Susceptibility of Clinical Isolates of Bacteria to Cefoxitin and Cephalothin

The in vitro effect of cefoxitin, cefamandole, cephalexin, and cephalothin was tested against 645 Two promising antibiotics have recently been developed in the search for a cephalosporin that would combine good in vitro activity with relative resistance to hydrolysis by beta-lactamase. Cefamandole is a new cephalosporin with the formula 7-D>mandelamido-3-[[(1-methyl-lH-tetrazol-5-yl)-thio]methyl]-3-cephem-4-carboxylic acid, formate (ester) sodium salt. Cefoxitin is a semisynthetic cephalosporin-like antibiotic with the formula 3-carbamoyloxymethyl-7-a-methoxy-7[2-(2-thienyl)acetamido]-3-cephem-4-carboxylic acid. Figure 1 illustrates the comparative structural formulas of the antibiotic tested. The purpose of this study is to compare the in vitro antibacterial activity of cefamandole, cefoxitin, cephalothin, and cephalexin against a wide spectrum ofbacteria from clinical sources.

Section: Discussionsupporting

confidence: 82%

Section: Discussionmentioning

confidence: 68%

In Vitro Comparison of Cefoxitin, Cefamandole, Cephalexin, and Cephalothin

Eickhoff

Ehret

1976

“…The second-generation cephalosporins, represented by cefamandole and cefoxitin, expanded the cephalosporin spectrum to include more gram-negative bacilli, as shown in this and other studies (3,9,11,12). This is due to their varying degrees of ability to resist hydrolysis by gramnegative ,8-lactamases.…”

Section: Discussionmentioning

confidence: 78%

Comparative in vitro studies of Ro 13-9904, a new cephalosporin derivative

Eickhoff¹,

Ehret²

1981

The in vitro activity of Ro 13-9904, a new cephalosporin derivative, was compared with the activities of cephalothin, cefamandole, cefoxitin, cefotaxime, and moxalactam against 591 clinical isolates of gram-negative and gram-positive organisms. The spectra of activity and potency of Ro and cefotaxime were quite similar; they were the most active agents against Enterobacteriaceae, Streptococcus pyogenes, Haemophilus influenzae, Neisseria gonorrhoeae, and Neisseria meningitidis. Moxalactam was only slightly less active against these organisms. Ro 13-9904, cefotaxime, and moxalactam were approximately equal in activity against Pseudomonas aeruginosa; concentrations of 50 to 100 ,Ig/ml inhibited over 90% of the strains tested. Cefamandole and cephalothin were the most active drugs tested against staphylococci. Moxalactam demonstrated the highest intrinsic activity against Bacteroides fragilis; a concentration of 1.6 yg/ ml inhibited over 50% of the strains. All six of the antibiotics were essentially inactive against group D streptococci. The action of all of the antibiotics was bactericidal, with minimal bactericidal concentrations generally being no more than twofold greater than miniimal inhibitory concentrations. The only exception to this was found when large inocula of Staphylococcus aureus were tested. Increased inoculum size generally sharply reduced the activity of Ro 13-9904, cefotaxime, and moxalactam against Enterobacteriaceae and P. aeruginosa.The chemotherapy of serious bacterial infections, particularly those which are hospital acquired, is a continuing clinical challenge. Organisms such as Serratia, Acinetobacter, Pseudomonas cepacia, and others once thought to cause disease only rarely, if at all, are now recognized as common pathogens. The need for antimicrobial agents with broad spectra of activity and resistance to the /3-lactamases of gramnegative organisms associated with nosocomial infection has motivated research resulting in the development of a great number of cephalosporin derivatives. Since the discovery of the fungus Cephalosporium acremonium in Sardinian sewage in 1945 (1), the cephalosporins have evolved into a complex group of antibiotics with significant differences in potency and antibacterial spectrum. Ro 13-9904 (Fig. 1) is a new product of the chemical manipulation of side chains joined to the 7-amino-cephalosporanic acid nucleus. It has been reported to be highly active against common gram-negative organisms and relatively resistant to inactivation by cephalosporinases; preliminary data also suggest that the expanded spectrum of activity includes Pseudomonas aeruginosa, Serratia marcesens, and most strains of Enterobacter (compound Ro 13-9904 preliminary data, Hoffmann-La Roche, Inc., 1979).The purpose of this study was to compare the in vitro activity of Ro 13-9904 with the activities of other drugs representing the three major generations of cephalosporin development. The first generation was represented by cephalothin, the second was represented by cefamandole and cefoxit...

“…The antibacterial activity of the clinically used cephalosporins is characterized by low Cefoxitin, which is not a cephalosporin but a cephamycin, has been found to be much more resistant to gram-negative beta-lactamases than cephalosporins and also to have a remarkably good effect on B. fragilis (1,6,7,10,12). Cefuroxime, which was synthesized later than cefoxitin and which is a cephalosporin, has been found to be more beta-lactamase resistant than other cephalosporins and, in addition, to have a better antibacterial effect on some gram-negative bacteria, such as H. influenzae and meningococci (2, 9).…”

Section: Resultsmentioning

confidence: 99%

Comparative Study of the In Vitro Antibacterial Activity of Cefoxitin, Cefuroxime, and Cephaloridine

Norrby

Brorsson²,

Seeberg³

1976

The in vitro antibacterial effects of cefoxitin, a semisynthetic cephamycin, cefuroxime, a new cephalosporin antibiotic, and cephaloridine were compared. With gram-positive bacteria, marked differences were found only in the effects against Streptococcus faecalis, where cephaloridine and cefuroxime were superior to cefoxitin. With gram-negative aerobic bacteria, cefoxitin, which is known to be more resistant to beta-lactamases from gram-negative bacteria than any cephalosporin, was found to be more effective than cefuroxime and cephaloridine against ampicillin-resistant strains of Escherichia coli and indole-positive strains of Proteus. Haemophilus influenzae was found to be more susceptible to cefuroxime than to cefoxitin and cephaloridine. When ampicillin-resistant strains of H. influenzae were tested, markedly higher minimal inhibitory concentration values were obtained with cephaloridine in comparison to those obtained with ampicillin-susceptible strains. These increases in the minimal inhibitory concentration values were not observed with cefoxitin and cefuroxime, probably due to the resistance of these two compounds to beta-lactamases. Strains ofBacteroides fragilis were found to be much more susceptible to cefoxitin than to cefuroxime, which in turn was superior to cephaloridine. The results obtained indicate that cefoxitin and cefuroxime both are superior in their antibacterial spectra to the cephalosporins that are now in clinical use.