Children's Corner

Rede, uitgesproken ter gelegenheid van het aanvaarden van het ambt van bijzonder hoogleraar met als leeropdracht Tropische Bacteriologie aan het Erasmus MC, faculteit van de Erasmus Universiteit Rotterdam op 22 december 200

Guillain-Barré Syndrome-related campylobacter jejuni in Bangladesh: ganglioside mimicry and cross-reactive antibodies

BACKGROUND: <br/> Campylobacter jejuni is the predominant antecedent infection in Guillain-Barré syndrome (GBS). Molecular mimicry and cross-reactive immune responses to C. jejuni lipo-oligosaccharides (LOS) precipitate the development of GBS, although this mechanism has not been established in patients from developing countries. We determined the carbohydrate mimicry between C. jejuni LOS and gangliosides, and the cross-reactive antibody response in patients with GBS in Bangladesh.<br/> METHODOLOGY:<br/> Sera from 97 GBS patients, and 120 neurological and family controls were tested for antibody reactivity against LOS from C. jejuni isolates from GBS patients in Bangladesh (BD-07, BD-39, BD-10, BD-67 and BD-94) by enzyme-linked immunosorbent assay (ELISA). Cross-reactivity to LOS was determined by ELISA. The LOS outer core structures of C. jejuni strains associated with GBS/MFS were determined by mass spectrometry.<br/> PRINCIPLE FINDINGS:<br/> IgG antibodies to LOS from C. jejuni BD-07, BD-39, BD-10, and BD-67 IgG antibodies were found in serum from 56%, 58%, 14% and 15% of GBS patients respectively, as compared to very low frequency (<3%) in controls (p<0.001). Monoclonal antibodies specific for GM1 and GD1a reacted strongly with LOS from the C. jejuni strains (BD-07 and BD-39). Mass spectrometry analysis confirmed the presence of GM1 and GD1a carbohydrate mimics in the LOS from C. jejuni BD-07 and BD-39. Both BD-10 and BD-67 express the same LOS outer core, which appears to be a novel structure displaying GA2 and GD3 mimicry. Up to 90-100% of serum reactivity to gangliosides in two patients (DK-07 and DK-39) was inhibited by 50 µg/ml of LOS from the autologous C. jejuni isolates. However, patient DK-07 developed an anti-GD1a immune response while patient DK-39 developed an anti-GM1 immune response.<br/> CONCLUSION:<br/> Carbohydrate mimicry between C. jejuni LOS and gangliosides, and cross-reactive serum antibody precipitate the majority of GBS cases in Bangladesh

Comparative in vitro activities of trovafloxacin (CP-99,219) against 445 gram-positive isolates from patients with endocarditis and those with other bloodstream infections

The in vitro activity of trovafloxacin (CP-99,219), a new fluoroquinolone, was compared with the in vitro activities of other commonly used quinolones and other antimicrobial agents against 445 gram-positive microorganisms isolated between 1986 and 1995 from patients with endocarditis and those with other bloodstream infections. The MICs at which 90% of the isolates are inhibited (MIC90) of trovafloxacin for methicillin-susceptible staphylococci, viridans group streptococci, and enterococci were 0.06, 0.25, and 0.5 mg/liter, respectively. The MIC90 of trovafloxacin for vancomycin-resistant enterococci as well as for methicillin-resistant Staphylococcus aureus and methicillin-susceptible and ciprofloxacin-resistant S. aureus, isolated from sources other than blood, was 1 mg/liter. For the quinolones the rank order of activity was trovafloxacin > sparfloxacin > ciprofloxacin = ofloxacin > pefloxacin. Depending on the species tested, trovafloxacin was 4- to 64-fold more active than ciprofloxacin. Further experimental and in vivo studies are warranted to evaluate the efficacy of trovafloxacin in the treatment of bacterial endocarditis and other infections caused by gram-positive organisms

Comparison of eight methods to detect vancomycin resistance in enterococci

A collection of genetically unrelated vancomycin-resistant enterococci (VRE) including 50 vanA, 15 vanB, 50 vanC1, and 30 vanC2 VRE were used to evaluate the accuracy of eight currently available susceptibility test methods (agar dilution, disk diffusion, E-test, agar screen plate, Vitek GPS-TA and GPS-101, and MicroScan overnight and rapid panels). vanA VRE were detected by all methods. vanB VRE were often not detected by Vitek GPS-TA and MicroScan rapid (sensitivities, 47 and 53%, respectively), though the new Vitek GPS-101 was found to be a significant improvement. E-test and the agar screen were the only two methods detecting all VRE, including the vanC1/C2 VRE

Guillain-Barré syndrome following varicella-zoster virus infection

We describe the frequency, clinical features, and electrophysiological and immunological phenotypes of Guillain-Barré Syndrome (GBS) patients treated at a single institution in Bangladesh who had preceding chicken pox (primary Varicella-zoster virus [VZV] infection) within 4 weeks of GBS onset. A literature review of GBS cases preceding VZV infection is also provided. Diagnosis of GBS was based on the National Institute of Neurological Disorders and Stroke criteria for GBS. Serum anti-VZV IgM and IgG antibodies were quantified by indirect chemiluminescence immunoassay (CLIA); anti-Campylobacter jejuni IgG, IgM, and IgA antibodies and anti-ganglioside GM1 IgM and IgG antibodies, by enzyme-linked immunosorbent assays. Neurophysiologic subtypes were categorized following the Hadden criteria. Of 536 patients with GBS, 7 (1.3%) had chicken pox within 4 weeks before GBS onset. Four of the seven cases were male (age range, 23 to 40 years old). All seven patients were bed-bound, six had sensory symptoms, and three required mechanical ventilation for respiratory failure. All seven patients had CSF albuminocytologic dissociation and evidence of demyelination in nerve conduction studies. Anti-VZV IgM antibodies were present and anti-GM1 and anti-Campylobacter jejuni lipo-oligosaccharides (LOS) were negative in all cases. All patients had excellent outcome at 1 year (able to run). A systematic literature review of GBS cases related to VZV revealed 39 previously reported patients with comparable clinical presentations and outcomes, of which 36 had neurophysiologic evidence of demyelination. VZV infection is associated with the demyelinating subtype of GBS, clearly distinct from the axonal form of GBS that predominate in countries like Bangladesh

Microarray screening of Guillain-Barré syndrome sera for antibodies to glycolipid complexes

__Objective:__ To characterize the patterns of autoantibodies to glycolipid complexes in a large cohort of Guillain-Barré syndrome (GBS) and control samples collected in Bangladesh using a newly developed microarray technique. __Methods:__ Twelve commonly studied glycolipids and lipids, plus their 66 possible heteromeric complexes, totaling 78 antigens, were applied to polyvinylidene fluoride-coated slides using a microarray printer. Arrays were probed with 266 GBS and 579 control sera (2 mL per serum, diluted 1/50) and bound immunoglobulin G detected with secondary antibody. Scanned arrays were subjected to statistical analyses. __Results:__ Measuring antibodies to single targets was 9% less sensitive than to heteromeric complex targets (49.2% vs 58.3%) without significantly affecting specificity (83.9% 85.0%). The optimal screening protocol for GBS sera comprised a panel of 10 glycolipids (4 single glycolipids GM1, GA1, GD1a, GQ1b, and their 6 heteromeric complexes), resulting in an overall assay sensitivity of 64.3% and specificity of 77.1%. Notable heteromeric targets were GM1:GD1a, GM1:GQ1b, and GA1:GD1a, in which exclusive binding to the complex was observed. __Conclusions:__ Rationalizing the screening protocol to capture the enormous diversity of glycolipid complexes can be achieved by miniaturizing the screening platform to a microarray platform, and applying simple bioinformatics to determine optimal sensitivity and specificity of the targets. Glycolipid complexes are an important category of glycolipid antigens in autoimmune neuropathy cases that require specific analytical and bioinformatics methods for optimal detection