Harrisondoc.txt

Retrieved documents :  [Document(page_content="The resistance of S. pneumoniae  to penicillin varies greatly with the source of the \nclinical sample tested (e.g., strains isolated from middle-ear fluid are most often \nresistant), the age of the patient (e.g., resistance is more frequent among children than \namong adults), the setting (e.g., resistance is more common in day-care centers), the \npatient's socioeconomic status (the frequency of resistance is highest in samples from \nsuburban and white patients), and the geographic region in which the specimen was \ncollected. Caution must be exercised in the interpretation of surveys of antimicrobial \nresistance among pneumococci in the United States, which can be strongly affected by \nthese types of sampling bias. In a national survey of clinical isolates from normally \nsterile body sites that was conducted in 1997 in various surveillance areas throughout \nthe United States by the Centers for Disease Control and Prevention (CDC), 11% \n(range, 6 to 19%) of 3110 isolates of S. pneumoniae  exhibited intermediate-level \nresistance to penicillin, and 14% (range, 8 to 26%) displayed high-level resistance. \nHowever, in another national survey of the antimicrobial susceptibility of clinical isolates \nobtained from respiratory tract sites between February and June 1997 at 27 U.S. \nmedical centers (SENTRY surveillance program), 28% of 845 isolates (with a range of \n11 to 52% at the various medical centers) displayed intermediate-level penicillin", metadata={'page': 81, 'source': '/home/prateekch/DATA_DIR/managed_folders/OPENAI/vmrPckuF/Harrison_short2.pdf'}), Document(page_content='Resistance to other antimicrobial agents, such as the macrolides (erythromycin, \nclarithromycin, and azithromycin), clindamycin, tetracycline and doxycycline, and \ntrimethoprim-sulfamethoxazole (TMP-SMZ), is also more common among \npenicillin-intermediate strains than among penicillin-susceptible strains, and it is most \ncommon among highly penicillin-resistant strains. Overall rates of resistance among S. \npneumoniae  strains are ~14% for the macrolides, 4% for clindamycin, up to 10% for \ntetracyclines, and 20 to 30% for TMP-SMZ. Rates of resistance to the newer \nfluoroquinolones levofloxacin, gatifloxacin, moxifloxacin, and sparfloxacin are <4%, \nregardless of penicillin susceptibility. At best, the older fluoroquinolones (e.g., \nciprofloxacin) have borderline activity, as judged by serum levels in relation to MICs of \nthese drugs against the pneumococcus.\nOptimally, the choice of antimicrobial drugs for empirical therapy should be guided by \nlocal resistance patterns, if known. Options for empirical antimicrobial therapy should be \nmodified in light of continually evolving antimicrobial resistance patterns resulting from \nthe introduction of new resistant clones into the community from other regions or the', metadata={'page': 81, 'source': '/home/prateekch/DATA_DIR/managed_folders/OPENAI/vmrPckuF/Harrison_short2.pdf'}), Document(page_content='pneumococci to all the available oral antimicrobial agents precludes the designation of \nany one agent as the clear drug of choice.\nStrains of S. pneumoniae  for which the minimal inhibitory concentration (MIC) of \npenicillin (as determined by the broth dilution method) is 0.1 to 1.0 ug/mL are \nconsidered to have intermediate-level resistance, while strains whose MIC is>1.0 ug/mL \nare considered to have high-level resistance. The current, less time-consuming method \nto screen for penicillin resistance is the use of a 1-ug oxacillin disk in a disk diffusion \nassay. Penicillin resistance (i.e., an MIC ³0.1 ug/mL) is indicated by a zone of growth \ninhibition of£19 mm. Antimicrobial gradient paper strips (the E-test), which yield the \nexact MIC, are as accurate as the broth dilution technique, can be performed as rapidly \nas the oxacillin disk diffusion assay, and have replaced the oxacillin disk test in many \ninstitutions.', metadata={'page': 80, 'source': '/home/prateekch/DATA_DIR/managed_folders/OPENAI/vmrPckuF/Harrison_short2.pdf'}), Document(page_content='medical centers (SENTRY surveillance program), 28% of 845 isolates (with a range of \n11 to 52% at the various medical centers) displayed intermediate-level penicillin \nresistance, and an additional 16% (with a range of 0 to 33%) displayed high-level \npenicillin resistance.\nAs a consequence of the production of altered penicillin-binding proteins with \ndecreasedb-lactam affinity, penicillin-resistant S. pneumoniae  exhibits at least some \ndegree of cross-resistance to allb-lactams, including the extended-spectrum third- and \nfourth-generation cephalosporins. Since the mechanism of penicillin resistance does not \ninvolve b-lactamase production,b-lactam/b-lactamase inhibitor combinations (e.g., \namoxicillin/clavulanate) offer no advantage. Indeed, the MICs  of penicillin and amoxicillin \nare nearly identical, but the serum levels after equivalent doses are much higher for \namoxicillin than for penicillin, a difference that may reflect a therapeutic advantage of \namoxicillin. Among the oral cephalosporins, cefaclor, cefadroxil, and cephalexin have \nvariable activity against penicillin-sensitive strains; cefuroxime and cefpodoxime have \nactivity against penicillin-susceptible strains but variable activity against \npenicillin-intermediate strains and no activity against highly penicillin-resistant strains.\nResistance to other antimicrobial agents, such as the macrolides (erythromycin, \nclarithromycin, and azithromycin), clindamycin, tetracycline and doxycycline, and', metadata={'page': 81, 'source': '/home/prateekch/DATA_DIR/managed_folders/OPENAI/vmrPckuF/Harrison_short2.pdf'})]