Antibiotics local factors

The achievable serum concentration for an antibiotic generally is used to guide decisions on sensitivity or resistance of a microorganism to that drug. However, the concentration at the infection site may be considerably lower than serum concentrations. Local factors e.g., low pH, high protein concentration, anaerobic conditions) also may impair drug activity. 

LOCAL FACTORS Antibiotic activity may be rednced significantly in pns, which contains phagocytes, cellular debris, and proteins that can bind dmgs or create conditions nnfavorable to drug action. The low pH that is characteristically found in abscesses and many confined infected sites can markedly reduce the activity of some agents, particularly the aminoglycosides. 

Empirical therapy should be directed at the most likely pathogen (s) for a specific patient, taking into account age, risk factors for infection (including underlying disease and immune dysfunction, vaccine history, and recent exposures), CSF Gram stain results, CSF antibiotic penetration, and local antimicrobial resistance patterns. 

One real patient brings all these factors together. A middle-aged man in Nepal has had a diagnosis of pulmonary tuberculosis for about four years. He supports his family by subsistence farming. There are no telephones, and he walks about 10 miles for an unscheduled clinic appointment when his breathlessness interferes too much with his work. At each clinic appointment his pleural effusions are drained (thus improving his breathlessness, which he appreciates), and a small supply of antibiotics is prescribed, probably with little effect (at best) because he cannot afford to pay for the prescriptions that he has been given, even if rifampicin is in stock locally. He cannot be admitted to hospital for more intensive treatment he has no adult children to help him in the fields, and his family would starve. How can the practice of pharmaceutical medicine adapt to this sort of environment ... 

Kadota and his associates [15] demonstrated an increase of neutrophil chemo-tactic activity (NCA) in BALE, which showed a clear correlation with neutrophil numbers. They further showed that inflammatory cytokines such as IL-8, IL-lp, and TNF-a were also increased in BALE from patients with chronic airway inflammatory diseases such as DPB and bronchiectasis [25]. They showed that treatment with 14-membered ring macrolide antibiotics such as EM caused a decline in both neutrophil number and these inflammatory cytokines and chemo-kines. These cytokines are potent activators of neutrophils, among which IL-8 is one of the most potent chemotactic factors in the airways [55, 56]. Therefore, it is probable that EM attenuates airway inflammatory responses by decreasing the local cytokine/chemokine levels and thus decreasing the recruitment of inflammatory cells such as neutrophils. 

Resistance factors, particularly those carried on mobile elements, can spread rapidly within human and animal populations. Multidrug-resistant pathogens are mobile on a local and global scale, with newly introduced pathogens spreading rapidly in susceptible hosts. Antibiotic resistance patterns may vary locally and regionally, hence... 

Susceptibility factors for osteonecrosis of the jaw have been sought in 34 cases [17 ]. The most frequently used bisphosphonate was zoledronic acid (n = 29). Microbiological data obtained in 25 patients showed that 72% of these were infected or colonized by an actinomycete. Eight of the 14 patients who received only medical treatment were cured. Of the 20 patients who underwent surgical treatment, only four were completely cured. Osteonecrotic lesions smaller than 1 cm were associated with a better prognosis in terms of treatment outcomes. Local treatments combined with long-term antibiotics also correlated with a better prognosis. 

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