Identification of Raoultella spp.: Comparison of three methods

Background: Raoultella is a Gram-negative bacteria, which commonly occur in the natural environment such as water, soil and on plants. In recent years, Raoultella spp. gained more interest. There is also an increasing number of publications describing mainly clinical cases involving these bacteria. Identification of Raoultella spp. is difficult due to a phylogenetic relationship with Klebsiella spp. Purpose: Available biochemical tests do not always allow for their identification to species. Thus, the aim of this study was to evaluate selected methods of identification of Raoultella spp. and their differentiation from genus Klebsiella. Materials and Methods: In this evaluation three methods were used such as manual test ID32E (bioMérieux), automatic test VITEK2 Compact (bioMérieux) and matrix-assisted laser desorption ionisation-time of flight mass spectrometry (MALDI-TOF MS) method (Bruker). Results: Good identification of the species was obtained for 81.4% of the strains in the ID32E test, 93.3% in VITEK2 Compact test, and 97.4% in MALDI-TOF MS method, respectively. Conclusion: It was established that MALDI-TOF MS method is reliable in identifying genus Raoultella.

Problems in the diagnosis of profound trichophytosis barbae.

Zoophilic species of human dermatophytoses, such as Trichophyton mentagrophytes are significantly rare. We present a case of a 42-year-old male who for 2 months had been unsuccessfully treated and then referred to hospital with suspected actinomycosis. Lesions on the skin on his neck, submandibular area, cheeks and groins were consistent with extremely painful, merging inflammatory tumours and infiltrations with the presence of numerous pustules in hair follicles that poured purulent contents forming into yellow crusts after compression. The treatment with terbinafine was successful. The final identification of the Trichopyton mentagrophytes var. granulosum strain was performed based on a microscopic assessment of the culture, and the result of species identification was confirmed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis.