Effect of pentamidine on the growth of Escherichia coli.

Since Thrower and Valentine (1943) observed the trypanocidal and bacteriostatic action of propamidine, a number of investigators have studied the antimicrobial action of the aromatic diamidines. Kohn (1943) reported the inhibition of growth of Escherichia coli and Staphylococcus aureus by propamidine. This observation was extended to include Lactobacillus casei and Streptococcus lactis strain R by Snell (1944), who showed that polyamines added at the same time as propamidine prevented the inhibition of growth. Bichowsky-Slomnitzki (1948a, b) found that nucleic acids would reverse the bacteriostatic effect of pentamidine and stilbamidine on Escherichia coli and Staphylococcus aureus as effectively as polyamines. Bernheim (1943) investigated the effect of propamidine on resting cells of Escherichia coli and observed the reduction of oxygen utilization on the substrates alanine and arginine and on peptone in presence of the drug. Respiration on glucose and pyruvate was much less sensitive to propamidine. Blaschko and Duthie (1945) suggested the inhibition of amine oxidases as a point of possible metabolic interference by these compounds. The present study of the inhibition by pentamidine of the growth of Escherichia coli strain K-12 was undertaken as one phase of the investigation of the effect of this diamidine on bacteriophage production in K-12. The reversal of growth inhibition by L-glutamic or a-ketoglutaric acids and the interference by pentamidine with transaminations involving glutamic acid constitute the subject matter of this paper.