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Biomedical subjects

R C Moellering

Publications and source records attributed to R C Moellering.

At least 217 records · Page 12Linked to original sources
PubMed1973

Penicillin-tobramycin synergism against enterococci: a comparison with penicillin and gentamicin.

Combinations of penicillin plus tobramycin have been compared with penicillin plus gentamicin against 27 strains of enterococci isolated from blood cultures. Penicillin plus gentamicin was synergistic against all strains. The combination of penicillin plus tobramycin was equally effective against strains of Streptococcus facalis, but was ineffective against all four strains of S. faecium tested.

Aminoglycosides↗
PubMed1973

Tobramycin concentrations during peritoneal dialysis.

A patient undergoing peritoneal dialysis for severe renal failure was treated with tobramycin. Peritoneal dialysis was inefficient in removing tobramycin from the serum. Tobramycin concentrations in the dialysis effluent were low. Despite acute oliguric renal failure, urine concentrations of tobramycin were sufficient to treat most gram-negative urinary tract infections.

Aged↗
PubMed1972

Antibiotic synergism against Listeria monocytogenes.

The effectiveness of ampicillin, penicillin, streptomycin, and gentamicin against 20 strains of Listeria monocytogenes was studied in vitro. For all strains, the minimal bactericidal concentration (MBC) of both ampicillin and penicillin was much higher than the minimal inhibitory concentration (MIC). The MBC of both streptomycin and gentamicin was close to the MIC, but relatively high concentrations of these antibiotics were necessary to inhibit the growth of most of the strains of Listeria. The combination of penicillin plus streptomycin was synergistic against 19 of 20 strains and in the remaining strain produced enhanced killing (but of less magnitude than our criterion for synergism). Combinations of penicillin plus gentamicin, ampicillin plus streptomycin, and ampicillin plus gentamicin produced enhanced killing against all strains tested. No antagonism was observed when ampicillin or penicillin was combined with streptomycin or gentamicin.

Ampicillin↗
PubMed1972

Evaluation of a computer-associated electronic zone analyzer in single-disc antimicrobial susceptibility testing.

A computer-associated electronic zone analyzer was evaluated for use in measuring zones of inhibition for single-disc antimicrobial susceptibility testing. This unit gave measurements which were reproducible and comparable to those obtained by the standard manual technique. By feeding results directly into the computer, this system eliminates errors in interpretation of zone sizes and in transcription of results to clinical reports. It has also been shown to eliminate possible sources of observer bias. In routine high-volume use, this system has resulted in a substantial saving of man-hours of work.

Computers↗
PubMed1971

Mechanism of resistance to antibiotic synergism in enterococci.

Enterococci exhibit two types of resistance to streptomycin. Moderately high-level resistance is observed in most naturally occurring strains and can be overcome by simultaneous exposure to penicillin. In addition, very high-level resistance is found in those strains against which penicillin plus streptomycin fail to produce synergism in vitro. To study the mechanism of streptomycin resistance in enterococci, ribosomes from a wild-type strain and from a highly streptomycin-resistant mutant were isolated, characterized, and studied in an in vitro amino acid incorporation system. The ribosomes from the organism with moderately high-level streptomycin resistance were sensitive to streptomycin in vitro, suggesting that this type of resistance is caused by failure of streptomycin to reach the ribosomes. Very high-level resistance (and lack of penicillin-streptomycin synergism), on the other hand, appears to be due to ribosomally mediated streptomycin resistance.

Amino Acids↗
PubMed1971

Studies on antibiotic syngerism against enterococci. II. Effect of various antibiotics on the uptake of 14 C-labeled streptomycin by enterococci.

The mechanism by which agents that inhibit bacterial cell wall synthesis produce a synergistic effect against enterococci when combined with aminoglycoside antibiotics has not been elucidated. Using (14)C-labeled streptomycin, it could be shown that uptake of this aminoglycoside antibiotic was markedly enhanced in enterococci growing in the presence of penicillin or other agents which inhibit the synthesis of bacterial cell walls. There was no enhancement of streptomycin uptake when the cells were incubated with antibiotics which primarily affect the bacterial cell membrane or inhibit protein synthesis. Increased streptomycin uptake was produced by penicillin only in actively growing bacteria. These observations are consistent with the hypothesis that enterococci exhibit a natural barrier to the entry of streptomycin which can be overcome by agents which inhibit cell wall synthesis, thus producing a synergistic effect.

Anti-Bacterial Agents↗