Activities of ciprofloxacin, levofloxacin, ofloxacin and sparfloxacin against speciated coagulase-negative staphylococci sensitive and resistant to fluoroquinolones.

A total of 119 strains of coagulase-negative staphylococci isolated from clinical specimens were speciated and tested for sensitivity to methicillin and four fluoroquinolones (ciprofloxacin, sparfloxacin, levofloxacin and ofloxacin). Resistance to fluoroquinolones was significantly more common in Staphylococcus haemolyticus (43%) than in Staphylococcus epidermidis (11%). Methicillin-resistant strains of S.

Development of the semi-synthetic penicillins and cephalosporins.

Semi-synthetic penicillins and cephalosporins both derive from their respective chemical nuclei, 6-aminopenicillanic acid (6-APA) and 7-aminocephalosporanic acid (7-ACA). Work leading to their isolation was being carried out in parallel, but following very different pathways, during the last half of the 1950s. The development of 6-APA was reviewed recently in this journal, and in the present article I take a closer look at early work on 'penicillin amidase' and revisit the steps that led to 7-ACA.

Antimicrobial properties of green tea catechins.

Extracts of leaves from the tea plant Camellia sinensis contain polyphenolic components with activity against a wide spectrum of microbes. Studies conducted over the last 20 years have shown that the green tea polyphenolic catechins, in particular (-)-epigallocatechin gallate (EGCg) and (-)-epicatechin gallate (ECg), can inhibit the growth of a wide range of Gram-positive and Gram-negative bacterial species with moderate potency. Evidence is emerging that these molecules may be useful in the control of common oral infections, such as dental caries and periodontal disease.