Microbiological Properties of a New Cephalosporin, BL-S 339: 7-(Phenylacetimidoyl-aminoacetamido)-3-(2-Methyl-1, 3,4-Thiadiazol-5-Ylthiomethyl)Ceph-3-em-4-Carboxylic Acid

Abstract

BL-S 339 is a new broad-spectrum, parenterally effective cephalosporin whose expression of antibacterial activity in vitro is markedly affected by the nature of the assay medium. When assayed in nutrient agar, BL-S 339 was more active than cephalothin against strains of Diplococcus pneumoniae, Streptococcus pyogenes, Escherichia coli, Serratia marcescens, Klebsiella pneumoniae, Enterobacter, and indole-positive Proteus sp. However, when assayed in MuellerHinton medium, its activity, especially against gram-negative bacteria, was reduced substantially, whereas the activity of cephalothin was virtually unaffected by the assay medium. The in vivo activity of BL-S 339 correlated well with its activity in nutrient agar; when administered subcutaneously to mice, it was therapeutically more efficacious than cephalothin in infections caused by both gram-positive and gram-negative bacteria. When BL-S 339 was administered intramuscularly to mice, the concentrations achieved in the blood were three times those achieved with cephalothin. BL-S 339 was bound to human serum proteins to the same extent as cephalothin. Recovery of BL-S 339 in the urine within the 24-hr period after intramuscular administration to rats was three times that of cephalothin.BL-S 339 is a new broad-spectrum, parenterally effective cephalosporin (Fig. 1). It was selected from a general cephalosporin-screening program and represents one of the most active compounds of a series of 7-(substitutedimidoylaminoacetamido) derivatives synthesized by C. Holdrege and S. Baker of Bristol Laboratories. This report presents comparative data on the microbiological and pharmacological properties of BL-S 339 and cephalothin, including the effect of the assay medium on their activity against a variety of clinical isolates. Data on the parenteral absorption, urinary excretion, and therapeutic efficacy of these compounds in rodents are also presented.MATERIALS AND METHODS Antibiotics. BL-S 339 was synthesized by S. R. Baker of the Bristol Laboratories Organic Chemistry Department. The crystalline form used in these studies was prepared by M. A. Kaplan of the Product Development Department and was more than 95% pure. Its solubility in water was limited to 5 mg/ml and in phosphate buffer (pH 7) to 10 mg/ml. When administered subcutaneously to mice in experimental infections, BL-S 339 was suspended in a polysorbatecarboxymethylcellulose formulation. Commercially available cephalothin (Keflin, Eli Lilly & Co.) was used as the control compound.In vitro antibacterial activity. The susceptibility of a number of clinical strains of Diplococcus pneumoniae, Streptococcus pyogenes, Staphylococcus aureus, Proteus sp., Klebsiella pneumoniae, Enterobacter sp., Serratia marcescens, Salmonella sp., and Escherichia coli to BL-S 339 and cephalothin was determined by a twofold agar dilution method. The antibiotics were incorporated into Mueller-Hinton medium (MHM, Difco) and into nutrient agar (NA) which was prepared by the addition of 1% lonagar

Topical application of acidified nitrite to the nail renders it antifungal and causes nitrosation of cysteine groups in the nail plate

“…Trichophyton rubrum (ATCC 10218) and T. mentagrophytes (ATCC 9533) were cultured in liquid Sabouraud media for 3 days at 28 °C 22 . Nail clippings were treated with a single application of 9% sodium nitrite/13·5% citric acid overnight.…”

Effect of Assay Medium on the Antibacterial Activity of Certain Penicillins and Cephalosporins

“…This also raises the question as to whether any standardized method of testing can be applied to all drugs. For example, data obtained in experimental infections of the mouse showed that the degree of therapeutic effectiveness of BL-P 1654 is more accurately predicted by susceptibility test results obtained on Mueller-Hinton medium than on NA (K. E. Price, unpublished data), whereas Misiek et al (7) found that the reverse situation applies in the case of BL-S 339. Appropriate clinical laboratory studies should ultimately establish the medium and test conditions that most accurately predict the degree of therapeutic efficacy of these compounds in man.…”

Miniaturization of the Structure Elucidation of Novel Natural Products - Two Trace Antibacterial Acylated Caprylic Alcohol Glycosides fromArctostaphylos pumila

“…The acylated 1-O-octylglucopyranosides will frequently elute in the same chromatographic fractions of our library production process and their retention times during HPLC-ELSD-MS analysis will match when normalized using the retention times of standard compounds. Based on the full NMR data ( 1 H, 13 C, DEPT, COSY, HSQC and HMBC) and the LR-/HR-ESI-MS, the structure of 1 was confirmed to be 2,6-diacetyl-3,4-diisobutyl-1-O-octylglucopyranoside. It was difficult to obtain the complete 13 C and DEPT NMR spectra for 2 on the obtained mass, however, their 2D NMR (HSQC and HMBC) spectra were completely acquired and the chemical shifts of all the protons and carbons including the quaternary carbons were observed, and unambiguously assigned due to the fact that 2 is an analogue of 1.…”

“…Based on the full NMR data ( 1 H, 13 C, DEPT, COSY, HSQC and HMBC) and the LR-/HR-ESI-MS, the structure of 1 was confirmed to be 2,6-diacetyl-3,4-diisobutyl-1-O-octylglucopyranoside. It was difficult to obtain the complete 13 C and DEPT NMR spectra for 2 on the obtained mass, however, their 2D NMR (HSQC and HMBC) spectra were completely acquired and the chemical shifts of all the protons and carbons including the quaternary carbons were observed, and unambiguously assigned due to the fact that 2 is an analogue of 1. Two other trace components (£ 5 mg) were obtained from the same preparative HPLC fraction containing 1 and 2.…”

“…HMBC experiments are performed with approximately 70 micrograms of material in 10 to 15 hours, which typically enable internal acceptance of the structure per commercial standards. 13 C-NMR data are acquired on amounts greater than 200 micrograms when required for specific internal and/or information releasing decisions. Based on our experiences working with the MicroCryoProbe TM and other conventional NMR probes, the CapNMR probe has a higher filling factor resulting in fewer non-deuterated artifacts allowing us to obtain superior 1 H-and COSY NMR spectra on as little as 5 to 10 micrograms of material.…”