Early and delayed post-pneumonectomy empyemas: Microbiology, management and prognosis.

INTRODUCTION: Post-pneumonectomy empyema (PPE) is the most severe complication of pneumonectomy. Microbiology and its impact on management and prognosis have rarely been reported METHODS: We retrospectively reviewed the files of a series of 37 consecutive patients with PPE over a 10-year period with a special focus on microbiology, means used to treat empyema and prognosis. RESULTS: PPE occurred within 14 days of pneumonectomy in 17 cases (early PPE) and after postoperative day 16 in 20 patients (delayed PPE). PPE was monomicrobial in 57% of cases. The most frequent pathogens were Staphylococcus sp. and Streptococcus sp. Polymicrobial empyema was more frequent in patients with early PPE than delayed PPE (65% vs 25%; P = .02). Video-assisted thoracoscopic approach for cavity lavage was performed in 22 patients without broncho-pleural fistulae (BPF), associated with antimicrobial therapy and drainage, and was successful in 13 cases (59%). Seventeen patients (46%) underwent an open window thoracostomy. Overall 90-day post empyema mortality was 19%, with 6 deaths because of empyema in the early PPE group (35%), versus one (5%) in the delayed PPE group (P = .02). CONCLUSION: We distinguished 2 different PPE presentations: an early occurrence, mostly with polymicrobial cultures, including Gram-negative bacteria, and associated with a high mortality rate. By contrast, delayed PPEs were mostly monomicrobial with Gram-positive bacteria and associated with a better prognosis. VATS approach was successful in the majority of cases without BPF, even if some patients required secondary thoracostomy. PPE was associated with an excess of mortality especially when occurring in the early course after pneumonectomy.

Bacillus cereus, an unusual cause of fulminant liver failure: diagnosis may prevent liver transplantation.

Bacillus cereus is a well-known cause of foodborne disease usually of benign course. Here, we present the case of a 15-year-old boy who developed reversible fulminant liver failure associated with rhabdomyolysis after pasta consumption. Suspecting B. cereus as the aetiological agent may prevent unnecessary liver transplantation.

Methicillin-resistant Staphylococcus aureus expressing low-level methicillin resistance may not be detected by the VITEK2® system.

Low-level methicillin-resistant Staphylococcus aureus may be difficult to detect with the VITEK® 2 system (VK2). Here, we suggest that S. aureus exhibiting VK2-oxacillin MIC of 1 or 2 mg/L and a negative cefoxitin screen should be tested for the presence of mecA or its gene product.

Comparison of the Diversilab® system with multi-locus sequence typing and pulsed-field gel electrophoresis for the characterization of Streptococcus agalactiae invasive strains.

Streptococcus agalactiae (or group B streptococcus; GBS) is a leading cause of neonatal morbidity and mortality in the developed countries. Several epidemiological typing tools have been developed for GBS to investigate the association between genotype and disease and to assess genetic variations within genogroups. This study compared the semi-automated repetitive sequence-based PCR Diversilab® system (DL) with MLST and pulsed field gel electrophoresis (PFGE) for determining the relatedness of invasive GBS strains. We analysed 179 unrelated GBS strains isolated from adult (n=108) and neonatal (n=71) invasive infections. By MLST, strains were resolved into 6 clonal complexes (CCs) including 23 sequence-types (STs), and 4 unique STs, whereas DL differentiated these isolates into 12 rep-PCR clusters (rPCs) and 9 unique rep-PCR types. The discriminatory power of both methods was similar, with Simpson's diversity indexes of 71.9% and 70.6%, respectively. However, their clustering concordance was low with Wallace concordance coefficients inferior to 0.4. PFGE was performed on 31 isolates representative of the most relevant DLrPCs clustered within the 3 major MLST CCs (CC-17, CC-23 and CC-1). As already observed with MLST, the concordance of DL with PFGE was low for all three CCs (Wallace coefficient <0.5), PFGE being more discriminative than rep-PCR. In summary, this work suggests that DL is less appropriate than MLST or PFGE to study GBS population genetic diversity.

Automated determination of serum alpha1-antitrypsin by antitryptic activity measurement.

BACKGROUND: Alpha1-Antitrypsin (A1AT) deficiency is currently detectable by protein immunoassay, phenotyping, and genotyping of the S and Z mutations, but no fully automated method for standard biochemical analyzers is yet available. Here, we present a method that measures the antitryptic activity in serum. This method is rapid, automated, and allows the easy evaluation of a large cohort of patients. METHODS: Our automated assay involves determining serum antitryptic capacity on the Olympus AU 400 autoanalyzer by using trypsin and succinylated gelatin as substrate in the presence of trinitrobenzene sulfonic acid. The results are expressed as a percentage of inhibition of the reaction of trypsin with succinylated gelatin. After we performed analytical validation studies and reference-interval determination based on serum samples from 120 healthy persons, we tested the assay on deidentified samples from 120 patients with various pathologies (primarily pulmonary) of unexplained origin and normal A1AT concentrations and phenotypes. RESULTS: The analysis rate was up to 120 samples per hour. Intraassay CVs ranged from 3.1%-16.2%, and interassay CV was 7.5%. The reference population showed mean (SD) 58.4 (6.7)% inhibition. The detection limit was 9.5% inhibition. The 120 studied patients displayed significantly lower mean activity than 120 healthy individuals (P < 0.0001). CONCLUSION: This assay is stable, reliable, and easily automated by use of open-system analyzers, allowing for the rapid evaluation of patients. After further validation on a larger randomized cohort, this new approach should function as a useful method to explore A1AT deficiency, especially in large-scale studies.

[The role of PET scan in gastrointestinal stromal tumors]. / Place de l'imagerie par Tomographie par Emission de Positons pour les tumeurs stromales gastro-intestinales.

Abdominal CT is considered the imaging method of choice for the staging and treatment monitoring of Gastrointestinal Stromal Tumors (GIST). The role of Whole-body FDG-PET seems limited for staging because of the low rate of extra-abdominal tumoral involvement and lower sensitivity than CT. However, PET provides assessment of therapeutic response to imatinib as early as 8 days after treatment is begun. The decrease in the metabolic tumor activity is often marked and intense and it is easier to evaluate than changes in tumor shrinkage and density measured on CT. PET may also be useful when morphological findings are unclear, treatment efficacy uncertain or when progression is identified on CT scan, especially when these findings do not agree with clinical data. PET and CT are complementary and hybrid PET/CT systems have been shown to be useful in GIST. PET may be proposed for the assessment of treatment response in prospective studies with imatinib or other molecules. In patients with GIST, FDG-PET should be performed based on a pluridisciplinary decision.