Drugs online research references
Zentralbl Veterinarmed B. 1999 May;46(4):261-9.
Experimental infections with Actinobacillus pleuropneumoniae in pigs--II. Comparison of antibiotics for oral strategic treatment.
Wallgren P, Segall T, Pedersen Morner A, Gunnarsson A.
National Veterinary Institute, Uppsala, Sweden.
The present study was aimed at scrutinizing the efficacy of oral antimicrobial treatments at experimental challenge using a strain of Actinobacillus pleuropneumoniae serotype 2 known to cause severe disease. SPF pigs aged 10 weeks were infected intranasally and the antimicrobial treatments were initiated 5 h prior to that exposure. Several antimicrobial drugs, as well as the length of the treatment period, were elucidated. The outcome of the challenge was monitored by registration of clinical symptoms, weight gains and the development of serum antibodies to A. pleuropneumoniae. At necropsy, the magnitude of pathological lesions in the respiratory tract and the rate of reisolation of the infective strain were recorded. Animals that became diseased displayed a decreased growth rate caused, to a large extent, by a reduced feed intake. The performance with respect to daily weight gain and feed conversion corresponded well with the clinical signs developed and serologic reactions, as well as with the findings made at necropsy. The results obtained among pigs treated with enrofloxacin, but also with florfenicol or chlortetracycline, were superior to those of pigs treated with penicillin, tiamulin or tilmicosin. A positive effect was obtained using a strategic in-feed medication against infection with A. pleuropneumoniae. Provided that the drug used is effective against the target microbe, initiating treatment prior to infection appeared to be more important than the length of the treatment. It should, however, be remembered that A. pleuropneumoniae was reisolated from all but one medicated group following an experimental challenge given after initiating the medication. Consequently medical treatment as described did not eradicate the microbe.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10379236&dopt=Abstract
Rev Mal Respir. 1992;9 Suppl 1:R39-43.
[Changes in the sensitivity of pneumococci to antibiotics. Therapeutic consequences]
[Article in French]
Geslin P, Fremaux A.
Centre National de Reference des Pneumocoques, GEEP, Service de Microbiologie, Centre Hospitalier Intercommunal, Creteil.
Streptococcus pneumoniae has a prominent role in infectious bronchopulmonary diseases. This organism is normally sensitive to a vast number of antibiotics. However, in recent years, acquired resistance against tetracyclines, macrolides, and, more recently, penicillins, has emerged. Since 1987, there is indeed a regular increase in the frequency of strains that have a lower sensitivity to penicillin G (less than 1% before 1986; 12% in 1990). However, this percentage of strains with a lower sensitivity is much more important among non-invasive as opposed to invasive organisms that are isolated from blood, pleural and spinal fluid cultures (3.3% in 1990). Among strains with abnormal sensitivity to penicillin G, there are very selective serotypes or serogroups: 4 types or groups (23, 19, 6 and 14) represent 80% of these strains. More than 80% of the strains of MIC greater than 2 mg/l are among only one stereotype, 23F. This abnormal sensitivity to penicillin G implies a modification of sensitivity to all beta-lactams, but MIC increase to a variable extent depending on the antiinfectious agent. The most efficient agents against strains of lower sensitivity are amoxicillin, imipenem and parenteral third generation cephalosporins. On the other hand, for all oral first, second and third generation cephalosporins, MIC increase to levels for which seric levels that are reached hardly demonstrate convincing efficiency. Even if resistance levels are less marked as shown by strains isolated from pulmonary infections as compared to what is seen in ENT, the trend in the development of abnormal sensitivity of pneumococci to beta-lactam agents urges the clinician to take into account these data in the therapeutic coverage of bronchopulmonary infections.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1589628&dopt=Abstract
J Bacteriol. 1992 Jul;174(14):4689-700.
A new mercury-penicillin V derivative as a probe for ultrastructural localization of penicillin-binding proteins in Escherichia coli.
Paul TR, Halligan NG, Blaszczak LC, Parr TR Jr, Beveridge TJ.
Department of Microbiology, College of Biological Sciences, University of Guelph, Ontario, Canada.
The precise ultrastructural localization of penicillin-binding protein (PBP)-antibiotic complexes in Escherichia coli JM101, JM101 (pBS96), and JM101(pPH116) was investigated by high-resolution electron microscopy. We used mercury-penicillin V (Hg-pen V) as a heavy-metal-labeled, electron-dense probe for accurately localizing PBPs in situ in single bacterial cells grown to exponential growth phase. Biochemical data derived from susceptibility tests and bacteriolysis experiments revealed no significant differences between Hg-pen V and the parent compound, penicillin V, or between strains. Both antibiotics revealed differences in the binding affinities for PBPs of all strains. Deacylation rates for PBPs were slow despite the relatively low binding affinities of antibiotics. Cells bound most of the Hg-pen V added to cultures, and the antibiotic-PBP complex could readily be seen by electron microscopy of unstained whole mounts as distinct, randomly situated electron-dense particles. Fifty to 60% of the antibiotic was retained by cells during processing for conventional embedding so that thin sections could also be examined. These revealed similar electron-dense particles located predominantly on the plasma membrane and less frequently in the cytoplasm. Particles positioned on the plasma membranes were occasionally shown to protrude into the periplasmic space, thereby reflecting the high resolution of the Hg-pen V probe. Moreover, some particles were observed free in the periplasm, suggesting, for the first time, that a proportion of PBPs may not be restricted to the plasma membrane but may be tightly associated with the peptidoglycan for higher efficiency of peptidoglycan assembly. All controls were devoid of the electron-dense particles. The presence of electron-dense particles in cells of the wild-type JM101, demonstrated that our probe could identify PBPs in naturally occurring strains without inducing PBP overproduction.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1624457&dopt=Abstract
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