Pathogenic bacterial infection

Biological Applications Detecting pathogens," bacterial infections treating age-related macular degeneration, bums, cancer, diabetes, obesity, fun-... 

The importance of the penicillins as a class of heterocyclic compounds derives primarily from their effectiveness in the treatment of bacterial infections in mammals (especially humans). It has been estimated that, in 1980, the worldwide production of antibiotics was 25 000 tons and, of this, approximately 17 000 tons were penicillins (81MI51103). The Food and Drug Administration has estimated that, in 1979 in the U.S.A., 30.1 x 10 prescriptions of penicillin V and 44.3 x 10 prescriptions of ampicillin/amoxicillin were dispensed. This level of usage indicates that, compared to other methods of dealing with bacterial infection, the cost-benefit properties of penicillin therapy are particularly favorable. Stated differently, penicillin treatment leads to the elimination of the pathogen in a relatively high percentage of cases of bacterial infection at a relatively low cost to the patient in terms of toxic reactions and financial resources. 

When considering anti-infective therapy, one first thinks of a curative treatment, aiming at the rapid elimination of the pathogen from the human organism. This concept holds true for the treatment of most bacterial infections with antibiotics however, in the case of antiviral therapy, a curative treatment is the exception rather than the rule. Many human virus infections are characterized by an acute, self-limiting... 

This very small organism, 0.5-1.0/zm long, has been used to test bacterial filters. It is not to be regarded as non-pathogenic, although infections arising from it are rare. 

Although viral infections are important causes of both otitis media and sinusitis, they are generally self-limiting. Bacterial infections m complicate viral illnesses, and are also primary causes of ear and sinus infections. Streptococcus pneumoniae and Haemophilus influenzae are the commonest bacterial pathogens. Amoxycillin is widely prescribed for these infections since it is microbiologically active, penetrates the middle ear, and sinuses, is well tolerated and has proved effective. 

The treatment of bacterial infections of the central nervous system highlights a number of important therapeutic considerations. Bacterial meningitis is caused by a variety of bacteria although their incidence varies with age. In the neonate, E. coli and group B streptococci account for the majority of infections, while in the preschool child H. influenzae is the commonest pathogen. Neisseria meningitidis has a... 

If conventional treatment fails, unresolved diaper rash can also lead to secondary bacterial infections. Staphylococcus aureus and streptococci are the most likely pathogens responsible for these infections and require treatment with systemic antibiotics.3 37 While topical protectants may be used as an adjunct in treatment, suspected bacterial infections should always be referred to a physician for accurate diagnosis and the selection of an appropriate antibacterial regimen.34 Figure 62-7 shows a useful algorithm for the effective treatment of diaper dermatitis. 

Table 8.10 Some pathogens (bacterial, fungal and protozoal) whose phagocytic-mediated destruction is impaired in persons suffering from CGD. Administration of IFN-y, in most cases, enhances the phagocyte s ability to destroy these pathogens. These agents can cause hepatic and pulmonary infections, as well as genitourinary tract, joint and other infections...

In addition to suppressive effects on conventional B cells, constitutive activation of the AhR causes the loss of peritoneal B-l cells.65 B-l cells, also called CD5+B cells, represent a small subset of B lymphocytes that plays an important role in innate immune responses to viral and bacterial infections. Consequently, the observation that constitutive AhR activation results in depletion of this specialized lineage suggests that TCDD may affect innate immunity to pathogens via as yet uncharacterized affects on B-l cells. 

When tested, the antibiotic compounds killed or inhibited the growth of two varieties of E. coli but had no effect on several other types of cells. These results show that in response to bacterial infection the ants elaborated an antibiotic that was selectively toxic to the pathogen. Their defense was tailored closely to their need. It is too soon to know more, but it seems that looking for new antibiotics in ants is a promising idea. Further research should establish whether ant antibiotics will lead to drugs for human use and also reveal whether other crowded species also synthesize antibiotics. 

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