Efficacy of vaccination with a Klebsiella pneumoniae siderophore receptor protein vaccine for reduction of Klebsiella mastitis in lactating cattle.

Clinical mastitis caused by Klebsiella spp. is an emerging problem in the US dairy industry and results in a high degree of financial losses to dairy workers. This study was conducted as a randomized, blinded, and placebo-controlled efficacy study of a Klebsiella pneumoniae siderophore receptor protein (SRP) vaccine (Kleb-SRP), with a total of 569 cows and heifers enrolled. The study was designed to look at vaccine effect on Klebsiella mastitis; however, the SRP in Klebsiella are highly conserved across coliform bacteria, which means that the vaccine has potential for cross-protection against all coliforms. Cows were paired based on parity, days in milk at enrollment, and somatic cell count. Within pairs, individuals were randomized to receive either Kleb-SRP or a placebo formulation. Following vaccination, the incidence of Klebsiella spp. and total coliform mastitis from natural exposure were compared to determine the efficacy of the vaccine. When analyzing all cows, the reduction of mastitis risk was not significant, though milk production increased 0.31 kg/d and somatic cell counts were reduced by 20.1%. When administered before calving, the vaccine reduced the risk of Klebsiella and total coliform mastitis by 76.9 and 47.5% respectively; however, we observed no significant effect when administered after calving. The vaccine, when administered before calving, also increased milk production by an average of 1.74 kg/d and reduced somatic cell counts by 64.8%. When administered after calving, we noted a slight decrease in daily milk production (0.39 kg) but no significant effect on somatic cell counts. All cows in the study (including vaccinates and placebo) received multiple doses of a commercially available licensed Escherichia coli bacterin. It should be noted that this herd was chosen because of the high number of clinical Klebsiella clinical mastitis cases this herd experienced before the trial and the extreme environmental challenge that was present from bedding with dried manure solids. The data from this study demonstrate efficacy of the Kleb-SRP vaccine against Klebsiella mastitis alone and coliform mastitis in general (including all coliforms) when administered before the initiation of a lactation cycle.

Ecological genomics of tropical trees: how local population size and allelic diversity of resistance genes relate to immune responses, cosusceptibility to pathogens, and negative density dependence.

In tropical forests, rarer species show increased sensitivity to species-specific soil pathogens and more negative effects of conspecific density on seedling survival (NDD). These patterns suggest a connection between ecology and immunity, perhaps because small population size disproportionately reduces genetic diversity of hyperdiverse loci such as immunity genes. In an experiment examining seedling roots from six species in one tropical tree community, we found that smaller populations have reduced amino acid diversity in pathogen resistance (R) genes but not the transcriptome in general. Normalized R gene amino acid diversity varied with local abundance and prior measures of differences in sensitivity to conspecific soil and NDD. After exposure to live soil, species with lower R gene diversity had reduced defence gene induction, more cosusceptibility of maternal cohorts to colonization by potentially pathogenic fungi, reduced root growth arrest (an R gene-mediated response) and their root-associated fungi showed lower induction of self-defence (antioxidants). Local abundance was not related to the ability to induce immune responses when pathogen recognition was bypassed by application of salicylic acid, a phytohormone that activates defence responses downstream of R gene signalling. These initial results support the hypothesis that smaller local tree populations have reduced R gene diversity and recognition-dependent immune responses, along with greater cosusceptibility to species-specific pathogens that may facilitate disease transmission and NDD. Locally rare species may be less able to increase their equilibrium abundance without genetic boosts to defence via immigration of novel R gene alleles from a larger and more diverse regional population.

Hereditary angioedema: 44 years of diagnostic delay.

We report a 64-year-old man who suffered from recurrent visible swelling attacks since the age of 20 as well as episodes with severe upper airway edema, resulting in 4 emergency tracheotomies. Eventually after 44 years he was diagnosed with hereditary angioedema (HAE) type II. The aims of this report is to emphasize the importance of awareness concerning HAE, which does not respond to traditional anti-allergic therapy, and remind physicians to test for functional C1-INH deficiency.