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Query: UMLS:C0014118 (endocarditis)
 15,629 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Amoxicillin is an aminopenicillin available in the United States only for oral use. It has an antibacterial activity and spectrum similar to that of ampicillin and is destroyed by gram-positive and gram-negative beta-lactamases. It is more active against enterococci and salmonellae than ampicillin, but less active against Shigella. It is better absorbed than ampicillin from the gastrointestinal tract with blood levels two to two and one half times those of ampicillin. Amoxicillin is an excellent agent to treat otitis media, bacterial sinusitis, bacterial exacerbations of bronchitis, acute lower-urinary-tract infections, gonorrhea, and typhoid. In special settings it may be useful as oral therapy of endocarditis, septic arthritis, and osteomyelitis and as prophylaxis to prevent endocarditis. When the cost of amoxicillin approaches that of ampicillin, it should replace that agent as the oral aminopenicillin of first choice.
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PMID:Diagnosis and treatment: drugs five years later. Amoxicillin. 3 42

Fifteen strains of Enterococcus faecalis, all clinical blood culture isolates from patients with endocarditis, were studied by kill-kinetic experiments using penicillin G, ampicillin and amoxicillin alone and in combination with tobramycin. The median minimal inhibitory concentrations (MIC), were penicillin 4 mg/l, ampicillin 2 mg/l, amoxicillin 2 mg/l and tobramycin 32 mg/l. Equipotent doses of the antibiotics (1/2 x MIC, 1 x MIC and 4 x MIC) were used in the kill-kinetic studies. Synergism was studied using a combination of 1/2 x MIC of the beta-lactam antibiotic and 8 mg/l of tobramycin. The bactericidal activity did not exceed 10(+3) cfu/ml at 5 hours for any single compound. After 5 h all three beta-lactam antibiotics in combination with tobramycin resulted in synergism, i.e. more than one hundredfold reduction of colony forming units (cfu) as compared to the most active single agent. Amoxicillin had a significantly higher bactericidal potential than ampicillin or penicillin both alone and in combination with tobramycin. The clinical significance of these findings warrants further studies in vivo.
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PMID:Bactericidal effect of penicillin, ampicillin, and amoxicillin alone and in combination with tobramycin against Enterococcus faecalis as determined by kill-kinetic studies. 190 88

In vitro and in vivo activity of amoxicillin and penicillin G alone or combined with a penicillinase inhibitor (clavulanate) were tested against five isogenic pairs of methicillin-resistant Staphylococcus aureus (MRSA) producing or not producing penicillinase. Loss of the penicillinase plasmid caused an eight times or greater reduction in the MICs of amoxicillin and penicillin G (from greater than or equal to 64 to 8 micrograms/ml), but not of the penicillinase-resistant drugs methicillin and cloxacillin (greater than or equal to 64 micrograms/ml). This difference in antibacterial effectiveness correlated with a more than 10 times greater penicillin-binding protein 2a affinity of amoxicillin and penicillin G than of methicillin and a greater than or equal to 90% successful amoxicillin treatment of experimental endocarditis due to penicillinase-negative MRSA compared with cloxacillin, which was totally ineffective (P less than .001). Amoxicillin was also effective against penicillinase-producing parent MRSA, provided it was combined with clavulanate. Penicillinase-sensitive beta-lactam antibiotics plus penicillinase inhibitors might offer a rational alternative treatment for MRSA infections.
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PMID:Beta-lactam resistance mechanisms of methicillin-resistant Staphylococcus aureus. 199 24

The activity of various antibacterial agents (amoxicillin, josamycin, doxycycline and metronidazole) was established in vitro using a rapid micromethod. The activity of these agents, which are widely used in oral medicine, was evaluated against microorganisms responsible for periodontitis and bucco-dental infections. Their action against alpha-hemolytic streptococci (including pneumococci) which make up the majority of the indigenous oral flora was also tested. Amoxicillin was found to be effective against all the strains tested. Doxycycline was active against periodontal bacteria, but not against 50% of the streptococcal flora. Josamycin was found to be effective against streptococci, but appeared without effect on Eikenella corrodens and Actinobacillus actinomycetemcomitans. Metronidazole, inactive against streptococci, displayed greater activity towards the strict anaerobes. The use of these antibiotics for the treatment of bucco-dental infections, especially periodontitis, is discussed. For periodontitis and periodontal suppurations, antimicrobial agents present a valuable adjunct to local treatments such as scaling or rootplaning. This may prevent more serious infections such as endocarditis that can develop after tooth extraction.
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PMID:Evaluation of the activity of four antimicrobial agents using an in vitro rapid micromethod against oral streptococci and various bacterial strains implicated in periodontitis. 214 28

Bacteremia following dental procedures may lead to bacterial endocarditis in susceptible patients. Traditional methods of chemoprophylaxis with a parenteral loading dose of penicillin followed by oral penicillin have proved impractical outside the hospital. In 1978, it was suggested in England that amoxicillin be substituted as the drug of choice in the prophylaxis of bacterial endocarditis. The recommended mode of treatment was a single oral dose of 3 g amoxicillin administered 1 hour before onset of the dental procedure. Amoxicillin is absorbed to a greater extent and more rapidly than penicillin V. It maintains its effectiveness throughout the critical postoperative period at concentrations well over the minimum necessary to combat Streptococcus viridans. Amoxicillin has two mechanisms of protection: bactericidal and inhibition of bacterial adherence to the thrombotic vegetation on injured heart valves. Data obtained from 206 susceptible patients undergoing dental treatment under chemoprophylaxis with amoxicillin showed that in no case did infective endocarditis occur. Only in 13.1% of the patients could very mild side effects of this drug be observed. With this new method, there is a higher incidence of patient compliance and administration is easier to supervise.
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PMID:New concept in chemoprophylaxis of bacterial endocarditis resulting from dental treatment. 345 44

Prophylaxis with amoxicillin (40 mg/kg) was studied in rats with aortic valve vegetations. Bacteria on the valves were quantitated early (10 min to 6 hr) and late (three days) after intravenous challenge with tolerant Streptococcus intermedius. Amoxicillin reduced by 40% the number of bacteria per valve 10 min after intravenous challenge with 10(5) S. intermedius (P less than .05) and by 74% the incidence of endocarditis three days thereafter (P less than .0001). Bacterial multiplication started 2 hr after challenge in control rats, whereas bacteria disappeared in 6 hr in amoxicillin-treated rats. Intravenous penicillinase 30 min after challenge abolished successful amoxicillin prophylaxis, a result demonstrating the necessity of prolonged growth inhibition for protection. Growth inhibition for 18 hr (two subsequent amoxicillin doses) was necessary for protection after intravenous challenge with 10(5) S. intermedius. Thus, in the absence of bacterial killing, inhibition of valvular colonization by amoxicillin was not as important a mechanism of endocarditis prophylaxis as was prolonged inhibition of bacterial growth, which allowed adherent bacteria to be cleared from the valves.
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PMID:Mechanisms of successful amoxicillin prophylaxis of experimental endocarditis due to Streptococcus intermedius. 349 May 21

Amoxicillin prophylaxis against experimental endocarditis due to one nontolerant and two tolerant strains of streptococci was studied in rats. Single-dose amoxicillin protected against the two tolerant strains in animals challenged with the 90% infective dose (ID90), but protection diminished with increasing inoculum sizes. Protection against the nontolerant strain was successful with inocula that were 100- and 1,000-fold larger than the ID90. Close correlation existed between the speed of bacterial killing in vitro, the time of exposure to bactericidal levels in vivo, and the range of inocula against which prophylaxis was effective. Amoxicillin seemed to protect by at least two mechanisms. (1) When in vitro tests indicated adequate bacterial killing, protection was independent of the inoculum size and was probably conferred by bacterial killing. (2) When in vitro tests indicated bacterial inhibition but not killing, protection was inoculum-dependent and was probably mediated by inhibition of bacterial adherence.
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PMID:Successful single-dose amoxicillin prophylaxis against experimental streptococcal endocarditis: evidence for two mechanisms of protection. 683

Serum and subcutaneous chamber fluid (CF) dynamics of penicillin G, ampicillin, and amoxicillin were studied in rabbits after single large parenteral doses comparable to doses used in treating gonorrhea and endocarditis. The effects of parenteral probenecid and of injection of an antibiotic directly into a subcutaneous chamber ("intrachamber" injection) also were studied. Peak serum antibiotic concentrations exceeded peak CF concentrations and occurred sooner. Antimicrobial activity persisted longer in CF than in serum. Percent penetration [100 x (CF peak/serum peak)] of CF was least after intramuscular ampicillin and amoxicillin, was greatest after intrachamber ampicillin and intramuscular aqueous procaine penicillin G, and was related to duration of antibiotic concentration gradients from serum to CF. Intramuscular aqueous crystalline penicillin G resulted in higher serum and CF penicillin G concentrations than intramuscular aqueous procaine penicillin G, which prolonged the duration of penicillin G in serum and CF. Amoxicillin diffused into CF more readily than ampicillin. Probenecid resulted in higher early serum and CF antibiotic concentrations, but had little or no effect on duration of antibiotic activity. Intrachamber ampicillin resulted in more prolonged serum and CF ampicillin activity than intramuscular ampicillin, but much lower peak serum concentrations. The data suggest a possible means by which probenecid improves the efficacy of gonorrhea therapy with aqueous procaine penicillin G. Intrachamber administration of penicillins could be useful in treating experimental infections requiring prolonged therapy.
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PMID:Serum and subcutaneous chamber fluid dynamics of penicillins after single large parenteral doses. 738 44

Antibiotic prophylaxis for infective endocarditis is recommended for cardiac patients at risk who undergo an at-risk procedure. Efforts should focus on patients with the highest risk, i.e., those with a prosthetic valve undergoing a dental procedure. Amoxicillin is the main recommendation in patients who are not allergic to penicillin. In patients allergic to penicillin clindamycin orally or vancomycin intravenously are proposed. Aminoglycosides are added for gastrointestinal or urological procedures.
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PMID:Antibiotic prophylaxis for infective endocarditis from an international group of experts towards a European consensus. Group of Experts of the International Society for Chemotherapy. 767 16

An antibiotic prophylaxis of infective endocarditis is recommended in patients at high risk for infective endocarditis (patients with valvular prosthesis, or cyanogen congenital or obstructive cardiac defect) or those with aortic, mitral or tricuspid valvulopathy, a non-cyanogen congenital or obstructive cardiac defect. Dental procedures (except treatment for superficial decay and preparation for the fitting of prostheses to teeth with intact pulp) are to be carried out under local antisepsis and a prophylactic antibiotics, such as 3 g of oral amoxicillin or in case of allergy to penicillin, 600 mg of clindamycin or 1g of pristinamycin, administered one hour prior to the procedure. A similar prophylaxis is recommended for the procedures on the upper respiratory tract. Amoxicillin, or vancomycin or teicoplanin are recommended for procedures under general anaesthesia. For surgery on the intestinal or urogenital tract, regimens combine amoxicillin with gentamicin, or in case of allergy to penicillin, vancomycin or teicoplanin with gentamicin.
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PMID:[Prevention of infectious endocarditis]. 777 15


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