[Susceptibility to macrolide antibiotics of Bordetella pertussis and Bordetella parapertussis strains isolated from whooping cough patients in 1968 and in 1997-99]

The activity of erythromycin, azithromycin, clarithromycin, dirithromycin, oleandomycin, roxithromycin, spiramycin and josamycin against 21 and 34 B. pertussis strains and against 6 and 8 B. parapertussis strains isolated respectively in the years 1968 and 1997-99 was examined. The antibiotic agar dilution method was used. The minimum concentration of macrolides which inhibited growth of B. pertussis and B. parapertussis was calculated for 50% (MIC50) and 90% (MIC90) of isolates. The susceptibility to macrolides of B. pertussis and B. parapertussis strains isolated in the years 1968 and 1997-99 did not differ significantly. The MIC90 values of erythromycin were the same for B. pertussis (MIC90 = 0.125 mg/l) and B. parapertussis strains (MIC90 = 0.25 mg/l) recovered in 1968 as for those recovered in the years 1997-99. The most active antibiotic against all strains was azithromycin (MIC90 = 0.06 mg/l). The least active antibiotics were oleandomycin (MIC90 = 2-4 mg/l) and spiramycin (MIC90 = 8 mg/l). The study showed that erythromycin remains the antibiotic of choice for treatment of whooping cough and in case of emergence of B. pertussis and/or B. parapertussis strains erythromycin resistant, can be replaced by azithromycin.

[Whooping cough in adolescents and adults]

In the nineties in many countries increase of whooping cough incidence among adolescents and adults was observed. Postvaccination immunity is not long-lasting so adolescents and adults become again susceptible to pertussis and now they are considered as major source of B. pertussis infection for children. Immunization of adolescents and adults with acellular pertussis vaccine could lead to the decrease of B. pertussis circulation and even to the elimination of this pathogen. In the article occurrence, clinical symptoms, pertussis diagnostics and immunization possibility of adolescents and adults against whooping cough was presented.

[Restriction analysis of Bordetella pertussis DNA isolated from patients with whooping cough in 1968 and 1995-98 and B. pertussis used for production of national vaccine strains]

The genotypic and serotypic analysis of B. pertussis strains isolated from the nasopharynx of children with whooping cough in the years 1968 and 1995-98 and B. pertussis vaccine strains was the aim of this study. The genotyping of the examined strains was done by electrophoretic division of DNA in pulsed field. The 3 types (A, B, C) and 2 subtypes (A1 and A2) of DNA restriction patterns were determined for the B. pertussis strains isolated in 1968. The 2 types (D and E) and 10 subtypes (D1-D10) of DNA restriction patterns were identified for B. pertussis strains from the years 1995-98. The DNA restriction patterns of B. pertussis strains isolated in the years 1968 and 1995-98 were not identical what was the evidence of the fact that in the sixties and nineties whooping cough was caused by different B. pertussis clones. The different DNA profiles were also observed for vaccine strains as well as for vaccine strains and current isolates. Differences in DNA patterns of vaccine strains and B. pertussis strains isolated in the years 1995-98 indicated a relationship possibility in some cases while lack of relationship between these strains in other cases. Serotyping of the examined B. pertussis strains was performed by the agglutination method with the sera against B. pertussis agglutinogens 1, 2 and 3. Most strains--15 (75%) isolated in 1968 possessed only agglutinogens 1 and 3. Serotype 1, 2, 3 was most frequently observed among isolates from the years 1995-98. This study indicates the expediency of periodical change of B. pertussis vaccine strains in the aspect of whooping cough resurgence in the years 1994-95 and 1997-98.

[Reliability of results evaluation for the passive hemagglutination test in pertussis obtained from WSSE laboratories]

This study was undertaken for assessing of the reliability of the passive haemagglutination test with B. pertussis endotoxin in 18 laboratories of the Sanitary Epidemiological Stations. Each laboratory determined the level of pertussis antibodies in three serum samples twice, at interval of two weeks. The correct results were obtained in 7 laboratories (38.9%). The results of pertussis antibodies determination in only one or two samples were differed more than twice from correct in 5 additional laboratories; in this way the test was carried out satisfactorily in 12 laboratories (66.7%). Reproducibility of the results was good in 12 laboratories (66.7%). The study showed the necessity of repeated interlaboratory controls and periodic training of laboratory workers for raising of the quality and reliability of serological investigations for pertussis.

[Humoral reaction to Bordetella pertussis antigens: pertussis toxin, filamentous hemagglutinin and lipopolysaccharide in children with clinical symptoms of whooping cough. II. Occurence and level of B. pertussis antigens in children with suspected whooping cough]

The aim of this study was to determine and evaluate IgG, IgM and IgA levels to pertussis toxin (PT), filamentous hemagglutinin (FHA) and endotoxin (LPS) of B. pertussis in children with clinical symptoms of whooping cough. The serum samples obtained from 265 children (age range: 2 months-16 years) suspected of pertussis were examined by indirect haemagglutination (IH) and ELISA tests. Higher antibody level was most frequently observed in IgA class to PT, FHA and LPS in 45.3%, 35.1% and 66% of pertussis patients sera respectively. The least positive results were obtained in IgM class to PT and FHA (in 9.8% and 2.6% of children sera respectively) but in the case of LPS applied as the antigen in ELISA, higher IgM level was determined in 46.8% of pertussis patients sera. The four times increase of antibody level to LPS determined by IH was observed in 86.7% of children suspected of pertussis. Humoral response to B. pertussis infection is mainly connected with higher IgA level to PT, FHA, LPS and IgM to LPS in children with clinical symptoms of whooping cough.

[Humoral reaction to Bordetella pertussis antigens: pertussis toxin, filamentous hemagglutinin and lipopolysaccharide in children with clinical symptoms of whooping cough. I. Antibody level for B pertussis antigens in children without respiratory tract infection symptoms]

The aim of the first part of this study was to determine antibody level to pertussis toxin, filamentous hemagglutinin and endotoxin of B. pertussis in children without symptoms of respiratory tract infection. The serum samples obtained from 276 children (age range: 6 weeks-16 years) were examined using indirect hemagglutination and ELISA tests. Normal antibody levels to 3 B. pertussis antigens were determined for 95% of the serum samples as the upper cut-off levels depending on children age. Very high level of IgG antibodies to B.perussis antigens was observed in the control population. The lowest antibody level was found in IgA class to pertussis toxin and lipopolysaccharide. It was also established that the IgM level to 3 B. pertussis antigens was rising together with children age.

[Evaluation of the usefulness of Bordetella pertussis toxins for serodiagnosis of whooping cough]

The results of serological tests for the detection of antibodies against pertussis toxin by means of the ELISA test, and endotoxin of B. pertussis in the passive haemagglutination test were analysed. The levels of IgG, IgM and IgA antibodies were determined for 95% of serum samples of 108 children in control group (without evidence of respiratory infections) for establishing of the correlation of these with the age of these children. In the light of these data the results were evaluated of testing of 136 serum samples taken from 127 children with suspected whooping-cough. The highest diagnostic importance had the demonstration of high IgA or/and IgG immunoglobulins level against pertussis toxin in ELISA test, or tracing of the rate of rise of antipertussis antibodies in the passive haemagglutination test with B. pertussis endotoxin in children with clinical symptoms of whooping-cough.

Bacterial growth and virulence factors production by different Bordetella pertussis strains

The aim of this study was to compare bacteria growth and pertussis antigens (pertussis toxin-PT, filamentous haemagglutinin-FHA and endotoxin-LPS) production by 11 Bordetella pertussis strains. A synthetic Stainer-Scholte culture medium supplemented with (2,6-0-dimethyl) beta-cyclodextrin (heptakis) or methylcellulose (for greater PT and FHA production) and solid modified Cohen-Wheeler medium (for LPS isolation) were used. Our results demonstrated that heptakis and methylcellulose were more effective for antigens production than for bacterial growth. It was interesting that these stimulated substances supported the bacterial growth from small inocula. The investigated strains differed in PT, FHA and LPS production. The best PT producer was the B. pertussis 134 strain, the worst B. pertussis 2897. The differences in FHA production are not as big as in PT production, but the B. pertussis 2897 was also the worst FHA producer. Isolated LPS consists of dry bacteria pellet ranging from 1,9% (B.p. Tohama) to 5,6% (B.p. 3803 strain). No great differences in serological activity of LPS isolated from different strains were observed. In the haemagglutination inhibition test the endotoxin isolated from B.p. 509 and B.p. Tohama strains showed the highest activity.