TY - JOUR
T1 - Evaluation of molecular typing for national surveillance of invasive clinical Haemophilus influenzae isolates from Denmark
AU - Slotved, Hans Christian
AU - Johannesen, Thor Bech
AU - Stegger, Marc
AU - Fuursted, Kurt
N1 - Funding Information:
Mikkel Benjamin Nielsen and Nadia Xenia Olsen are acknowledged for their skillful laboratory work and input to this study. We acknowledge the Danish departments of clinical microbiology for submitting Haemophilus influenzae isolates for national surveillance throughout the study period. This study is a part of the national surveillance program for severe H. influenzae infections.
Publisher Copyright:
Copyright © 2022 Slotved, Johannesen, Stegger and Fuursted.
PY - 2022/11/17
Y1 - 2022/11/17
N2 - Haemophilus influenzae is a gram-negative coccobacillus known to cause respiratory and invasive infections. It can possess a polysaccharide capsule that can be categorized into six different serotypes (i.e., Hia, Hib, Hic, Hid, Hie, and Hif) and non-encapsulated strains that are defined as non-typeable. Furthermore, H. influenzae can be characterized into eight biotypes (I–VIII). Traditionally, isolates have been serotyped and biotyped using phenotypic methods; however, these methods are not always reliable. In this study, we evaluate the use of whole-genome sequencing (WGS) for national surveillance and characterization of clinical Danish H. influenzae isolates. In Denmark, all clinical invasive isolates between 2014 and 2021 have been serotyped using a traditional phenotypic latex agglutination test as well as in silico serotyped using the in silico programs “hinfluenzae_capsule_characterization” and “hicap” to compare the subsequent serotypes. Moreover, isolates were also biotyped using a phenotypic enzyme test and the genomic data for the detection of the genes encoding ornithine, tryptophan, and urease. The results showed a 99–100% concordance between the two genotypic approaches and the phenotypic serotyping, respectively. The biotyping showed a 95% concordance between genotyping and phenotyping. In conclusion, our results show that in a clinical surveillance setting, in silico serotyping and WGS-based biotyping are a robust and reliable approach for typing clinical H. influenzae isolates.
AB - Haemophilus influenzae is a gram-negative coccobacillus known to cause respiratory and invasive infections. It can possess a polysaccharide capsule that can be categorized into six different serotypes (i.e., Hia, Hib, Hic, Hid, Hie, and Hif) and non-encapsulated strains that are defined as non-typeable. Furthermore, H. influenzae can be characterized into eight biotypes (I–VIII). Traditionally, isolates have been serotyped and biotyped using phenotypic methods; however, these methods are not always reliable. In this study, we evaluate the use of whole-genome sequencing (WGS) for national surveillance and characterization of clinical Danish H. influenzae isolates. In Denmark, all clinical invasive isolates between 2014 and 2021 have been serotyped using a traditional phenotypic latex agglutination test as well as in silico serotyped using the in silico programs “hinfluenzae_capsule_characterization” and “hicap” to compare the subsequent serotypes. Moreover, isolates were also biotyped using a phenotypic enzyme test and the genomic data for the detection of the genes encoding ornithine, tryptophan, and urease. The results showed a 99–100% concordance between the two genotypic approaches and the phenotypic serotyping, respectively. The biotyping showed a 95% concordance between genotyping and phenotyping. In conclusion, our results show that in a clinical surveillance setting, in silico serotyping and WGS-based biotyping are a robust and reliable approach for typing clinical H. influenzae isolates.
KW - capsular genes
KW - Denmark
KW - genotyping
KW - Haemophilus influenzae
KW - serotyping
UR - http://www.scopus.com/inward/record.url?scp=85143368302&partnerID=8YFLogxK
U2 - 10.3389/fmicb.2022.1030242
DO - 10.3389/fmicb.2022.1030242
M3 - Journal article
AN - SCOPUS:85143368302
SN - 1664-302X
VL - 13
JO - Frontiers in Microbiology
JF - Frontiers in Microbiology
M1 - 1030242
ER -