 |
 |
|
Rapid Responses to:
|
|
Electronic letters published:
![[Read Rapid Response]](/icons/misc/sectionDOWN.gif){kind=icon}
Re: Ampicillin plus Ceftriaxone for HLAR E. faecalis Endocarditis
Ampicillin plus Ceftriaxone for HLAR E. faecalis Endocarditis
|
|
|||
|
Joan Gavaldà, M.D.; Ph.D. Servei Malalties Infeccioses. Hospital Vall d'Hebron., Oscar Len, Benito Almirante, Albert Pahissa.
Send rapid response to journal:
jgavalda{at}ir.telefonica.net Joan Gavaldà, et al.
|
We read with interest the letter by Dr. Singh [1] regarding our article “Brief communication: treatment of Enterococcus faecalis endocarditis with ampicillin plus ceftriaxone” [2]. First of all, we would like to clarify that the cure rate for HLAR E. faecalis endocarditis was 71.4%, far away from the best cure rate reached with a cell wall susceptible agent alone or in combination. Carefully reading the article we did not find any figure or data that could address anyone to confussion. Second; considering the limitations of space established by Annals of Internal Medicine, we could not give detailed information about Dr. Singh’s concerns [1]. In any case, the first Singh’s question about the sinergic effect of ampicillin plus ceftriaxone was evaluated in vitro by Mainardi et al (3) and by our group in different studies in the experimental endocardis model (4,5). Mainardi et al (3), with amoxicillin and cefotaxime, proposed that “at low amoxicillin concentrations, the low- molecular-weight penicillin-binding proteins (PBPs) 4 and 5 would be partially saturated, but the nonessential PBPs 2 and 3 could participate in building the cell wall; the combination with cefotaxime would totally saturate PBPs 2 and 3, producing the bactericidal synergistic effect”. Thereafter, our group showed that the combination of ampicillin plus ceftriaxone was as effective as ampicillin plus gentamicin for the treatment of experimental endocarditis due to E.faecalis without high resistance to Ags (4) and a greater efficacy than ampicillin alone in the experimental endocarditis model due to HLRAg E.faecalis (5). Third, although we agree with Dr. Singh’s about the possible usefulness of the combination of ampicillin plus gentamicin if the aminoglycoside's MIC is between 500 and 1000 mg/L it may be only a theoretical question and probably with the results of our study the combination of ampicillin plus ceftriaxone would be more successful. Potential conflicts of interest. All authors: no conflicts. References 1. Singh A. Ampicillin plus ceftriaxone for HLAR E. faecalis endocarditis (letter). Ann Intern Med 2007;146:56 2. Gavalda J, Len O, Miro JM, et al. Brief communication: treatment of Enterococcus faecalis endocarditis with ampicillin plus ceftriaxone. Ann Intern Med 2007;146:574-9. 3. Mainardi JL, Gutmann L, Acar JF, Goldstein FW. Synergistic effect of amoxicillin and cefotaxime against Enterococcus faecalis. Antimicrob Agents Chemother. 1995;39:1984-7. Erratum in: Antimicrob Agents Chemother 1995;39:2835 4. Gavalda J, Onrubia PL, Gomez MT, Gomis X, Ramirez JL, Len O, Rodriguez D, Crespo M, Ruiz I, Pahissa A. Efficacy of ampicillin combined with ceftriaxone and gentamicin in the treatment of experimental endocarditis due to Enterococcus faecalis with no high-level resistance to aminoglycosides. J Antimicrob Chemother. 2003;52:514-7 5. Gavalda J, Torres C, Tenorio C, Lopez P, Zaragoza M, Capdevila JA, Almirante B, Ruiz F, Borrell N, Gomis X, Pigrau C, Baquero F, Pahissa A. Efficacy of ampicillin plus ceftriaxone in treatment of experimental endocarditis due to Enterococcus faecalis strains highly resistant to aminoglycosides. Antimicrob Agents Chemother. 1999;43:639-46 Conflict of Interest:None declared |
|||
|
|
|||
|
Akashdeep Singh, MD, DM Christian Medical College and Hospital
Send rapid response to journal:
drsinghakashdeep{at}gmail.com Akashdeep Singh
|
The antimicrobial synergism of ampicillin plus ceftriaxone for the treatment of Enterococcus faecalis endocarditis as shown by Joan Gavalda and collegues is appreciable. There are certain basic quires which need to be answered before it can be incorporated into the day to day practice. First, enterococci are inherentally resistant to cephalosporins including ceftriaxone. Second, ampicillin and ceftriaxone are both β-lactam antibiotics having a common mechanism of action - inhibition of synthesis of the bacterial peptidoglycan cell wall. Antimicrobial agents acting at different targets may enhance the overall antimicrobial activity. Then how can it be believed that there will be synergism between these two drugs. Treatment of HLAR E. faecalis depends on precise determination of antibiotic susceptibilities, testing for bactericidal activity, ascertainment of the serum inhibitory and bactericidal titres, and monitoring of drug concentrations in the serum. Although aminoglycoside- resistance is often present, these drugs can still synergize with cell- wall inhibitors provided that the aminoglycoside's MIC is 1000 mg/L or less.1 Streptomycin is worth testing because it can be active against enterococci that are resistant to other aminoglycosides.2 The cure rates for HLAR E. faecalis in the present study was 52% with the ampicillin plus ceftriaxone combination therapy which is not different from cure rate with a cell wall susceptible agent alone.3 (40- 50%) References 1. F Caron, M Pestel, MD Kitzis, JF Lemeland, G Humbert and L Gutmann, Comparison of different beta-lactam-glycopeptide-gentamicin combinations for an experimental endocarditis caused by a highly beta- lactam-resistant and highly glycopeptide-resistant isolate of Enterococcus faecium, J Infect Dis 171 (1995), pp. 106–112. 2. B Hoen, F Alla and C Selton-Suty et al., Changing profile of infective endocarditis, results of a 1-year survey in France, JAMA 288 (2002), pp. 75–81. 3. Eliopoulos GM: Aminoglycoside-resistant enterococcal endocarditis. Infectious Disease Clinics of North America. 1993, 7: 117- 133. Conflict of Interest:None declared |
|||
Falcó, Benito Almirante, and Albert Pahissa
