Detection of Neisseria meningitidis in cerebrospinal fluid samples from suspicious cases of meningococcal meningitis using polymerase chain reaction and counterimmunoelectrophoresis

Rapid diagnosis of meningococcal disease followed by an early treatment is essential. However, blood or cerebrospinal fluid cultures may not be successful because antibiotic treatment is often started before proper specimens are collected and because bacteria may die during transportation to the laboratory. Improvements in antibiotic therapy for specific microorganisms will require the use of more than one method for immunodiagnosis. In this study a collection of cerebrospinal fluid samples from Brazilian patients was analyzed. Gram stains, culture, counterimmunoelectrophoresis and clinical evaluations for meningococcal diseases were available. The sensitivity of nested PCR (nPCR) was 73 for cerebrospinal fluid of clinically suspected cases, whereas both sensitivity and specificity were 100 when subtypes of Brazilian epidemic strains (P1.7, P1.9 and P1.15) isolated from the samples were used.

The use of filter paper monoclonal antibodies in a Dot-blot test for typing Neisseria meningitidis B

A simple method for the collection, preservation, shipment, and testing of minute amounts of dried monoclonal antibodies for typing Neisseria meningitidis B is described. The monoclonal antibodies collected on filter paper were extracted in PBS and evaluated by Dot-blot employing whole cells of N. meningitidis B as antigen. The dried filter paper with monoclonal antibodies could be stored at room temperature for as long as 30 days without detectable changes in antibody response when used for typing outer membrane antigens of N. meningitidis B

Production and immunochemical characterization of Neisseria meningitidis group B antiserum for the diagnosis of purulent meningitis

Unlike Neisseria meningitidis groups A, C, Y and W135, the group B capsular polysaccharide has been shown to be chemically and immunologically identical to the capsular polysaccharide of Escherichia coli K1. Both components are sialic acid homopolymers and are poorly immunogenic. Nevertheless, due to the high incidence of Neisseria meningitidis group B meningitis in the population of the State of São Paulo, preparing antiserum to this serogroup for diagnostic purposes has become a matter of high priority. Of the many immunization schemes proposed, intravenous inoculation of whole bacteria previously inactivated with formaldehyde and simultaneous intradermal inoculation with a mixture of the bacterial polysaccharide fraction and whole bacteria in complete Freund;s adjuvant have produced the best results. The antiserum was treated with immunoadsorbents prepared with aluminum chloride and protein and/or polysaccharide antigens from each of the following heterologous bacteria: Haemophilus influenzae type b, Streptococcus pneumoniae, Escherichia coli other than K1, and Staphylococcus aureus, in order to eliminate cross-reactivity. For quality control analysis, the antiserum was assessed by the immunodiffusion, counterimmunoelectrophoresis, dot-ELISA, and immuno-blot techniques against homologous antigens. Specificity was obtained after treating the antiserum with Haemophilus influenzae type b polysaccharide immunosorbent.