A multicenter evaluation of safety of early extubation in liver transplant recipients.

Small single-institutional studies performed prior to the introduction of organ allocation using the Model for End-Stage Liver Disease (MELD) suggest that early airway extubation of liver transplant recipients is a safe practice. We designed a multicenter study to examine adverse events associated with early extubation in patients selected for liver transplantation using MELD score. A total of 7 institutions extubated all patients meeting study criteria and reported adverse events that occurred within 72 hours following surgery. Adverse events were uncommon: occurring in only 7.7% of 391 patients studied. Most adverse events were pulmonary or surgically related. Pulmonary complications were usually minor, requiring only an increase in ambient oxygen concentration. The majority of surgical adverse events required additional surgery. Analysis of a limited set of perioperative variables suggest that blood transfusions and technical factors were associated with an increased risk of adverse events. In conclusion, while early extubation appears to be safe under specified circumstances, there are performance differences between institutions that remain to be explained.     

Serologic detection of infection with cagA+ Helicobacter pylori strains.

Approximately 60% of Helicobacter pylori isolates possess the cagA gene and express its 120- to 140-kDa product (CagA). In this study, the cagA gene was detected in H. pylori isolates from 26 (81.3%) of 32 patients with duodenal ulcers (DU), 17 (68.0%) of 25 patients with gastric ulcers, and 23 (59.0%) of 39 patients with nonulcer dyspepsia (NUD). By Western blotting (immunoblotting) with antiserum to CagA, in vitro CagA expression was demonstrated for 95.5% of cagA+ strains compared with 0% of strains lacking cagA. Sera from patients infected with cagA+ strains (n = 66) reacted with recombinant CagA in an enzyme-linked immunosorbent assay to a significantly greater extent than either sera from patients infected with strains lacking cagA (n = 30) or sera from uninfected persons (n = 25) (P < 0.001). A strain lacking cagA was isolated from eight patients who had serum immunoglobulin G antibodies to CagA, which suggests that these patients were infected with multiple strains. Serum immunoglobulin G antibodies to CagA were present in 87.5, 76.0, and 56.4% of patients with DU, gastric ulcers, and NUD, respectively (odds ratio, 5.41; 95% confidence interval, 1.44 to 24.72; P = 0.004 [DU versus NUD]). These data demonstrate an association between infection with cagA+ H. pylori and the presence of duodenal ulceration and indicate that serologic testing is a sensitive method for detecting infection with cagA+ strains.     

Evaluation of the E test for quantitative antimicrobial susceptibility testing of Helicobacter pylori.

The Progressive Diagnostics Manufacturers epsilometer test (E test; AB Biodisk, Solna, Sweden), a quantitative variant of the disk diffusion technique, was evaluated comparatively to an agar dilution method for the antimicrobial susceptibility testing of Helicobacter pylori. A collection of 79 H. pylori clinical strains, including isolates with known resistance to various antimicrobial agents, was tested against 12 different antimicrobial agents. All strains were tested on Columbia agar supplemented with 10% horse blood. Plates were incubated at 37 degrees C in microaerobic atmosphere (5% O2, 10% CO2), and readings were done after 3 days of incubation. In general, E test MICs were easy to interpret and the correlation between MICs by the agar dilution method and the E test was good, with 86 and 99.5% of results being within, respectively, 1 and 2 log2 dilution steps in a total of 936 tests. All strains of H. pylori with documented resistance to the tested agents were detected by the E test. Thus, the E test appears to be an easy and reliable method for determination of MICs of antibiotics for H. pylori, and it may offer an interesting alternative to MIC determination by the agar dilution technique.     

Efficient Detection of Carbapenemase Activity in Enterobacteriaceae by Matrix-Assisted Laser Desorption Ionization?Time of Flight Mass Spectrometry in Less Than 30 Minutes

The recognition of carbapenemase-producing Enterobacteriaceae (CPE) isolates is a major laboratory challenge, and their inappropriate or delayed detection may have negative impacts on patient management and on the implementation of infection control measures. We describe here a matrix-assisted laser desorption ionization−time of flight (MALDI-TOF)-based method to detect carbapenemase activity in Enterobacteriaceae. After a 20-min incubation of the isolate with 0.5 mg/ml imipenem at 37°C, supernatants were analyzed by MALDI-TOF in order to identify peaks corresponding to imipenem (300 Da) and an imipenem metabolite (254 Da). A total of 223 strains, 77 CPE (OXA-48 variants, KPC, NDM, VIM, IMI, IMP, and NMC-A) and 146 non-CPE (cephalosporinases, extended-spectrum β-lactamases [ESBLs], and porin defects), were tested and used to calculate a ratio of imipenem hydrolysis: mass spectrometry [MS] ratio = metabolite/(imipenem + metabolite). An MS ratio cutoff was statistically determined to classify strains as carbapenemase producers (MS ratio of ≥0.82). We validated this method first by testing 30 of our 223 isolates (15 CPE and 15 non-CPE) 10 times to calculate an intraclass correlation coefficient (ICC of 0.98), showing the excellent repeatability of the method. Second, 43 strains (25 CPE and 18 non-CPE) different from the 223 strains used to calculate the ratio cutoff were used as external controls and blind tested. They yielded sensitivity and specificity of 100%. The total cost per test is <0.10 U.S. dollars (USD). This easy-to-perform assay is time-saving, cost-efficient, and highly reliable and might be used in any routine laboratory, given the availability of mass spectrometry, to detect CPE.     

Pathogenesis of systemic scleroderma: immunological aspects

Systemic sclerosis (SSc) is a connective tissue disorder that is characterized by excessive collagen synthesis by fibroblasts and by vascular hyperreactivity and obliteration phenomena. Excessive collagen production is the consequence of abnormal interactions between endothelial cells, fibroblasts and mononuclear cells. Immunological abnormalities are present very early in the development of SSc. Mononuclear cells, particularily macrophages and T lymphocytes play a prominent role in fibroblast activation and collagen synthesis through the cytokines they produce. Thus, lymphocytic infiltrates in the skin and in the lung are preferentially composed of CD8+ T lymphocytes, that produce important amounts of interleukin 4 (IL-4). The effects of IL-4 are added to these of transforming growth factor B (TGF-B) and connective tissue growth factor (CTGF) that stimulate collagen synthesis by fibroblasts. T lymphocytes produce important amounts of gamma interferon (INF-gamma) that is the best inhibitor of collagen synthesis by fibroblasts. However, the inhibitory effect of INF-gamma on collagen synthesis is diminished in SSc patients. Numerous autoantibodies can be evidenced in the serum of SSc patients. Three of them are specific for SSc and mutually exclusive: anti-centromere antibodies (Ab) in limited SSc, anti-Scl70 Ab in diffuse SSc and anti-RNA polymerase III Ab in diffuse SSc with renal involvement. These autoantibodies are good prognosis markers but their pathogenic role remains uncertain.     

Evaluation of the βLACTA Test,a Novel Commercial Chromogenic Test for Rapid Detection of Ceftazidime-Nonsusceptible Pseudomonas aeruginosa Isolates

A novel commercial chromogenic technique, the βLACTA test (Bio-Rad, Marnes-la-Coquette, France), was evaluated to detect nonsusceptibility to ceftazidime in Pseudomonas aeruginosa isolates. Easily implemented in the routine microbiology laboratory, this rapid test was sensitive (95%) and specific (87%) and presented negative and positive predictive values of 99% and 100%, respectively.     

FDG uptake at the bronchial stump after curative lobectomy for non-small cell lung cancer

Purpose

Focal areas of FDG uptake may occur at the bronchial stump following curative lobectomy for non-small-cell lung carcinoma (NSCLC), even in the absence of suspicious CT changes. The purpose of our study was to investigate the significance of such PET/CT findings.

Methods

FDG-PET/CT scans performed in 54 patients after lobectomy for NSCLC were reviewed. The presence of focal areas of FDG uptake at the bronchial stump, associated CT abnormalities, SUVmax, and normalized SUV (SUVnorm = SUVmax/mean liver SUV) were recorded. Final diagnosis was based on biopsy or imaging follow-up.

Results

Focal areas of FDG uptake at the bronchial stump were detected in 30 patients (56 %). Mean SUVmax was 4.0?±?1.9 (range; 2.2–12.1) and mean SUVnorm was 1.8?±?0.8 (range; 0.9–4.5). Biopsy showed recurrence in two patients. In these patients, SUVnorm was respectively 4.4 and 4.5 (with SUVmax of 8.8 and 12.1), whereas SUVnorm was lower than 4.0 in those without recurrence, with mean SUVnorm of 1.6?±?0.5 (range; 0.9–3.4) and mean SUVmax of 3.6?±?0.9 (range; 2.2–5.8). The CT component of the PET/CT revealed ill-defined peribronchial soft tissue opacity only in both patients with recurrence.

Conclusion

FDG uptake at the bronchial stump is a frequent finding after pulmonary lobectomy. Moderate levels of FDG uptake (i.e., SUVnorm?<?4.0) without corresponding abnormal CT findings might be a dual criterion for diagnosing benign post-surgical changes.

     

Optimal assessment of the ability of children with recurrent respiratory tract infections to produce anti-polysaccharide antibodies

Specific anti-polysaccharide antibody deficiency (SPAD) is an immune disorder. Diagnostic criteria have not yet been defined clearly. One hundred and seventy-six children evaluated for recurrent respiratory tract infections were analysed retrospectively. For each subject, specific anti-pneumococcal antibodies had been measured with two enzyme-linked immunosorbent assays (ELISAs), one overall assay (OA) using the 23-valent pneumococcal polysaccharide vaccine (23-PPSV) as detecting antigen and the other purified pneumococcal polysaccharide serotypes (serotype-specific assay, SSA) (serotypes 14, 19F and 23F). Antibody levels were measured before (n = 176) and after (n = 93) immunization with the 23-PPSV. Before immunization, low titres were found for 138 of 176 patients (78%) with OA, compared to 20 of 176 patients (11%) with the SSA. We found a significant correlation between OA and SSA results. After immunization, 88% (71 of 81) of the patients considered as responders in the OA test were also responders in the SSA; 93% (71 of 76) of the patients classified as responders according to the SSA were also responders in the OA. SPAD was diagnosed in 8% (seven of 93) of patients on the basis of the absence of response in both tests. Thus, we propose to use OA as a screening test for SPAD before 23-PPSV immunization. After immunization, SSA should be used only in case of a low response in OA. Only the absence of or a very low antibody response detected by both tests should be used as a diagnostic criterion for SPAD.