Subtype distribution of Haemophilus influenzae isolates from North India

Abstract

A total of 120 Haemophilus influenzae isolates from blood, cerebrospinal fluid, sputum and throat swabs of patients and carriers in North India was characterised by biotyping, ribotyping and random amplification of polymorphic DNA (RAPD)-PCR. Of these, 77 isolates (64%) were serotype b; the other 43 (36%) were non-typable. Biotype I was the most predominant among the typable strains and biotype II among the non-typable strains. Ribotyping with restriction endonucleases HaeIII and EcoRI differentiated the isolates into three and six ribotypes, respectively. However, RAPD fingerprints generated by the application of arbitrary primers AP1 and AP2 provided a higher level of discrimination. RAPD typing revealed distinct polymorphism among the serologically typable isolates. This study is the first report that stratifies the subtypes of H. influenzae strains from India by molecular techniques.

Hypermutable Haemophilus influenzae with mutations in mutS are found in cystic fibrosis sputum

“…Restriction with EcoRI produced only three distinct ribotypes with fragment sizes ranging from 300 to 6000 bp (data not shown); ribotyping with EcoRI is known to be limited in its discriminatory ability among non-typable isolates (Sharma et al, 2002). Six isolates (C2408, C2561, C2562, C2687, C2692 and C2696) produced an identical ribotype pattern, distinct from all other strains.…”

Outer-membrane-protein subtypes of Haemophilus influenzae isolates from North India

“…An important finding of our study is that isolates from blood, CSF and sputum samples of patients showed complete agreement in their profiles produced by molecular approaches (Sharma et al, 2002) and OMP analysis. In the OMP analysis, the same three isolates from blood that presented ribotype A with EcoRI and RAPD type a with primers AP1 and AP2 in our previous study showed OMP subtype 6, while the strain of ribotype D and RAPD type d showed OMP subtype 8.…”

“…A total of 305 CSF samples and 41 blood samples from infants, throat swabs of 63 healthy children and adults and sputum samples from 25 adult patients were screened. Details of the samples and strains obtained were provided previously (Sharma et al, 2002).…”

“…A total of 120 H. influenzae isolates was obtained from cerebrospinal fluid (CSF), blood, sputum samples and throat swabs of patients and healthy carrier population, of which 77 were Hib and 43 NTHi. Details of patients and numbers of samples screened have been given previously (Sharma et al, 2002). The same samples were used for analysis in the present study.…”

“…Subtyping of the present isolates based on molecular techniques has been reported earlier from our laboratory (Sharma et al, 2002). An alternative to this was sought, since the methods were expensive and their application in a country like ours was not satisfactory.…”