Antimicrobial susceptibility of Haemophilus influenzae strains isolated from invasive disease in Italy

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Variation in expression of HMW1 and HMW2 adhesins in invasive nontypeable Haemophilus influenzae isolates

<p>Abstract</p> <p>Background</p> <p>Among surface antigens of nontypeable <it>Haemophilus influenzae </it>(NTHi), the HMW1 and HMW2 proteins are the major adhesins promoting colonization of the upper respiratory tract. Since they are potential vaccine candidates, knowledge concerning variation in HMW proteins expression among clinical isolates is of great interest. In this study, expression of <it>hmw1A </it>and <it>hmw2A </it>genes was evaluated by quantitative real-time reverse transcription-PCR in 3 NTHi invasive isolates (strains 56, 72, 91) and in the prototype strain 12. Number of 7-bp repeats within the <it>hmwA </it>promoters and presence of HMW proteins by Western blotting were also determined.</p> <p>Results</p> <p>Results showed that gene transcription varied not only among different isolates but also between the <it>hmw1A </it>and <it>hmw2A </it>genes from the same isolate. Compared to that found in prototype strain 12, up-regulation of the <it>hmw1A </it>gene expression was found in strain 56, down-regulation of both <it>hmw1A </it>and <it>hmw2A </it>genes transcripts was observed in strain 72 whereas the two <it>hmwA </it>genes appeared differentially expressed in strain 91 with the <it>hmw1A </it>transcript enhanced but the <it>hmw2A </it>transcript reduced.</p> <p>Conclusion</p> <p>Increasing numbers of 7-bp repeats within the <it>hmwA </it>promoters generally correlated with decreased amounts of mRNA transcript, however additional control mechanisms contributing to modulation of <it>hmw1A </it>gene seem to be present.</p

Invasive Type e Haemophilus influenzae Disease in Italy

We describe the first reported cases of invasive type e Haemophilus influenzae disease in Italy. All five cases occurred in adults. The isolates were susceptible to ampicillin and eight other antimicrobial agents. Molecular analysis showed two distinct type e strains circulating in Italy, both containing a single copy of the capsulation locus

Genetic Characterization of the Capsulation Locus of Haemophilus influenzae Serotype e▿

The capsulation (cap) locus of Haemophilus influenzae type e (Hie) was characterized and sequenced. No IS1016 element was found to flank the locus. The 18.2-kb locus included 14 open reading frames (ORFs), which were grouped into three functional regions. Eight new ORFs (named ecs1 to ecs8) were identified in the Hie capsule-specific region II