Evaluation of ceforanide as treatment for staphylococcal and streptococcal endocarditis

The role of aminoglycosides in combination with a beta-lactam for the treatment of bacterial endocarditis: a meta-analysis of comparative trials

BACKGROUND

The addition of an aminoglycoside to a beta-lactam for the treatment of patients with infective endocarditis has been supported by data from laboratory and animal studies.

PURPOSE

We sought to review the evidence from the available comparative clinical trials regarding the role of aminoglycosides in combination with a beta-lactam for the treatment of bacterial endocarditis caused by Gram-positive cocci.

DATA SOURCES

The studies for our meta-analysis were retrieved from searches of the PubMed and Cochrane Central Register of Controlled Trials databases, as well as from the references cited in relevant articles. No limits were set regarding the language and date of publication of the studies.

STUDY SELECTION

Included studies were prospective studies that provided comparative data regarding the effectiveness of the treatment and/or mortality in patients receiving monotherapy with a beta-lactam or beta-lactam/aminoglycoside combination therapy.

DATA EXTRACTION

Two independent reviewers performed the literature search, study selection and extraction of data from relevant studies.

DATA SYNTHESIS

No clinical trial comparing beta-lactam monotherapy with beta-lactam/aminoglycoside combination therapy for the treatment of enterococcal endocarditis was found. We performed a meta-analysis of five available comparative trials [four randomized controlled trials (RCTs) and one comparative prospective trial], which included 261 patients with bacterial endocarditis in native valves due to Staphylococcus aureus (four studies) or streptococci of the viridans group (one study). There was no statistically significant difference between beta-lactam monotherapy and beta-lactam/aminoglycoside combination therapy regarding mortality [odds ratio (OR) = 0.59, 95% confidence interval (95% CI) = 0.21-1.66], treatment success (OR = 1.25, 95% CI = 0.49-3.05), treatment success without surgery (OR = 1.66, 95% CI = 0.64-4.30) or relapse of endocarditis (OR = 0.79, 95% CI = 0.15-4.29). Nephrotoxicity was less common in the beta-lactam monotherapy arm than in the beta-lactam/aminoglycoside combination therapy arm (OR = 0.38, 95% CI = 0.16-0.88, P = 0.024). No difference between the two treatment arms was found in subanalyses of the four studies that included only patients with staphylococcal infections in terms of mortality (OR = 0.69, 95% CI = 0.26-1.86, fixed effects model), treatment success (OR = 1.27, 95% CI = 0.47-3.43, fixed effects model) or relapse (OR = 0.76, 95% CI = 0.12-4.92, fixed effects model).

LIMITATIONS

The relatively small number of available comparative trials was the major limitation of this meta-analysis.

CONCLUSIONS

The limited evidence from the available prospective comparative studies does not offer support for the addition of an aminoglycoside to beta-lactam treatment of patients with endocarditis caused by Gram-positive cocci. A large multicentre RCT is necessary to reach a definitive conclusion on this issue.

Vancomycin for Staphylococcus aureus endocarditis in intravenous drug users

The clinical courses of 13 consecutive intravenous drug users with Staphylococcus aureus endocarditis treated principally with vancomycin were reviewed. Two patients, one with only right-sided endocarditis and the other with tricuspid and mitral valve endocarditis, had recurrences of positive blood cultures 2 days after completing a 4-week course of vancomycin. Two patients, both of whom eventually were cured, had modifications of therapy because of bacteremia persisting 7 and 16 days into therapy. One patient required an operation for recurrent fevers, and the resected vegetation showed evidence of active infection. Time-kill studies performed with nafcillin and vancomycin for 10 isolates of S. aureus showed that vancomycin was less rapidly bactericidal than nafcillin. Although vancomycin is used as an alternative to penicillinase-resistant penicillins for treatment of staphylococcal endocarditis, these findings raise the question of whether it is equivalent to these drugs in efficacy.

Ceforanide. A review of its antibacterial activity, pharmacokinetic properties and clinical efficacy

Ceforanide is a 'second generation' cephalosporin administered intravenously or intramuscularly. It is similar to cefamandole and cefonicid in its in vitro superiority to 'first generation' cephalosporins against several species of Enterobacteriaceae as well as its activity against Haemophilus influenzae, including beta-lactamase-producing strains. Its activity against Staphylococcus aureus is less than that of cefamandole, cefuroxime and first generation cephalosporins. The in vitro activity against Neisseria gonorrhoeae is excellent. Pseudomonas, Acinetobacter and Serratia species, and Bacteroides fragilis are resistant, as are many strains of Proteus and Providencia species. The elimination half-life is relatively long, although shorter than that of cefonicid, and in most clinical trials ceforanide has been administered twice daily. It appeared to be comparable in therapeutic efficacy to procaine penicillin and cephazolin in the treatment of patients with community-acquired pneumonia, to cephazolin in the treatment of skin and soft tissue infections due to S. aureus or beta-haemolytic streptococci and to cefapirin in S. aureus endocarditis in parenteral drug abusers. Also, it was comparable in efficacy to cephalothin in the prophylaxis of infection in patients undergoing open heart surgery or vaginal hysterectomy, and to cephazolin in patients undergoing cholecystectomy. Thus, ceforanide is an alternative to first and certain other second generation cephalosporins in several important therapeutic and prophylactic situations. It has no advantage over other cephalosporins with regard to spectrum of antibacterial activity, but has a longer half-life than other second generation cephalosporins, except cefonicid, and can be administered according to a twice daily dosage schedule.

Cephalosporins in gram-positive infections

Infections caused by Gram-positive bacteria are an important and common cause of morbidity and mortality. Staphylococci and streptococci are the most frequent infecting organisms in skin and soft tissue infections, pneumonia, bone and joint infections, and endocarditis. Anaerobic Gram-positive bacteria such as Clostridia spp. cause infections that can rapidly produce tissue necrosis and death. The cephalosporins are indicated for the treatment of infections caused by Gram-positive bacteria in certain circumstances. These include selected patients with endocarditis, osteomyelitis, septic arthritis and cellulitis. They are also used as alternatives to the penicillins in penicillin-allergic patients and for 'mixed' infections caused by Gram-positive and Gram-negative organisms. This article discusses the indications for the cephalosporin group of antibiotics in patients suffering from infections caused by Gram-positive bacteria.

Staphylococcal endocarditis. Laboratory and clinical basis for antibiotic therapy

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.

Review of the new second-generation cephalosporins: cefonicid, ceforanide, and cefuroxime

The new second-generation cephalosporins, cefonicid, ceforanide, and cefuroxime, have recently become available. These agents are generally less active against gram-positive cocci than first-generation cephalosporins and, at best, equal to cefoxitin and cefamandole against many gram-negative bacteria. Cefuroxime, however, is the most active cephalosporin for beta-lactamase-producing Haemophilus influenzae. These newer agents have superior pharmacokinetic characteristics over cefoxitin and cefamandole. Smaller doses, longer dosing intervals and, potentially, a reduction in total drug cost may be the real advantage of these agents. Open trials and a limited number of comparative studies have documented the effectiveness of cefonicid, ceforanide, and cefuroxime in the treatment of most mild-to-serious infectious diseases, although failures with cefonicid in the treatment of staphylococcal infections have been reported. Notably, cefuroxime has received approval for the treatment of common pediatric bacterial meningitis infections. Replacement of cefamandole or cefoxitin with one of these "longer-acting" agents may be cost-beneficial; however, clinicians must be on alert for the development of bacterial resistance or decreased efficacy.

Third-generation and investigational cephalosporins: II. Microbiologic review and clinical summaries

In vitro susceptibility of Streptococcus pyogenes, Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Serratia marcescens, Hemophilus influenzae, Bacteroides fragilis, and Neisseria gonorrhea to three new second-generation and eight third-generation cephalosporins is tabulated. In general, the newer cephalosporins have an extended spectrum of activity against gram-negative bacteria, including Serratia marcescens, Pseudomonas aeruginosa, and Neisseria gonorrhea. They also tend to be active against anaerobes, including Bacteroides fragilis. However, they generally have less activity against gram-positive bacteria when compared with the first- and second-generation cephalosporins. Clinical summaries are given for each of the cephalosporins, with emphasis on the results of comparative clinical trials. These cephalosporins may prove especially useful in nosocomial infections with resistant organisms, intraabdominal infections, febrile episodes in the granulocytopenic patient, and meningitis.

Ceforanide: antibacterial activity, pharmacology, and clinical efficacy

Ceforanide is a new cephalosporin with a longer elimination half-life than any currently available cephalosporin. Its activity is very similar to that of cefamandole, a second-generation cephalosporin, except that ceforanide is less active against most gram-positive organisms. Many coliforms, including Escherichia coli, Klebsiella, Enterobacter, and Proteus, are susceptible to ceforanide, as are most strains of Salmonella, Shigella, Hemophilus, Citrobacter and Arizona species. However, most strains of Serratia marcescens and all Pseudomonas aeruginosa are resistant to this compound. Peak serum concentrations in excess of 100 micrograms/ml are achieved after a 1 g intravenous dose. The elimination half-life of ceforanide is about 3 hrs in patients with normal renal function; this allows twice daily dosing for the majority of patients. As renal excretion amounts for 85-90% of drug elimination, the serum half-life increases to approximately 20 hours in anuric patients. Tissue penetration studies demonstrate inhibitory concentrations in cardiac tissue, bone, and joint fluid. Minor adverse effects have been reported after large doses of ceforanide. Clinical trials indicate that ceforanide is effective in the treatment of skin and soft tissue, pulmonary and urinary tract infections, bone and joint infections, and endocarditis. Ceforanide also has been shown to be as effective as cephalothin or cephaloridine when given prophylactically for vaginal hysterectomy.

Penetration of ceforanide and cefamandole into the right atrial appendage, pericardial fluid, sternum, and intercostal muscle of patients undergoing open heart surgery

Doses of 30 mg of ceforanide or cefamandole per kg were administered intravenously to 26 patients just before their chests were opened for coronary artery bypass or cardiac valve replacement surgery. Samples of right atrial appendage, pericardial fluid, plasma, aortic wall, intercostal muscle, and sternum were obtained at different times after the antibiotic was injected, and these samples were assayed for cephalosporin concentration. For ceforanide the pre-bypass plasma half-life was 2.5 h, and the atrial appendage half-life was 2.1 h; for cefamandole the pre-bypass plasma half-life was 0.75 h and the atrial appendage half-life was 0.72 h. At 3 h the concentrations of ceforanide and cefamandole in atrial appendages were 28.0 and 5.0 micrograms/g, respectively. Ceforanide achieved higher and more sustained concentrations in other tissues than cefamandole. Considering the minimal inhibitory concentrations of these drugs for staphylococci, cefamandole and ceforanide should provide adequate protection against infection by these organisms for the duration of the surgical procedure.