Phenotypic diversity of Haemophilus influenzae and Haemophilus parainfluenzae isolates depending on origin and health condition

Background. Haemophili are common human microbiota representatives. The aim of our study was to investigate a diversity of Haemophilus spp. isolates selected from clinical specimens on the basis of biochemical characteristics, biotypes distribution, protein profiles and antimicrobial resistance. Results. A total of 893/1025 (87%) of haemophili isolates were identified: 260/1025 (25%) as H. influenzae and 633/1025 (62%) as H. parainfluenzae. Moreover, a group of 107/1025 (10%) isolates without species identification (with e.g. abnormal numerical profile) was described as Haemophilus spp. Within the H. influenzae isolates, biotypes II and III were in a great majority (92/893; 10%, each), whereas among H. parainfluenzae, the most commonly occurring was biotype I and II (301/893, 34% and 178/893, 20%, respectively). A similar prevalence of biotypes was obtained regardless of the patient’s age or health condition or the type of specimen. A production of beta-lactamases was shown in 46/893 (5%) haemophili, both H. influenzae (13/46, 28%) and H. parainfluenzae (33/46, 72%) isolates. On the basis of haemophili biochemical characteristics, the cluster analysis using the UPGMA method demonstrated a high degree of phenotypic similarity due to a small distances between isolates taken from both unhealthy children and adults. Conclusion. Based on biochemical characteristics, about 90% of haemophili clinical isolates representing human-specific respiratory microbiota were positively identified as H. influenzae and H. parainfluenzae. The same differences in biotypes and antimicrobial resistance among isolates selected from healthy people or from patients with chronic and recurrent diseases were detected.