Khames, M. (Mammar)

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    If You're Not Confused, You're Not Paying Attention: Ochrobactrum Is Not Brucella
    (2023) Bertu, W.J. (Wilson J.); Güler, L. (Leyla); Caswell, C.C. (Clayton C.); Araj, G.F. (George F.); Suárez-Esquivel, M. (Marcela); Lopez-Goñi, I. (Ignacio); Al-Dahouk, S. (Sascha); Roop, M. (Martin); Pembroke, J.T. (J. Tony); Chacon-Diaz, C. (Carlos); Middlebrook, E.A. (Edgar A.); Blasco, J.M. (José María); Loperena-Barber, M. (Maite); Keriel, A. (Anne); Salvador-Bescós, M. (Miriam); Dadar, M. (Maryam); O'Callaghan, D. (David); Moriyon, I. (Ignacio); De-Massis, F. (Frabizio); Altamirano-Silva, P. (Pamela); Barquero-Calvo, E. (Elías); Chaves-Olarte, E. (Esteban); Neubauer, H. (Heinrich); Whatmore, A.M. (Adrian M.); Wareth, G. (Gamal); De-Lima-Santos, R. (Renato); Arenas-Gamboa, A. (Ángela); Welburn, S.C. (Susan C.); Godfroid, J. (Jacques); Diaz, R. (Ramón); Splitter, G. (Gary); Garin-Bastuji, B. (B.); Gusi, A.M. (Amahyel M.); Sangari, F.J. (Félix Javier); Melzer, F. (Falk); Comerci, D.J. (Diego J.); Salcedo, S.P. (Suzana P.); Arce-Gorvel, V. (Vilma); Zuñiga-Ripa, A. (Amaia); Vizcaíno, N. (Nieves); Ruiz-Villalonos, N. (Nazaret); Erdenlig-Gürbilek, S. (Sevil); Muñoz, P. (Pilar); Tsolis, R.M. (Renee M.); Mora-Cartin, R. (Ricardo); Gorvel, J.P. (Jean Pierre); Ryan, M.P. (Michael P.); Iriarte-Cilveti, M. (Maite); Seimenis, A. (Aristarchos); Tabbaa, D. (Darem); Khames, M. (Mammar); Cravero, S. (Silvio); Celli, J. (Jean); Moran-Gilad, J. (Jacob); Bosilkovski, M. (Mile); Letesson, J.J. (Jean Jacques); Cook, E. (Elizabeth); Oñate-Landa, A.(A.); Moreno, E. (Edgardo); Ariza, J. (J.); Pandey, P. (Piyush); Escobar, G.I. (Gabriela I.); McGiven, J. (John); Guzman-Verri, C. (Caterina); Trangoni, M.D. (Marcos David); Pappas, G. (Georgios); Köhler, S. (Stephan); Foster, J.T. (Jeffrey T.); De-Boelle, X. (Xavier); Hernández-Mora, G. (Gabriela); Conde-Alvarez, R. (Raquel); Cadmus, S. (Simeon); Battelli, G. (Giorgio); Ficht, T.A. (Thomas A.); Hai, J. (Jiang); Jacob, N.R. (Nestor R.); Ocholi, R.A. (Reuben A.); Fernandez-Lago, L. (Luis)
    Bacteria of the genus Brucella are facultative intracellular parasites that cause brucellosis, a severe animal and human disease. Recently, a group of taxonomists merged the brucellae with the primarily free-living, phylogenetically related Ochrobactrum spp. in the genus Brucella. This change, founded only on global genomic analysis and the fortuitous isolation of some opportunistic Ochrobactrum spp. from medically compromised patients, has been automatically included in culture collections and databases. We argue that clinical and environmental microbiologists should not accept this nomenclature, and we advise against its use because (i) it was presented without in-depth phylogenetic analyses and did not consider alternative taxonomic solutions; (ii) it was launched without the input of experts in brucellosis or Ochrobactrum; (iii) it applies a non-consensus genus concept that disregards taxonomically relevant differences in structure, physiology, population structure, core-pangenome assemblies, genome structure, genomic traits, clinical features, treatment, prevention, diagnosis, genus description rules, and, above all, pathogenicity; and (iv) placing these two bacterial groups in the same genus creates risks for veterinarians, medical doctors, clinical laboratories, health authorities, and legislators who deal with brucellosis, a disease that is particularly relevant in low- and middle-income countries. Based on all this information, we urge microbiologists, bacterial collections, genomic databases, journals, and public health boards to keep the Brucella and Ochrobactrum genera separate to avoid further bewilderment and harm.
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    The CO2-dependence of Brucella ovis and Brucella abortus biovars is caused by defective carbonic anhydrases
    (2018) Miguel, M.J. (María Jesús) de; Moriyon, I. (Ignacio); Zuñiga-Ripa, A. (Amaia); Muñoz, P. (Pilar); Iriarte-Cilveti, M. (Maite); Khames, M. (Mammar); Pérez-Etayo, L. (Lara); Raquel
    Brucella bacteria cause brucellosis, a major zoonosis whose control requires efficient diagnosis and vaccines. Identification of classical Brucella spp. has traditionally relied on phenotypic characterization, including surface antigens and 5¿10% CO2 necessity for growth (CO2-dependence), a trait of Brucella ovis and most Brucella abortus biovars 1¿4 strains. Although molecular tests are replacing phenotypic methods, CO2-dependence remains of interest as it conditions isolation and propagation and reflects Brucella metabolism, an area of active research. Here, we investigated the connection of CO2-dependence and carbonic anhydrases (CA), the enzymes catalyzing the hydration of CO2 to the bicarbonate used by anaplerotic and biosynthetic carboxylases. Based on the previous demonstration that B. suis carries two functional CAs (CAI and CAII), we analyzed the CA sequences of CO2-dependent and -independent brucellae and spontaneous mutants. The comparisons strongly suggested that CAII is not functional in CO2-dependent B. abortus and B. ovis, and that a modified CAII sequence explains the CO2-independent phenotype of spontaneous mutants. Then, by mutagenesis and heterologous plasmid complementation and chromosomal insertion we proved that CAI alone is enough to support CO2-independent growth of B. suis in rich media but not of B. abortus in rich media or B. suis in minimal media. Finally, we also found that insertion of a heterologous active CAII into B. ovis reverted the CO2-dependence but did not alter its virulence in the mouse model. These results allow a better understanding of central aspects of Brucella metabolism and, in the case of B. ovis, provide tools for large-scale production of diagnostic antigens and vaccines.