Long-term survival of nonreplicating

No abstract

The immunogenicity of a plasmid DNA vaccine incorporating Sindbis virus RNA replicase functions (pSINCP) and expressing antigen 85A (Ag85A) from Mycobacterium tuberculosis was compared with a conventional plasmid DNA vector encoding Ag85A. pSINCP-85A was highly immunogenic in mice and gave enhanced long-term protection against M. tuberculosis compared with the conventional vector

As monotherapy, modified proline-rich antimicrobial peptides (PrAMPs) protect animals from experimental bacteremia in a dose-dependent manner. We evaluated the in vitro synergy of a modified PrAMP, A3-APO, a dimer, previously shown to inhibit the 70 kDa bacterial heat shock protein DnaK, with imipenem or colistin against two antibiotic-resistant pathogens; a carbapenemase-expressing Klebsiella pneumoniae strain K97/09 and Acinetobacter baumannii (ATCC BAA-1605). Combining antimicrobials resulted in synergy for PrAMP/colistin combination against both K. pneumoniae and A. baumannii (ΣFIC = 0.08 both) and additive activity for the A3-APO/imipenem combination against K. pneumoniae (ΣFIC = 0.53). Chex1-Arg20, (designated as ARV-1502 in preclinical development), the single chain PrAMP monomer of A3-APO, showed synergy with meropenem against a carbapenem-resistant uropathogenic Escherichia coli strain (ΣFIC = 0.38). In a murine bacteremia model using K97/09, A3-APO at 1 mg/kg demonstrated improved survival when co-administered with standard (10 mg/kg) or subtherapeutic (1 mg/kg) doses of colistin at 36 h (p < 0.05). Surprisingly, the survival benefit of A3-APO was augmented when the A3-APO dose was decreased by 50% to 0.5 mg/kg (p < 0.02) in conjunction with a subtherapeutic colistin dose (1 mg/kg). ARV-1502, as monotherapy demonstrated prolonged (>24 h) activity in a mouse Escherichia coli infection assay. Co-treatment with ARV-1502 and subtherapeutic doses of ceftazidime (150 mg/kg) was studied in a mouse model of melioidosis. ARV-1502 provided a 50% improvement in long-term (62 days) survival, but only at the lowest of 3 administered doses; survival advantage was demonstrated at 2.5 mg/kg but not at 5 or 10 mg/kg. The mortality benefit of combination therapies was not routinely accompanied by a parallel decline in blood or tissue bacterial counts in surviving animals, suggesting that the anti-infective activity of the host defense peptides (HDP) is broader than simply bacterial eradication. In fact, the hormetic effect observed in either animal models suggest that low dose HDP treatment may change the dominant mode of action in experimental bacteremia.

No abstract

Fusidic acid has been in clinical use outside the United States (US) since 1962 for skin infections, including methicillin-resistant Staphylococcus aureus (MRSA). Non-US labeling reflects safety concerns related to gastrointestinal, allergic, hematologic, and neurologic adverse events. We sought to survey available safety data on fusidic acid through the review of published global literature between 1962 and 2007 that contained data on oral fusidic acid safety and a centralized database (VigiBase) of spontaneous safety reports. Overall, the data were concordant with current product labeling, and no serious adverse events, such as death, hospitalization, or hepatotoxicity, were convincingly linked to fusidic acid monotherapy in skin infection patients. Other indications for fusidic acid use were also common, including osteomyelitis with similar reporting of labeled safety characteristics. Study quality was highly varied with limited structure to safety data collection methodology. Significant concerns for recall bias are present, yet these data remain informative in providing signals that require attention in the design and conduct of adequate and well-controlled clinical studies of fusidic acid for potential registration in the United States.

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Botulism is caused by botulinum neurotoxin (BoNT), the most poisonous substance known. BoNTs are also classified as tier 1 biothreat agents due to their high potency and lethality. The existence of seven BoNT serotypes (A to G), which differ by 35% to 68% in amino acid sequences, necessitates the development of serotype-specific countermeasures.