agents (n = 76). Ototoxicity was assessed in patients who completed two audiograms and were not receiving ototoxic agents (n = 63). No significant difference was found between the two groups for favourable clinical response: 47/51 (92.1%) and 49/52 (94.2%) in the od and bd groups, respectively. In 34 patients vancomycin was the only effective antibiotic. Fifteen of 18 (83.3%) evaluated episodes in the od and 12/16 (75.0%) evaluated episodes in the bd group showed a favourable bacteriological response. There were no significant differences between the od and bd groups for all adverse events. Nephrotoxicity developed in 4/37 (10.8%) and 3/39 (7.7%) patients, respectively. Hearing loss developed in 1/31 (3.2%) and 5/32 (15.6%). Phlebitis occurred in 7/51 (13.7%) and 12/52 (23.0%). Red man syndrome occurred in 7/51 (13.7%) and 5/52 (9.6%) in od and bd groups, respectively. The efficacy and safety profile of od administration of vancomycin is similar to that of the customary, but less convenient, bd administration.

Adolescent↗

PubMed2002

Resistance of Helicobacter pylori isolated in Israel to metronidazole, clarithromycin, tetracycline, amoxicillin and cefixime.

The resistance of Helicobacter pylori isolated in Israel to metronidazole, clarithromycin, tetracycline, amoxicillin and cefixime was tested in 138 isolates, including 28 from treatment failures. No resistance to tetracycline was detected. Resistance to amoxicillin was found in one isolate (MIC = 1.5 mg/L) from an untreated patient, and resistance to cefixime in two isolates from each group (P = 0.18). Resistance to metronidazole and clarithromycin was much higher in the isolates from treated than from untreated patients: 60.7% and 38.2% for metronidazole (MIC >or= 8 mg/L) (P = 0.03); 46.4% and 8.2% for clarithromycin (MIC >or= 2 mg/L) (P < 0.001). Therapeutic outcome would benefit from susceptibility testing, especially after treatment failure.

Amoxicillin↗

PubMed2002

Efficacy of subcutaneous tunneling for prevention of bacterial colonization of femoral central venous catheters in critically ill children.

BACKGROUND: Blood stream infections are a common and serious complication of central venous catheters (CVCs). To decrease catheter colonization, some authors advocate tunneling the catheter in the subcutaneous tissue during insertion. This technique has proved effective in adults, but there are no data on its safety and efficacy in critically ill children. Our objective was to evaluate the efficacy and safety of subcutaneous tunneling of short term, noncuffed CVCs for the prevention of CVC-related infections in critically ill children. METHODS: A prospective randomized controlled trial was performed at a tertiary children's medical center in Israel and included children ages 0 to 18 years admitted to the pediatric intensive care unit or the pediatric cardiac intensive care unit from September 2000 to April 2001 who required placement of a femoral central venous catheter for >48 h. The children were randomized for tunneled or nontunneled insertion. The main outcome measures were bacterial colonization of proximal and distal catheter segments tested by semiquantitative technique and infectious or noninfectious complications of the CVC. RESULTS: Of 98 eligible children, 49 received tunneled catheters and 49 received nontunneled catheters. Patients' age ranged from 1 month to 16.5 years (mean, 3.07 +/- 2.48 years). There were no significant differences between the groups in age, sex, disease severity [Pediatric Risk of Mortality III (PRISM) score], duration of catheterization and underlying diseases. Bacterial colonization was found in 11 (22.4%) catheters in the nontunneled group compared with 3 (6.1%) in the tunneled group (P = 0.004). Proximal segment colonization occurred in 7 (14.2%) nontunneled catheters and 2 (4.8%) tunneled catheters (P = 0.07), and distal segment colonization occurred in 3 (6.1%) and 9(18.3%) tunneled and nontunneled catheters, respectively (P = 0.053). The main pathogens were coagulase-negative staphylococci, Pseudomonas spp. and Klebsiella spp. There was no statistically significant difference between the groups in the rate of bloodstream infection (2 in the tunneled group, 3 in the nontunneled). Except for 1 case of subcutaneous hematoma, which resolved, there were no immediate or late complications of the tunneling procedure. CONCLUSION: Subcutaneous tunneling of CVCs in the femoral site is a safe procedure and decreases significantly the rate of CVC colonization in critically ill children.

Bacteremia↗

PubMed2002

Listeria monocytogenes infection in Israel and review of cases worldwide.

Listeria monocytogenes, an uncommon foodborne pathogen, is increasingly recognized as a cause of life-threatening disease. A marked increase in reported cases of listeriosis during 1998 motivated a retrospective nationwide survey of the infection in Israel. From 1995 to 1999, 161 cases were identified; 70 (43%) were perinatal infections, with a fetal mortality rate of 45%. Most (74%) of the 91 nonperinatal infections involved immunocompromised patients with malignancies, chronic liver disease, chronic renal failure, or diabetes mellitus. The common clinical syndromes in these patients were primary bacteremia (47%) and meningitis (28%). The crude case-fatality rate in this group was 38%, with a higher death rate in immunocompromised patients.

Adolescent↗

PubMed1995

Risk factors and a clinical index for diagnosis of Pseudomonas aeruginosa bacteremia.

OBJECTIVE: To define risk factors significantly and independently associated with Pseudomonas aeruginosa bacteremia and to combine them in a diagnostic index which will define groups of septic patients at low or high risk of bloodstream infection caused by P. aeruginosa. METHODS: Logistic regression analysis was used to identify risk factors associated with pseudomonal bacteremia among all patients with bacteremia at St Thomas' Hospital, London, from 1969 to 1989. The coefficients of the final logistic model were used to compile a linear model for the diagnosis of pseudomonal bacteremia. The index was validated in another set of patients with bacteremia detected at Beilinson Medical Center, Petah Tiqva, Israel, from 1988 to 1991. RESULTS: Seven factors were significantly and independently predictive of pseudomonal bacteremia: 1) neutropenia; 2) previous or current treatment with antibiotics; 3) cytotoxic or corticosteroid treatment; 4) hospital acquisition of infection; 5) detection in the intensive care unit; 6) male gender; and 7) focus of infection. High-risk foci were the urinary tract with catheter or post-instrumentation, or unknown source. Low-risk foci were bone, joint, meninges, female genital tract and upper respiratory tract. The index score divided patients into three groups with increasing likelihood of P. aeruginosa bacteremia: 1%, 7% and 19%, respectively (p=0.0001). In the validation set, the percentage of P. aeruginosa bacteremia in the three respective groups defined by the index were 5%, 18% and 22% (p=0.0001). CONCLUSIONS: The use of simple clinical and laboratory data known within hours of detection of an infectious episode can define patients at high and low risk for P. aeruginosa bacteremia.

Journal Article↗