phenylephrine-hydrochloride and Actinomycetales-Infections

There is currently no licensed vaccine that protects foals against Rhodococcus equi-induced pneumonia. Oral administration of live, virulent R. equi to neonatal foals has been demonstrated to protect against subsequent intrabronchial challenge with virulent R. equi. Electron beam (eBeam)-inactivated R. equi are structurally intact and have been demonstrated to be immunogenic when administered orally to neonatal foals. Thus, we investigated whether eBeam inactivated R. equi could protect foals against developing pneumonia after experimental infection with live, virulent R. equi. Foals (n = 8) were vaccinated by gavaging with eBeam-inactivated R. equi at ages 2, 7, and 14 days, or gavaged with equal volume of saline solution (n = 4), and subsequently infected intrabronchially with live, virulent R. equi at age 21 days. The proportion of vaccinated foals that developed pneumonia following challenge was similar among the vaccinated (7/8; 88%) and unvaccinated foals (3/4; 75%). This vaccination regimen did not appear to be strongly immunogenic in foals. Alternative dosing regimens or routes of administration need further investigation and may prove to be immunogenic and protective.

Topics: Actinomycetales Infections; Administration, Oral; Animals; Antibody Formation; Antibody Specificity; Bronchi; Electrons; Horse Diseases; Horses; Immunity, Cellular; Immunoglobulin G; Interferon-gamma; Leukocytes, Mononuclear; Nose; Rhodococcus equi; Treatment Outcome; Ultrasonography; Vaccination; Virulence

Acinetobacter baumannii is a major causative agent of healthcare-associated infection and develops multidrug resistance rapidly. However, little is known in the host defense mechanisms against this infection. In this study, we examined if mice recovered from a previous intranasal A. baumannii infection (recovered mice) are fully protected against a subsequent reinfection. We found that, despite the presence of specific serum IgG and mucosal IgA responses prior to the reinfection, the recovered mice were only marginally better protected against intranasal challenge with low doses of homologous or heterologous A. baumannii strains than the naïve mice. Post-challenge immune and inflammatory (cells and cytokines) responses were generally comparable between recovered and naïve mice although the recovered mice produced significantly higher amounts of IFN-γ and IL-17 and had higher percentages and numbers of resident lung CD44(hi)CD62L(-)CD4(+) and CD19(+) B lymphocytes. Taken together, our results suggest that mice recovered from a previous A. baumannii infection remain susceptible to reinfection, indicating the complexity of immune protection mechanism for this Gram-negative, multidrug-resistant emerging pathogen.

Topics: Actinomycetaceae; Actinomycetales Infections; Animals; Bacterial Load; Disease Resistance; Host-Pathogen Interactions; Mice; Nose

Human infection due to Nocardiopsis, an actinomycete, is rare and the majority of those infections are due to Nocardiopsis dassonvillei. This agent has been implicated in cutaneous, pulmonary, eye and disseminated infections. It has never been isolated from the nose or any nasal infection. We report here a rare case of nasal vestibular abscess due to N. dassonvillei in an adult diabetic patient. The bacterium was identified on the basis of morphological and biochemical characteristics, and confirmed by sequencing the 16S rRNA and hsp65 genes. The patient was successfully treated with clarithromycin and levofloxacin. Though N. dassonvillei infections may be rare, the study highlights that it may cause a wide spectrum of disease manifestations, and laboratories should take care to isolate and identify the easily treatable pathogen.

Topics: Abscess; Actinomycetales; Actinomycetales Infections; Bacterial Typing Techniques; Cluster Analysis; Diabetes Complications; DNA, Bacterial; Humans; Male; Middle Aged; Molecular Sequence Data; Nose; Phylogeny; Sequence Analysis, DNA