cefoxitin and Skin-Diseases

Cefamandole, cefoxitin, cefotetan, ceftizoxime, imipenem plus cilastatin, and ampicillin plus sulbactam were compared in the eradication of subcutaneous abscess in mice caused by Bacteroides fragilis group organisms and Escherichia coli alone or in combination. The abscesses were examined 5 d after inoculation. B. fragilis group reached log10.1-11.0 organisms per abscess and E. coli log11.6-12.5. Imipenem plus cilastatin significantly reduced (in 6.9-10.6 logs) the number of E. coli and all members of B. fragilis group alone or in all combinations. Ampicillin plus sulbactam reduced the numbers of all B. fragilis group (in 4.2-7.2 logs) but was less effective against E. coli (reduction of 1.8-4.2 logs). Cefoxitin was effective in significantly reducing (in 4.9-6.2 logs) the number of E. coli and all members of B. fragilis group alone or in all combinations. Cefotetan was effective against B. fragilis (reduction of 5.1-6.6 logs) and E. coli alone or in combination but did not reduce the number of Bacteroides thetaiotaomicron, Bacteroides vulgatus, and Bacteroides ovatus. Ceftizoxime was effective against only B. ovatus (reduction of 3.7-5.8) and E. coli (reduction of 6.0-8.1 logs); it did not reduce the number of other organisms. Cefamandole was effective against only E. coli and was not effective against any member of the B. fragilis group. These in vivo data confirm the in vitro activity of these antimicrobials.

Topics: Abscess; Ampicillin; Animals; Anti-Bacterial Agents; Bacteroides fragilis; Bacteroides Infections; Cefamandole; Cefotetan; Cefoxitin; Ceftizoxime; Cilastatin; Cilastatin, Imipenem Drug Combination; Disease Models, Animal; Drug Combinations; Drug Therapy, Combination; Escherichia coli; Escherichia coli Infections; Imipenem; Male; Mice; Skin Diseases; Sulbactam

The relationships between capsulate and non-capsulate Bacteroides fragilis strains and Escherichia coli, and between capsulate and non-capsulate strains of the B. melaninogenicus group and Streptococcus pyogenes, were studied in a subcutaneous abscess model in mice. Selective antimicrobial agents directed against either aerobic or anaerobic bacteria were used alone or in combination to explore the effect of eradication of one component of the mixed infection. Single agent therapy effective against both aerobic and anaerobic flora was also employed. Single therapy of mixed infection directed at the elimination of only one organism (S. pyogenes, E. coli or Bacteroides sp.) caused significant reductions in the numbers of sensitive organisms and also smaller yet significant decreases in the numbers of insensitive organisms. However, the abscesses were not eliminated after such therapy. Combination therapy or use of a single agent (cefoxitin) directed against the aerobic and anaerobic components of the infection was more effective. Non-capsulate Bacteroides spp. became capsulate after passage in mice mixed with either S. pyogenes or E. coli. Therapy directed at the elimination of S. pyogenes and E. coli did not prevent the emergence of capsulate Bacteroides spp. These data demonstrate the synergy between all members of the B. fragilis group and E. coli and between the B. melaninogenicus group and S. pyogenes, and reiterate the need to direct antimicrobial therapy at the eradication of the aerobic and anaerobic components of mixed infections.

Topics: Abscess; Aerobiosis; Anaerobiosis; Animals; Bacteroides; Bacteroides fragilis; Bacteroides Infections; Cefoxitin; Disease Models, Animal; Drug Resistance, Microbial; Drug Therapy, Combination; Escherichia coli; Escherichia coli Infections; Gentamicins; Leucomycins; Male; Metronidazole; Mice; Microbial Sensitivity Tests; Prevotella melaninogenica; Skin Diseases; Streptococcal Infections; Streptococcus pyogenes