Klebsiella terrigena is very rarely isolated from humans; as yet, its clinical significance is
uncertain. The aim of the present study was to evaluate whether this species is able to express
putative virulence factors. A total of 72 faecal (n = 50) and clinical (n = 22) K. terrigena
isolates was investigated and compared with faecal and clinical strains of K. pneumoniae.
Mannose-sensitive haemagglutination (MSHA) was observed less often in K. terrigena
(64–74%) than in K. pneumoniae strains. In contrast, the incidence of mannose-resistant
haemagglutinin indicative of type 3 pili (MR/K-HA) (77–94%), serum resistance properties
(10–23%), and production of enterobactin (100%) was similar in both species. None of the K.
terrigena isolates were able to synthesize aerobactin; however, the frequency of aerobactin
synthesis in K. pneumoniae was also only 5%. Serotyping showed capsular types K5 and K70
to be predominant. The virulence-associated serotype K2 was common in both K. terrigena
and K. pneumoniae isolates. Taken together, the present results suggest that K. terrigena and K.
pneumoniae are indistinguishable with respect to the expression of virulence factors.