Haemophilus influenzae Infections among Hospitalized Adult Patients

Furrer, Markus; Cottagnoud, Philippe; Mühlemann, Kathrin

doi:10.1007/s150100070004

Cited by 6 publications

(5 citation statements)

References 12 publications

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“…Nontypeable Haemophilus influenzae (NTHi) is responsible for respiratory tract infection and, especially in adults with underlying conditions, invasive disease such as septicemia and meningitis [ 1 , 2 ]. Several adherence factors, including HMW1/HMW2 proteins, Hia, Hap and hemaglutinating pili, promote colonization of the upper respiratory tract, a prerequisite for disease [ 3 ].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2008

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Background: Among surface antigens of nontypeable Haemophilus influenzae (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 hmw1A and hmw2A 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 hmwA promoters and presence of HMW proteins by Western blotting were also determined.

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Section: Introductionmentioning

confidence: 99%

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

et al. 2008

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“…Distinct sets of conserved amino acid motifs were identified within each group of sequences using the MEME/MOTIFSEARCH tool. Since HMW adhesins could represent candidates for future vaccines, identification of specific patterns of conserved motifs in otherwise highly variable regions is of great interest.Nontypeable Haemophilus influenzae (NTHi) is regarded as an important human pathogen, able to cause human respiratory tract disease and, especially in adults, invasive diseases such as meningitis and septicemia (11,12). The initial step in the pathogenesis of NTHi disease involves establishment of bacteria on the rhinopharyngeal respiratory mucosa followed by contiguous spread within the respiratory tract and, occasionally, to sterile sites.…”

mentioning

confidence: 99%

“…Nontypeable Haemophilus influenzae (NTHi) is regarded as an important human pathogen, able to cause human respiratory tract disease and, especially in adults, invasive diseases such as meningitis and septicemia (11,12). The initial step in the pathogenesis of NTHi disease involves establishment of bacteria on the rhinopharyngeal respiratory mucosa followed by contiguous spread within the respiratory tract and, occasionally, to sterile sites.…”

mentioning

confidence: 99%

Conservation and Diversity of HMW1 and HMW2 Adhesin Binding Domains among Invasive Nontypeable Haemophilus influenzae Isolates

Giufrè¹,

Muscillo

Spigaglia³

et al. 2006

Infect Immun

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The pathogenesis of nontypeable Haemophilus influenzae (NTHi) begins with adhesion to the rhinopharyngeal mucosa. In almost 80% of NTHi clinical isolates, the HMW proteins are the major adhesins. The prototype HMW1 and HMW2 proteins, identified in NTHi strain 12, exhibit different binding specificities. The two binding domains have been localized in regions of maximal sequence dissimilarity (40% identity, 58% similarity). Two areas within these binding domains have been found essential for full level adhesive activity (designated the core-binding domains). To investigate the conservation and diversity of the HMW1 and HMW2 core-binding domains among isolates, PCR and DNA sequencing were used. First, we separately amplified the hmw1A-like and hmw2A-like structural genes in nine invasive NTHi isolates, discovering two new hmwA alleles, whose sequences are herein reported. Then, the hmw1A-like and hmw2A-like PCR products were used as the template in nested PCR to produce amplicons encompassing the encoding sequences of the two core-binding domains. In-depth sequence analysis was then performed among sequences of each group, with the support of specific computer programs. Overall, extensive sequence diversity among isolates was highlighted. However, similarity plots showed patterns consisting of peaks of relatively high similarity alternating with strongly divergent regions. The phylogenetic tree clearly indicated the HMW1-like and HMW2-like core-binding domain sequences as two clusters. Distinct sets of conserved amino acid motifs were identified within each group of sequences using the MEME/MOTIFSEARCH tool. Since HMW adhesins could represent candidates for future vaccines, identification of specific patterns of conserved motifs in otherwise highly variable regions is of great interest.Nontypeable Haemophilus influenzae (NTHi) is regarded as an important human pathogen, able to cause human respiratory tract disease and, especially in adults, invasive diseases such as meningitis and septicemia (11,12). The initial step in the pathogenesis of NTHi disease involves establishment of bacteria on the rhinopharyngeal respiratory mucosa followed by contiguous spread within the respiratory tract and, occasionally, to sterile sites. A number of adherence factors, including both pilus and nonpilus adhesins, have been identified (24). In almost 80% of NTHi clinical isolates, the HMW proteins are the major adhesins responsible for attachment to human epithelial cells (29). They were originally identified as a group of high-molecular-weight, surface-exposed proteins, predominant targets of human serum antibody response during acute otitis media (1).Given their functional role and their immunogenic character, HMW proteins have gained special consideration as NTHi vaccine candidates. The prototype proteins were detected in NTHi strain 12 and were designated HMW1 and HMW2 (2). They are encoded by separate chromosomal loci, hmw1 and hmw2, respectively, the hmwA gene encoding the structural protein, and two accessory genes, called hm...

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“…However, occasionally otitis, sinusitis, epiglottitis, and pneumonia as well as more invasive bacteremic infections can occur [35].…”

Section: Respiratory Disease In the Adultmentioning

confidence: 99%

The other siblings: Respiratory infections caused by Moraxella catarrhalis and Haemophilus influenzae

Lutwick

Fernandes²

2006

Curr Infect Dis Rep

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Respiratory infections remain substantial causes of morbidity and mortality globally. In this paper, two substantial players in bacterial-associated respiratory disease are assessed as to their respective roles in children and adults and in the developed and developing world. Moraxella catarrhalis, although initially thought to be a nonpathogen, continues to emerge as a cause of upper respiratory disease in children and pneumonia in adults. No vaccine is currently available to prevent M. catarrhalis infection. Haemophilus influenzae type b, originally thought to be the cause of influenza, has now been limited epidemiologically in the developed world due to an effective immunization but it continues to be a major player in the developing world. Nonencapsulated strains of H. influenzae still remain as significant causes of respiratory infections in the developing world especially in exacerbation of chronic obstructive lung disease. Finally, and in brief, the spectrum of Brazilian purpuric fever due to a specific biotype of H. influenzae is discussed.

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Haemophilus influenzae Infections among Hospitalized Adult Patients

Abstract: Hi remains an important cause of lower respiratory and invasive disease associated with high lethality among polymorbid adult patients. The frequency of Hib infections may also decrease in adults due to herd immunity induced by universal vaccination of children.

Cited by 6 publications

References 12 publications

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

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

Conservation and Diversity of HMW1 and HMW2 Adhesin Binding Domains among Invasive Nontypeable Haemophilus influenzae Isolates

The other siblings: Respiratory infections caused by Moraxella catarrhalis and Haemophilus influenzae

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