Sensitive strain

Pefloxacin (33) is the N-methyl analogue of norfloxacin (58) and is at least partly converted to it by metabolic enzymes in vivo. It has been launched in France for the treatment of a number of infections including those caused by sensitive strains of Pseudomonas aeruginosa. It can be synthesized starting with the Gould-Jacobs reaction of 3-chloro-4-fluoroaniline (28) and diethyl ethoxymethylenemalonate in an addition-elimination sequence leading to 29 which undergoes... 

In the more recent Chicago outbreak of Salmonellosis, which has been attributed to milk contaminated with a tetracycline-resistant strain of Salmonella typhimurium. there were two deaths verified as resulting from infections with the resistant strain of Salmonel la in 16 284 confirmed cases. If one pools these cases with those cited in the NRDC petition then the incidence of mortality (0.09%) is similar or than that of persons affected by antibiotic-sensitive Salmone1 la (0.21%) also cited by NRDC. Thus the similarity of risks of human infections with resistant and sensitive strains of SaImone 11a agrees with research data obtained in controlled experiments (Smith 15). 

For 38 outbreaks of confirmed mode or source (Table II), multiply resistant salmonella were involved in 33% of the community based outbreaks, 40% of the nosocomial, and 75% of the outbreaks involving both community and hospital. In addition, it has been estimated that each culture-documented case among human beings may represent as many as 100 undocumented cases (10). Agency participation for these cases was made at the request of the local health officials and therefore the survey was not random. However, the resistant strains displayed a fatality rate 21 times that of antibiotic sensitive strains. O Brien et al. (10) found that characterization of plasmid DNA from antibiotic resistant salmonella suggests extensive commingling of human and animal bacteria. 

The outbreak of Salmonella foodborne illness in Illinois in April 1985 was attributed to a tetracycline-resistant strain of Salmonella typhimurium. It evidently had no connection with feeding antibiotics in livestock. The resistant strain was of lower virulence than the average sensitive strain. 

Holmberg s mortality rate of 0.2% for sensitive Salmonella would have produced 28 deaths in the Illinois outbreak of 14,000 cases. His mortality rate of 4.2% for resistant Salmonella would have led to 588 deaths in the Illinois outbreak, 1985. Clearly the resistant strain in the Illinois outbreak was less virulent than the average sensitive strain. Clearly, we can breathe more freely about antibiotics in livestock feeds, in spite of the "media blitz."... 

Using the "CDC rates," there should have been 684 deaths from antibiotic-resistant infections, and 34 deaths from infections with sensitive strains. 

In order to determine the significance of the 1,5-H shift and the secondary radical species for antimalarial activity, the trioxanes 22a-c were synthesized and tested . The diastereomeric trioxanes 22a and 22b possessed very different antimalarial activity against both chloroqnine-resistant and chloroqnine-sensitive strains of the parasite the A-fi isomer was approximately twice as active as artemisinin while the A-a isomer and the disubsti-tnted trioxane were more than sixty times less potent. The anthors proposed that the a-snbstitnent prevented the snprafacial 1,5-H shift and therefore snppressed the activity of these componnds. 

Macrolides and lincosamides have the same receptor site. They bind to the bacterial 50s ribosomal subunit, inhibiting protein synthesis and hence cell growth. Macrolides are usually bacteriostatic at low concentrations, but can become bactericidal for sensitive strains at high concentrations. 

Hayazawa, N., Motohashi, M., Saito, Y, and Kawata, S. 2005. Highly sensitive strain detection in strained silicon by surface enhanced Raman spectroscopy. Appl. Phys. Lett. 86 263114. 

Both compounds (Figure 4.7) are non-competitive inhibitors of chitin synthase and also interfere with the Bremner-Greenberg methylation pathway.6 Their activity is dependent upon the oxidation of the phosphorous - sulfur linkage, a feature that is the basis of resistance development, which is common sensitive strains of P. oryzae metabolise the compounds more rapidly than resistant strains. 

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