Comparison of oral, nebulized and combination antibiotic treatment of Bordetella bronchiseptica in baboons (Papio spp.).

Incidence of Bordetella pertussis, the causative agent of whooping cough, is rising in some global human populations despite high vaccination rates, and significant research is underway to address the issue. Baboons are an established model for pertussis research, but like many mammals, they can be naturally infected with Bordetella bronchiseptica. Because B. bronchiseptica interferes with B. pertussis research, it must be excluded from baboons under consideration for enrollment in pertussis studies. In addition to research-related concerns, B. bronchiseptica can sometimes cause clinical disease in baboons and other nonhuman primates. This study examined the use of antibiotics to clear B. bronchiseptica in naturally infected baboons. Thirty-five juvenile baboons were divided into five treatment groups: oral sulfamethoxazole/trimethoprim (TMS), nebulized gentamicin (gentamicin), combination (TMS + gentamicin) in positive animals, combination (TMS + gentamicin) as a prophylactic in exposed animals and no treatment (control). Combination of oral TMS and nebulized gentamicin given to positive animals was most effective, producing long-term clearance in 11 out of 12 treated animals. To avoid unnecessary use of antibiotics, our primary management strategy is screening and separating to allow natural clearance and limiting exposure to non-infected animals, but this study investigates an antibiotic regimen that could be used in special circumstances.

Cellular senescence in aging primates.

The aging of organisms is characterized by a gradual functional decline of all organ systems. Mammalian somatic cells in culture display a limited proliferative life span, at the end of which they undergo an irreversible cell cycle arrest known as replicative senescence. Whether cellular senescence contributes to organismal aging has been controversial. We investigated telomere dysfunction, a recently discovered biomarker of cellular senescence, and found that the number of senescent fibroblasts increases exponentially in the skin of aging baboons, reaching >15% of all cells in very old individuals. In addition, the same cells contain activated ataxia-telangiectasia mutated kinase and heterochromatinized nuclei, confirming their senescent status.