Bordetella bronchiseptica pneumonia a thread in the diagnosis of human immunodeficiency virus infection

Identification of a broad-spectrum lytic Bordetella phage and assessments of its potential for combating Bordetella infections

Bordetella bronchiseptica (Bb) is a zoonotic respiratory pathogen that frequently causes infections in farming and companion animals, posing threats to agricultural economics and public health. However, Bb strains are intrinsically resistant to several antibiotics commonly used to treat respiratory infections. Phage therapy has been recognized as a promising strategy to combat bacterial infections. In this study, a novel Bordetella phage, designated PY223, was isolated using Bb strains as indicators. Genome network analysis with different phages showed PY223 was related to 15 viral clusters but was not included in any of these clusters. PY223 did not carry any known genes involved in lysogeny and/or horizontal gene transfer. Host range analysis showed that PY223 exhibited the capacity to lyse 70 Bb strains isolated from pigs and/or cats. Measurement of the one-step growth curve showed that PY223 had an incubation period of 10 min and a rapid growth period of 80 min. The burst size was estimated to be approximately 109 PFU/cell. In addition, PY223 displayed the capacity to inhibit the growth of Bb for up to 17 h. PY223 was stable under environmental temperatures ranging from 4 °C to 60 °C and/or pH values between 5.0 and 9.0. It remained stable even when exposed to UV light for 30 min. Notably, PY223 effectively eliminated Bb biofilms, inhibited the growth of prophage-harboring Bb strains, and cleared Bb from the environment. In vivo testing in mouse models highlighted its excellent potential for treating respiratory Bordetella infections.

Usefulness of business intelligence to guide antimicrobial treatment decision in infections by infrequent microorganism such as Bordetella bronchiseptica

Human infections by Bordetella bronchiseptica are increasing in recent years. However, due to the lack of clinical susceptibility/resistance breakpoints, antimicrobial treatment is complex. Business Intelligence (BI) is a tool that allows to record and analyze large amounts of data in a very short time. The aim of this study was to analyze a cohort of patients with B. bronchiseptica infections focusing on how BI can help guide empirical antimicrobial therapy Demographic, clinical, and microbiological data about B. bronchiseptica infections were recovered. Then, MIC50/90 of several antibiotics was automatically calculated through the BI. Thirteen B. bronchiseptica infections were identified. The lowest MICs90 were for carbapenem, aminoglycoside, fluoroquinolones, and tetracyclines. The EUCAST PK-PD (non-species related) breakpoints showed that only piperacillin/tazobactam, imipenem and meropenem would be appropriate treatments to use empirically. In conclusion, BI systems have great potential to optimize the empirical antibiotic treatment in these types of infections.

Outer Membrane Vesicles Coating Nano-Glycyrrhizic Acid Confers Protection Against Borderella bronchiseptica Through Th1/Th2/Th17 Responses

Purpose

Outer membrane vesicles (OMVs) are spherical nano-sized proteolipids secreted by numerous pathogenic Gram-negative bacteria. Due to the immunostimulatory properties and protective efficacy, OMVs have received increasing attention as a candidate for the vaccine to prevent and treat bacterial infections. However, the immune response remains elusive due to the low structural stability and poor size homogeneity of the vesicles. In this study, OMVs were used to coat self-assembled glycyrrhizic acid nanoparticles (GANs) and obtain a stable OMV vaccine. The immunoprotective effects and anti-infection efficacy were evaluated in vivo and in vitro.

Methods

The OMVs were prepared by ultrafiltration method and fused with GAN through mechanical extrusion. The characteristics, including morphology, hydrodynamic size, zeta potential, and stability were evaluated. The in vitro immunological function of GAN-OMV on the macrophages and in vivo immune efficacy and anti-infection effect were examined and compared.

Results

The results showed that the GAN-OMV were homogenous with a size of 130 nm and a stable core-shell structure. Micropinocytosis-dependent and clathrin-mediated endocytotic pathways effectively internalized the GAN-OMV into the macrophages and promoted cell proliferation, cytokine secretion, and M1 polarization. Furthermore, subcutaneous GAN-OMV vaccination contributed to significantly higher Borderella bronchiseptica (Bb)-specific antibody production and lymphocyte proliferation. The splenic lymphocytes of mice immunized with GAN-OMVs displayed a higher ratio of CD4+/CD8+ T cells and CD19+ B cells and produced significantly higher levels of Th1/Th2/Th17 cytokines. GAN-OMV also effectively prevented Bb reinfection.

Conclusion

In this study, GAN-OMV was developed successfully to stimulate Th1/Th2/Th17 immune responses against Bb and provide a promising strategy for novel vaccine development against the microbial pathogen.

Bordetella bronchiseptica pneumonia in an immunocompetent pig farmer

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B. bronchiseptica has rarely been isolated from humans despite exposure to animals.

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Working with farm animals, COPD or AIDS are risk factors to develop pneumonia.

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B. bronchiseptica pneumonia may lead to misdiagnosis with other infections.

Bordetella bronchiseptica is a gram negative bacterium, a common pathogen in respiratory infections of various mammals, mainly dogs and pigs, being extremely rare in humans, occurring in these cases especially in immunosuppressed individuals. We present the case of a male pig breeder with no evidence of immunosuppression, initially focused on possible pulmonary tuberculosis, who was diagnosed of B. bronchiseptica pneumonia, successfully treated with fluoroquinolones and doxycycline.

Pathogenicity and virulence of Bordetella pertussis and its adaptation to its strictly human host

The highly contagious whooping cough agent Bordetella pertussis has evolved as a human-restricted pathogen from a progenitor which also gave rise to Bordetella parapertussis and Bordetella bronchiseptica. While the latter colonizes a broad range of mammals and is able to survive in the environment, B. pertussis has lost its ability to survive outside its host through massive genome decay. Instead, it has become a highly successful human pathogen by the acquisition of tightly regulated virulence factors and evolutionary adaptation of its metabolism to its particular niche. By the deployment of an arsenal of highly sophisticated virulence factors it overcomes many of the innate immune defenses. It also interferes with vaccine-induced adaptive immunity by various mechanisms. Here, we review data from invitro, human and animal models to illustrate the mechanisms of adaptation to the human respiratory tract and provide evidence of ongoing evolutionary adaptation as a highly successful human pathogen.