Clinical features of group B Streptococcus prosthetic joint infections and molecular characterization of isolates.

Twelve group B Streptococcus (GBS) prosthetic joint infection (PJI) cases are reported. The mean patient age was 55 years. Eleven infections were caused by GBS alone. The associated isolates belonged to phylogenetic lineages different from those that cause neonatal meningitis. The clinical outcome was favorable for the eight patients for whom follow-up data were available.

Revisited distribution of nonfermenting Gram-negative bacilli clinical isolates.

Nonfermenting Gram-negative bacilli (NF-GNB) are ubiquitous environmental opportunistic bacteria frequently misidentified by conventional phenotypic methods. The aim of this study was to determine the distribution of NF-GNB species by 16 S rRNA gene sequencing (used as reference method) and to compare performances of biochemical tests and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). From nine French hospitals, 188 NF-GNB isolates (except P. aeruginosa and A. baumannii) were prospectively collected from 187 clinical samples between December 2008 and May 2009. By using the genotypic approach, 173 (92%) and 188 (100%) isolates were identified to the species and genus level, respectively. They covered 35 species and 20 genera, with a predominance of Stenotrophomonas maltophilia, Achromobacter xylosoxidans, and Pseudomonas putida group bacteria. Of the 173 species-level identified strains, concordant identification to the species-level was obtained for 75.1%, 83% and 88.9% of isolates with API 20 NE strip, the VITEK-2 (ID-GN card) system and MALDI-TOF-MS, respectively. By excluding S. maltophilia isolates accurately identified by the three methods, genus-level identification was much higher for MALDI-TOF-MS (92.9%), compared with API 20 NE and VITEK-2 (76.2% and 80.8%, respectively). In conclusion, MALDI-TOF-MS represents a rapid, inexpensive, and accurate tool for routine identification of NF-GNB in human clinical samples.

New parameters on the hematology analyzer XN-10 (SysmexTM) allow to distinguish childhood bacterial and viral infections.

INTRODUCTION: Complete blood counts (CBC) performed for infected children admitted for fever mostly disclose leukocytosis. Yet, the recently developed XN-10® provides novel CBC parameters which could be useful to ascertain infection and discriminate between bacterial and viral etiologies. These were the main objectives of the study presented here. METHODS: Blood samples from 90 children, 1 month to 5 years old, admitted to an emergency unit for fever benefited from a CBC, C-reactive protein, and procalcitonin assays. For 58, a bacterial infection was documented while a viral cause was disclosed for 32. Concomitantly, 30 healthy children of the same age range were selected as a control group. RESULTS: Complete blood counts parameters and leukocyte differentials allowed to statistically significantly disclose infection, compared to reference children, in the age group of 1-5 years old. Among the eight novel discriminant parameters, a particular interest appeared for Neutr-RI and Delta-He. They both were successfully incorporated in a score together with age and immature granulocytes (IG). ROC curves and AUCs were calibrated using a Hosmer-Lemeshow test. Moreover, novel lymphocyte parameters allowed to segregate bacterial and viral infections in the whole group of 90 febrile children. CONCLUSION: Complete blood counts is the most broadly performed rapid laboratory investigation. Here, we show that XN-10® provides complementary information allowing to confirm infection in febrile children, moreover discriminating between bacterial or viral origin.

Lymphocyte expansion after unrelated cord blood allogeneic stem cell transplantation in adults.

Limited information is available regarding the incidence and features of lymphocyte expansions after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Large granular lymphocytes (LGL) expansions have been reported after bone marrow or peripheral blood, but not after unrelated cord blood (UCB) allo-HSCT, associated with indolent clinical courses and favorable outcomes. Here, we considered 85 recipients of UCB allo-HSCT to more broadly define the impact of lymphocytosis, not limited to LGL. Sustained lymphocytosis was observed in 21 (25%) patients at a median onset of 12.6 months and with a median duration of 12 months. Immunophenotypic analysis showed predominantly CD8+ T and/or polyclonal B-cell expansions. Three patients only had monoclonal T-cell expansion. CMV reactivation was significantly more frequent in the group of patients with lymphocytosis (76% vs 28%, P=0.0001), but was not associated with survival. Conversely, 2-year disease-free survival and overall survival were significantly higher for lymphocytosis patients (85% vs 55%, P=0.01 and 85% vs 63%, P=0.03, respectively). In conclusion, expansion of T or B lymphocytes after UCB allo-HSCT in adults is not a rare event. Although occurring relatively late after transplant, this feature is predictive of a better outcome for the patients.