Experimental Urinary Tract Infection in Rats Caused by Candida albicans.

The increased clinical use of broad-spectrum antibiotics, immunosuppressives, and anti-inflammatory agents is thought to have contributed to the increased incidence of renal infections due to Candida albicans. To aid in the search for improved anticandidal agents, we developed an experimental model in which C. albicans is injected into the medulla of the surgically exposed kidney of the rat. The ensuing infection is restricted to the urinary tract and can be treated successfully with amphotericin B. This model promises to be of merit in the evaluation of agents potentially useful in treating candidiasis of the urinary tract.

Activity of selected penicillins in vitro and in experimental bacterial infections in mice.

The minimal inhibitory concentration and the 50% mouse protective dose for five key penicillins are presented. Such data provide a useful guide in evaluating the activity of new penicillins, in comparison with those already commercially available, and establishes the amounts of antibiotic necessary to obtain a PD(50) for several experimental model infections in mice.

Comparison of the chemotherapeutic and pharmacodynamic activities of cephradine, cephalothin, and cephaloridine in mice.

Cephradine, a new semisynthetic cephalosporin derivative, is 7[d(-)-2-amino-2-(1,4-cyclohexadien-1-yl) acetamido]-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid hydrate. The compound has a broad spectrum of antimicrobial activity in vitro. When given subcutaneously to mice, cephradine was appreciably more effective than cephalothin against infections induced by penicillinase-producing Staphylococcus, Escherichia coli, Klebsiella pneumoniae, or Enterobacter cloacae strains. Cephradine and cephaloridine possessed equivalent activity in treating infections caused by these same three gram-negative bacteria. The mean total bioactivity of cephradine in the serum of mice peaked within 30 min (59 mug/ml) after parenteral administration and was approximately threefold that of cephalothin (20 mug/ml), but less than that of cephaloridine (83 mug/ml). Nearly all of the administered cephradine (84%) and cephaloridine (70%) were excreted in the urine as the parent compounds. In contrast, only 47% (total bioactivity) of administered cephalothin was recovered, an amount that represented only 15 to 20% of the parent substance.

Biological characterization of prasinomycin, a phosphorus-containing antibiotic.

Prasinomycin, a new antibiotic from the green spore streptomycete, Streptomyces prasinus, primarily inhibits the growth of gram-positive microorganisms. Like penicillin, it is effective only against growing cells. Though primarily bacteriostatic at levels about the minimal inhibitory concentration, it is bactericidal at higher levels. Neither synergism nor antagonism could be demonstrated for prasinomycin with a variety of other antibiotics. It is highly active upon subcutaneous administration to mice infected with Staphylococcus aureus, Streptococcus pyogenes C203, or Diplococcus pneumoniae. Prasinomycin has a unique prophylactic action whereby one dose protects mice against experimental infections for as long as 2 months. It is more effective against S. aureus infections in mice when administered subcutaneously 20 hr prior to infection than when given in divided doses 1 hr before and 4 hr after infection.