The Aggregation of Brucella abortus Occurs Under Microaerobic Conditions and Promotes Desiccation Tolerance and Biofilm Formation

Marta A Almirón1, *, Mara S Roset1, Norberto Sanjuan2
1 Instituto de Investigaciones Biotecnológicas (IIB-INTECH), Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de San Martín, Buenos Aires, Argentina
2 Laboratorio de Microscopía Electrónica y Patología Experimental, Departamento de Microbiología, Parasitología e Inmunología. Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina

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© Almiron et al.; Licensee Bentham Open.

open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.

* Address correspondence to this author at the UNSAM- Campus Miguelete- IIB, Av. 25 de Mayo y Francia, (1650) San Martín, Buenos Aires, Argentina Tel: (5411) 4006 1500; Fax: (5411) 4006 1559; E-mail:


Brucella abortus causes brucellosis mainly in cattle. The infection is transmitted to humans by ingestion of animal products or direct contact with infected material. While the intracellular lifestyle of Brucella is well characterized, its extracellular survival is poorly understood. In nature, bacterial persistence is associated with biofilms, where aggregated cells are protected from adversity. The inability of Brucella abortus to aggregate under aerobiosis and that fact that the replicative niche of Brucella is characterized by microaerobic conditions prompted us to investigate the capacity of this pathogen to aggregate and grow in biofilms under microaerobiotic conditions. The results show that B. abortus aggregates and produces biofilms. The aggregates tolerate desiccation better than planktonic cells do, adhere and displace even in the absence of the lipopolysaccharide-O antigen, flagella, the transcriptional regulator VjbR, or the enzymes that synthesize, transport, and modify cyclic β (1,2) glucan.

Keywords: Aggregation, biofilms, Brucella, desiccation, flotation, VjbR.