Culture-independent Multilocus Sequence Typing (MLST) screening for Haemophilus influenzae cross-infection in non-cystic fibrosis bronchiectasis (NCFB)

Abstract

Background There is some evidence of Pseudomonas aeruginos across-infection between patients with non-cystic fibrosis bronchiectasis (NCFB), and clear evidence in Cystic Fibrosis. Haemophilus influenzae (H. influenzae) is the more common pathogen in NFCB patients, yet cross-infectionremains unexplored. We present the novel application of culture-independent Multilocus Sequence Typing (MLST) to screen for cross-infection of H. influenzae in NCFB in both culture-positive and -negative samples. Methods We interrogated DNA from 32 sputum samples (26 patients) in our NCFB biorepository, who were known to have H.influenzae in their sputum by preceding 16S rRNA sequencing. Fragments of 7 H. influenzae housekeeping genes were amplified and sequenced. Sequence types were allocated via the MLST scheme. For 5 patients, multiple sputum samples taken at least 4 months apart were assessed longitudinally. Results Culture-independent MLST identified 31 of 32 sputum samples as harboring H. influenzae. Of these, 26 were positive for H. influenzae using culture methods. 25 of the 26 culture-positive samples were MLST positive. All 6 culture-negative samples were MLST positive. A MLST sequence type (ST) was allocated to 27 of 32 sputum samples. Five patients had multiple sputum samples with matching STs, indicating strain stability and the consistency of MLST. Two patients who were known household contacts had matching STs and possibly transmitted H.influenzae in their household. The remaining 15 STs were unique, suggesting no evidence of cross-infection. Conclusion Culture-independent MLST identifies H. influenzae in culture-negative patients with NCFB and is a potential screening tool for cross-infection. This study did not reveal potential cross-infection events in this cohort.

Immunoinformatics design of multi-epitope peptide-based vaccine against Haemophilus influenzae strain using cell division protein

“…It is the source of an extensive range of bacterial illnesses (Butler and Myers 2018 ). They are divided into two types: encapsulated and non-encapsulated (Wilson et al 2020 ). Non-typeable Hi ( NTHi ) strains do not express a polysaccharide capsule, but Hi serotypes (i.e., Hia , Hib , Hic , Hid , Hie , and Hif ) do, with Type B being the most prevalent cause of pneumonia, infecting predominantly children and immunocompromised people (Wilson et al 2020 ).…”