Brucellosis in mammals of Costa Rica: An epidemiological survey.

Brucellosis has been an endemic disease of cattle and humans in Costa Rica since the beginning of XX century. However, brucellosis in sheep, goats, pigs, water buffaloes, horses and cetaceans, has not been reported in the country. We have performed a brucellosis survey in these host mammal species, from 1999-2016. In addition, we have documented the number of human brucellosis reported cases, from 2003-2016. The brucellosis seroprevalence in goat and sheep herds was 0.98% and 0.7% respectively, with no Brucella isolation. Antibodies against Brucella were not detected in feral or domestic pigs. Likewise, brucellosis seroprevalence in horse and water buffalo farms was estimated in 6.5% and 21.7%, respectively, with no Brucella isolation. Six cetacean species showed positive reactions against Brucella antigens, and B. ceti was isolated in 70% (n = 29) of striped dolphins (Stenella coeruleoalba). A steady increase in the diagnosis of human brucellosis cases was observed. Taking into account the prevalence of brucellosis in the various host mammals of Costa Rica, different measures are recommended.

Deletion of the Correia element in the mtr gene complex of Neisseria meningitidis.

The mtr gene complex in Neisseria meningitidis encodes an efflux pump that is responsible for export of antibacterial hydrophobic agents. The promoter region of the mtrCDE operon harbours an insertion sequence known as a Correia element, and a binding site for the integration host factor (IHF) is present at the centre of the Correia element. It has been suggested that the expression of the mtrCDE operon in meningococci is subject to transcriptional regulation by the IHF and post-transcriptional regulation by cleavage in the inverted repeat of the Correia element. The promoter region of the mtrCDE operon as well as the association of changes at that point with decreased susceptibility to antimicrobial drugs in 606 Neisseria meningitidis strains were analysed in this study. Two different deletions were present in the analysed region. The first one, found in seven strains, corresponded to absence of the Correia element. The second one, affecting the -10 region and first 100 bp of the mtrR gene and present in 57 isolates, was only found in ST-1624 isolates. None of the deletions were associated with decreased susceptibility to antimicrobial drugs. Although most of the meningococcal strains carry the Correia element at that position, its deletion is not an exception.

Molecular characterization of invasive serogroup Y Neisseria meningitidis strains isolated in the Latin America region.

OBJECTIVES: To improve the understanding of serogroup Y invasive meningococcal disease (IMD) in Latin America, particularly IMD molecular epidemiology; 166 Y serogroup isolates received at the National Reference Laboratories of Argentina, Brazil, Chile, Colombia, and Costa Rica during 2000-2006 were characterized by their molecular markers. METHODS: This analysis included serological assays to determine serogroup/serotype/serosubtype, DNA sequencing and genotyping of the porB and/or porA genes, multilocus sequence typing (MLST) and fetA allele determination. RESULTS: Sixteen different antigenic combinations were observed. Sixty-two (37.3%) isolates were NT:P1.5 and 36 (21.7%) isolates were 14:NST. Thirty-two different STs appeared, but 3 STs (ST-1624, ST-23, and ST-5770) accounted for 69.9% (116) of the strains. Most of the IMD isolates belonged to the ST-23, ST-167 clonal complexes or the group composed by ST-5770 and related STs. CONCLUSIONS: Isolates obtained in Colombia and Costa Rica were similar to that of the United States, in that most sequence types belonged to the ST-23 clonal complex. IMD isolates found in Argentina appear to be the result of an independent event and did not spread from nearby countries, being the sequence type ST-1624 (ST-167 clonal complex) the most frequently found. We were unable to correlate an antigenic shift of outer membrane proteins with an increase of serogroup Y meningococcal cases in our collection of isolates.

Prevalencia de anticuerpos séricos contra la bacteria Brucella sp. en una población humana tropical

Prevalence of serum antibodies for the bacterium Brucella sp. in a tropical human population. Brucellosis is a systemic bacterial disease that can last years if not treated properly. The laboratory diagnosis is made by serological tests or isolation of the agent. We studied the prevalence of antibodies against Brucella sp. in inhabitants of rural communities of Cartago, Costa Rica, who are dedicated mainly to dairy cattle activities. We analyzed 714 representative samples with the Rose Bengal plate agglutination test (RBT) and the standard agglutination test in microplate (SAT). The overall prevalence was 0.87 %. No seroconversion was demonstrated for seropositive individuals. Even though 71 % of the population mentioned consuming non-pasteurized milk, no statistically significant association was found (1.09 %, IC 0.30-2.77) between milk consumption and the presence of antibodies suggestive of infection by Brucella sp. As a brucellosis high-risk population, the absence of symptoms in the population agrees with the observed titers of antibodies, suggesting a low previous exposure to the agent. Rev. Biol. Trop. 55 (2): 385-391. Epub 2007 June, 29.

La brucelosis es una enfermedad bacteriana generalizada con tendencia a la cronicidad si no se trata adecuadamente. El diagnóstico de laboratorio se realiza por el aislamiento e identificación del agente o en la mayoría de los casos mediante pruebas serológicas. En este estudio se informa la prevalencia de anticuerpos séricos contra Brucella sp. en habitantes de comunidades rurales de Cartago dedicadas principalmente a la ganadería de leche. Se analizó un total de 714 muestras representativas de la población mediante la técnica de aglutinación Rosa de Bengala en lámina (RBT) y la prueba de aglutinación en microplaca (SAT). Se encontró una prevalencia de 0.87 %, y en ninguna persona seropositiva se demostró seroconversión. Aún, cuando el 71 % de la población refirió consumir leche no pasteurizada, no se encontró asociación estadísticamente significativa (1.09 %, IC 0.30-2.77) entre el consumo de leche no pasteurizada y la presencia de anticuerpos sugestivos de infección por Brucella sp. A pesar de ser una zona de alta prevalencia de brucelosis bovina por Brucella abortus, la ausencia de síntomas en la población y los bajos títulos de anticuerpos observados sugieren una escasa exposición previa al agente.

[Prevalence of serum antibodies for the bacterium Brucella sp. in a tropical human population]. / Prevalencia de anticuerpos séricos contra la bacteria Brucella sp. en una población humana tropical.

Prevalence of serum antibodies for the bacterium Brucella sp. in a tropical human population. Brucellosis is a systemic bacterial disease that can last years if not treated properly. The laboratory diagnosis is made by serological tests or isolation of the agent. We studied the prevalence of antibodies against Brucella sp. in inhabitants of rural communities of Cartago, Costa Rica, who are dedicated mainly to dairy cattle activities. We analyzed 714 representative samples with the Rose Bengal plate agglutination test (RBT) and the standard agglutination test in microplate (SAT). The overall prevalence was 0.87%. No seroconversion was demonstrated for seropositive individuals. Even though 71% of the population mentioned consuming non-pasteurized milk, no statistically significant association was found (1.09 %, IC 0.30-2.77) between milk consumption and the presence of antibodies suggestive of infection by Brucella sp. As a brucellosis high-risk population, the absence of symptoms in the population agrees with the observed titers of antibodies, suggesting a low previous exposure to the agent.

Identification of strain-specific genes located outside the plasticity zone in nine clinical isolates of Helicobacter pylori.

Helicobacter pylori is a Gram-negative bacterium that is associated with the development of peptic ulcers and gastric carcinoma in humans. This species appears to be one of the most genetically variable bacteria described to date. The overall level of heterogeneity within strains of this organism was determined by comparing the genome sequences of two reference strains, J99 and 26695. The aim of this study was to measure the genetic diversity within strains of H. pylori by looking for strain-specific genes in nine H. pylori strains isolated from patients suffering from chronic gastritis (n=3), duodenal ulcers (n=3) or gastric cancer (n=3). Seven loci that contained strain-specific genes in strains J99 and 26695 were studied. These regions were subsequently amplified from most of the clinical isolates studied and their sequences were determined. ORFs were predicted from the sequence data and were compared to sequences within the databases. The results showed that the genes flanking the ORFs specific to either strain J99 or strain 26695 were also present in a similar configuration in the genomes of the nine clinical isolates. Moreover, in most regions, ORFs homologous to those found in the corresponding loci in the two reference strains were detected. However, in 10 regions, genes similar to those located at another locus in the genome of J99 or 26695 were found. Finally, six strain-specific genes were identified in three regions of three of the H. pylori strains isolated from patients with duodenal ulcers (n=2) and gastric cancer (n=1). Of these six genes, five were putative genes and one was an orthologue of a gene encoding a transposase in Thermotoga maritima. However, no association with disease was found for these genes.