Mercedes Berlanga

Berlanga, Mercedes

Hemeroteca Cientifica Catalana

BOOK REVIEWSINTERNATIONAL MICROBIOLOGY (2011) 14: 235-236ISSN: 1139-6709 www.im.microbios.org Brucella.Molecularmicrobiology and genomicsIGNACIO LÓPEZ-GOÑI,DAVID O’CALLAGHAN(EDS)2012. Caister Academic Press261 pp, 18 × 25 cmPrice: £159ISBN 978-1-904455-93-6Brucellosis is a zoonotic infection transmitted from animalsto humans by the ingestion of infected food products, directcontact with an infected animal, or the inhalation of aerosols.Among these, inhalation is remarkably efficient given therelatively low concentration of organisms (10–100 bacteria)needed to establish infection in humans. Brucella is a facul-tative intracellular pathogen that survives and multiplies inphagocytes, and it has evolved to avoid the host’s immunesystem. Brucellosis is usually characterized by the long-termpersistence of the bacteria in the body. The diagnosis can bechallenging since the disease can involve any body organ orsystem, and its symptoms may overlap with those of a widespectrum of infectious, as well as non-infectious conditions.The clinical presentations of brucellosis are not only undu-lant fever but also joint manifestations, such as spondylitis,and neurological complications, often associated with per-sonality changes (anxiety, amnesia, delusions, hallucina-tions, delirium, phobias and irritability), in addition to pro-longed frontal or occipital headaches. Additional symptomsare anorexia and abdominal pain.“Micrococcus melitensis” was first isolated in 1887 byDavid Bruce (1855–1931), who detected the bacterium in thespleen of humans who had died from undulant fever inMalta. It is believed that Florence Nightingale (1820–1910,the famous nurse driving implement of hygiene in hospitals)endured over 25 years of the illness, including personalitychanges (neurobrucellosis) and spondylitis, which left herbedridden for six years. The severity of this disease and thelack of vaccines suitable for use in humans have led to theinvestigation of Brucella as bioterrorism agents. Indeed, theAmerican military weaponized Brucella suis in 1954; how-ever, changing global politics resulted in the abandonment ofthese studies following the Biological and Toxic WeaponsConvention of 1972.The book Brucella. Molecular microbiology andgenomics introduces the reader to what is known thus far andto the current challenges in the taxonomy, genomics and pro-teomics, diagnosis and epidemiology, vaccine development,virulence mechanisms, and life cycle posed by these enig-matic bacteria. The authors of the 13 chapters are experts inthe field and they are the book’s editors, Ignacio López-Goñi(University of Navarra, Spain) and David O’Callaghan(INSERM, Nimes, France).The genus Brucella belongs to the alphaproteobacteria. Inaddition to the type genus Brucella, six further genera,Crabtreella, Daeguia, Mycoplana, Ochrobactrum, Paeno-chrobactrum, and Pseudochrobactrum, are currently recog-nized within the family Brucellaceae. The closest phyloge-netic neighbor of Brucella is Ochrobactrum. Initially, twospecies were described for Brucella, B. melitensis (melitensisin Latin refers to the Malta island) and B. abortus (namedafter the discovery that the organism is responsible for spon-taneous abortion in cattle, Chapter 1). Currently, the genusBrucella consists of ten species with validly publishednames. Of these, the six so-called classical species show apreferential host range and other distinguishing phenotypicfeatures: B. melitensis (infects mainly sheep and goats),B. abortus (cattle and other bovidae), B. suis (swine), B. ovis(sheep), B. neotomae (desert woodrats) and B. canis (dogs).The remaining four species comprise two from marine mam-mals, B. ceti and B. pinnipedialis, and the novel B. microti(common voles) and B. inopinata (recently isolated from abreast-implant infection in an elderly woman). In 2002, two Brucella genomes were sequenced and ana-lyzed. At present, 40 Brucella genomes have been sequenced(Chapter 2). The Brucella genome is composed of two chro-mosomes. Expression analysis in Brucella grown in vitro hasconfirmed a higher rate of synthesis of proteins encoded inchromosome I than in chromosome II (Chapter 5). The pres-ence of two chromosomes could be consistent with the abili-ty of Brucella to adapt and live in at least two very differentenvironments, as free-living bacteria and intracellularly. Inthe latter, the bacterium must metabolically adapt to the intra-cellular environment and then manipulate its host cell’s biol-ogy to create conditions for its survival and multiplication.BOOK REVIEWSINT. MICROBIOL. Vol. 14, 2011236Thus, the identification of protein shifts and interactions isnecessary to understand the Brucella life cycle (Chapter 6).A major aspect of the pathogenicity of Brucella is its sur-vival and replication within host macrophages. However, theBrucella genome does not seem to encode the classical viru-lence factors found in other bacterial pathogens; rather, itsmain virulence factors are a lipopolysaccharide (LPS) of lowendotoxicity (Chapter 7), the BvrR/BvrS system, which con-trols the expression of a set genes involved in a broad rangeof species-specific functions (Chapter 10), and the type IVsecretion system (Chapter 11). An interesting aspect ofBrucella, albeit one thus far incompletely studied, is its geneclusters acquired by horizontal transfer, including genomicislands, whose acquisition and deletion may be related to thehost preference manifested by the corresponding Brucellaspecies (Chapter 3). The genomic islands contained inBrucella are made up of functional classes of genes that havebeen divided into two groups: one comprising virulence fac-tors and the other, genes of metabolic or unknown function.Moreover, virulence may also depend on metal acquisition(Chapter 9).Traditionally, brucellosis is diagnosed using cultural andserological approaches. The potential of molecular assays forBrucella identification based on 16S rRNA, the cell surfaceprotein bcsp31, IS711, etc., is a subject of current investiga-tions (Chapter 4). However, such assays will need to be val-idated in clinical samples before they can be adapted for rou-tine laboratory testing.Brucellosis is an important bacterial zoonosis worldwide.In endemic areas (Mediterranean Europe, Middle East, LatinAmerica), the incidence of the disease in humans may bemore than 200 per 100,000 habitants. The classical treatmentof brucellosis consists of a course of antibiotics (doxycyclineand rifampicin) for six weeks. New antibacterials that arespecifically active at the intracellular phase of Brucella arebeing developed. Such drugs would also have the potential tolimit the selection pressure favoring the growth of resistantmutants, thereby reducing the secondary effects of antibiotictreatment on the human microbiota (Chapter 12). Otherstrategies aimed at the control of Brucella include a vaccine(Chapter 13). Brucella. Molecular microbiology and genomics can berecommended to microbiologists, immunologists, veterinari-ans, and clinicians with an interest in microbial pathogenesis,host-bacterium interactions, and microbial diagnosis.MERCEDES BERLANGAUniversity of Barcelonamberlanga@ub.edu

Brucella. Molecular microbiology and genomics

http://revistes.iec.cat/index.php/IM/article/download/60575/60649

Brucella. Molecular microbiology and genomics

Abstract

Similar works

Full text

Available Versions

Hemeroteca Cientifica Catalana