SPECIFIC PATHOGENS

Previous antibiotic exposure (May provide clues as to colonization or infection with new specific pathogens or pathogens that may be resistant to certain antimicrobials)... 

Previous hospitalization or health care utilization (Also a key determinant in selecting therapy because the patient may be at risk for specific pathogens and/or resistant pathogens)... 

Hall, GA., Rutter, J.M. and Beer, R.J. (1976) A comparative study of the histopathology of the large intestine of conventionally reared, specific pathogen free and gnotobiotic pigs infected with Trichuris suis. Journal of Comparative Pathology 86, 285—292. 

The majority of Fur-regulated gene products are involved in iron uptake. Genes for transport and biosynthesis of enterobactin have been studied in E. coli K-12 (Earhart, 1996). It is assumed that this system is found in nearly every E. coli strain. Also the ferrichrome transport system seems to have a very broad distribution. The ferric citrate transport system (fee), however, is only present in some E. coli strains and may be part of a pathogenicity island. The aerobactin and yersiniabactin biosynthesis and transport systems are not found in all E. coli strains and are integrated into pathogenicity islands (Schubert et al., 1999). The ability to utilize haem seems also to be a specific pathogenicity-related adaptation. Haem transport systems are used in the animal or human host, where transferrin and lactoferrin create an iron-poor environment for bacteria. 

Another field of research is the possibility offered by phytochemicals in protecting plants against diseases and pathogens (fungus, bacteria and nematodes). Numerous studies have suggested that plant-pathogen interactions are partially mediated via plant secondary metabolite production, despite the inconsistency revealed by some works on the ability of particular compounds to provide resistance to a specific pathogen. 

Therefore, the unresolved question remains of whether chronic, recurring inflammation is the result of a persistent infection with a specific pathogen, an exaggerated exposure to resident normal luminal bacteria products because of increased intestinal permeability or alteration of mucus composition, or an abnormally aggressive immune response to luminal components. 

Incubation times for diseases resulting from infection vary depending on the specific pathogen, but are generally on the order of days to weeks. Exposures to extremely high doses of some pathogens may reduce the incubation period to as short as several hours. 

Empiric antimicrobial therapy should be instituted as soon as possible to eradicate the causative organism (Table 36-2). Antimicrobial therapy should last at least 48 to 72 hours or until the diagnosis of bacterial meningitis can be ruled out. Continued therapy should be based on the assessment of clinical improvement, cultures, and susceptibility testing results. Once a pathogen is identified, antibiotic therapy should be tailored to the specific pathogen. 

The treatment of bacterial pneumonia initially involves the empiric use of a relatively broad-spectrum antibiotic (or antibiotics) effective against probable pathogens after appropriate cultures and specimens for laboratory evaluation have been obtained. Therapy should be narrowed to cover specific pathogens once the results of cultures are known. 

Diversity between individuals and ability to respond to specific pathogens... 

More severe disease than is usually expected for a specific pathogen or failure to respond to standard therapy... 

ROS production by an extracellular agar oligosaccharide oxidase Appressoria formation in the specific pathogenic oomycete Pythium porpyrae... 

Since direct studies and calculations of the survival rate of the specific pathogenic agents and viruses is complex and excessively laborious, we evaluated the possibility of risks to hygiene by means of indices of fecal contamination (streptococci and coliforms). 

Various dry powder attributes are assessed at release and on stability. These include physieal eharaeteristies sueh as appearance, content uniformity, delivered dose uniformity, and partiele size distribution. Chemieal attributes that may be assessed include drug eontent, purity, and identity, as well as the water content. Dry powders may also undergo mieroseopie evaluation for foreign particulate matter, unusual agglomeration, and partiele size. Mierobial limits should also be examined, including the total aerobie, yeast, and mold eounts. The presence of specific pathogens should be ruled out. The dry powders may be dissolved to test for pH. 

In addition, eertain eompendial requirements for content and delivered dose uniformity should be measured. The USP and EP propose that the total aerobic count not exceed 100 CFU/g (colony-forming imits) that the total yeast and mold counts not exceed 10 CFU/g and that no specific pathogens be detectable. Specifications for the other attributes should be based on the intended use and the historical performance of the product. As with other dosage forms, specifications must be met throughout the intended shelf life of the product. 

Jones DA Takemoto D (2004) Plant innate immunity direct and indirect recognition of general and specific pathogen-associated molecules. Curr Opin Immunol 16 48-62... 

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