Abstract
The in vitro susceptibility ofHaemophilus influenzae type b to rifampin, cefotaxime, ceftazidime, ceftriaxone and cefuroxime was examined at inocula of 105 and 107 CFU/ml. Time-kill curves were then obtained using antibiotic concentrations at one-half the MIC for each drug at the two inocula with combinations of rifampin plus each of the cephalosporins. There was a pronounced inoculum effect with all of the cephalosporins except for cefuroxime, but the MIC values were also higher for the latter drug. The rare failure of some cephalosporins to promptly sterilize the cerebrospinal fluid in meningitis should encourage investigation of the relationship between the inoculum effect, minimum bactericidal concentration and cerebrospinal fluid antibiotic levels in these clinical situations. A marked synergistic effect was noted for most of the isolates, and therefore, cephalosporin-rifampin combinations might show clinical utility.
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References
Committee on Infectious Diseases:Haemophilus influenzae infections. In: Peter G (ed): Report of the Committee on Infectious Diseases. American Academy of Pediatrics, Elk Grove Village, IL, 1988, p. 204–210.
Jadavji T, Prober CG, Cheung R: In vitro interactions between rifampin and ampicillin or chloramphenicol againstHaemophilus influenzae. Antimicrobial Agents and Chemotherapy 1984, 26: 91–93.
National Committee for Clinical Laboratory Standards: Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically, M-7A. NCCLS, Villanova, PA, 1985.
Schoenknecht FD, Sabath LD, Thornsberry C: Susceptibility tests: special tests. In: Lennette EH, Balows A, Hausler HJ, Shadomy S (ed): Manual of clinical microbiology. American Society for Microbiology, Washington DC, 1985, p. 1000–1008.
Berenbaum MC: Correlations between methods for measurement of synergy. Journal of Infectious Diseases 1980, 142: 476–478.
Norden CW: Reply. Journal of Infectious Disease 1980, 142: 478–479.
Moellering RC: Comment. Journal of Infectious Diseases 1980, 142: 479–480.
Laferriere C., Marks MI, Welch DF: Effect of inoculum size onHaemophilus influenzae. type b susceptibility to new and conventional antibiotics. Antimicrobial Agents and Chemotherapy 1983, 24: 287–289.
Feldman WE: Concentration of bacteria in CSF of patients with bacterial meningitis. Journal of Pediatrics 1976, 88: 549–552.
Jacobs RF, Wright MW, Diskin RL, Bradsher RW: Delayed sterilization ofHaemophilus influenzae type b meningitis with twice daily ceftriaxone. Journal of the American Medical Association 1988, 259: 392–394.
Arditi M, Herold BC, Yogev R: Cefuroxime treatment failure andHaemophilus influenzae. meningitis: case report and review of literature. Pediatrics 1989, 84: 132–135.
Gerding DN, Peterson LR, Hughes CE, Bamberger DM: Extravascular antimicrobial distribution in man. In:Lorian V (ed): Antibiotics in laboratory medicine. Williams and Wilkins, Baltimore, 1986, p. 938–994.
Farr B, Mandell GL: Rifampin. In: Cunha BA (ed): Symposium on antimicrobial chemotherapy. Medical Clinics of North America 1982, 66: 157–168.
Berenbaum MC: Minor synergy and antagonism may be clinically important. Journal of Antimicrobial Chemotherapy 1987, 19: 271–273.
Lewis MA, Priestly BL: Addition of rifampicin in persistentHaemophilus influenzae type b meningitis. British Medical Journal 1986, 292: 448–449.
Haines CI, Patfield M: Addition of rifampicin in persistentHaemophilus influenzae. type b meningitis. British Medical Journal 1986, 292: 900.
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Gordon, R.C., Wofford-McQueen, R. & Shu, K. In vitro synergism of rifampin-cephalosporin combinations againstHaemophilus influenzae type b. Eur. J. Clin. Microbiol. Infect. Dis. 9, 201–205 (1990). https://doi.org/10.1007/BF01963838
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DOI: https://doi.org/10.1007/BF01963838