Diagnostic Yield of Pneumococcal Antigen Detection in Cerebrospinal Fluid for Diagnosis of Pneumococcal Meningitis Among Children in China

OBJECTIVE

To determine the diagnostic accuracy of pneumococcal antigen detection in diagnosis of pneumococcal meningitis in children.

METHODS

Purulent meningitis was diagnosed according to European Society for Clinical Microbiology and Infectious Diseases (ESCMID) guideline between July 2014 and June 2016. Along with a cerebrospinal fluid (CSF) culture, pneumococcal antigen detection in cerebrospinal fluid (CSF) was performed, and further identification of pathogens was done with 16S rDNA-PCR and high-throughput sequencing.

RESULTS

CSF samples collected from 184 children (median age of 1.92 mo). CSF culture was used as the gold standard. 46 (25%) had positive results for culture and 10 (5.4%) were pneumococci; 34 (18.5%) were pneumococcal antigen positive. The sensitivity and specificity of pneumococcal antigen detection were 100% (95% CI: 89.4%-100%) and 86.2% (95% CI: 96.4%-99.9%), respectively. 92.3% (12/13) were confirmed by nucleic acid detection to be pneumococci.

CONCLUSIONS

Pneumococcal antigen detection in CSF has adequate sensitivity and specificity in diagnosing pneumococcal meningitis.

The diagnostic value of metagenomic next-generation sequencing for identifying Streptococcus pneumoniae in paediatric bacterial meningitis

BACKGROUND

There is currently no research on the diagnostic value of metagenomic next-generation sequencing (mNGS) for a single pathogens in CSF. The aim of this study was to analyse the value of mNGS for identifying Streptococcus pneumoniae (S. pneumoniae) in paediatric bacterial meningitis.

METHODS

Bacterial meningitis (BM) cases from October 23, 2014, to December 31, 2016, and December 1, 2017, to July 31, 2018 at Beijing Children's Hospital were reviewed. Clinical features and pathogens were analysed.

RESULTS

We diagnosed 135 patients with BM in this study. A total of 43 S. pneumoniae were identified by combination methods. 26/135 (19.3%) patients had positive results in S. pneumoniae by blood and/or cerebrospinal fluid (CSF) culture. Alere BinaxNow®Streptococcus pneumoniae Antigen test was positive in 35/135(25.9%) cases. 32/135 (23.7%) S. pneumoniae were identified by mNGS. Six CSF samples were identified as S. pneumoniae only by mNGS technology. Taking culture as the gold standard, the sensitivity and specificity of mNGS for diagnosing S. pneumoniae meningitis were 73.1 and 88.1%, respectively. The positive predictive value (PPV) and negative predictive value (NPV) of diagnosing S. pneumoniae meningitis by mNGS were 59.4 and 93.2%, respectively. When comparison between mNGS and combined tests (culture and Alere BinaxNow®Streptococcus pneumoniae Antigen test), the sensitivity and specificity of mNGS for S. pneumoniae identification were 70.3 and 93.9%, the PPV and NPV in the identification of S. pneumoniae by mNGS were 81.4 and 89.3%, respectively. The difference in number of unique reads of S. pneumoniaein from CSF sample (< 14 days onset) and CSF sample (> 14 days from onset) was statistically significant (170.5 VS. 13, P = 0.019). The difference in the collected time of CSF for culture and mNGS was statistically significant (4 days VS. 14 days, P < 0.001).

CONCLUSIONS

mNGS has high sensitivity and specificity for S. pneumoniae identification. The pathogen load (number of unique reads) of S. pneumonia is related to the CSF collection time. mNGS was less affected than culture by the use of antibiotics before CSF collection.

Cerebrospinal fluid Lyme multiplex assay results are not diagnostic in horses with neuroborreliosis

BACKGROUND

The accuracy of the Lyme multiplex assay for the diagnosis of neuroborreliosis in horses is unknown.

HYPOTHESIS/OBJECTIVES

To describe Lyme multiplex results in horses with a postmortem diagnosis of neuroborreliosis. The hypothesis was that paired serum and cerebrospinal fluid (CSF) results and a CSF : serum ratio would allow differentiation of horses with neuroborreliosis from those with other neurologic diseases.

ANIMALS

Ninety horses that had neurologic examinations, serum and CSF Lyme multiplex analyses, and postmortem examination of the nervous system performed.

METHODS

Retrospective study. Data collected included signalment, ante- and postmortem diagnoses, and serum and CSF Lyme multiplex results. The CSF : serum ratio was calculated by dividing CSF median fluorescent intensity (MFI) by serum MFI for each result.

RESULTS

Ten horses had a final diagnosis of neuroborreliosis, 70 were diagnosed with other neurologic diseases, and 10 had no neurologic disease. Not all horses with neuroborreliosis had positive results: 4/10 had at least 1 positive serum result, 5/10 had at least 1 positive CSF result, and 3/10 had at least 1 CSF result 4-fold higher than the corresponding serum result. Results were similar for the 70 horses with other neurologic diseases: 53% had at least 1 positive serum result, 50% had at least 1 positive CSF result, and 16% had at least 1 CSF result 4-fold higher than the corresponding serum result.

CONCLUSIONS AND CLINICAL IMPORTANCE

Positive Lyme multiplex results were common in horses with neurologic diseases and did not adequately differentiate horses with neuroborreliosis from horses with other disorders.

Early diagnosis of tuberculous meningitis by an indirect ELISA protocol based on the detection of the antigen ESAT-6 in cerebrospinal fluid

Background

Early diagnosis of tuberculous meningitis (TBM) is still a challenge; the present study aimed to establish a method of detecting the antigen early secreted antigenic target 6 (ESAT-6) in cerebrospinal fluid (CSF) by an indirect enzyme-linked immunosorbance assay (ELISA) protocol and to study the value of detecting ESAT-6 in CSF in the early diagnosis of TBM.

Methods

An indirect ELISA protocol was used, employing a monoclonal antibody (mAb) against ESAT-6, which was used to demonstrate ESAT-6 in the CSF from TBM patients and non-TBM controls. CSF was obtained from 100 patients: confirmed TBM, clinically diagnosed TBM, disease controls, and healthy controls (n = 10). Pure recombinant ESAT-6 (standard product) was used in serial dilutions to detect the absorbance and to establish a standard curve from the data; the concentration was on the X axis vs. absorbance on the Y axis, and the standard curve was used to interpolate the concentration of ESAT-6 in samples.

Results

The indirect ELISA method provided 88 % sensitivity and 92 % specificity for the diagnosis of TBM using a mAb to ESAT-6. The mean concentration of ESAT-6 in TBM patients was significantly higher than that of the non-TBM groups. There was also a significant difference in the mean ESAT-6 expression between the confirmed TBM patients and the clinically diagnosed TBM patients (p < 0.01).

Conclusions

Detection of ESAT-6 in the CSF of TBM patients by indirect ELISA protocol gives a reliable early diagnosis and can be used to develop an immunodiagnostic assay with increased sensitivity and specificity.

Detection of bacterial antigen in cerebrospinal fluid in patients with bacterial meningitis: a literature review

Rapid detection of bacterial pathogen causing meningitis is very important to guide antimicrobial therapy before the standard culture result is available. Other than gram stain, one of the most useful rapid methods is the detection of bacterial antigen in cerebrospinal fluid. This article reviewed the methods of bacterial antigen detection for diagnosis of meningitis as well as a microbiology aspect of this life-threatening disease.

Electroimmunotransferblot assay for the detection of mycobacterialantigens in the cerebrospinal fluid for diagnosis of tubercular meningitis

BACKGROUND

The diagnosis of tubercular meningitis (TBM) is often delayed as it presents initially with non-specific signs and symptoms leading to delay in appropriate therapy. Conventional modes of diagnosis are time-taking and immunodiagnosis has its own pitfalls. Antigen detection assays have been found to be quite promising in this aspect.

AIM

In the present study, attempts were made to evaluate the ElectroImmunoTransferBlot (EITB) test for detection of Mycobacterium tuberculosis antigens in CSF.

METHODS

A total of 46 CSF specimens were collected from 26 clinically suspected cases of TBM and 20 non-TBM cases. The mycobacterial antigens were concentrated by immunoprecipitation and separated based on their molecular weight by SDS-PAGE which were further transferred and immobilized onto a matrix and detected by EITB.

RESULTS

In TBM CSF specimens distinct bands of molecular weight 12 kDa, 30-32 kDa, 71 kDa, 86 kDa, 96 kDa, 110 kDa and 120 kDa were seen in addition to 50 kDa Immunoglobulin (Ig) heavy chain, 25kDa Ig light chain and an indistinct human albumin band at 69kDa. The control group CSF specimens also showed the Ig and albumin bands but showed no cross-reactive antigens. The following proteins 12 kDa (7.7%), 30-32 kDa (23%), 71 kDa (19.2%), 86kDa (77%), 96 kDa (57.5), 110 kDa (23%) and 120 kDa (15.4%) were identified as reactive bands. The results were compared to the reverse passive latex agglutination test.

CONCLUSION

The likelihood of diagnosing TBM as evidenced by detecting at least a single mycobacterium specific band was 88.4% by our protocol for antigen detection in CSF. The specificity of EITB for diagnosing TBM was found to be 100% when the 86k Da antigen was excluded from the analysis. However, the method of diagnosis is labour/reagent intensive and needs substantial validation.

Detection of antigenuria for diagnosis of invasive Haemophilus influenzae type b disease

BACKGROUND

Haemophilus influenzae type b (Hib) diseases are responsible for an estimated 400,000 childhood deaths, mostly in developing countries.

OBJECTIVES

To determine the value of the Wellcogen quantitative latex agglutination test (LA) in urine for the diagnosis of Hib pneumonia and meningitis.

METHODS

Healthy and sick children aged <5 y were enrolled in Dhaka Shishu (Children's) Hospital. Boiled and non-concentrated urine specimens underwent LA testing. In vaccinated subjects, urine was tested by LA at 24 h, 4-6 and 7-10 d after vaccination.

RESULTS

Of 1302 enrolled cases, 201 were healthy (90 Hib vaccine recipients and 111 provided NP) and 1101 were sick with either pneumonia (n=974) or meningitis (n=127). Among the healthy children enrolled, 41 (41/111, 37%) were colonised with Hib and two (2/41, 5%) were positive by LA test. Hib antigenuria among the children who had received Hib vaccination was mainly detected only on day 1 (7/90, 8%) of vaccination. Among the sick children, LA test for Hib antigen was positive for all confirmed cases of Hib pneumonia (10) and meningitis (35). In contrast, none of the urine specimens from the cases with a known aetiology other than Hib (n=104) was positive. Quantitative analysis of antigenuria of sick children showed that it is positive at least up to 1:8 and 1:16 dilutions for pneumonia and meningitis, respectively, in contrast with <or=1:4 for healthy children. In addition to the ten cases of culture-proven Hib, the test detected an additional 16 Hib pneumonia cases among children diagnosed as pneumonia, based on the presence of antigenuria >or=1:8 dilutions.

CONCLUSIONS

The Wellcogen LA test for Hib using boiled and non-concentrated urine is more sensitive than blood culture alone and is highly specific.

Detection of aHelicobacter pyloriAntigen in Cerebrospinal Fluid of Patients with Meningitis

Meningitis is a common life threatening disease which may be caused by a bacterium, fungus, or virus. Here, the presence of a Helicobacter pylori antigen was investigated in serum and CSF samples from 173 individuals with meningitis. The influence of H. pylori infection on CSF levels of Thl/Th2 cytokines was also evaluated. H. pylori antigen was detected using ELISA and Western blot based on specific anti-H. pylori antibody. Thl/Th2 cytokines (IFN-gamma & IL-10, respectively) were also determined. A target epitope of 58-kDa was detected in selected CSF and serum samples using Western blot. H. pylori antigen was detected in the CSF samples of 75% of meningitis patients showing H. pylori antigen in their sera. A significant correlation (p < 0.001, r = 0.21) was shown between serum and CSF levels of 58-kDa H. pylori antigen. Only the levels of Thl cytokine (IFN-gamma) were significantly higher (p < 0.05) in CSF of meningitis patients positive for H. pylori antigen than negative patients with meningitis. In conclusion, the 58-kDa H. pylori antigen crossed the blood brain barrier and entered the CSF of patients with meningitis. A significant upregulation of Thl response may be associated with H. pylori infection in patients with meningitis.

Rapid diagnosis of tuberculous meningitis: a comparative evaluation of in-house PCR assays involving three mycobacterial DNA sequences, IS6110, MPB-64 and 65 kDa antigen

A PCR was standardized for amplifying three different mycobacterial--IS6110, MPB-64, 65 kDa DNA sequences. A comparative evaluation of the three PCR assays was carried out for the rapid diagnosis of tuberculous meningitis (TBM) using cerebrospinal fluid (CSF) specimens. While the IS6110 PCR was a single-step amplification reaction, the MPB-64 and 65 kDa antigen PCR assays were nested reactions. A total of 176 cerebrospinal fluid (CSF) samples from 176 patients were subjected to amplification of the three different mycobacterial sequences. Amongst them, 45 samples were obtained from confirmed cases of TBM (culture positive) and 56 samples were obtained from clinically suspected cases of TBM which were culture-negative. The remaining 75 CSF samples were categorized under the non-infectious and infectious illness of the central nervous system (CNS). Against a gold standard of culture, a sensitivity of 98% (NPV=99%) and a specificity of 100% (PPV=100%) was observed with the IS6110 PCR. Among the nested PCRs, a sensitivity of 91% (NPV=94%) and a specificity of 91% (PPV=85%) was observed with the MPB-64 assay, while the 65 kDa protocol had an associated sensitivity of 51% (NPV=76%) and a specificity of 92% (PPV=79%). These findings suggest that among the nested PCR assays, the MPB-64 PCR assay was associated with an enhanced degree of sensitivity and was comparable in terms of specificity. Our study also demonstrates that the IS6110 assay, while being a single-step PCR had the advantage of being a rapid test for the diagnosis of TBM, with increased sensitivity and enhanced specificity as compared to the nested PCR protocols.

Report of two cases of aseptic meningitis with persistence of pneumococcal cell wall components in cerebrospinal fluid after Pneumococcal meningitis

We describe two cases of aseptic meningitis occurring some time after pneumococcal meningitis. Both cases may have resulted from an inflammatory response to persistent pneumococcal cell membrane components, as the cerebrospinal fluid samples were positive by the Binax NOW Streptococcus pneumoniae antigen test. Potential mechanisms and diagnostic impact are discussed.

Phenotypical and functional analysis of memory and effector human CD8 T cells specific for mycobacterial antigens

Mycobacterium tuberculosis infects one-third of the global population and claims two million lives every year. Because memory CD8 T cells exhibit a high heterogeneity in terms of phenotype and functional characteristic, we investigated the frequency, phenotype, and functional properties of Ag85A epitope-specific HLA-A*0201 CD8 T cells in children affected by tuberculosis (TB) before and 4 mo after chemotherapy and healthy contact children. Using Ag85A peptide/HLA-A*0201 pentamer, we found a low frequency of blood peptide-specific CD8 T cells in tuberculous children before therapy, which consistently increased after therapy to levels detected in healthy contacts. Ex vivo analysis of the expression of CD45RA and CCR7 surface markers indicated a skewed representation of Ag85A epitope-specific CD8 T cells during active TB, with a predominance of T central memory cells and a decrease of terminally differentiated T cells, which was reversed after therapy. Accordingly, pentamer-specific CD8 T cells from tuberculous patients produced low levels of IFN-gamma and had low expression of perforin, which recovered after therapy. The finding of an elevated frequency of pentamer-specific CD8 T cells with T effector memory and terminally differentiated phenotypes in the cerebrospinal fluid of a child with tuberculous meningitis strongly indicates compartmentalization of such CD8 effectors at the site of disease. Our study represents the first characterization of Ag-specific memory and effector CD8 T cells during TB and may help to understand the type of immune response that vaccine candidates should stimulate to achieve protection.

Detection of antigen and antibody in childhood tuberculous meningitis

OBJECTIVE

Mycobacterium tuberculosis excretory secretory 31 kDa, a serine protease antigen (M. tb ES-31), prepared from Mycobacterium tuberculosis H37Ra culture medium has been shown to have potential in detecting tuberculosis. Precise diagnosis and management of tuberculous meningitis, in children in particular, is essential to curtail mortality and morbidity.

METHODS

In this study, M. tb ES-31 antigen, was used in Indirect ELISA to detect tuberculous IgG antibody, in sera and CSF samples while affinity purified anti ES-31 goat antibody was used in sandwich ELISA for detection of tuberculous antigen. In sixty-five samples each of CSF and sera from cases with neurotuberculosis and control with non-tuberculous diseases were collected from Kasturba Hospital, Sevagram.

RESULTS

Among the 20 patients suffering from neurotuberculosis the IgG antibody was detected in 17(85%) of CSF and 16(80%) of sera samples, while antigen was detected in 18 (90%) in CSF and 16 (80%) in sera. Overall specificity of the assay for both IgG antibody and antigen detection in CSF was 96% while in sera it was 94% for IgG antibody and 96% for antigen detection.

CONCLUSION

This study showed the usefulness of mycobacterial serine protease antigen and its antibody in detecting neurotuberculosis.

Post-streptococcal opsoclonus-myoclonus syndrome associated with anti-neuroleukin antibodies

BACKGROUND

Adult opsoclonus-myoclonus (OM), a disorder of eye movements accompanied by myoclonus affecting the trunk, limbs, or head, is commonly associated with an underlying malignancy or precipitated by viral infection.

METHODS

We present the first two reports of post-streptococcal OM associated with antibodies against a 56 kDa protein. Two young girls presented with opsoclonus and myoclonus following a febrile illness and pharyngitis. Protein purification techniques were employed. Amino acid sequences of human neuroleukin (NLK) and streptococcal proteins were compared using the protein-protein BLAST application.

RESULTS

The antigen was identified as NLK (glucose-6-phosphate isomerase, GPI). GPI is present on the cell surface of streptococcus making the protein a candidate target for molecular mimicry.

CONCLUSIONS

We have identified NLK as an antigenic target in two patients with post-streptococcal OM. The pathogenicity of the antibodies is uncertain. The potential role of anti-neuroleukin antibodies in the pathogenesis of OM is discussed. We propose that OM may represent a further syndrome in the growing spectrum of post-streptococcal neurological disorders. The role of streptococcus in OM and the frequency with which anti-NLK responses occur in both post-infectious and paraneoplastic OM should be investigated further.

Evaluation of the Pastorex meningitis kit for the rapid identification of Neisseria meningitidis serogroups A and W135

The recent emergence of Neisseria meningitidis W135 as a cause of epidemic bacterial meningitis and the availability of a trivalent ACW135 vaccine have created a need for accurate and timely meningococcal serogroup determination for organization of epidemic vaccine response. The sensitivity and specificity of the Pastorex meningitis kit (Bio-Rad) to identify serogroups A and W135 in the African meningitis belt was assessed using PCR testing as the gold standard. The sensitivity and specificity for serogroups A and W135 were 87 and 85%, respectively, while the specificities were 93 and 97%. The positive and negative likelihood ratios for A were 12 and 0.14 and for W135 were 33 and 0.16. The positive and negative predictive values, computed to simulate an epidemic of meningococcal meningitis with an estimated 70% prevalence of N. meningitidis among suspected cases, were 97% and 75% for A and 99% and 73% for W135. In remote locations of the African meningitis belt, latex agglutination is the only currently available test that can rapidly determine meningococcal serogroup. This study showed that latex agglutination performs well and could be used during the epidemic season to determine appropriate vaccine response.

Rapid diagnosis of pneumococcal meningitis: implications for treatment and measuring disease burden

BACKGROUND

Streptococcus pneumoniae is the leading cause of childhood pneumonia and meningitis worldwide. Isolation of this organism, however, is uncommon in resource-poor countries, in part because of extensive use of prior antibiotics. A rapid, highly sensitive immunochromatographic test (ICT) for S. pneumoniae was evaluated for the diagnosis of meningitis.

METHODS

Cerebrospinal fluid (CSF) from 450 children with suspected meningitis was tested with ICT, and results were compared with CSF culture, latex agglutination test (LAT) and/or polymerase chain reaction (PCR). Serial CSF specimens from 11 patients were also evaluated for duration of positive results during effective antimicrobial therapy.

FINDINGS

All 122 cases of pyogenic pneumococcal meningitis positive either by culture (N = 87) or PCR (N = 35) were positive by ICT, yielding 100% (122 of 122) sensitivity. All purulent CSF specimens from patients with meningitis caused by other bacteria by culture (N = 149) or by LAT (N = 48) or those negative by culture, LAT and LytA and thus of unknown etiology (N = 20), and normal CSF specimens (N = 104) were negative by ICT. Thus the specificity of ICT also was 100% (321 of 321), although negativity of ICT was not confirmed by PCR, if it was positive for other organisms either by culture or LAT. Serotyping of S. pneumoniae strains revealed 28 different serotypes, indicating that outcome of ICT are independent of diverse capsular serotype of pneumococcus. Antigen was detected by ICT for at least 10 days after presentation, and 1 was still positive on day 20, which was longer than for either LAT or PCR.

INTERPRETATION

ICT for pneumococcal antigen in CSF is 100% sensitive and specific in diagnosing pyogenic pneumococcal meningitis and can detect approximately 30% more pneumococcal meningitis cases than with culture alone. The simplicity of the test procedure and the longevity of CSF antigen detection suggest the potential utility of ICT to estimate the true burden of pneumococcal disease, as for Haemophilus influenzae type b using data from meningitis, and to guide selection of appropriate antibiotic treatment, especially in resource-poor countries with widespread prehospital antimicrobial use.

Demonstration of components of antigen 85 complex in cerebrospinal fluid of tuberculous meningitis patients

Tuberculous meningitis (TBM) is the most common form of chronic infection of the central nervous system. Despite the magnitude of the problem, the general diagnostic outlook is discouraging. Specifically, there is no generally accepted early confirmative diagnosis protocol available for TBM. Various Mycobacterium tuberculosis antigens are now recognized as potential markers for diagnosis of TBM. However, their presence remains questionable, and many of these antigens are reported in the blood but not in the cerebrospinal fluid (CSF). This study identifies a specific protein marker in CSF which will be useful in early diagnosis of TBM. We have demonstrated the presence of a 30-kDa protein band in CSF of 100% (n = 5) of confirmed and 90% (n = 138) of suspected TBM patients out of 153 TBM patients. The 30-kDa band was excised from the gel, destained extensively, and digested with trypsin. The resulting peptides were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Partially purified proteins from CSF samples of TBM were analyzed by two-dimensional polyacrylamide gel electrophoresis and Western blotting. Immunoblotting and enzyme-linked immunosorbent assay (ELISA) were performed to confirm the presence of proteins in the 30-kDa protein band. The antigen 85 (Ag 85) complex was detected in CSF of TBM patients by indirect ELISA using antibodies against Ag 85 complex. The results of this study showed the 30-kDa protein band contained MTB proteins Rv3804c (Ag85A) and Rv1886c (Ag 85B), both members of the Ag85 complex. This was also confirmed by using immunotechniques such as indirect ELISA and the dot immunobinding assay. Detection of Ag85 complex was observed in CSF of 89% (71 out of 80) of suspected TBM patients that were 30-kDa protein positive. The observed 30-kDa protein in the CSF is comprised of the MTB Ag85 complex. This protein was earlier reported to be present in the blood of patients with extra-central nervous system tuberculosis. Therefore, this finding suggests that this protein can be used as a molecular marker for any type of tuberculous infection. It also provides a more sensitive immunoassay option for the early and confirmatory diagnosis of TBM.

Development of a sandwich dot–enzyme linked immunosorbent assay for Streptococcus pneumoniae antigen detection in cerebrospinal fluid

A new sandwich dot-enzyme linked immunosorbent assay (sdot-ELISA) was developed using omniserum prepared against different strains of Streptococcus pneumoniae as capture antibody and also as second or revealing antibody after its conjugation with horseradish peroxidase (HRP) for detection of pneumococcal antigen in cerebrospinal fluid (CSF). A total of 103 CSF samples of different categories were screened with newly developed dot-ELISA and results were compared with commercially available latex agglutination (LA) kit. The newly developed sdot-ELISA was more sensitive than LA test and can be used as an alternative diagnostic tool in laboratory and in field conditions. An added advantage of this ELISA system was that it did not require antibodies produced in two different animal species.

Immunodiagnosis of tuberculous meningitis: detection of antibody reactivity to antigens of Mycobacterium tuberculosis and Cysticercus cellulosae in cerebrospinal fluid tuberculous meningitis patients by ELISA

Enzyme-linked immunosorbent assay (ELISA) was standardized and evaluated for detection of antibody response in cerebrospinal fluid (CSF) to antigens of Mycobacterium tuberculosis and Cysticercus cellulosae. Sonicated extracts of heat killed M. tuberculosis H37Rv and C. cellulosae were prepared and used in ELISA to detect respective antibody response in CSFs for a definitive diagnosis as to tuberculous meningitis (TBM)/neurocysticercosis (NCC). ELISA was performed in a total of 201 CSF samples, which include Group I: chronic infections of the central nervous system (CNS) with possible diagnosis of TBM, tuberculoma, or NCC (n = 70), and Group II: control group of patients with infectious neurological (n = 19), non-infectious neurological (n = 82), and non-infectious non-neurological conditions, i.e., spinal anaesthesia CSFs (n = 30). Specificity in this study was 99.9% and no true cross-reactivity between antimycobacterial antibodies and C. cellulosae antigens and vice-versa was observed. However, in 17.14% of CSFs (12/70), both antimycobacterial and anticysticercal antibodies were detected, 50% of these cases were diagnosed as TBM. But none of the proven NCC cases showed presence of antimycobacterial antibodies. Results of this study would indicate that it would be beneficial if both antibody and antigen responses are detected in CSFs to infectious aetiologies such as M. tuberculosis, C. cellulosae, and C. neoformans in order to enhance the diagnostic accuracy and proper management, as these diseases are highly endemic in underdeveloped and developing countries.

Clinicopathological Abnormalities and Treatment Response in 24 Dogs Seroreactive to Bartonella vinsonii (berkhoffii) Antigens

Bartonella vinsonii (B. vinsonii) subspecies berkhoffii is a recently recognized cause of endocarditis, myocarditis, and granulomatous disease in dogs. In an effort to elucidate other potential disease manifestations, the case records of 24 dogs that were seroreactive to B. vinsonii (berkhoffii) antigens were studied retrospectively. Diagnoses included immune-mediated hemolytic anemia, neutrophilic or granulomatous meningoencephalitis, neutrophilic polyarthritis, cutaneous vasculitis, and uveitis. Repeated B. vinsonii (berkhoffii) antibody titers became negative after treatment. This study indicates that a diverse spectrum of disease manifestations and clinicopathological abnormalities can be detected in dogs that are seroreactive to B. vinsonii (berkhoffii) antigens.

Bacterial antigen detection test in meningitis

OBJECTIVE

To evaluate the role of bacterial antigen detection test in cerebrospinal fluid (CSF) for a rapid etiological diagnosis of bacterial meningitis.

METHODS

The study included 36 cases of bacterial meningitis and 14 controls. Latex particle agglutination test (LPA test) for detection of bacterial antigen was done in the CSF using slidex meningitis kit (Biomeriux, France).

RESULTS

Using LPA test, an etiological diagnosis could be made in 83% cases of bacterial meningitis. In contrast, CSF Gram stain and culture showed 36% and 6% positivity, respectively. The sensitivity and specificity of LPA test were 83% and 100%, respectively. The common etiological organisms were S. pneumoniae, H. influenzae type b and N. meningitidis A. S. pneumoniae was encountered in all age groups while H. influenzae type b was found only below one year of age.

CONCLUSIONS

LPA test is a rapid and superior diagnostic tool as compared to CSF Gram stain and culture. The study recommends LPA test as an adjunct laboratory test for rapid etiological diagnosis of bacterial meningitis for prompt institution of proper antibiotics.

Pneumococcal antigen detection in cerebrospinal fluid: a comparative study on counter immunoelectrophoresis, latex agglutination and coagglutination

The sensitivity, specificity, accuracy and predictive values of counter immunoelectrophoresis (CIE), latex agglutination (LA) and coagglutination (CoAg) tests were compared for detection of pneumococcal antigen in cerebrospinal fluid (CSF) of patients suspected of meningitis. A total of 95 CSF samples comprising 15 culture proven, 47 clinically suspected but culture negative cases of meningitis and 33 controls were screened by above tests. Among three tests, LA was found to have high sensitivity and moderately high negative predictive value than CIE and CoAg tests. However, CIE had slightly better specificity than LA and CoAg tests. Accuracywise CIE and LA tests were comparable than CoAg test. CIE and LA tests had high positive predictive value than CoAg test.

The evolving epidemiology of invasive meningococcal disease: a two-year prospective, population-based study in children in the area of Athens

In response to an increase in the incidence in invasive meningococcal disease (IMD) due to Neisseria meningitidis, a system of hospital- and laboratory-based surveillance was used in a prospective epidemiological and clinical assessment of IMD in children 0-13 years of age hospitalized in the Athens area between 1 January 1999 and 31 December 2000. The annual incidence of laboratory-confirmed disease was 10.2/100,000. Serogroup B strains were predominant. There was a sharp decrease in serogroup C from 19% of cases in 1999 to 3% in 2000 (P=0.013). Of note was the emergence of serogroup A responsible for 7% of the cases. The overall case fatality rate was 4.5%, but 2.8% for microbiologically confirmed cases. A remarkable decrease in disease severity assessed by admissions to intensive care units was noted during the second study year. Polymerase chain reaction-based methods for detection of meningococcal DNA were the sole positive laboratory test in 45% of the cases and the only test on which serogroup determination was based in 52% of groupable cases. The epidemiological and clinical profile of meningococcal disease appears to be rapidly evolving and close monitoring is required particularly for input into decisions regarding use of meningococcal vaccines.

Detection of heat stable mycobacterial antigen in cerebrospinal fluid by Dot-Immunobinding assay

BACKGROUND

Isolation of Mycobacterium tuberculosis in cerebrospinal fluid (CSF) specimen in patients with tuberculous meningitis (TBM) is infrequent and carries low sensitivity. Thus development of an alternative laboratory diagnostic test is essential for the early diagnosis and treatment of TBM.

OBJECTIVE

A simple, rapid Dot immunobinding assay (Dot-Iba), for the laboratory diagnosis of TBM is devised. This method minimizes the risk of handling infectious material in the laboratory.

METHOD

The Dot-Iba was standardized with heat-inactivated M tuberculosis antigen (PPD). The heat-inactivated CSF from TBM and non-TBM patients was similarly assayed and it can detect antigen upto 1ng/ml in CSF.

RESULT

A positive result was obtained in all the five culture positive patients with TBM and in 20/25 probable TBM. A negative result was obtained in 38/40 CSF from disease control group. The overall sensitivity and specificity of Dot-Iba was 83.3% and 95% respectively.

CONCLUSION

Dot-Iba can be used as an adjunct for the laboratory diagnosis of TBM, particularly in culture negative TBM patients and also in those clinical situations where no laboratory tests are available to distinguish between TBM and partially treated pyogenic meningitis.

Immunocytochemical method for early laboratory diagnosis of tuberculous meningitis

A simple immunocytochemical method was standardized for the direct demonstration of mycobacterial antigen in cerebrospinal fluid (CSF) specimens of patients with tuberculous meningitis (TBM). CSF-cytospin smears were prepared from 22 patients with a clinical diagnosis of TBM and also from an equal number of patients with nontuberculous neurological diseases (disease control). Immunocytological demonstration of mycobacterial antigens in the cytoplasm of monocytoid cells was attempted, by using rabbit immunoglobulin G to Mycobacterium tuberculosis as the primary antibody. Of the 22 CSF-cytospin smears from TBM patients, 16 showed positive immunostaining, while all of the CSF-cytospin smears from the disease control showed negative immunostaining for mycobacterial antigen. The technical aspects of this immunocytological method for the demonstration of mycobacterial antigens are simple, rapid, and reproducible, as well as specific, and therefore can be applied for the early diagnosis of TBM, particularly in patients in whom bacteriological methods did not demonstrate the presence of M. tuberculosis in the CSF.

A comparative evaluation of dot immunobinding assay (Dot-Iba) and polymerase chain reaction (PCR) for the laboratory diagnosis of tuberculous meningitis

The results of a Dot immunobinding assay (Dot Iba) for the detection of mycobacterial antigen in the cerebrospinal fluid (CSF) of 45 patients with tuberculous meningitis (TBM) were compared with the results of a polymerase chain reaction (PCR) for the detection of Mycobacterium tuberculosis. In eight patients with culture proven TBM, Dot-Iba gave positive results, while PCR yielded positive results only in six patients. The overall sensitivities of Dot-Iba and PCR in 37 patients with culture negative (probable) TBM were 75.67% and 40.5% respectively. Dot-Iba, in contrast to PCR is a rapid and relatively easier method. More importantly, Dot-Iba is suitable for the routine application for the laboratory diagnosis of TBM and therefore best suited to laboratories in the developing world.

[Bacterial meningitis in Yaoundé (Cameroon) in 1999-2000]

All cephalo-spinal fluid (CSF) samples sent to the Yaoundé Pasteur Centre in Cameroon, between July 1999 and June 2000, were cultured and tested for soluble antigens. The percentage of positive samples was 10.4%. The main etiological agents detected were Streptococcus pneumoniae (56.2%), Haemophilus influenzae (18.5%) et Neisseria meningitidis (13.4%). Most of these cases of bacterial meningitis were children (86.7%). The susceptibility of the isolates to antibiotics was investigated. The streptococci and meningococci were mostly susceptible to beta-lactams, but the Gram-negative bacteria were not. Combinations of amino-penicillin and aminoside or chloramphenicol continue to be effective, as are third generation cephalosporins used alone. Meningococci appear to have emerged during the year 1999/2000, with 23 such isolates identified, of which 17 were serogroup A, subtype P1-9, clone III-1, which was responsible for the second pandemic. It should also be noted that 4 strains of N. meningitidis of serogroup W135 were isolated in Yaoundé.

Immunodiagnosis of pneumococcal meningitis using Dot-enzyme-linked immunosorbent assay

A diagnosis of bacterial meningitis requires isolation of the pathogen from cerebrospinal fluid (CSF). However, cultures of CSF are usually insensitive, thus, in the majority of patients, the etiology is rarely determined. A total of 90 CSF samples from pediatric patients with clinical diagnosis of bacterial meningitis were evaluated by Dot-ELISA. This method was standardized in order to detect pneumococcal polysaccharide antigen in CSF samples previously treated with 0.1 M EDTA and dotted on nitrocellulose membrane strips. Pneumococcal omniserum diluted 1:200 was employed for pneumococcal antigen detection. Dot-ELISA showed relative indices of 100 and 90 per cent for sensitivity and specificity, respectively. This method is cheaper than counter immunoelectrophoresis for pneumococcal antigen detection.

Lack of sensitivity of the latex agglutination test to detect bacterial antigen in the cerebrospinal fluid of patients with culture-negative meningitis

For culture-negative meningitis, use of the latex agglutination test for detection of bacterial antigen in the CSF has a sensitivity of only 7%. Routine use of the latex agglutination test may not contribute to the management of suspected acute bacterial meningitis, since patients are treated on the basis of their clinical presentations and CSF findings.

Immunodiagnosis of tuberculous meningitis: rapid detection of mycobacterial antigens in cerebrospinal fluid by reverse passive hemagglutination assay and their characterization by Western blotting

Tuberculous meningitis (TBM) is one of the commonest chronic infections of the central nervous system (CNS). Diagnosis of TBM has been a problem as it causes various clinical manifestations which can be confused with those of other chronic infections of the CNS such as neurocysticercosis (NCC), neurobrucellosis and cryptococcal meningitis, that are prevalent in many underdeveloped and developing countries. Differential diagnosis of TBM can be made by detecting circulating mycobacterial antigens in CSF by immunoassays. In this study, a reverse passive hemagglutination (RPHA) has been developed using rabbit antimycobacterial IgG for detection of circulating mycobacterial antigens in CSFs from chronic infections of the CNS in order to develop a rapid, simple, sensitive and cost-effective method. Circulating mycobacterial antigens were characterized by immunoblot assay. The sensitivity limit of RPHA was 400 ng ml(-1). RPHA was specific as antimycobacterial IgG did not show any reaction with porcine Cysticercus cellulosae which was used as a control antigen. RPHA could detect mycobacterial antigens in CSF at a sensitivity level of 94.11% with a specificity of 99.0%. Immunoblot analysis of RPHA positive CSFs revealed predominantly 30-32 kDa and 71 kDa antigens whilst 6, 86, 120, 96 and 110 kDa showed varied degree of reactivity. Antigens of masses 30-32 and 71 kDa were absent in culture filtrate of Mycobacterium tuberculosis H37Rv grown in Proskeur-Beck liquid medium. RPHA is a rapid, simple and sensitive immunological method with a long shelf life of 6-8 weeks if stabilized coated erythrocytes are stored at +4 degrees C. RPHA could be used as an additional immunodiagnostic tool in both differential diagnosis and prognosis of TBM. Immunoblot results indicate that 30-32 kDa and 71 kDa antigens are cell wall derived.

Diagnostic particle agglutination using ultrasound: a new technology to rejuvenate old microbiological methods

Microbial antigen in clinical specimens can be detected rapidly by commercial test-card latex agglutination, but poor sensitivity is a potential difficulty. Antigen detection by immuno-agglutination of coated latex micro-particles can be enhanced in comparison with the conventional test-card method in both rate and sensitivity by the application of a non-cavitating ultrasonic standing wave. Antibody-coated micro-particles suspended in the acoustic field are subjected to physical forces that promote the formation of agglutinates by increasing particle-particle contact. This report reviews the application of ultrasound to immuno-agglutination testing with several commercial antibody-coated diagnostic micro-particles. This technique is more sensitive than commercial card-based agglutination tests by a factor of up to 500 for fungal cell-wall antigen, 64 for bacterial polysaccharide and 16 for viral antigen (in buffer). The detection sensitivity of meningococcal capsular polysaccharide in patient serum or CSF has been increased to a stage where serotyping by ultrasound-enhanced agglutination is comparable to that achievable with the PCR, but is available more rapidly. Serum antigen concentration as measured by ultrasonic agglutination has prognostic value. Increasing the sensitivity of antigen detection by increasing the acoustic forces that act on suspended particles is considered. Employing turbidimetry to measure agglutination as part of an integrated ultrasonic system would enable the turnover of large numbers of specimens. Ultrasound-enhanced latex agglutination offers a rapid, economical alternative to molecular diagnostic methods and may be useful in situations where microbiological and molecular methods are impracticable.

Increasing microbiological confirmation and changing epidemiology of meningococcal disease on Merseyside, England

OBJECTIVES

To determine, for the last 5 years in children on Merseyside with clinical meningococcal disease (MCD), the impact on diagnostic yield of newer bacteriologic methods; bacterial antigen detection (AD) and polymerase chain reaction (PCR).

METHODS

Prospective data collection at Royal Liverpool Children's Hospital over two epochs: 1 September 1992 to 30 April 1994 (epoch A, n = 126) and 17 November 1997 to 15 September 1998 (epoch B, n = 85).

RESULTS

Epoch A was compared with epoch B. Diagnosis was confirmed by detection of meningococci in 78 of 126 (61.9%) versus 64 of 85 (75.3%, P = 0.04), but with a significantly lower rate of positive blood and cerebrospinal fluid culture in the later epoch. The proportion of cases receiving penicillin pretreatment was unchanged at 32%, but the proportion undergoing lumbar puncture decreased significantly. Median ages were higher in epoch B: 1.7 years versus 2.49 years (P = 0.013, Mann-Whitney). There was a significant increase in the proportion of cases due to serogroup C (14/78 (18%) versus 30/64 (46.9%), P = 0.001).

CONCLUSIONS

Culture detection of meningococci from children with MCD has reduced, as less lumbar punctures are done. However, improved diagnosis by PCR and AD has increased microbiological confirmation overall. Serogroup C disease and the median age of cases continue to rise.

Significance of laboratory findings for the diagnosis of neurosyphilis

Our objective is to assess the specificity and sensitivity, and thus elaborate the relevance, of different laboratory findings for the diagnosis of neurosyphilis. One hundred and fourteen HIV-negative pairs of serum and cerebrospinal fluid (CSF) samples were examined by the Venereal Disease Research Laboratory (VDRL) test, a fluorescent treponemal antibody-absorption (FTA-ABS) test, microhaemagglutination assay with Treponema pallidum antigen (MHA-TP) test (serum) and Treponema pallidum haemagglutination assay (TPHA) test (CSF); further, albumin, total protein, and total IgG were determined and, in the CSF, cell count was performed. The donors were 60 patients with active neurosyphilis and 54 healthy persons with a former history of syphilis and with persisting positive results in the T. pallidum haemagglutination tests (serum: MHA-TP, CSF: TPHA), who supplied specimens for control. Albumin quotient, IgG index, TPHA index, modified TPHA index, Intrathecally produced T. pallidum Antigen (ITpA) index, its 2 modifications and, in 12 samples, the adenovirus group antibody (AVGA)/TPHA index were ascertained. The specificity and sensitivity of the TPHA index were 100% and 98.3%, of the modified TPHA index 50.0% and 96.7%, of the ITpA index 42.6% and 90.0%, of the modified ITpA indices 51.8% and 68.3% (first modification) and 53.7% and 63.3% (second modification). The AVGA/TPHA index yielded a specificity of 91.7% (11/12). The CSF VDRL test was positive in 55/60 (91.7%) of samples from patients with neurosyphilis and in none of the controls (0/54). A CSF-TPHA titre greater than 1:320 was observed in 59/60 (98.3%) of the neurosyphilis specimens and in none of the controls (0/54). A TPHA index above an outcome of 70, a positive CSF-TPHA test at a titre greater than 1:320 and, with lower sensitivity, the criteria of the Centers for Disease Control (CDC) guidelines yield the most reliable results for laboratory support to a diagnosis of neurosyphilis. The modified TPHA index, the ITpA index, and its 2 modifications produce results of minor sensitivity and poor specificity. Observations on the AVGA/THPA index are too limited yet for judgement. The diagnostic significance of a CSF-TPHA titre above 320 needs further confirmation on a greater number of observations made by different laboratories.

Rapid diagnosis of tuberculous meningitis by a dot immunobinding assay To detect mycobacterial antigen in cerebrospinal fluid specimens

In the present prospective study, a dot immunobinding assay (Dot-Iba) was standardized to measure the circulating mycobacterial antigen in cerebrospinal fluid (CSF) specimens for the laboratory diagnosis of tuberculous meningitis (TBM). Immunoglobulin G antibody specific for Mycobacterium tuberculosis in a CSF specimen from a patient with culture-proven TBM was isolated and was coupled with activated cyanogen bromide-Sepharose 4B. By immunosorbent affinity chromatography, a 14-kDa antigen was isolated from the culture filtrate of M. tuberculosis. Antibody to the 14-kDa mycobacterial antigen was raised in rabbits. The Dot-Iba in this study gave no false-positive results with CSF specimens from patients with nontuberculous neurological diseases. The assay gave positive results for all five patients with culture-proven TBM. The Dot-Iba described in the present report is simple, rapid, sensitive, specific, and, more importantly, suitable for routine application in laboratories in developing countries.

Detection of antibodies to Brucella cytoplasmic proteins in the cerebrospinal fluid of patients with neurobrucellosis

The diagnosis of human neurobrucellosis usually relies on the detection of antibodies to Brucella lipopolysaccharide (LPS) in cerebrospinal fluid (CSF) by agglutination tests or enzyme-linked immunosorbent assay (ELISA). Here we describe the detection of immunoglobulin G (IgG) to cytoplasmic proteins (CP) of Brucella spp. by ELISA and Western blotting in seven CSF samples from five patients with neurobrucellosis. While IgG to CP (titers of 200 to 12, 800) and IgG to LPS (800 to 6,400) were found in the CSF of these patients, these antibodies were not detected in CSF samples from two patients who had systemic brucellosis without neurological involvement. The latter, however, had serum IgG and IgM to both LPS and CP. No reactivity to these antigens was found in CSF samples from 14 and 20 patients suffering from nonbrucellar meningitis and noninfectious diseases, respectively. These findings suggest that, in addition to its usefulness in the serological diagnosis of human systemic brucellosis, the ELISA with CP antigen can be used for the specific diagnosis of human neurobrucellosis.

[The prospects for the diagnosis of bacterial meningitis]

The samples of spinal fluid arriving to the Clinical Infectious Hospital in 1994-1996 with the clinical diagnosis "generalized form of meningococcal infection" or "purulent meningitis of unclear etiology" were studied. The etiological agent was bacteriologically identified in 35% of 487 patients (in 25% of cases Neisseria meningitidis, in 7% of cases Streptococcus pneumoniae and in 2% of cases Haemophilus influenzae, type b, were detected). The method of latex agglutination, used in this study, was highly specific (100%) and moderately sensitive (67%); this method made it possible to diagnose 25% of cases additionally (N. meningitidis in 15% of cases, S. pneumoniae in 5% of cases and H. influenzae in 3% of cases). Diagnostics with the use of PCR was characterized by high specificity (> 97%) and sensitivity (> 85%) relatively to the "golden standard" of microbiological diagnostics. There were few false positive results (3 samples), caused probably by contamination at the moment of taking the samples. For this reason the results obtained by PCR could be used for diagnostic purposes even in cases of negative results given by other methods. Tests with the use of PCR made it possible to diagnose 29% more cases additionally (in 26% of cases N. meningitidis DNA and in 3% of cases S. pneumoniae DNA were detected. Thus the complex of methods used in this study permitted the detection of the etiological agent altogether in 87% of cases.

CSF bacterial antigen detection tests offer no advantage over Gram's stain in the diagnosis of bacterial meningitis

While bacterial antigen detection (BAD) tests have been used on cerebrospinal fluid (CSF) with success in the diagnosis of bacterial infection in developing countries, their value in the developed world has been recently questioned. In Darwin, Northern Territory (NT), there are good diagnostic resources but high rates of infectious disease, so it was unclear which findings were applicable to our own population. This study aimed to determine the utility of the BAD tests in detection of bacterial meningitis from CSF in patients studied at Darwin, using a retrospective review of hospital case records and microbiology laboratory reports, over a 19 month period, and utilising a clinical component in the case definition of bacterial meningitis. The sensitivity of the BAD test in the diagnosis of acute bacterial meningitis was 28.6%, with a specificity of 98.7% and a positive predictive value of 85.7%. The cost per positive test was computed at $240. No cases of bacterial meningitis which were positive on the BAD test were missed on Gram's stain of CSF. We conclude that in our setting BAD tests alone are not sensitive enough to confidently diagnose bacterial meningitis. BAD tests are more costly and offer no advantage in speed of diagnosis or in antibiotic pre-treated patients, compared to routine Gram's stain.

Diagnosis of tuberculous meningitis by detection of antigen and antibodies in CSF and sera

OBJECTIVE

To evaluate diagnostic potential of three immunological tests, namely, detection of H37Rv antigen of M. Tuberculosis in CSF, detection of antibodies (IgG) against H37Rv in CSF and detection of antibodies (IgG) against H37Rv in serum for diagnosis of tuberculous meningitis in children.

SUBJECTS

50 children diagnosed as patients of tuberculous meningitis were included as cases and 48 children with CNS diseases of nontubercular etiology [pyogenic meningitis (n = 31), encephalitis (n = 10), seizure disorder of unknown etiology (n = 5), brain tumor (n = 2)] served as controls.

METHODS

H37Rv antigen of M. tuberculosis was detected in CSF by Dot ELISA, and antibodies (IgG) against H37Rv in CSF and serum were detected by Plate ELISA.

RESULTS

Detection of H37Rv antigen in CSF was the most sensitive (90%) and specific (95.83%) with positive and negative predictive values of 95.74% and 90.19%, respectively, followed by detection of antibodies in CSF (sensitivity-74%, specificity-89.58%, positive predictive value-88.10%, negative predictive value-76.78%). Detection of antibodies in serum had low sensitivity (50%), specificity (91.67%), positive predictive value (86.21%) and negative predictive value (63.76%).

CONCLUSIONS

Detection of antigen in CSF is a rapid, sensitive and specific test for diagnosis of tuberculous meningitis in children. Detection of antibody in CSF may be useful in some cases but needs further evaluation. Detection of antibody in serum does not appear to be useful for diagnosis of tuberculous meningitis.

Augmented intrathecal secretion of interferon-gamma in response to Borrelia garinii in neuroborreliosis

The Lyme disease agent Borrelia garinii has been suggested to be neurotrop, preferentially affecting the nervous system. We compared the secretion of interferon-gamma in response to outer surface proteins from Borrelia garinii and Borrelia afzelii in 10 patients with neuroborreliosis. In cerebrospinal fluid, stimulation with Borrelia garinii revealed higher numbers of interferon-gamma-secreting cells in all patients, whereas in blood, only five displayed higher numbers. This further strengthens the hypothesis of Borrelia garinii being associated with the development of neuroborreliosis.

Humoral immune response to mycobacterial heat shock protein (hsp)65 in the cerebrospinal fluid of neuro-Behçet patients

Although systemic immune reactivity to 65-kD mycobacterial hsp65 (m-hsp65) has been shown previously in Behçet's disease (BD), local immune response was not investigated. We studied anti-m-hsp65 IgG, IgM and IgA antibodies in the serum and cerebrospinal fluid (CSF) of 25 BD patients with cerebral parenchymal involvement (p-NBD), seven BD patients with intracranial hypertension (ih-NBD), eight BD patients without central nervous system (CNS) involvement, 30 patients with multiple sclerosis (MS) and 24 patients with non-inflammatory CNS disorders (NIC). Significantly higher CSF IgG responses were detected in p-NBD patients (ELISA ratio 1.3 +/- 0.9) compared with NIC (0.7 +/- 0.4, P < 0.01). In p-NBD patients' IgG, IgM or IgA CSF anti-m-hsp65 positivity rate was 48% (12/25); this was significantly higher when compared with MS (3/30; P < 0.03) and NIC (3/24; P < 0.01). CSF anti-m-hsp65 IgG ratios correlated with the duration of BD (r = 0.4, P < 0.04) but not with the duration of neurological involvement. Serum IgM and IgA responses were elevated in ih-NBD, suggesting a different type of involvement than p-NBD. These results implicate an increased local humoral response to m-hsp65 in the CSF of p-NBD patients, which might be related to the pathogenesis of neurological involvement.

Analysis of the intrathecal immune response in neuroborreliosis to a sonicate antigen and three recombinant antigens of Borrelia burgdorferi sensu stricto

The intrathecal synthesis of borrelial-specific IgM- and IgG-antibodies was studied in 67 patients with neuroborreliosis and in 14 patients with neurosyphilis (controls). Antibody concentrations in serum and in the cerebrospinal fluid were determined by an enzyme immunoassay (EIA) using, as antigens, a sonicate of Borrelia burgdorferi, the recombinant 14 kDa flagellin fragment, the outer surface protein C (22 kDa), and the high molecular mass protein p83 (83 kDa). In the sonicate EIA, IgG- and/or IgM-antibodies to Borrelia burgdorferi in serum were detected in all patients with neuroborreliosis and in 71% of patients with neurosyphilis. Intrathecal synthesis of borrelial-specific IgG- and/or IgM-antibodies was demonstrated in 82% of patients with neuroborreliosis and in 71% of patients with neurosyphilis. Immunoglobulin G- and/or IgM-antibodies in serum against any of the recombinant antigens were detected in 92% of patients with neuroborreliosis and in none of those with neurosyphilis. Intrathecal synthesis of IgG- and/or IgM-antibodies to individual recombinant antigens was demonstrated in 67% of patients with neuroborreliosis and in none of those with neurosyphilis. The sensitivity of the recombinant antigens in serum was almost equal to that of the sonicate EIA, whereas the recombinant antigens were clearly less sensitive in the estimation of the intrathecal specific immune response. It was concluded that in suspected cases of neuroborreliosis, the estimation of high specific antibodies in the recombinant EIA will be helpful in confirming the diagnosis.

Post immunization Hib antigen detection in the CSF of a patient with meningococcal meningitis

We report a case of meningococcal meningitis where the cerebrospinal fluid was negative for Neisseria meningitidis but positive for Haemophilus influenzae type b by rapid antigen detection test. We believe that this was due to prior immunization with Haemophilus influenzae type b vaccine. We recommend caution in interpretation of the rapid antigen detection tests especially in patients who had been vaccinated against organisms screened by these tests.

Meningococcal meningitis among Rwandan refugees: diagnosis, management, and outcome in a field hospital

OBJECTIVE

To study the diagnostic process, clinical course, and outcome of Rwandan refugees with meningococcal meningitis, treated in an Israeli field hospital in Goma, Zaire, in the summer of 1994.

METHODS

Patient hospital charts and laboratory records were reviewed with critical evaluation of clinical presentation and diagnostic tests. Patients were treated as part of a disaster relief effort in a refugee camp experiencing several coexisting lethal epidemics.

RESULTS

A total of 65 patients were identified as having group A meningococcal meningitis. Latex agglutination test for Neisseria meningitidis soluble antigen in the cerebrospinal fluid was found to be a superior diagnostic tool, as compared to Gram stain, and at least as effective as culture. The mortality rate was 14%; mortality was markedly affected by co-morbidity (e.g., dysentery, pneumonia, and malnutrition).

CONCLUSIONS

The outcome of patients with meningococcal meningitis, treated in referral centers within a disaster area may be favorable, despite overwhelming coexisting epidemics, and may be comparable to that achieved in advanced medical facilities. Encephalopathy may be a diagnostic pitfall in the perspective of coexisting epidemics, requiring a high index of suspicion and routine lumbar puncture. The latex agglutination test is highly useful in achieving prompt diagnosis of meningococcal meningitis, in particular when sample handling for culture and microscopy is suboptimal.

Early detection of tuberculous meningitis using one step competitive ELISA

A one step competitive Enzyme-Linked Immunosorbent assay (ELISA) method was developed to detect mycobacterial antigen in cerebrospinal fluid (CSF) for the diagnosis of tuberculous meningitis and compared with a standard competitive ELISA method. Indigenously prepared soluble extract of Mycobacterium tuberculosis H37 Rv was used as antigen. The study was conducted using CSF of 230 clinically diagnosed cases of tuberculous meningit is and 208 control subjects. A cutoff value of 0.57 ng/ml by the one step ELISA and 0.5 ng/ml by the standard ELISA method were determined. The specificity of both methods were 100% and positivity was 68.26% and 70.43% respectively. A follow up study was conducted in 63 cases at various interval of time after starting anti-tubercular therapy i.e. at 3 weeks (63 cases), 6 weeks (27 cases) and > or = 4-12 months (13 cases). It was observed that antigen levels decreased gradually, but were much above the cutoff range. Indigenously prepared antigen was compared with antigen prepared in other laboratories and standard molecular weight markers using SDS PAGE (Sodium Do-decyl Sulphate Polycrylamide Gel Electrophoresis).