Streptococcus pneumoniae serotype 1 burden in the African meningitis belt: exploration of functionality in specific antibodies.

Streptococcus pneumoniae serotype 1 (Sp1) constitutes an important cause of seasonal endemic meningitis in all age groups in the African meningitis belt. Despite a higher meningitis incidence, the Burkinabé population has an Sp1-specific antibody seroprevalence similar to that reported in the United Kingdom (UK). We aimed to establish whether the opsonophagocytic activity (OPA) of pneumococcal IgG naturally present in Burkina Faso differs from that seen in individuals in the UK and to compare the OPAs generated by natural and vaccine-induced immunity. Samples collected from pneumococcal vaccine-naive Burkinabé and UK subjects were matched for age (1 to 39 years) and anti-Sp1 IgG level, analyzed for OPA to 3 S. pneumoniae serotypes (1, 5, and 19A), and compared to postvaccine samples. Furthermore, the Burkinabé samples were assessed for IgG avidity and serotype-specific IgM concentrations. One hundred sixty-nine matched serum samples from both populations were selected. A greater proportion of Burkinabé subjects aged 1 to 19 years had functional Sp1 activity (OPA ≥ 8) compared to UK subjects (12% versus 2%, P < 0.001); however, the proportions were similar among adults (9%). The correlation between Sp1 IgG concentration and OPA was good (P < 0.001), but many individuals had nonfunctional IgG, which was not related to avidity. While the Sp1 IgM concentrations correlated with OPA, not all of the function in serum samples with low IgG could be attributed to IgM. Finally, vaccine-induced Sp1-specific IgG was more functional than equivalent amounts of naturally occurring IgG. In conclusion, despite a substantially higher pneumococcal meningitis incidence, no decreased functional immunity to Sp1 could be evidenced in the Burkinabé population compared to that in the population from the UK. Furthermore, the naturally induced antibodies were less functional than vaccine-induced antibodies.

Impact of influenza during the post-pandemic season: epidemiological picture from syndromic and virological surveillance.

INTRODUCTION: Following the observation that 1 or 2 pandemic peak due to the circulation ofAHINlv had occurred in most countries and in most World Health Organization (WHO) Regions, WHO declared on August 10"h, 2010 that the world was moving into the post-pandemic period, whose surveillance presents considerable interest both from epidemiological and clinical point of view. We described the epidemiological picture emerged from syndromic and virological surveillance during the post-pandemic season in Liguria, Italy. MATERIALS AND METHODS: An Emergency Department Syndrome surveillance system, based on data collected at "San Martino" and IRCCS "G. Gaslini" Liguria Regional Reference University Hospitals for adults and children is active since July 2007. Monitored syndromes include "Influenza-Like Illness" (ILl) and "Low Respiratory Tract Infections" (LRTI). The Ligurian Regional Reference laboratory for Influenza virological surveillance and diagnosis offers rapid detection of influenza viruses by real-time and block RT-PCR, viral culture and genetic characterization by entire sequence analysis of haemagglutinin- and neuraminidase-coding regions in accordance with the international standards established by the global laboratory network. RESULTS AND DISCUSSION: The integration of syndromic surveillance system and laboratory surveillance for rapid detection and characterization of the disease responsible agent represented a specific and sensitive tool for influenza surveillance. The post-pandemic season was characterized by early onset and by the heaviest impacts for ILI and LRTI among the recent epidemic seasons. In contrast to the picture observed during the pandemic season, the 2010/11 winter was characterized by the intensive circulation of pandemic AH1N1v coupled with sustained activity due to influenza B and Respiratory Syncytial Virus (RSV). Antigenic and molecular characterization of influenza strains confirmed the good matching between circulating and 2010/11 vaccine viruses.

Sequential outbreaks of multidrug-resistant Acinetobacter baumannii in intensive care units of a tertiary referral hospital in Italy: combined molecular approach for epidemiological investigation.

A laboratory-based surveillance study was conducted from January 2007 to May 2010 in San Martino Tertiary Referral Hospital in Genoa, Italy in which the molecular epidemiology of multidrug-resistant Acinetobacter baumannii was investigated in the five intensive care units (ICUs). A total of 53 A. baumannii strains were isolated from patients admitted to ICUs (69.8%) and to other epidemiologically linked hospital wards (30.2%) and were genotyped by repetitive extragenic palindromic polymerase chain reaction (REP-PCR), multilocus sequence typing (MLST) and adeB sequence typing. REP-PCR fingerprinting analysis, MLST and adeB typing results were well correlated and allowed us to classify strains causing epidemic events into three major epidemic clones: A (REP-I/ST4, adeB-STII genotype) isolated for the first time in May 2007, B (REP-IV/ST95, adeB-STI genotype) from November 2007 to May 2009 and C (REP-VII/ST118, adeB-STII genotype) from July 2008 to May 2010. MLST results demonstrated that epidemic clones A and C were related as they were members of the widespread clonal complex CC92. The genetic determinants of carbapenem resistance were investigated and resistance associated with the presence of the bla(OxA-58-like) gene with ISAba2 and ISAba3 elements flanking it in clone A, and with the bla(OxA-23-like) gene flanked by ISAba1 in clones B and C. A molecular approach allowed the prompt introduction of infection control measures and the evaluation of data in a global epidemiological context.

Role of congenital rubella reference laboratory: 21-months-surveillance in Liguria, Italy.

INTRODUCTION: Rubella is generally a mild rush fever disease when acquired in childhood, but when infection occurs during the first months of pregnancy, high risk of trans-placental transmission to the foetus and of congenital anomalies exists. In November 2003, a National Plan for measles and congenital rubella elimination was approved in Italy. The aim was to reduce and maintain Congenital Rubella Syndrome incidence lower than 1 case per 100,000 live births/year by 2007. Since June 2006, Liguria Administrative Region recognized U.O. Hygiene, "San Martino" University Hospital, Genoa, as regional reference laboratory for diagnosis of rubella infection during pregnancy and post-partum. METHODS: Twenty-one-month virological-surveillance results between April 2007 and December 2008 were reported in terms of demographic data, risk factors, access reasons, clinical picture, vaccination, previous rubella disease, laboratory results of pregnant women and newborns. RESULTS AND CONCLUSION: Since the beginning of surveillance, 65 pregnant women with suspected virus infection and 18 newborns with suspected congenital rubella were followed up. The results of laboratory surveillance highlighted (i) the importance of an early screening, (ii) the suboptimal specificity of chemiluminescent assays, that often yield false positive IgM results and (iii) the fundamental role of second-level laboratory to confirm the serological diagnosis and to detect the virus by molecular techniques.

Migratory pathways of gammadelta T cells and response to CXCR3 and CXCR4 ligands: adhesion molecules involved and implications for multiple sclerosis pathogenesis.

Gammadelta T lymphocytes are thought to be involved in multiple sclerosis (MS) pathogenesis. In this work, we discuss the characteristics of these cells and possible implications in the pathogenesis of MS, focusing on the mechanism(s) underlying extravasation and tissue localization. Phenotype and transendothelial migration of gammadelta T cells from healthy donors and patients with relapsing-remitting MS were studied. In MS patients the V delta 2 T cell subset, expressing NKRP1A/CD161 adhesion molecule, is expanded and capable of transendothelial migration. V delta 1/V delta 2 subsets use distinct signal transduction pathways: V delta 1 cells lack NKRP1A and express PECAM-1/CD31, which drives transmigration, while V delta 2 cells are PECAM-1 negative and use NKRP1A. V delta 2 migration is coupled with CAMKII, whereas V delta 1 depend on PI-3K. NKRP1A and PECAM-1 selectively activate the two pathways: indeed, oligomerization of NKRP1A on V delta 2 T cells leads to CAMKII activation, occupancy of PECAM-1 on V delta 1 cells triggers the PI-3K-dependent Akt/PKB pathway. Moreover, V delta 2 T cells are CXCR3(bright)CXCR4(dull), while V delta 1 are mostly CXCR4(+). V delta 1 and V delta 2 cells transmigrate in response to IP-10/CXCL10 and SDF-1/CXCL12 according to the expression of their specific receptors. In a fraction of V delta 1 T cells coexpressing CXCR3 and CXCR4, the homeostatic chemokine 6Ckine/SLC/CCL21 is more effective. IP-10/CXCL10 or 6Ckine/SLC/CCL21 and SDF-1/CXCL12-induced transmigration is coupled to PI-3K/Akt/PKB, but only CXCR3 is capable of inducing CAMKII activation. We suggest that both subsets of gammadelta T lymphocytes may migrate to the site of lesion in MS using two different signaling pathways to extravasate and responding to different chemokines.