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Category: Bacterial Pathogenesis
Development of an Antibiotic: Microbiology, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555815929/9781555812379_Chap04-1.gif /docserver/preview/fulltext/10.1128/9781555815929/9781555812379_Chap04-2.gifAbstract:
This chapter deals with the antibacterial agent that is only one molecule among a series of compounds prepared by chemists before becoming a drug. Preselection is a crucial stage in the life of a new drug. Once a molecule is synthesized, its in vitro activity against a panel of strains belonging to selected bacterial genera and species is determined. Activity against S. aureus producing penicillinase is added, as well as that against P. aeruginosa and Acinetobacter. Strains resistant to clindamycin and cephamycins must be included for gram-negative bacilli. Nondiscriminatory models are prepared during the preselection phase of a molecule. After determining the in vitro activity, it is essential to determine the in vivo activity parenterally and orally. In fact, the in vitro activity is not necessarily correlated with good in vivo activity. In these systemic infection models, activity is tested against gram-positive cocci, Enterobacteriaceae, and P. aeruginosa. The susceptibility of the bacterial strain considered responsible for the infection is determined in the clinical microbiology laboratory of the center in which the study is being conducted. However, semiautomatic devices related to the antibiotic sensitivity test are used by some microbiology laboratories. Determination of breakpoints is one of the major factors for an antibiotic. The mechanism of resistance is an important factor for determining breakpoints for given bacteria. The MIC at which these bacterial species are shown to be resistant is the cutoff and can be considered as the concentration under which the strain is considered susceptible.
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In vitro activities of cephalosporins against S. pneumoniae a
Comparative in vitro and in vivo activities of erythromycin A and roxithromycin a
In vivo activities of macrolides a
Medium effect on teicoplanin MICs a
Effects of Mueller-Hinton medium origin on MICs of teicoplanin and vancomycin
Stability of ansamycins in 7 H9 medium with or without Tween 80 a
In vitro inoculum effect on parenteral cephalosporins a
Activities of β-lactams in media with and without horse serum a
Effect of urine on the activities of ofloxacin and norfloxacin a
Radius for levofloxacin according to Joan Stokes’s method a
In vitro activities of combination of cefotaxime and its main metabolite
In vitro activities of carbapenems against MRSA strains a
In vitro activity of quinupristin-dalfopristin against different antibiotic phenotypes of S. aureus a
Breakpoints of metronidazole against H. pylori
In vitro activities of different antibiotics against Borrelia spp. a
Zone of inhibition for 50% of clinical isolates resistant to aminoglycosides (1989 to 1991)
Activities of β-lactams against ampicillin-resistant and non-β-lactamase-producing H. influenzae
Performance of telithromycin when microdilution panels were prepared with eight different types of working solutions of telithromycin a