Chimpanzee Adenovirus Vaccine Provides Multispecies Protection against Rift Valley Fever.

Rift Valley Fever virus (RVFV) causes recurrent outbreaks of acute life-threatening human and livestock illness in Africa and the Arabian Peninsula. No licensed vaccines are currently available for humans and those widely used in livestock have major safety concerns. A 'One Health' vaccine development approach, in which the same vaccine is co-developed for multiple susceptible species, is an attractive strategy for RVFV. Here, we utilized a replication-deficient chimpanzee adenovirus vaccine platform with an established human and livestock safety profile, ChAdOx1, to develop a vaccine for use against RVFV in both livestock and humans. We show that single-dose immunization with ChAdOx1-GnGc vaccine, encoding RVFV envelope glycoproteins, elicits high-titre RVFV-neutralizing antibody and provides solid protection against RVFV challenge in the most susceptible natural target species of the virus-sheep, goats and cattle. In addition we demonstrate induction of RVFV-neutralizing antibody by ChAdOx1-GnGc vaccination in dromedary camels, further illustrating the potency of replication-deficient chimpanzee adenovirus vaccine platforms. Thus, ChAdOx1-GnGc warrants evaluation in human clinical trials and could potentially address the unmet human and livestock vaccine needs.

In vitro susceptibility of Staphylococcus aureus strains isolated from cows with subclinical mastitis to different antimicrobial agents

Sensitivity to commercial teat dips (nonoxinol-9 iodine complex and chlorhexidine digluconate) of 56 Staphylococcus (S.) aureus strains isolated from quarter milk samples of various German dairy herds treated with different teat dipping schemes was investigated in this study. The minimum inhibitory concentration was determined using a broth macrodilution method according to the German Veterinary Association guidelines. The main objective of the current study was to induce in vitro resistance induction of S. aureus to chemical disinfectants. Ten different strains were repeatedly passed ten times in growth media with sub-lethal concentrations of disinfectants. Nine strains showed a significant reduction in susceptibility to the nonoxinol-9 iodine complex but only one strain developed resistance to chlorhexidine digluconate. Stability of the acquired resistance was observed in all S. aureus strains adapted to the nonoxinol-9 iodine complex and chlorhexidine digluconate. In contrast, simultaneous resistance to different antibiotics was not observed in any of the ten investigated S. aureus strains. However, the isolates exhibited a high degree of resistance to penicillin G. Based on these results, resistance of S. aureus to chemical disinfectants may be more likely to develop if the chemicals are used at concentrations lower than that required for an optimal biocidal effect.