Bacteremia and chorioamnionitis due to cryptic genospecies of Haemophilus Influenzae biotype I

Clinical significance of isolation of Haemophilus no ducreyi in genital samples. Systematic review

INTRODUCTION AND OBJECTIVES

Currently, the microbiological diagnosis of genital infections is carried out with molecular methods, which allow the detection of less frequent etiological agents but with potential pathogenic importance, such as Haemophilus spp. The objective of this review is to analyse and highlight the clinical importance of the isolation of Haemophilus spp. in genital and rectal infections, excluding Haemophilus ducreyi.

MATERIAL AND METHODS

A systematic review was carried out based on an exhaustive search of the publications included in the MEDLINE database up to August 5, 2021, on the presence of Haemophilus spp. in genital and rectal infections, excluding H. ducreyi.

RESULTS

After reviewing what was described in the literature, Haemophilus spp. (excluding H. ducreyi: HSNOD) was detected in 2397 episodes of genital infection, the most frequently isolated species being H. influenzae and H. parainfluenzae. Most of the episodes (87,6%) are constituted by single isolation. There is a slight predominance in women (48,3%) where it can cause vaginitis, salpingitis, endometritis or complications during pregnancy. In men, the clinical picture usually corresponds to urethritis. Most of the samples correspond to vaginal and urethral exudates, with a minority representation at the rectal level (2.3%).

CONCLUSION

HSNOD plays a relevant pathogenic role in episodes of genital infection, so microbiological diagnostic protocols must include methods that allow their detection, as well as include them in the etiological spectrum of this type of clinical picture.

Haemophilus influenzae Sepsis and Placental Abruption in an Unvaccinated Immigrant

Background

Haemophilus influenzae infections have declined dramatically in the United States since implementation of the conjugate vaccine. However, in countries where widespread immunization is not routine, H influenzae remains a significant cause of morbidity and mortality. We report a case of a previously unvaccinated immigrant with confirmed H influenzae sepsis and placental abruption leading to spontaneous abortion.

Objectives

To alert emergency medicine practitioners that H influenzae should be recognized as a maternal, fetal, and neonatal pathogen. Clinicians should consider this diagnosis in immigrants presenting with uncertain vaccination history, as H influenzae can cause significant morbidity and mortality.

Case Presentation

A 36-year-old female was referred to our emergency department (ED) with lower abdominal pain with some vaginal spotting. The patient had an initial visit with normal laboratory investigations and normal imaging results, with complete resolution of symptoms. The patient returned to the ED with sudden onset of vaginal bleeding and abdominal pain. She presented at this time with sepsis, which progressed to septic shock, causing placental abruption and ultimately, spontaneous abortion. The patient was treated with pressors and antibiotics and was admitted to the medical intensive care unit where she received ampicillin, gentamycin, and clindamycin for suspected chorioamnionitis. The patient's blood cultures came back positive after 1 day for H influenzae. The patient did well and was discharged from the hospital 4 days later.

Conclusion

Haemophilus influenzae should be recognized as a neonatal and maternal pathogen. Clinicians should consider this diagnosis in immigrants presenting with uncertain vaccination history, especially in pregnant females, as H influenzae can cause significant morbidity and mortality.

Identification of a novel trimeric autotransporter adhesin in the cryptic genospecies of Haemophilus

Haemophilus biotype IV strains belonging to the recently recognized Haemophilus cryptic genospecies are an important cause of maternal genital tract and neonatal systemic infections and initiate infection by colonizing the genital or respiratory epithelium. To gain insight into the mechanism of Haemophilus cryptic genospecies colonization, we began by examining prototype strain 1595 and three other strains for adherence to genital and respiratory epithelial cell lines. Strain 1595 and two of the three other strains demonstrated efficient adherence to all of the cell lines tested. With a stably adherent variant of strain 1595, we generated a Mariner transposon library and identified 16 nonadherent mutants. All of these mutants lacked surface fibers and contained an insertion in the same open reading frame, which encodes a 157-kDa protein designated Cha for cryptic haemophilus adhesin. Analysis of the predicted amino acid sequence of Cha revealed the presence of an N-terminal signal peptide and a C-terminal domain bearing homology to YadA-like and Hia-like trimeric autotransporters. Examination of the C-terminal 120 amino acids of Cha demonstrated mobility as a trimer on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the capacity to present the passenger domain of the Hia trimeric autotransporter on the bacterial surface. Southern analysis revealed that the gene that encodes Cha is conserved among clinical isolates of the Haemophilus cryptic genospecies and is absent from the closely related species Haemophilus influenzae. We speculate that Cha is important in the pathogenesis of disease due to the Haemophilus cryptic genospecies and is in part responsible for the apparent tissue tropism of this organism.

Genetic identification of cryptic genospecies of Haemophilus causing urogenital and neonatal infections by PCR using specific primers targeting genes coding for 16S rRNA

Previous genetic analysis of Haemophilus influenzae strains isolated from genital and neonatal infections identified a group of biotype IV that constitutes a cryptic genospecies only distantly related to H. influenzae and H. Haemolyticus. Small-subunit rRNA genes of two representative strains of this genital Haemophilus genospecies (strains 16N and 2406) were sequenced. The analysis indicated that these strains form a monophyletic unit with H. haemolyticus and H. influenzae biogroups Influenzae and Aegyptius and are more closely related to H. haemolyticus than to H. influenzae biogroups Influenzae and Aegyptius. 16S rRNA gene sequences were used to formulate primers for PCR-based identification of cryptic genital Haemophilus organisms. A 242-bp fragment was amplified from strains belonging to the genital Haemophilus genospecies but not from strains of 12 other Haemophilus species, including strains of H. influenzae biotype IV sensu stricto.