Hyman Wallick

Cefoxitin, a Semisynthetic Cephamycin Antibiotic: Susceptibility Studies

Cefoxitin, 3-carbamoyloxymethyl-7-α-methoxy-7-[2-(2-thienyl)acetamido]-3-cephem-4- carboxylic acid, is a new semisynthetic cephamycin with broad antibacterial activity. It is highly active against gram-negative microorganisms including indole-positive Proteus and Serratia strains, which are ordinarily reistant to the cephalosporins. Cefoxitin is also highly active against many strains of Escherichia coli and Proteus mirabilis which are resistant to the cephalosporins. Furthermore, E. coli and Klebsiella strains which are susceptible to the cephalosporins are generally more susceptible to the cephamycin analog. The susceptibility of the gram-positive bacteria falls well within the effective range of the antibiotic for gram-negative organisms, but cefoxitin is less active than cephalothin or cephaloridine. As is the case with the cephalosporins, strains of Pseudomonas and group D streptococci are resistant to cefoxitin. Changes in pH, inoculum density, and growth medium have no significant effect on the activity of the antibiotic.

Coenzyme Q. XVII. Isolation of coenzyme Q10 from bacterial fermentation

Abstract Crystalline coenzyme Q10 has been newly isolated from a fermentation using Pseudomonas denitrificans. Previously, the presence of Q9 in Pseudomonas fluorescens, and Q10 in Neurospora crassa and in Chromatium was reported by others, but without evidence based on characterization of isolated crystalline material. We found Q9 in five other species of Pseudomonas, Q8 and Q9 in Pseudomonas fluorescens, and evidence for the presence of some form of Q in 32 cultures, representing 20 species out of 107 cultures which were examined. Coenzyme Q10 can now be produced by a suitable fermentation, rather than by isolation from mammalian tissue.

Cephamycins, a New Family of β-Lactam Antibiotics: Antibacterial Activity and Resistance to β-Lactamase Degradation

The susceptibility to some cephalosporin antibiotics and to cephamycin C, a member of a new family of β-lactam antibiotics, was evaluated for 466 cultures representing 11 different genera or species of gram-negative clinical isolates. The susceptibility of 39 gram-negative cultures known to produce β-lactamase was also determined. The β-lactamase activity of a representative group of the clinical isolates and the 39 enzyme producers was studied with the cephalosporins (cephalothin and cephaloridine) and cephamycin C as substrates and was related to the in vitro disc susceptibility to these same antibiotics. The significant resistance to β-lactamase displayed by the cephamycins is reflected in the kinetics of enzyme activity (Km and Vmax) that are reported for the cephalosporins and the cephamycins. Resistance to β-lactamase is probably one of the reasons that many cephalosporin-resistant cultures are susceptible to cephamycin C.