Nontypeable Haemophilus influenzae (NTHi)

doi:10.1016/j.tim.2018.05.001

Trends in Microbiology

Volume 26, Issue 8, August 2018, Pages 727-728

https://doi.org/10.1016/j.tim.2018.05.001 Get rights and content

In this infographic the diseases caused by nontypeable Haemophilus influenzae (NTHi), including otitis media, are discussed.

Encapsulated type b Haemophilus influenzae (Hib) was responsible for most of the invasive disease (meningitis) prior to the use of Hib vaccines. As Hib vaccines have no effect on infections due to nontypeable H. influenzae (NTHi), in areas where Hib vaccines are used, nontypeable strains are now the most common cause of invasive disease. Moreover, NTHi contributes to the ∼21 000 otitis media (OM)-associated deaths per year. Due to this collective global morbidity and mortality, concerted vaccine development is underway. In addition to preventing disease, an effective vaccine will likely help to mitigate the global crisis of antibiotic resistance. Since 1973, ampicillin resistance due to NTHi’s production of β-lactamase has been recognized; however, a significant concern is the more recent emergence and spread of β-lactamase-negative-ampicillin-resistant (BLNAR) strains in many regions of the world. As such, H. influenzae is one of 12 bacterial pathogens that are considered priority pathogens by the World Health Organization.

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Acknowledgments

Scanning electron micrograph of a bacterial biofilm formed by NTHi on the surface of polarized human airway epithelial cells from Kenneth L. Brockman, PhD.

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Cited by (40)

Phase variable acetylation of lipooligosaccharide modifies antibody production and opsonophagocytic killing of non-typeable Haemophilus influenzae
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Non-typeable Haemophilus influenzae (NTHi) causes millions of infections each year. Though it is primarily known to cause otitis media, recent studies have shown NTHi is emerging as a primary pathogen for invasive infection, prompting the need for new vaccines and treatments. Lipooligosaccharide (LOS) has been identified as a potential vaccine candidate due to its immunogenic nature and outer membrane localization. Yet, phase variable expression of genes involved in LOS synthesis has complicated vaccine development. In this study, we used a chinchilla model of otitis media to investigate how phase variation of oafA, a gene involved in LOS biosynthesis, affects antibody production in response to infection. We found that acetylation of LOS by OafA inhibited production of LOS-specific antibodies during infection and that NTHi expressing acetylated LOS were subsequently better protected against opsonophagocytic killing. These findings highlight the importance of understanding how phase variable modifications might affect vaccine efficacy and success.
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Citation Excerpt :
The current study showed that LSF had a significant impact against the major global respiratory pathogens, H. influenzae and RSV. Hib vaccine development has successfully reduced Hib-related infections in many countries [47, 48] but these vaccines are not effective against NTHi [49]. Although the ten-valent pneumococcal conjugate vaccine (PCV10) contains the carrier protein D from NTHi, it has variable efficacy against NTHi [50, 51].
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Microbe of the MonthNontypeable Haemophilus influenzae (NTHi)

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Microbe of the Month
Nontypeable Haemophilus influenzae (NTHi)