Proteomics-based screening and antibiotic resistance assessment of clinical and sub-clinical Brucella species: An evolution of brucellosis infection control

Brucellae are intracellular sneaky bacteria and they can elude the host’s defensive mechanisms, resulting in therapeutic failure. Therefore, the goal of this investigation was to rapid identification of Brucella species collected from animals and humans in Saudi Arabia, as well as to evaluate their resistance to antibiotics. On selective media, 364 animal samples as well as 70 human blood samples were cultured. Serological and biochemical approaches were initially used to identify a total of 25 probable cultured isolates. The proteomics of Brucella species were identified using the MALDI Biotyper (MBT) system, which was subsequently verified using real-time polymerase chain reaction (real-time PCR) and microfluidic electrophoresis assays. Both Brucella melitensis (B. melitensis) and Brucella abortus (B. abortus) were tested for antimicrobial susceptibility using Kirby Bauer method and the E-test. In total, 25 samples were positive for Brucella and included 11 B. melitensis and 14 B. abortus isolates. Twenty-two out of 25 (88%) and 24/25 (96%) of Brucella strains were recognized through the Vitek 2 Compact system. While MBT was magnificently identified 100% of the strains at the species level with a score value more than or equal to 2.00. Trimethoprim-sulfamethoxazole, rifampin, ampicillin-sulbactam, and ampicillin resistance in B. melitensis was 36.36%, 31.82%, 27.27%, and 22.70%, respectively. Rifampin, trimethoprim-sulfamethoxazole, ampicillin, and ampicillin-sulbactam resistance was found in 35.71%, 32.14%, 32.14%, and 28.57% of B. abortus isolates, correspondingly. MBT confirmed by microfluidic electrophoresis is a successful approach for identifying Brucella species at the species level. The resistance of B. melitensis and B. abortus to various antibiotics should be investigated in future studies.

Live attenuated bacterium limits cancer resistance to CAR-T therapy by remodeling the tumor microenvironment

The tumor microenvironment (TME) is characterized by the activation of immune checkpoints, which limit the ability of immune cells to attack the growing cancer. To overcome immune suppression in the clinic, antigen-expressing viruses and bacteria have been developed to induce antitumor immunity. However, the safety and targeting specificity are the main concerns of using bacteria in clinical practice as antitumor agents. In our previous studies, we have developed an attenuated bacterial strain (Brucella melitensis 16M ∆vjbR, henceforth Bm∆vjbR) for clinical use, which is safe in all tested animal models and has been removed from the select agent list by the Centers for Disease Control and Prevention. In this study, we demonstrated that Bm∆vjbR homed to tumor tissue and improved the TME in a murine model of solid cancer. In addition, live Bm∆vjbR promoted proinflammatory M1 polarization of tumor macrophages and increased the number and activity of CD8+ T cells in the tumor. In a murine colon adenocarcinoma model, when combined with adoptive transfer of tumor-specific carcinoembryonic antigen chimeric antigen receptor CD8+ T cells, tumor cell growth and proliferation was almost completely abrogated, and host survival was 100%. Taken together, these findings demonstrate that the live attenuated bacterial treatment can defeat cancer resistance to chimeric antigen receptor T-cell therapy by remodeling the TME to promote macrophage and T cell-mediated antitumor immunity.

Estudio seroepidemiológico de Toxoplasma gondii en caprinos del Perú y su asociación a factores de riesgo

El objetivo del estudio fue determinar la seroprevalencia y su asociación con los factores de riesgo en la infección por Toxoplasma gondii en caprinos del Perú. Se trabajó con un grupo de 1119 sueros de caprinos colectados entre 2017-2018 de 23 de los 24 departamentos del país por el Servicio Nacional de Sanidad Animal (SENASA) para un monitoreo de Brucella melitensis. El número de muestras fue proporcional a la población de cabras de cada departamento. Se consideraron las variables edad (<1, 1-3, >3 años), sexo, procedencia (Zona Costa Norte, Zona Costa Centro-Sur, Zona Sierra-oriente, altitud (0-500, >500-2500, >2500 msnm) y tipo de crianza (intensiva, extensiva). Los sueros fueron analizados con un kit comercial de ELISA indirecta multi-especie y los factores de riesgo se determinaron mediante regresión logística. La prevalencia general encontrada de T. gondii fue de 28.15% (IC 95%: 25.5-30.9). La mayor prevalencia se encontró en la Sierra-oriente y Costa Centro-Sur), a una altitud <2500 msnm y bajo crianza intensiva.

Brucellosis in Herat Province, Afghanistan: Epidemiological Status and Risk Factors

Background: Human brucellosis, also known as Malta fever, is an acute systemic zoonotic disease in several parts of the world. The most pathogenic Brucella specie is Brucella melitensis that occurs in the human population of all age groups and of both sexes. Objectives: The present study aimed to investigate human Brucella infection in Afghanistan. Methods: The participants in this cross-sectional study were 44 patients diagnosed with Brucella infection during eight months and confirmed using Wright test by physicians of Iran Clinic Hospital. For data analysis, a statistical model was used through SPSS. Results: The most affected patients were female housewives (40.9%) and students (18.18%). The most frequent clinical manifestations were recurrent attacks of fever (95.34%), weight loss (81.39%), loss of appetite (79.06%), musculoskeletal pain (69.76%), boredom (67.44%), and lethargy (60.46%). A total of 41 (93.18%) patients mentioned the consumption of unpasteurized milk as the source of infection. Conclusions: The study results revealed that the main route of Brucella transmission in Afghanistan is the consumption of contaminated dairy products. The highest prevalence of brucellosis was observed among the young and middle-aged populations and housewives.

Seroprevalence of Brucella antibodies among vaccine manufacturing workers in contact with the Brucella melitensis Rev.1 vaccine strain

ABSTRACTBackgroundCattle vaccination remains an essential measure for the control of brucellosis. Strict preventive measures are applied to protect vaccine manufacturing workers (VMW) employed in processing these live attenuated vaccines. We analyzed the serological responses of VMW in contact with the Brucella melitensis Rev.1 strain.MethodsWe conducted an observational study of a cohort of VMW in a Spanish biopharmaceutical company, a leader in manufacturing veterinary products. The results of the Brucella serological tests carried out on these workers between 2012 and 2019 were reviewed, as well as demographic data, length of time in the company (seniority), and level of exposure. Multivariate analysis was performed with the logistic regression test.ResultsOf the 115 VMW studied, 47 (41%) showed positive Rose Bengal tests during company check-ups. Exposure levels were correlated with seropositivity, with an adjusted OR of 6.6 (95% CI: 2.1-20.3) for the high exposure and 2.0 (95% CI: 0.6-6.7) for the medium exposure groups. Sixteen (34%) seropositive VMW demonstrated an acute serologic pattern of IgG and IgM antibodies seropositivization, while 31 (66%) manifested a chronic serologic pattern of constant or intermittent positive IgG antibodies with persistently negative IgM antibodies. Seniority was inversely associated with the acute pattern: adjusted OR of 0.88 (95% CI: 0.79-0.97) for each year added. No seropositive VMW showed evidence of active brucellosis during follow up.ConclusionDespite strict safety measures, a percentage of VMW were exposed to the Rev.1 strain. Exposure levels were correlated with seropositivity. None of them developed symptomatic infection during follow-up. Two different serological patterns were observed: an acute IgM-positive pattern or a chronic IgM-negative pattern. Seniority was associated with the chronic pattern.

The FtcR-Like Protein ActR in Azorhizobium caulinodans ORS571 Is Involved in Bacterial Motility and Symbiosis With the Host Plant

Bacterial signal transduction pathways are important for a variety of adaptive responses to environment, such as two-component systems (TCSs). In this paper, we reported the characterization of a transcriptional regulator in Azorhizobium caulinodans ORS571, ActR, with an N-terminal receiver domain and one C-terminal OmpR/PhoB-type DNA binding domain. Sequence analysis showed that ActR shared a high similarity with FtcR regulator of Brucella melitensis 16M known to be involved in flagellar regulation. The structural gene of this regulator was largely distributed in Alphaproteobacteria, in particular in Rhizobiales and Rhodobacterales, and was located within clusters of genes related to motility functions. Furthermore, we studied the biological function of ActR in A. caulinodans grown at the free-living state or in association with Sesbania rostrata by constructing actR gene deletion mutant. In the free-living state, the bacterial flagellum and motility ability were entirely deleted, the expression of flagellar genes was downregulated; and the exopolysaccharide production, biofilm formation, and cell flocculation decreased significantly compared with those of the wild-type strain. In the symbiotic state, ΔactR mutant strain showed weakly competitive colonization and nodulation on the host plant. These results illustrated that FtcR-like regulator in A. caulinodans is involved in flagellar biosynthesis and provide bacteria with an effective competitive nodulation for symbiosis. These findings improved our knowledge of FtcR-like transcriptional regulator in A. caulinodans.

Brucellosis in humans and livestock / Brucelose em humanos e animais

A brucelose é a principal doença antropo zoonótica, em todo o mundo representa um sério problema em humanos e animais em países com economia baixa e média, 500.000 casos são relatados anualmente em humanos em todo o mundo, no entanto, a incidência real é estimada em 5.000.000 a 12.500.000 casos anualmente. É transmitido ao homem por contato direto, com animais doentes ou pela ingestão de produtos não pasteurizados infectados. Gênero Brucella, com bordas retas ou ligeiramente convexas, extremidades arredondadas e imóveis com 0,5–0,7μm de largura por 0,6-1,5 μm de comprimento. Apresentam-se individualmente e raramente em pequenos cachos, não possuem cápsulas, esporos ou flagelos, e são aeróbicos A apresentação clínica, a gravidade e a evolução da infecção em humanos variam dependendo da espécie infectante de Brucella, da concentração do inóculo, do estado físico do paciente e da história de outros sofrimentos. Apresentação clínica em gado, ao contrário da brucelose humana, o aborto espontâneo em ruminantes infectados é a característica da infecção, a apresentação clínica em populações animais varia muito de acordo com a espécie afetada. No México, como na maioria dos países da América Latina, o controle de doenças em animais é complicado, pelas características de resistência bacteriana ao meio ambiente, a falta de rebanhos livres de brucelose para repovoar (principalmente caprinos que são reservatórios da Brucella melitensis a mais patogênica para o homem), o diagnóstico e a eliminação tardia dos animais positivos, que permanecem nos currais por tempo suficiente para perpetuar a infecção. Aspectos econômicos que afetam a renda dos proprietários por terem que eliminar os animais confirmados com a doença, o consumo de queijos artesanais e derivados do leite não pasteurizadores são fatores que dificultam a aplicação das normas e regulamentações vigentes relacionadas à prevenção e controle de doenças em animais , impactando negativamente na saúde pública humana.