[Prevention and therapy of airway infections in patients with cystic fibrosis].
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Adolescent↗
Biomedical subjects
J Dankert
Publications and source records attributed to J Dankert.
[Absence of meningitis caused by Haemophilus influenzae type b in The Netherlands following twofold vaccination].
OBJECTIVE: To determine the two-year results of nationwide vaccination with Haemophilus influenzae type b (Hib) vaccine on the occurrence of Hib meningitis in the Netherlands. DESIGN: Retrospective controlled study. SETTING: The Netherlands. METHOD: Children born since April 1, 1993 are vaccinated at the age of 3, 4, 5 and 11 months to protect them from infections with Hib. The number of Hib meningitis patients in the period 1 April, 1993 to 1 April, 1995, among infants born in this period who were offered the Hib vaccine (study group), was compared with the number of Hib meningitis patients in the period 1 April, 1991 to 1 April, 1993 among children born in last-mentioned period (control group). RESULTS: Twenty-one cases of meningitis by Hib were observed in the study group. Twelve children who, as a consequence of their age, had only been vaccinated once or not at all; 7 children were not vaccinated for several reasons. In addition one patient was infected by H. influenzae type f strain and one by a non-typable strain. In the control group 185 cases of Hib meningitis occurred. CONCLUSION: Hib meningitis was not observed among infants who had been vaccinated at least twice.
Haemophilus Vaccines↗
Opsono-phagocytosis of non-encapsulated Haemophilus influenzae.
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Enzyme-Linked Immunosorbent Assay↗
Inherited complement deficiency in children surviving fulminant meningococcal septic shock.
UNLABELLED: We evaluated the complement system in 29 children (mean age: 4.5 years) who survived fulminant meningococcal septic shock. No terminal complement deficiencies were found. One patient, who experienced the most dramatic disease course, had a decreased haemolytic activity in the haemolysis-in-gel test for the alternative pathway. The properdin concentration in serum of this patient was < 0.1 microgram/ml (n = 17.1-27.7 micrograms/ml). Coagulation studies revealed a heterozygeous type I protein C deficiency as well. He was the only patient with a Neisseria meningitidis group Y infection. CONCLUSION: Fulminant meningococcal disease due to uncommon serogroups should lead to screening of the alternative pathway of complement activation.
Adolescent↗
Multiple Haemophilus influenzae strains and strain variants coexist in the respiratory tract of patients with cystic fibrosis.
To investigate the epidemiology of nontypeable Haemophilus influenzae in the respiratory tract of cystic fibrosis (CF) patients, H. influenzae isolates from sputum specimens of 40 CF patients were analyzed longitudinally for 2 years. The isolates were characterized by analysis of the major outer membrane protein (MOMP) patterns. MOMP variant H. influenzae strains were discriminated from distinct strains by randomly amplified polymorphic DNA analysis of genomic DNA. Multiple H. influenzae strains and MOMP variant strains were isolated from single sputum specimens of 29 patients. In 22 patients, a distinct H. influenzae strain persisted over time (median persistence, 8 months; range 2-24). In general, the appearance of MOMP variant strains did not coincide with the occurrence of exacerbations.
Bacterial Outer Membrane Proteins↗
Fulminant meningococcal septic shock in a boy with combined inherited properdin and protein C deficiency.
A 7-year-old patient with fulminant septic shock due to Neisseria meningitidis of the uncommon serogroup Y developed extensive gangrene of the limbs. Multiple amputations were necessary and a pulmonary embolism occurred within 2 days post-operatively. Complement and haemostatic system studies, done after recovery, showed a complete absence of properdin antigen and a low protein C antigen and activity level in plasma. Defective haemolytic activity in gel by the alternative pathway of complement activation could be restored with purified properdin, indicating a properdin deficiency type 1. Protein C antigen level as well as activity were in agreement with a protein C deficiency type I. The polymerase chain reaction (PCR) product of exon five of the protein C gene showed a substitution of 72Gly by Arg. Both deficiencies were traced among relatives of the patient. Serum of the father of the patient's mother was also properdin-deficient. Microsatellite haplotyping of the X-chromosome of the patient and his relatives showed that a distinct haplotype cosegregated with the properdin deficiency (Lodscore 2.25; four informative meioses). The protein C type I deficiency was present in the patient's mother and her mother and cosegregated with the mutation found. So far as is known, this is the first patient described with combined inherited properdin deficiency and protein C deficiency.
Adult↗
Construction of recombinant neisserial Hsp60 proteins and mapping of antigenic domains.
Here we report the cloning and expression, in Escherichia coli, of PCR-amplified DNA encoding the 63-kDa stress-inducible protein of Neisseria gonorrhoeae strains VP1 and PID2, Neisseria meningitidis 2996 and the commensal Neisseria flavescens. DNA sequence analysis revealed in all cases one open reading frame of 541-544 amino acids corresponding to a protein of approximately 57,000 Da. The various neisserial proteins were > 96% identical at the amino acid level and showed extensive homology with proteins belonging to the Hsp60 heat-shock-protein family. We constructed defined glutathione S-transferase fusion polypeptides of the gonococcal Hsp60 homologue to locate antigenic domains on the recombinant protein. Variation in the immunoreactivity of two monoclonal antibodies recognizing a conserved and a neisseria-unique antigenic Hsp60 determinant, respectively, could thus be deduced to result from single amino acid substitutions. Analysis of the antibody response in patients' sera demonstrated reactivity with the same fusion polypeptides in six out of nine sera, indicating that neisserial Hsp60 is expressed during the natural infection and that distinct domains on the protein are immunodominant in vivo.
Amino Acid Sequence↗
Serotypes and subtypes of Neisseria meningitidis: results of an international study comparing sensitivities and specificities of monoclonal antibodies.
An international study supported by the World Health Organization comparing monoclonal antibodies for serotyping and serosubtyping of Neisseria meningitidis strains was performed and the results were assessed in 1992. A collection of 6 serotype-specific (1, 2a, 2b, 4, 14, and 15) and 12 serosubtype-specific (P1.1, P1.2, P1.4, P1.5, P1.6, P1.7, P1.9, P1.10, P1.12, P1.14, P1.15, and P1.16) monoclonal antibodies was provided to 11 participating laboratories throughout the world. Monoclonal antibodies were tested on 85 Neisseria meningitidis strains with known reference results. Whole-cell enzyme-linked immunosorbent assay was used for analysis in 10 of 11 laboratories. The sensitivities and specificities of individual serotype- and subtype-specific monoclonal antibodies were evaluated. Differences in individual laboratories and with individual monoclonal antibodies were assessed. Relatively large differences in sensitivities were achieved in individual laboratories. On the contrary, the specificities remained at high levels in all laboratories. The sensitivities of serotype-specific monoclonal antibodies ranged from 72.0 to 100%. Individual serosubtype-specific monoclonal antibodies showed sensitivities ranging from 64.1 to 98.1%. The most frequent reason for the incorrect results obtained with the monoclonal antibodies were false-negative results. The collaborative study demonstrated that some monoclonal antibodies are not very sensitive. Another study to define the most suitable monoclonal antibodies is planned.
Antibodies, Bacterial↗
Antibody responses to the capsular polysaccharide of Neisseria meningitidis serogroup B in patients with meningococcal disease.
We measured antibody responses to meningococcal serogroup B (MenB) polysaccharide (PS) by enzyme-linked immunosorbent assay (ELISA) in sera from 94 patients from The Netherlands with disease caused by Neisseria meningitidis group B. The patients ranged in age from 3 to 73 years (mean age, 18.8 years). In initial studies we showed that the binding of a panel of MenB PS-reactive human immunoglobulin M (IgM) paraproteins to biotinylated MenB PS bound to avidin-coated microtiter wells was inhibited > 90% by the addition of soluble MenB PS or encapsulated group B meningococci. In contrast, inhibition of IgM anti-MenB PS antibody-binding activity in many of the patient sera was less than 50% (range, 20 to 94%). These data suggested a high frequency of nonspecific binding in the patient sera. Therefore, all serum samples were assayed in replicate in the presence or absence of soluble MenB PS, and only the inhibitable fraction of the binding signal was used to calculate the anti-MenB PS antibody concentrations. In 17 control patients with meningococcal disease caused by serogroup A or C strains, there was no significant difference in the respective IgM or IgG anti-MenB PS antibody concentrations in paired acute- and convalescent-phase sera. In contrast, in patients with MenB disease, the geometric mean IgM anti-MenB PS antibody concentration increased from 3.9 units/ml in acute-phase serum to 10.5 units/ml in convalescent-phase serum (P < 0.001). The corresponding geometric mean IgG anti-MenB PS antibody titers were 1:27 and 1:36 (P < 0.05). There was only a weak relationship between age and the magnitude of the logarithm of the antibody concentrations in convalescent-phase sera (for IgM, r2 = 0.06 and P < 0.05; for IgG, r2 = 0.08 and P < 0.01). Our data indicate that precautions are needed to avoid nonspecificity in measuring serum antibody responses to MenB PS by ELISA. Furthermore, although this PS is thought to be a poor immunogen, patients as young as 3 years of age recovering from MenB disease demonstrate both ImG and IgG antibody responses in serum.
Adolescent↗
Paracytosis of Haemophilus influenzae through cell layers of NCI-H292 lung epithelial cells.
Haemophilus influenzae penetrates the respiratory epithelium during carriage and invasive disease, including respiratory tract infections. We developed an in vitro model system consisting of lung epithelial NCI-H292 cells on permeable supports to study the passage of H. influenzae through lung epithelial cell layers. The NCI-H292 cells formed tight layers with a Ca(2+)-dependent transepithelial resistance of around 40 omega.cm2. H. influenzae passed through the cell layers without affecting the viability of the cells and [3H]inulin penetration. The passage time was independent of the inoculum of H. influenzae in the apical compartment and was not influenced by the presence of capsule or fimbriae on H. influenzae or by the ability of the bacteria to adhere to the epithelial cells. However, highly adherent strains showed greater paracytosis. Different strains passed through the cell layer independently. The passage time was shorter for rapidly growing strains than for slowly growing strains (10 to 18 h and 30 h, respectively). Microscopic examination revealed the presence of clusters of H. influenzae bacteria between the epithelial cells, indicating that bacterial passage was due to paracytosis. After the addition of chloramphenicol, no bacteria were cultured from the basolateral side, and no bacterial clusters between the epithelial cells were seen, suggesting that de novo bacterial protein synthesis was needed for the bacteria to reach the intercellular space. We conclude that H. influenzae passes through viable cell layers of the human lung epithelial cell line NCI-H292 by paracytosis, requiring bacterial protein synthesis.
Bacterial Adhesion↗
Involvement of bactericidal factors from thrombin-stimulated platelets in clearance of adherent viridans streptococci in experimental infective endocarditis.
Platelets activated with thrombin release bactericidal factors. We studied the role of the susceptibility of viridans streptococci to these bactericidal factors in the development of infective endocarditis (IE). By using the experimental endocarditis rabbit model, the initial adherence and the development of IE were assessed for 10 viridans streptococcal strains differing in their susceptibilities to releasate (material released) from thrombin-activated platelets. Six strains were susceptible and four strains were resistant to these releasates. The numbers of vegetations (VGs) colonized at 5 min and 48 h after intravenous challenge with 10(4) CFU were determined. At 5 min after challenge, significantly more VGs were colonized with bacteria of the six platelet releasate-susceptible strains than with bacteria of the four releasate-resistant strains (P < 0.005). In the releasate-susceptible group of strains, the number of colonized VGs decreased significantly between 5 min and 48 h after intravenous inoculation (P < 0.001). Such a decrease was not observed with the releasate-resistant strains. As a result, the final developments of IE due to releasate-susceptible and -resistant strains were not significantly different. The releasate-susceptible strain 1 and the releasate-resistant strain 2 were selected for more detailed experiments. Rabbits were killed at 5 and 30 min and 2, 4, and 48 h after inoculation. The number of culture-positive VGs as well as the number of adherent bacteria on the individual VGs were determined. The 90% infective dose for each strain was 10(5) CFU. At low inoculum concentrations (10(3) and 10(4) CFU) a larger proportion of the inoculated bacteria of both strains was found to be adherent on VGs than at higher challenge doses. The number of culture-positive VGs as well as the number of adherent bacteria per VG decreased rapidly in the first 30 min after challenge with strain 1 but not after challenge with strain 2. Additional experiments with the platelet releasate-susceptible strain S224 and the platelet releasate-resistant stain S182 confirmed the data obtained with strains 1 and 2 and indicated that releasate-susceptible strains disappeared from the VGs with time, whereas releasate-susceptible strains persisted. In vitro studies with VGs excised 5 min after challenge with stain 1 or 2 showed that clearance of the releasate-susceptible strain 1 was not caused by complement bactericidal activity or surface phagocytosis by polymorphonuclear cells. Bacterial cells of strain 1 adherent on excised VTGs were rapidly cleared by exposure to fresh clotting blood or to releasates from thrombin-stimulated platelet suspension.(ABSTRACT TRUNCATED AT 400 WORDS)
Animals↗
Variable expression of class 1 outer membrane protein in Neisseria meningitidis is caused by variation in the spacing between the -10 and -35 regions of the promoter.
The class 1 outer membrane protein encoded by the porA gene of Neisseria meningitidis is a candidate for a vaccine against meningococcal infection. The expression of class 1 outer membrane protein displays phase variation between three expression levels. Northern (RNA) blot and primer extension analysis revealed that this phase variation is regulated at the transcriptional level. The start site for transcription is located 59 bp upstream of the translational initiation codon. Sequence analysis of the promoter region of the porA gene of a variant without class 1 protein expression revealed nine contiguous guanidine residues between the -10 and -35 domains. Comparison of promoter sequences of different phase variants indicated that the length of the polyguanidine stretch correlated with the expression level of the class 1 outer membrane protein; the presence of 11, 10, or 9 contiguous guanidine residues results in high levels, medium levels, or no expression of class 1 mRNA, respectively. These results suggest that the variable porA expression levels seen in different isolates are modulated by guanidine residue insertion and/or deletion due to slipped-strand mispairing on the polyguanidine stretch within the intervening sequence of the -35 and -10 regions of the promoter. The phase variation of class 1 outer membrane protein may provide a molecular mechanism to evade the host immune defense. Therefore, the protective efficacy of a vaccine based on class 1 outer membrane protein may be questioned.
Bacterial Vaccines↗
Comparison of commercial diagnostic tests for identification of serogroup antigens of Neisseria meningitidis.
In the study that is described the sensitivities and specificities of three commercial tests and the standard Reference Laboratory test, used since 1961, to identify Neisseria meningitidis serogroups were compared. The tests marketed by Difco, Murex/Wellcome, and Sanofi/Pasteur showed overall sensitivities of 92, 95, and 100%, respectively, and specificities of 67, 88, and 82%, respectively. When limited to the common serogroups A, B, and C, the three tests yielded sensitivities of 93, 97, and 100%, respectively, and specificities of 98, 100, and 98%, respectively. However, determination of the uncommon serogroups X, W-135, Y, Z, and 29E with these tests is either unreliable or not possible.
Antigens, Bacterial↗
Virulence factors in the colonization and persistence of bacteria in the airways.
Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa are commonly isolated from sputum specimens of patients with lower respiratory tract infections. Haemophilus influenzae, S. pneumoniae, and M. catarrhalis have several pathogenic properties in common. These bacteria are able to interact with mucus, to exert ciliotoxic activity, to adhere to bronchial epithelial cells, and to invade airway epithelium. Haemophilus influenzae and S. pneumoniae strains persist for many months in the respiratory tract of patients with chronic obstructive pulmonary disease (COPD), despite the specific antibodies present in serum and sputum against the persistent strain. Especially during exacerbations persistent strains with changes in their antigenic composition are isolated. Among H. influenzae strains, the antigenic characteristics of the outer membrane protein composition vary. Variation in S. pneumoniae occurs in capsular polysaccharides, the major immunogens of this bacterium. Such variations affect the efficacy of the antibody-mediated defense mechanisms against the bacteria. Between exacerbations, particularly H. influenzae, S. pneumoniae strains are recovered from the sputum of patients with COPD. Recovery may continue for periods up to 2 yr, although not continuously. Besides ineffective antibody-mediated defense mechanisms, it is likely that hiding of the bacteria in tissue contributes to the persistence of these bacteria in patients with COPD.
Bacterial Infections↗
Predicted disappearance of Haemophilus influenzae type b meningitis in Netherlands.
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Haemophilus Vaccines↗
Lyme borreliosis.
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Borrelia burgdorferi Group↗
Evaluation of central nervous system involvement in Lyme borreliosis patients with a solitary erythema migrans lesion.
To determine whether early dissemination of Borrelia burgdorferi to the central nervous system occurs in stage I of Lyme borreliosis, neurological and cerebrospinal fluid examination was performed in 48 consecutive patients in whom the only sign of infection was a solitary erythema migrans lesion. Long-term follow-up after treatment with tetracycline was carried out by telephone interview. At presentation, neurological findings were normal in all 48 patients. Cerebrospinal fluid samples were obtained from 29 (60%) patients. Mild pleocytosis and mild impairment of the blood-brain barrier were present in four and one of these patients, respectively. No significant amount of tumor necrosis factor or interleukin 6 was found in the cerebrospinal fluid samples. Culture results of 13 cerebrospinal fluid samples were negative. Borrelia burgdorferi DNA was only detected by the polymerase chain reaction in one of two aliquots of the cerebrospinal fluid sample of one patient. None of 46 patients who were interviewed 12 to 51 (median 25) months after antibiotic treatment developed manifestations consistent with disseminated or chronic Lyme borreliosis. Thus, no compelling evidence was found for the presence of asymptomatic central nervous system involvement in patients with clinically localized Lyme borreliosis.
Adult↗
Septata intestinalis frequently isolated from stool of AIDS patients with a new cultivation method.
Two species of microsporidia, Enterocytozoon bieneusi and Septata intestinalis have been reported as intestinal parasites of AIDS patients. In attempts to establish E. bieneusi in vitro, spores were concentrated from stool samples from 4 AIDS patients with biopsy-proven E. bieneusi infections. After sterilization of the concentrate in antibiotic solution, the spores were added to monolayers of RK13 cells grown on the membranes of Transwells. Cultures were established from 7 stool samples from the 4 patients but in every case the species established was S. intestinalis not E. bieneusi. On retrospective examination of the stools, a very small number of spores of a size comparable to that of S. intestinalis was found but this species was not detected in biopsies. Typical septate vacuoles containing Type I tubules were observed in vitro but in contrast to the original description, meronts were intravacuolar and sporogony was mainly disporoblastic. The cultivation system, used for the first time for microsporidia, revealed the presence of unsuspected S. intestinalis infections and indicates that this species may be much more common than hitherto suspected. S. intestinalis has not previously been cultured.
Acquired Immunodeficiency Syndrome↗