The recent literature was reviewed with regard to the risks of
superinfection following
beta-lactam chemotherapy. The summary publications for the pseudomonas-active
penicillins (
azlocillin,
carbenicillin,
mezlocillin,
piperacillin and
ticarcillin),
cefoperazone,
cefotaxime,
ceftazidime,
imipenem and
moxalactam show marked variations.
Moxalactam was most likely to produce both gram-negative (5-38%) and enterococcal (2.2-12%)
superinfections.
Ceftazidime or
moxalactam therapy was more often associated with anaerobic
superinfections, usually by Clostridium spp., than the other
beta-lactams. Comparable and lower incidences of
superinfections were cited for
cefoperazone,
ceftazidime,
mezlocillin and
imipenem. The most common pathogens for the above drugs were the fungi (Candida spp.), Pseudomonas spp. and some
beta-lactamase-producing Enterobacteriaceae. Staphylococcal, Escherichia coli and Klebsiella spp.
secondary infections were more common in patients receiving the newer
penicillins.
Cefotaxime had a very low incidence of
superinfections (1.1%), especially caused by gram-positive organisms such as enterococci. The reasons for this favorable feature seem to be: excellent inhibitory activity and
beta-lactamase stability against a wide variety of bacterial pathogens, synergistic interactions of
cefotaxime and its desacetyl metabolite, enhanced anti-enterococcal activity of
cefotaxime in the presence of a human serum factor and interactions of
cefotaxime and desacetyl
cefotaxime to suppress the development of antimicrobial resistance. The most common
superinfections following
cefotaxime treatment were with Pseudomonas spp., Enterobacter spp. and fungi.
Cefotaxime appears to possess physical-chemical characteristics that react favorably with bacteria and the host to minimize gram-positive
superinfections, especially with most enteric Streptococcus spp. (Streptococcus faecalis and Streptococcus faecium).