临床药师与抗菌药物合理应用lcysykgyywhlyy.ppt

* In 1945, a few years after Penicillin was introduced to the world, Fleming created a strain of Staphylococcus aureus that was resistant to penicillin. This was accomplished by exposing s. aureus to sub-optimal doses of Penicillin. Fleming warned the world about antibiotic resistance during an interview with the New York Times. Between 1945 and 1955, Penicillin was available to the public over the counter, without a prescription. During those ten years the public did in vivo what Fleming did in vitro: People stopped taking PCN as soon as they began to feel better, they took PCN for viral infections, some reports even say PCN was used to treat male pattern baldness… * * * Selective toxicity - greater harm to microbes than host, done by interfering with essential biological processes common in bacteria but not human cells. LD50 vs. MIC - Therapeutic index (the lowest dose toxic to the patient divided by the dose typically used for therapy). High TI are less toxic to the patient. Bactericidal vs. bacteriostatic：伤其十指不如断其一指 Static rely on normal host defences to kill or eliminate the patogen after its growth has been inhibited. (UTIs) CIDAL given when host defenses cannot be relied on to remove or destroy pathogen. Favorable pharmacokinetics - drug interxns, how drug is distributed, metabolized and excreted in body (unstabel in acid, can it cross the Blood-brain barrier, etc) Spectrum of activity broad spectrum - wide Narrow spectrum - narrow range (pathogen must be ID’d) Lack of “side effects” allergic, toxic side effects, suppress normal flora Little resistance development * * In one study, hands of 131 healthcare workers (HCWs) were cultured before, and hands and gloves after, routine care. A mean of 56% of body sites and 17% of environmental sites were VRE positive. After touching the patient and environment, 75% of ungloved HCWs hands and 9% of gloved HCWs hands were contaminated with VRE. After touching only the environment, 21% of unglo