Application of Pulsed field gel electrophoresis (PFGE) for typing sudy base on Haemophilus influenzae molecular

The study was conducted to compare the molecular differences of Haemophilus influenzae type b (Hib) strains causing meningitis in young children with H. influenzae strains causing acute upper respiratory tract infection, 44 Hib strains and 37 H. influenzae strains were analysed by pulsed field gel electrophoresis (PFGE) with SmaI restriction enzyme. The results: 44 Hib strains were mainly distributed into 4 DNA restriction patterns (PFGE patterns) whereas 37 H. influenzae strains were distributed into 22 patterns and 81% of them were not encapsulated. The genome of Hib strains causing bacterial meningitis showed less variation than that of H. influenzae causing acute upper respiratory infection. PFGE is a useful tool for epidemiological research.

Familial factor in contagiousness of Haemophilus influenzae type B meningitis in children

Seventy-nice pediatric patient - family pairs were detected for Hib or Hib-antigen. The study also examined 22 pairs of H. influenzae strains isolated from CSF of patients and from upper respiratory tract of the family members of the patients to determine serotype, biotype, presence of Beta-lactamase, PCR with Hib-specified primers, and PFGE with SmaI restriction enzyme. The results showed that 44.4% of the patients` families had Hib carriers; all of 22 H. influenzae isolated pairs from patients and their families had serotype b; 17 of 22 pairs had characteristics of biotype II; 16 of 22 pairs had Beta-lactamase; and 9 of 22 pairs had both the PCR pattern and PFGE pattern. Close contact with Hib carriers was a factor of Hib meningitis contagiousness in children under 5 years of age

Haemophilus influenzae type b (Hib) molecular relationship of Hib pathogenous strains isolated in Hanoi

34 Haemophilus influenzae type b (Hib) strains isolated from cerebrospinal fluids (CSFs) of meningitis patients at National Hospital of Pediatrics, Hanoi, between 11/2002 and 12/2003 were biotyped, serotyped and analyzed by using PCR with specific primers, Pulsed field gel electrophoresis (PFGE) with Smal restriction enzyme. The results showed that 24 of 34 Hib strains (70.6%) belong to biotype II; 8 of 34 (23.5%) belong to biotype I. PCR patterns with capsular polysaccharide type b specified primers of the 34 Hib strains were identical. DNA restriction patterns generated by PFGE (so-called PFGE patterns) of the 34 Hib strains were mainly distributed into 2 PFGE patterns. DNA restriction patterns had close relationship to biotype. The presence of PFGE patterns of Hib strains was not related to season

Use of mycobacterium vaccae as immuno-stimulant in the preparation of H.influenzae type b (Hib) antisera

In order to enhance the capability of antiserum production rabbits, Mycobacterium vaccae was used to stimulate rabbit’s immune system unspecifically before immunization with Haemophilus influenzae type b (Hib). The results showed that only single immunization with Hib antigen: the number of rabbits had response fulfill depended-time requirements (harvested after 1 or 6 months) varied from 30% to 70%, harvesting time for antiserum with fulfilled quantity and quality was 24 weeks (6 months) (2 courses induced immunization). Stimulating rabbit’s immune system by M. vaccae, then inducing rabbit’s immunization with Hib antigen: the number of rabbits had response fulfiling requirements varied from 71.4% to 100%; harvesting time for antiserum with fulfilled quantity and quality was 5 weeks (only after 1 course induced immunization). Sensitivity and specificity of antiserum were unchanged

Some techniques of detection of type B Haemophilus influenza in the diagnosis of meningitis due to type B H. influenza

Some techniques of detection of Hib were compared, including classic techniques such as bacterial culture and modern techniques such as PCR method. The results were as follows: 21% (+) culture with Hib compared to the total of clinically diagnosed cases, Hib-latex agglutination with 95% sensitivity and 99.6% specificity, counter immunophoresis assay to detect Hib by 97% sensitivity and 100% specificity. PCR increased the number of positive cases of Hib meningitis by 42.8% compared to culture alone. Blood culture gave a highly significant value to diagnose (51% Hib-possitive culture)

Early diagnosis of meningitis due to haemophilus influenzae type b in children under 5 years of age

Clinical characteristics and cerebrospinal fluid abnormalities in 100 cases of confirmed B type of H.influenzae (Hib) meningititis were analysed in comparing with 105 cases of meningitis caused by other bacterial pathogens. The basic criteria for early diagnosis of Hib meningitis in under five year old children were found out. Results showed that 48.8% of cases of meningititis were due to Hib; 96% of CSF samples due to Hib had physiological change in comparing with 72.4% in meningitis due to other bacterial pathogens, in 92% there were clinical manifestations and biochemical/cytological typical changes in CSF, in 100% of cases of Hib meningitis(+), there were typical changes; 51% of cases there were positive blood culture and 47% there were Hib positive CSF and blood culture concurrently