Showing papers by "Edgardo Moreno published in 2019"

Neutrophils as Trojan Horse Vehicles for Brucella abortus Macrophage Infection

Abstract: Brucella abortus is a stealthy intracellular bacterial pathogen of animals and humans. This bacterium promotes the premature cell death of neutrophils (PMN) and resists the killing action of these leukocytes. B. abortus-infected PMNs presented phosphatidylserine (PS) as “eat me” signal on the cell surface. This signal promoted direct contacts between PMNs and macrophages (Ms) and favored the phagocytosis of the infected dying PMNs. Once inside Ms, B. abortus replicated within Ms at significantly higher numbers than when Ms were infected with bacteria alone. The high levels of the regulatory IL-10 and the lower levels of proinflammatory TNF-α released by the B. abortus-PMN infected Ms, at the initial stages of the infection, suggested a non-phlogistic phagocytosis mechanism. Thereafter, the levels of proinflammatory cytokines increased in the B. abortus-PMN-infected Ms. Still, the efficient bacterial replication proceeded, regardless of the cytokine levels and M type. Blockage of PS with Annexin V on the surface of B. abortus-infected PMNs hindered their contact with Ms and hampered the association, internalization, and replication of B. abortus within these cells. We propose that B. abortus infected PMNs serve as “Trojan horse” vehicles for the efficient dispersion and replication of the bacterium within the host.

Neutrophils Dampen Adaptive Immunity in Brucellosis.

Abstract: Brucella organisms are intracellular stealth pathogens of animals and humans. The bacteria overcome the assault of innate immunity at early stages of an infection. Removal of polymorphonuclear neutrophils (PMNs) at the onset of adaptive immunity against Brucella abortus favored bacterial elimination in mice. This was associated with higher levels of interferon gamma (IFN-γ) and a higher proportion of cells expressing interleukin 6 (IL-6) and inducible nitric oxide synthase (iNOS), compatible with M1 macrophages, in PMN-depleted B. abortus-infected (PMNd-Br) mice. At later times in the acute infection phase, the amounts of IFN-γ fell while IL-6, IL-10, and IL-12 became the predominant cytokines in PMNd-Br mice. IL-4, IL-1β, and tumor necrosis factor alpha (TNF-α) remained at background levels at all times of the infection. Depletion of PMNs at the acute stages of infection promoted the premature resolution of spleen inflammation. The efficient removal of bacteria in the PMNd-Br mice was not due to an increase of antibodies, since the immunoglobulin isotype responses to Brucella antigens were dampened. Anti-Brucella antibodies abrogated the production of IL-6, IL-10, and IL-12 but did not affect the levels of IFN-γ at later stages of infection in PMNd-Br mice. These results demonstrate that PMNs have an active role in modulating the course of B. abortus infection after the adaptive immune response has already developed.

Genetic and Phenotypic Characterization of the Etiological Agent of Canine Orchiepididymitis Smooth Brucella sp. BCCN84.3.

Abstract: This work was supported by FEES-CONARE, Costa Rica; Fondo Institucional de Desarrollo Academico (FIDA), Universidad Nacional; Wellcome Trust; CITA-INIA, Spain (project Bru-Epidia 291815-FP7/ERANET/ANIHWA); MINECO (AGL2014-58795-CA), and Aragon Government (Consolidated Group A14). Authors from the Sanger Institute were supported by Wellcome Trust (098051). NR-V was partially sponsored by a scholarship from the University of Costa Rica. KB was founded by a Wellcome Trust Postdoctoral Training Fellowship for Clinicians (106690/Z/14/Z). MS-E was granted with a fellowship from SEP, Universidad de Costa Rica.

Brucella sequence Type 27 isolated from Dwarf Sperm Whale (Kogia sima) stranded in the Costa Rican Pacific Coast

Abstract: Brucella organisms are Gram-negative, intracellular facultative extracellular bacteria that infect a variety of animals. On March 2018, a pregnant dwarf sperm whale (Kogia sima), stranded and aborted on Herradura beach at the Pacific coast of Costa Rica. K. sima is a criptic species; very little is known of its biology and worldwide distribution, however it is still hunted in Asia. Brucella sp. was recovered from multiple tissues of the female and the calf, and examined by biochemical tests, MLVA-16, brucellader and HRM real time. The isolates were used for whole genome sequencing and the reads were aligned to Brucella abortus 9–941 as the reference, alltogether with other Brucella species. A total of 27 365 variable sites were extracted and a phylogenetic reconstruction by maximum likelihood was produced. The phylogenetic tree revealed that the K. sima isolates are related to Brucella sp. F5/99, a singular strain recovered on 1992 from a bottlenose dolphin captive in California, classified as sequence type (ST) 27 by multi-locus sequence type. This ST27 was described in Brucella isolates with zoonotic capacity and therefore transmission to humans from Peru and New Zealand. This is the first report of Brucella ST27 recovered from a host of the Eastern Tropical Pacific and of Brucella infection in a dwarf sperm whale. Our results shows that the range of marine mammals infected by Brucella sp. is wider than our current knowledge, and that biosafety measures should be increased when handling the stranded mammals, as the zoonotic transmission is of major risk.