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L Riff

Publications and source records attributed to L Riff.

7 recordsLinked to original sources
PubMed1983

Chloramphenicol kills Haemophilus influenzae more rapidly than does ampicillin or cefamandole.

The bactericidal effects of chloramphenicol and three beta-lactams (ampicillin, cefamandole, and penicillin G) were measured for 27 strains of Haemophilus influenzae type b isolated from the blood or cerebrospinal fluid of infected infants. Of the ampicillin-susceptible strains, 75% were killed by less than 2.0 micrograms of each antibiotic per ml; however, the concentration of the beta-lactam agents required for bactericidal activity was higher than that required for inhibitory activity. Chloramphenicol was the only agent which had no marked discrepancy between inhibitory and bactericidal concentrations regardless of beta-lactamase production. Importantly, chloramphenicol was more rapidly bactericidal than either ampicillin or cefamandole. The bactericidal requirement of ampicillin was increased by the presence of chloramphenicol for about one-third of the isolates examined. Neither the inhibitory nor the bactericidal activity of chloramphenicol was influenced by ampicillin. Synergy occurred for only two beta-lactamase-positive isolates. The more rapid bactericidal action of chloramphenicol persisted even in the presence of ampicillin. The rapid bactericidal action of chloramphenicol with or without ampicillin supports the use of chloramphenicol alone or with ampicillin for H. influenzae infections.

Ampicillin↗
PubMed1977

Antimicrobial therapy of experimental group B streptococcal infection in mice.

Group B beta-hemolytic streptococci (GB-BHS) frequently cause severe infection in newborns. Previous in vitro studies showed accelerated killing of GB-BHS by ampicillin plus gentamicin as compared with ampicillin alone. To extend the in vitro observations, mice were infected experimentally with GB-BHS and treated with gentamicin plus ampicillin or ampicillin alone. Untreated mice died within 10 to 48 h. Compared with treatment with ampicillin alone, ampicillin-and-gentamicin therapy resulted in improved survival when the antibiotics were given in established infection or as a single dose at the time of infection. Ampicillin and gentamicin accelerated the clearing of bacteremia as compared with treatment with ampicillin alone. In view of these findings, the therapy of GB-BHS infection in newborns and other patients should be reconsidered in that a combination of ampicillin or penicillin G plus gentamicin might be superior to the use of ampicillin or penicillin G alone.

Ampicillin↗
PubMed1976

Antibiotic-killing kinetics of group B streptococci.

Group B streptococci are uniformly susceptible to penicillin or ampicillin. Nevertheless, morbidity and mortality in newborn infants infected with group B streptococci is a major clinical problem. Bacteriologic determinants in the outcome of this infection were studied. Streptococcal killing kinetics were studied for ampicillin alone and in combination with gentamicin. In all cases killing was accelerated by the combination. The practice of discontinuing administration of the aminoglycoside antibiotic when group B streptococcal infection is confirmed should be re-evaluated.

Ampicillin↗