Comparison between Vitek MS, Bruker Biotyper, Vitek2, and API20E for differentiation of species of the genus Raoultella

Case Report: Multidrug Resistant Raoultella ornithinolytica in a Septicemic Calf

“…Although conventional biochemical methods were not used in our case study, identification was confirmed both by MALDI-TOF MS and WGS. The increasing availability of MALDI-TOF MS in hospitals and diagnostic laboratories will likely result in a better and more frequent recognition of R. ornithinolytica in the years to come (6). On the other hand, this bacterium is likely underdiagnosed in septicemic animals, because blood culture enrichment is rarely used in veterinary practice and particularly not in food-producing animals, even though blood culture is the most appropriate sampling technique for presumed sepsis cases (1).…”

“…Raoultella ornithinolytica is an encapsulated Gram-negative bacterium, until 2001 classified within the Klebsiella genus, reflecting that identification of this species using only conventional biochemical methods can be challenging (5). The genus Raoultella contains four species, of which R. ornithinolytica is described as the most virulent species in humans (6). Aside from its ubiquitous presence in aquatic environments (4, 6, 7), R. ornithinolytica is an opportunistic pathogen mainly involved in hospitalacquired infections, often after invasive procedures and in immunocompromised patients (4,5,7).…”

“…Aside from its ubiquitous presence in aquatic environments (4, 6, 7), R. ornithinolytica is an opportunistic pathogen mainly involved in hospitalacquired infections, often after invasive procedures and in immunocompromised patients (4,5,7). This species has been linked with bacteremia, biliary tract and urinary tract infections, as well as pancreatitis and wound infections in humans (4,(6)(7)(8). To the best of our knowledge, septicemia caused by R. ornithinolytica, has not been described in other mammals.…”

First Case of Raoultella planticola Urinary Tract Infection Reported in Western Romania

“…MALDI-TOF has a better sensitivity of 97.4% compared to 93.3% on VITEK ® 2 compact automated system, where Raoultella spp. was firstly identified [ 18 ].Another study conducted in 2019 which used different assays in order to identify 30 strains of Raoultella planticola found MALDI-TOF equipment (with a sensitivity of 98.88% and specificity of 57.89%) to be superior over the VITEK ® 2 (with a sensitivity of 95.12% and specificity of 14.93%) [ 24 ].…”

Image_1.tif

“…However, the commercial biochemical identification system did not effectively differentiate Raoultella species from Klebsiella species (data not shown). Then, MALDI-TOF MS was applied by mass spectra data analysis, and strain 160-1 was identified as R. ornithinolytica (Supplementary Figure S1) (de Alegria Puig et al, 2019). Therefore, according to the results of the morphological features of colonies and cells, the physiological and biochemical characteristics, and MALDI-TOF MS identification, strain 160-1 was defined as Raoultella and named R. ornithinolytica 160-1.…”