Brucellosis of the Common Vole (Microtus arvalis)

Abstract

A systemic disease occurred in a wild population of the common vole Microtus arvalis in South Moravia (Czech Republic) during the years 1999-2003. Acute infections were characterized by edema of extremities, occasionally with colliquating abscesses, arthritis, lymphadenitis, perforations of the skin resulting from colliquated abscesses, orchitis, and peritoneal granulomas. From the clinical samples, small Gram-negative coccobacilli were isolated and identified as Ochrobactrum intermedium by API 20NE and colistin sensitivity profiles. However, subsequent rrs (16S rRNA) and recA (recombinase A) gene sequencing analysis of two isolates (CCM 4915=CAPM 6434; CCM 4916=CAPM 6435) identified them as Brucella sp. with sequence identities of 100% to other Brucella spp. Analysis of the omp2a/b genes confirmed the two isolates as Brucella. In AMOS polymerase chain reaction (PCR), a 2000-bp fragment was generated that was not seen in other brucellae. Experimental infection of outbred ICR mice with these isolates resulted in a mortality rate of 50%. Based on the results of the molecular investigations and the mortality observed in experimentally infected mice we conclude that the epizootic was caused by Brucella sp. and not by Ochrobactrum intermedium. The study demonstrates the limitations of commercial biochemical test systems in accurately differentiating among Ochrobactrum and Brucella.

Isolation ofBrucella microtifrom Soil

“…The organism is characterized by rapid growth on standard media and high metabolic activity, which is atypical for Brucella (2). The biochemical profi le of B. microti is more similar to that of Ochrobactrum spp., of which most species are typical soil bacteria.…”

“…and the high metabolic activity of B. microti, we hypothesized that this Brucella species might also have a reservoir in soil. To test this hypothesis, we investigated 15 soil samples collected on December 11, 2007, from sites in the area where B. microti was isolated from common voles in 2000 (2). Ten of the samples were collected from the surface and at a depth of up to 5 cm near different mouse burrows 5 m apart.…”

“…Literary evidence for malaria infection dates back to the early Greek period when Hippocrates described the typical undulating fever (1), highly suggestive of plasmodial infection. Although it is believed that malaria widely affected early pre-Hippocrates populations, until now only 1 study, which used molecular analysis, clearly identifi ed P. falciparum in a Roman infant dating back to the 5th century AD (2). Two other studies used molecular analysis to identify more recent plasmodial DNA in ancient human remains, i.e., from 100-400 years ago (3,4).…”

Intraspecies Biodiversity of the Genetically Homologous Species Brucella microti

“…Indeed, the phenotype of B. microti resembles that of Ochrobactrum rather than that of Brucella. Hence, B. microti has been misidentified as Ochrobactrum intermedium by use of commercially available biochemical tests, such as the API 20 NE test (bioMérieux, Nürtingen, Germany) (17).…”

Blood Cultures for the Diagnosis of Human Brucellosis

“…Identification of members of the genus Brucella is based of the presence of typical small Gram-negative coccobacilli (see Figure 1); positive oxidase, catalase, and urease tests; no fermentation of sugars; CO 2 requirement; lack of motility; and confirmed by a positive agglutination reaction with specific antiserum [14] or, alternatively, the isolate'sbiochemical profile is determined by a commercial system. The main drawbacks of this traditional approach is the slow turnaround time (2 to 3 days) and the possible misidentification of brucellae as Ochrobactrum anthropi [60], Ochrobactrum intermedium [61], Bergeyella zoohelcum [62], or Moraxella phenylpyruvica by commercial kits; a serious mistake that has already lead to an outbreak of laboratory-acquired infection [63]. …”