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

Despite optimal use of available antibacterial agents, endocarditis due to Pseudomonas aeruginosa is commonly associated with poor response to medical treatment. Two patients are described in whom emergence of resistance to beta-lactam antibiotics was associated with clinical failure. A subpopulation of resistant mutants (10(-7)) was found within the initial, apparently sensitive population of bacteria. These resistant mutants were similar to posttherapy isolates in their increased production of beta-lactamase and in their identical pattern of resistance to beta-lactam antibiotics. Moreover, the only beta-lactamase produced was type Id, and this enhanced production proved to be constitutive. A relatively large inoculum (10(6) colony-forming units/g of tissue) of bacteria was found postoperatively in the heart valves of both patients. The failure to respond is postulated to be due to the selection of these producers of high levels of beta-lactamase in a large bacterial inoculum.
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PMID:Failure of therapy in pseudomonas endocarditis: selection of resistant mutants. 348 25

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

We have described a case of tricuspid valve endocarditis caused by beta-lactamase-producing H influenzae that responded well to four weeks of cefamandole therapy.
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PMID:Endocarditis caused by beta-lactamase-producing Haemophilus influenzae. 349 41

Cefonicid is a 'second generation' cephalosporin administered intravenously or intramuscularly. It is similar to cefamandole in its superiority to first generation cephalosporins against several enterobacteriaceae as well as its activity against Haemophilus influenzae, including beta-lactamase-producing strains. Its activity against Staphylococcus aureus is similar to that of cefoxitin and inferior to cefamandole and first generation cephalosporins. It has excellent in vitro activity against Neisseria gonorrhoeae, but is inactive against Pseudomonas, Acinetobacter, Serratia, and Bacteroides fragilis. Due to high achievable plasma concentrations and a relatively long half-life, in most clinical trials cefonicid has been administered once daily. It was comparable in efficacy with cefamandole or cefazolin in the treatment of patients with urinary tract, lower respiratory tract, and soft tissue and bone infections. It has also been compared with penicillin in the treatment of uncomplicated gonorrhoea. Results from a small series of patients with endocarditis appear to indicate that cefonicid should not be used in patients with serious staphylococcal infections. Single doses of cefonicid given preoperatively appear to offer a similar degree of protection against post-surgical infection as multiple doses of other antibiotics, but further data from studies involving larger numbers of patients are needed to confirm these impressions. Patients who require prolonged antibiotic therapy, such as those with osteomyelitis being treated as outpatients after a relatively short inpatient course, could benefit from the once daily dose regimen of cefonicid.
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PMID:Cefonicid. A review of its antibacterial activity, pharmacological properties and therapeutic use. 353 Jul 3

Septicemia is a rare but serious complication of infection with Yersinia enterocolitica (Y.e.). Seven cases of Y.e. septicemia are presented. Five of the patients had no underlying disease predisposing to septicemia. Five patients displayed recurrent episodes of septicemia, despite treatment with recommended doses of antibiotics to which the isolates were sensitive in vitro. One patient developed endocarditis which required surgical replacement of the aortic valve. Other clinical manifestations were arthritis, diverticulitis and pulmonary abscesses. The outcome was fatal to 3 elderly patients. The serological response to Y.e. was followed by tube agglutination and a diffusion-in-gel enzyme-linked immunosorbent assay. One patient, with a benign course of illness, had transient elevated Y.e. antibody titres, while the 3 cases with a protracted disease showed sustained antibody responses for 6-18 months. Blood isolates of Y.e. had ordinary virulence characteristics identical to fecal isolates and produced extracellular beta-lactamase. All isolates were sensitive in vitro to trimethoprim-sulfamethoxazole, mecillinam, piperacillin, cefotaxime, ceftazidime, chloramphenicol and gentamicin. The lowest MIC values were recorded for mecillinam. Full synergistic activity was demonstrated when mecillinam was combined with trimethoprim-sulfamethoxazole, cefuroxime or rifampicin.
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PMID:Yersinia enterocolitica septicemia: clinical and microbiological aspects. 353 2

The emergence of multi-beta-lactam resistance is a limiting factor in treating invasive Pseudomonas infections with newer cephalosporins. The in vivo efficacy of ciprofloxacin, a new carboxy-quinolone, was evaluated in experimental aortic valve endocarditis caused by a strain of Pseudomonas aeruginosa which is stably derepressed for beta-lactamase production and is resistant to ceftazidime and multiple other beta-lactam agents. A total of 51 catheterized rabbits with aortic catheters in place were infected with this strain and then received no therapy (controls), ceftazidime (75 mg/kg per day), or ciprofloxacin (80 mg/kg per day). Ciprofloxacin sterilized all blood cultures and significantly lowered vegetation densities of P. aeruginosa by day 2 of treatment versus controls (P less than 0.0005) and animals receiving ceftazidime (P less than 0.0005). This beneficial effect of ciprofloxacin was also noted on therapy days 6 and 11. Ciprofloxacin rendered most vegetations (85%) culture negative over the 11-day treatment period and achieved bacteriologic cure in 73% of animals (P less than 0.0005 versus other therapy groups). Ciprofloxacin prevented bacteriologic relapse at 6 days posttherapy. No ciprofloxacin resistance was detected among Pseudomonas isolates from cardiac vegetations. Ciprofloxacin warrants further evaluation in vivo versus multi-drug-resistant gram-negative bacillary infections.
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PMID:Efficacy of ciprofloxacin in experimental aortic valve endocarditis caused by a multiply beta-lactam-resistant variant of Pseudomonas aeruginosa stably derepressed for beta-lactamase production. 353 7

Neisseria flavescens is a rare cause of human disease. This is the first reported case of endocarditis caused by N. flavescens. The organism produced beta-lactamase, and penicillin therapy failed to cure the infection. Therapy with cefotaxime, to which the organism was highly sensitive, led to a complete and uneventful recovery.
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PMID:Infective endocarditis caused by Neisseria flavescens. 379 78

Antibiotic therapy for staphylococcal endocarditis is based on in vitro susceptibility, antibiotic efficacy in experimental endocarditis, and clinical experience. Native valve endocarditis due to Staphylococcus aureus in non-addicts is treated with four to six weeks of a penicillinase-resistant penicillin, a cephalosporin, or vancomycin. An aminoglycoside can be added for the initial three to five days, but longer-term multiple-drug therapy (adding an aminoglycoside and rifampin) is reserved for unresponsive infection. Right-sided native valve endocarditis in addicts usually responds to less vigorous therapy than that for native valve endocarditis in non-addicts. Vancomycin is the drug of choice for endocarditis due to methicillin-resistant S. aureus. Intrinsic methicillin-resistance in Staphylococcus epidermidis is often cryptic, requiring special tests for detection. Methicillin-resistant S. epidermidis is the major cause of prosthetic valve endocarditis. Vancomycin, rifampin, and gentamicin therapy for two weeks, followed by vancomycin plus rifampin, is recommended for treating this infection. Despite potent antimicrobial therapy, surgery is important in the therapy of complicated endocarditis, particularly prosthetic valve endocarditis.
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PMID:Staphylococcal endocarditis. Laboratory and clinical basis for antibiotic therapy. 389 13

Aztreonam--a new, synthetic, monocyclic beta-lactam antibiotic with excellent in vitro activity and beta-lactamase stability--was used for the treatment of 26 serious infections due to gram-negative bacteria in 23 patients: nine cases of bacteremia, one of endocarditis, one of pneumonia, one of septic arthritis, six of osteomyelitis, five of abscess or soft tissue infection, and three of meningitis. The majority of patients had serious underlying disease, and 18 were in critical or poor condition. The mean age of the patients was 62 years, and the mean duration of therapy was 19 days. The clinical condition of all 23 patients improved during therapy; 20 infections were cured according to clinical criteria. Three of the six instances of therapy failure were due to inadequate debridement. No superinfections, resistant pathogens, or significant adverse reactions were seen. Aztreonam was effective and safe for the treatment of serious gram-negative infections.
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PMID:Clinical evaluation of aztreonam therapy for serious infections due to gram-negative bacteria. 390 40

In 12 patients treated with cefsulodin for Pseudomonas aeruginosa infections, resistance to cefsulodin developed in the infecting strains of two patients who failed to improve clinically. In both cases, cross-resistance also appeared for a broad spectrum of new antipseudomonal beta-lactams, except imipenem. The resistant isolate from one patient had a new constitutive beta-lactamase for cephalothin which also had modest activity for cefsulodin, ceftazidime, and carbenicillin. Furthermore, all of the non-hydrolyzed beta-lactams appeared to be bound by a beta-lactamase in this isolate. The origin and role in beta-lactam resistance of the observed beta-lactamase activity are obscure. The resistant isolate from the other patient had no demonstrable beta-lactamase activity that could account for the beta-lactam resistance. In five patients treated with imipenem for P. aeruginosa infections, resistance to imipenem developed in the strains of two patients who failed to improve clinically. The strain from one patient was already resistant to all other antipseudomonal beta-lactams before imipenem therapy. The initial strain from the other patient was broadly susceptible, and it developed resistance only to imipenem. Prior to imipenem therapy, another patient, who had P. aeruginosa endocarditis, had isolates from blood with three different susceptibility patterns: susceptible to all antipseudomonal beta-lactams, resistant to all but imipenem, and resistant to imipenem alone. There was no demonstrable beta-lactamase activity to account for imipenem resistance in any of the isolates in these patients. None of the resistant P. aeruginosa isolates had a change in penicillin-binding proteins from those of their susceptible counterparts that might explain the development of resistance.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Emergence of resistance to beta-lactam antibiotics in Pseudomonas aeruginosa during treatment with new beta-lactams. 392 Dec 67


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