If You're Not Confused, You're Not Paying Attention: Ochrobactrum Is Not Brucella.

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.

Serological study of brucellosis in Argentine Creole sheep / Estudio serológico de brucelosis en ovejas criollas de Argentina

Ovine cattle was introduced into America during the Spanish conquest with the second journey of Columbus to the Antilles and was disseminated throughout the region. In 1587, sheep were introduced into Argentina, later developing into the "Creole" breed. We selected 486 animals from different Argentine provinces with the aim of determining the serological status of brucellosis caused by Brucella melitensis and Brucella ovis. For the detection of antibodies against smooth Brucella spp., the Rose Bengal test (RBT) was performed as screening test while the serum agglutination test (SAT) and 2 mercapto-ethanol (2ME) were run as a confirmatory technique. Moreover, for the detection of antibodies against rough Brucella spp., we used the rapid slide agglutination test (RSAT) for screening and an indirect ELISA (IELISA) as confirmatory assay. This study showed that the total positive percentage of brucellosis due to B. ovis was 2.9%. Excluding the animals mixed with the Suffolk breed; seropositivity would be 0.6%. All animals tested negative for brucellosis caused by B. melitensis.

El ganado ovino fue introducido en América durante el segundo viaje de Colón a las Antillas y rápidamente se diseminó por la región. En 1587 entraron a la Argentina las primeras ovejas, estas se adaptaron a las condiciones naturales y se desarrolló así la denominada «oveja criolla¼. Se seleccionaron 486 animales de diferentes provincias para conocer el estado serológico de la enfermedad producida por Brucella melitensis y Brucella ovis. Para detectar anticuerpos anti-Brucella en fase lisa se utilizó la prueba de rosa de Bengala (RBT) como tamiz y como confirmatorias seroaglutinación lenta en tubo (SAT) y 2-mercaptoetanol (2ME). En fase rugosa se realizó como tamiz la prueba rápida de aglutinación (RSAT) y ELISA indirecto como prueba confirmatoria (IELISA). Este estudio mostró un porcentaje de seropositividad de brucelosis causada por B. ovis del 2,9%. Excluyendo los animales cruzados con la raza Suffolk, la seropositividad sería del 0,6%. Todos los animales fueron negativos a brucelosis causada por B. melitensis.

Serological study of brucellosis in Argentine Creole sheep.

Ovine cattle was introduced into America during the Spanish conquest with the second journey of Columbus to the Antilles and was disseminated throughout the region. In 1587, sheep were introduced into Argentina, later developing into the "Creole" breed. We selected 486 animals from different Argentine provinces with the aim of determining the serological status of brucellosis caused by Brucella melitensis and Brucella ovis. For the detection of antibodies against smooth Brucella spp., the Rose Bengal test (RBT) was performed as screening test while the serum agglutination test (SAT) and 2 mercapto-ethanol (2ME) were run as a confirmatory technique. Moreover, for the detection of antibodies against rough Brucella spp., we used the rapid slide agglutination test (RSAT) for screening and an indirect ELISA (IELISA) as confirmatory assay. This study showed that the total positive percentage of brucellosis due to B. ovis was 2.9%. Excluding the animals mixed with the Suffolk breed; seropositivity would be 0.6%. All animals tested negative for brucellosis caused by B. melitensis.

Human brucellosis at a pig slaughterhouse.

Seventeen workers in a pig slaughterhouse with signs and symptoms compatible with brucellosis were clinically examined at the outpatient service of different health institutions and studied by serological tests during the period 2005-2011. Eleven blood cultures were taken and six Brucella suis strains were isolated, three biovar 1 and three with atypical characteristics. In order to confirm that these cases had no common source, a variable number of tandem repeat (VNTR) analyses were performed on 5 of the 6 strains whose results showed substantial heterogeneity in the genotypes, thereby demonstrating that the immediate origin was not the same. Two hundred adult pigs admitted for slaughter at the plant were sampled by convenience and tested by buffered antigen plate test (BPAT), serum agglutination test (SAT) and 2-mercapto-ethanol test (MET). Seven of 62 males (11%) and 25/138 (18%) females tested positive. The study results contribute information on risk scenarios for packing plant workers and underscore the need to improve plant workers' education on appropriate containment measures and to actively screen animals for swine brucellosis.

Congenital brucellosis in an infant.

Brucellosis has been reported mainly among pregnant women, and it may lead to spontaneous abortion, intrauterine fetal death, or delivery of an infected neonate. Transmission through breast milk has also been described, but congenital cases are not commonly reported. We present the clinical findings, laboratory studies, treatment, and final outcome of a late prenatal transmission from a mother to her term infant of Brucella melitensis biovar 1. Because the maternal disease was undetected due to lack of clinical suspicion, diagnosis was made possible only by the results of infant blood cultures. Differential diagnosis of fever of unknown origin (FUO) misdiagnosed could result, as in our case, in the administration of inappropriate antimicrobial therapy. Primary health care physicians should be alerted to the clinical and laboratory findings of this infection, and pregnant women should routinely be tested serologically in areas where brucellosis is still a problem.

Recent trends in human Brucella canis infection.

There is little information in the literature regarding the clinical progress of brucellosis in patients affected by other diseases. We report Brucella canis human infection link to Gaucher's disease and Guillain Barré syndrome and discuss complications observed in a case with infective endocarditis. The three cases described came from areas of socio-economic deprivation and scarce epidemiological information where the healthcare personnel did not even consider such diagnosis. The growth of large urban populations deprived from basic services has created a new set of global health challenges. Changes in the urban environment due to slum communities' expansion have resulted in increased dog populations in the peridomiciliary environment. Eleven laboratory employees working with the strains found and their identification were examined. Sanitary authorities should focus on the zoonotic aspect of B. canis considering the dramatic increase of canine roamers near urban centers.

Application of variable number of tandem repeats typing to describe familial outbreaks of brucellosis in Argentina.

Consumption of inadequately pasteurized dairy products is the most common means of transmission of brucellosis. This report describes two foodborne outbreaks that occurred in families infected after consumption of fresh home-made cheese bought in different Argentine provinces. High resolution variable number of tandem repeats (VNTR)-based analysis revealed two well-defined groups comprising essentially identical profiles and corresponding to the two different outbreaks. Similar clinical findings in members of the same family could indicate that the differential virulence of different bacterial clones, as indicated by VNTR data, could have influenced the course of the disease. We observed the importance of adequate treatment in early stages of the disease; combination therapy and extended treatment for 6 weeks or longer yielded significantly better results. The risk of the foodborne transmission of this zoonotic disease and disease prevention should be considered.

Brucella canis causing infection in an HIV-infected patient.

From the blood culture of an HIV-positive patient with a febrile syndrome (CD4 count 385 cells/microL and viral load nondetectable), Brucella canis was isolated. The patient was presumptively infected from his dogs, which tested positive, and showed good outcome after the therapy with doxycycline-ciprofloxacin, and the HIV infection would seem not to have been influenced by brucellosis. To our knowledge, no other case of B. canis in the setting of HIV infection has been reported in the literature, and the emerging zoonotic potential of the disease in urban areas should be considered.

[Canine brucellosis in dogs in the city of Buenos Aires]. / Brucelosis canina en perros de la ciudad de Buenos Aires.

Canine brucellosis, caused by Brucella canis, provokes epidydimitis, testicular atrophy and sterility in male dogs, while in females the major symptom is miscarriage. Transmission to humans may be through contact with semen, urine and/or aborted fetuses of infected animals. Our study, observational and cross-sectional, focused on dogs in lower class neighborhoods and slums with a high rate of unmet basic needs (UBN) in 8 areas of the city of Buenos Aires. We studied 219 dogs: 184 females and 35 males, that tested negative to the buffered plate antigen test (BPAT), which ruled out infection with smooth species of Brucella. We detected anti-B. canis antibodies in 16 dogs (7.3%): 9 females and 7 males, relevant data since the urine of males is considered one of the vectors for the spread of the infection. Although we could run blood cultures on only 175 animals, we isolated B. canis in 3 (2 females and 1 male). Only 3 of the owners of dogs that tested positive consented to a serological diagnosis and two of them were positive. We highlight that the agar gel immunodiffusion test (IGID) proved to have low sensitivity, having detected only one of the 16 positive cases and none of the three confirmed by isolation. We conclude that in the areas studied, the detection of serologically positive dogs and the isolation of B. canis in 3 cases are indicators of the health hazard for the population exposed to it.

Brucelosis canina en perros de la ciudad de Buenos Aires / Canine brucellosis in dogs in the city of Buenos Aires

La brucelosis canina, causada por Brucella canis, provoca epididimitis, atrofia testicular y esterilidad en los perros, mientras que en las hembras el síntoma principal es el aborto. La transmisión al hombre puede ser por contacto con el semen, orina, y/o fetos abortados de animales infectados. El presente estudio de tipo observacional de corte transversal, se realizó en caninos de barrios y asentamientos con alto índice de necesidades básicas insatisfechas (NBI) en 8 áreas de la ciudad de Buenos Aires. Se estudiaron 219 perros, 184 hembras y 35 machos, que fueron negativos a la prueba de aglutinación con antígeno tamponado (BPAT), que descartó la infección con especies lisas del género Brucella. Sedetectaron anticuerpos anti-B. canis en 16 perros (7.3%), 9 hembras y 7 machos, este último dato es relevante ya que la orina de los machos es considerada uno de los medios de diseminación de la infección. Aunque sólo se pudieron tomar hemocultivos a 175 animales, en 3 (2 hembras y un macho) se aislaron B. canis. Sólo 3 de los dueños de los perros positivos accedieron al diagnóstico serológico y dos resultaron positivos. Destacamos que la prueba de inmunodifusión en gel de agar (IGDA) ha demostrado ser poco sensible, detectó sólo uno de los 16 casos positivos y ninguno de los tres confirmados por aislamiento. Concluimos que en las áreas estudiadas el hallazgo de perros serológicamente positivos y el aislamiento de B. canis en 3 casos, son indicadores del riesgo en el que se encuentra la salud de la población expuesta.

Canine brucellosis, caused by Brucella canis, provokes epidydimitis, testicular atrophy and sterility in male dogs, while in females the major symptom is miscarriage. Transmission to humans may be through contact with semen, urine and/or aborted fetuses of infected animals. Our study, observational and cross-sectional, focused on dogs in lower class neighborhoods and slums with a high rate of unmet basic needs (UBN) in 8 areas of the city of Buenos Aires. We studied 219 dogs: 184 females and 35 males, that tested negative to the buffered plate antigen test (BPAT), which ruled out infection with smooth species of Brucella. We detected anti-B. canis antibodies in 16 dogs (7.3%): 9 females and 7 males, relevant data since the urine of males is considered one of the vectors for the spread of the infection. Although we could run blood cultures on only 175 animals, we isolated B. canis in 3 (2 females and 1 male). Only 3 of the owners of dogs that tested positive consented to a serological diagnosis and two of them were positive. We highlight that the agar gel immunodiffusion test (IGID) proved to have low sensitivity, having detected only one of the 16 positive cases and none of the three confirmed by isolation. We conclude that in the areas studied, the detection of serologically positive dogs and the isolation of B. canis in 3 cases are indicators of the health hazard for the population exposed to it.

Diagnosis of human brucellosis caused by Brucella canis.

The transmission of Brucella canis to man commonly occurs through contact with infected dogs or their secretions, or through direct laboratory exposure. The disease is underdiagnosed due to a general lack of serological testing facilities and misconceptions concerning its prevalence. This report shows the potential use of an indirect ELISA (IELISA) for the diagnosis of human brucellosis caused by B. canis in a population of patients negative by smooth-Brucella antigen tests but positive by rapid slide agglutination test (RSAT). One hundred and ten sera from asymptomatic people found negative by tests using smooth Brucella abortus antigen and by RSAT showed an IELISA specificity of 100 % when a cut-off value of 27 % positivity (%P) was selected. For 17 sera from patients with positive B. canis culture or in close contact with culture-positive dogs, the IELISA sensitivity was 100 % with the same cut-off value. The positive patients presented clinical symptoms similar to brucellosis caused by other species of Brucella and some of them received antibiotic treatment and made good progress. Using this cut-off value, we studied 35 patients with negative blood cultures but positive RSATs, and IELISA detected 18 as positive; of the 17 IELISA-negative, two were RSAT-positive at dilution 1 : 2 and 15 were weakly positive with pure serum. These samples were probably from patients at an early stage of infection or indicate false-positive results. No cross-reaction was observed among the sera from nine cases with a diagnosis other than brucellosis, but cross-reactivity was evident in sera from patients infected with smooth-Brucella species. Since routine brucellosis diagnosis does not include B. canis investigation, infection with this species may be more widespread than is currently suspected. The RSAT could be a suitable screening test for the diagnosis of B. canis human brucellosis, and a supplementary technique, such as IELISA, performed on all positive RSAT samples that were negative by B. abortus antigen could ensure diagnostic specificity and confirm the diagnosis.

Unusual clinical presentation of brucellosis caused by Brucella canis.

Brucella canis is considered a rare cause of human brucellosis. The clinical importance of this infection may have been underestimated so far because of difficulties with presumptive diagnosis. The case described here presented symptoms compatible with brucellosis but the routine tests using Brucella abortus antigen were negative. The infection would have remained undiagnosed if culture had not been positive. This case illustrates the potential for a favourable outcome in Brucella canis diagnosis and supports recommendations for the use of B. canis serology. The infection should be suspected in patients with compatible symptoms and negative serology for B. abortus antigen.

Fluorescence polarization assay for diagnosis of human brucellosis.

Fluorescence polarization immunoassay (FPA) uses molecular rotational properties to measure antibody binding to antigen directly. The potential use of this method was assessed in comparison to a competitive enzyme immunoassay (CELISA) and conventional serological tests for the diagnosis of brucellosis on a total of 587 human sera. Based on 340 sera from asymptomatic blood donors with no evidence of brucellosis, the specificity of the FPA was 97.9 % using a cut-off value of 72 mP. Sera from Brucella-infected patients (11 Brucella melitensis, 32 Brucella abortus, 32 Brucella suis and one Brucella sp.) yielded a sensitivity estimate of 96.1 %. In tests on 84 sera from suspected brucellosis patients, the FPA detected 80 cases. Of 87 sera from patients with probable infection, 15 were detected by both CELISA and FPA, three by CELISA only and four by FPA only. The discrepancies in both groups involved sera with low, declining titres. The FPA uses a sample of 40 micro l serum, takes about 5 min to complete and has been demonstrated to be accurate for the detection of antibodies to B. abortus, B. melitensis and B. suis and for identifying patients suffering relapses. Because of the ease of the procedure, it could be readily adopted for use in clinical laboratories and blood banks.