IMPROVEMENT OF BACTERIAL RHINOSINUSITIS DIAGNOSTIC PROCEDURES

The research included evaluation of express-diagnosis capability of immunochromatographic assay (ICA) Binax NOW (Alere, Inc., USA) for diagnosis of the rhinosinusitis caused by to detect the Streptococcus pneumoniae antigen directly in clinical samples. The unique feature of the method included obtaining samples with an electric suction machine in order to evaluate aspirate from deep parts of the nasal cavity. Diagnostic capability of the Binax NOW was determined in a comparative study using classical bacteriological method in 100 clinical samples. Pneumococcus was isolated in 16 patients (16±3,7%) via bacteriological method. ICA utilization allowed to reveal pneumococcal antigen in 20 cases (20±4,0%). ICA test sensitivity equaled 87,5%, specificity - 92,9%. Obtained results allow us to recommend ICA for identification of pneumococcal infection in patients with sinusitis for practicing physicians. The advantages of the evaluated method were fast results (for up to 15 min) and possibility of non-invasive sampling technique of clinical specimens.

Effect of Deletion of Gene Cluster involved in Synthesis of Enterobacterial Common Antigen on Virulence and Immunogenicity of Live Attenuated Salmonella Vaccine when Delivering Heterologous Streptococcus pneumoniae Antigen rPspA

Background: Enterobacterial common antigen (ECA) is a family-specific surface antigen shared by all members of the Enterobacteriaceae family. Previous studies showed that the loss of ECA results in Salmonella attenuation, indicating its usefulness as a vaccine candidate for Salmonella infection, but no studies have shown whether the mutation resulting from the deletion of the ECA operon in conjunction with other mutations could be used as an antigen vehicle for heterologous protein antigen delivery.Results: In this study, we introduced a nonpolar, defined ECA operon deletion into wild-type S. Typhimurium χ3761 and an attenuated vaccine strain χ9241, obtaining two isogenic ECA operon mutants, namely, χ12357 and χ12358, respectively. A number of in vitro and in vivo properties of the mutants were analyzed. We found that the loss of ECA did not affect the growth, lipopolysaccharide (LPS) production and motility of S. Typhimurium wild type strain χ3761 and its attenuated vaccine strain χ9241 but significantly affected the virulence when administered orally to BALB/c mice. Furthermore, the effects of the ECA mutation on the immunogenicity of a recombinant S. Typhimurium vaccine strain χ9241 when delivering the pneumococcal antigen rPspA were determined. The result showed that the total anti-PspA IgG level of χ12358 (pYA4088) was slightly lower than that of χ9241 (pYA4088), but the protection rate was not compromised.Conclusions: ECA affects virulence and benefits the Th2 immunity of Salmonella Typhimurium, therefore, it is feasible to use a reversibly ECA mutant mode to design future Salmonella vaccine strains for heterologous protective antigens.

Evaluation of the Sofia S. pneumoniae FIA for Detection of Pneumococcal Antigen in Patients with Bloodstream Infection

ABSTRACT The usefulness of pneumococcal urinary antigen tests (UATs) in severe pneumococcal infection relies heavily on the performance in bacteremic patients. Fluorescence technology and automatic reading of test results may improve UAT performance. We evaluated the automatically read Sofia S. pneumoniae FIA for diagnosing pneumococcal bloodstream infection (BSI) in hospitalized adult patients. First, the Sofia FIA was evaluated on 97 patients with pneumococcal (n = 47) and nonpneumococcal (n = 50) BSI and compared with results by the visually read BinaxNOW S. pneumoniae immunochromatographic test (ICT) and ImmuView S. pneumoniae and Legionella pneumophila ICT. In four cases (4.1%), the Sofia FIA showed invalid test results, three of which showed invalid results by the ImmuView ICT previously. Based on 93 valid cases, the Sofia FIA showed similar sensitivity (for both comparisons: 68% versus 62%; P = 0.45) and specificity (for both comparisons: 91% versus 93%; P = 1.00) as the visually read UATs. Second, the Sofia FIA was prospectively evaluated on 82 consecutive nonfrozen urine samples, detecting pneumococcal antigen in 10 of 14 (sensitivity, 71%) pneumococcal BSI patients, similarly to the visually and automatically read BinaxNOW ICT (both 12 of 14; sensitivity, 86%; P = 0.50). Of five nonpneumococcal BSI cases, the Sofia FIA showed an invalid test result in one case, but no positive UAT results were obtained. Thus, the sensitivity and specificity of the Sofia FIA were similar to the performance rates of other UATs in patients with BSI, but invalid test results are of concern for the usefulness in pneumococcal BSI.