Abstract
The drug susceptibility pattern of clinical isolates from perforative peritonitis (first level) obtained in 1996 was investigated. The results are summarized as follows:
1. Extend-spectrum β-lactamase (ESBL) producers of similar β-lactamase producers are present in multiple drug resistant strains of Escherichia coli. The drug susceptibility patterns were divided into 14 patterns against 50 isolated strains. We found that 6 cefotiam (CTM)-resistant strains were also ampicillin (ABPC) and cefazolin (CEZ)-resistant, and 3 strains of cefmetazole (CMZ)-resistant strains were.
2. Piperacillin (PIPC) and CEPs-resistant strains of Peptostreptococcus spp. were about 20%.
3. The frequency of detection of CMZ-resistant Bacteroides fragilis group was high and the MIC90's of PIPC, CEZ, CTM and CMZ were high for both low and high β-lactamase producers. These results, strongly suggest that the resistance of the B. fragilis group to those drugs is caused by β-lactamase.
4. The frequency of detection of β-lactamase-producing Prevotella spp. was high, and the drug susceptibility pattern of β-lactamase producers was similar to that of the B. fragilis group.
5. Antimicrobial activities of sulbactam/cefoperazone (SBT/CPZ) against CEPs-resistant E. coli, ABPC and SBT/ABPC against CEPs-resistant Peptostreptococcus spp. and SBT/ABPC and SBT/CPZ against β-lactamase-producing Prevotella spp. were strong.
6. Parts of the B. fragilis group and Prevotella spp. were presumed etiologic agents of polymicrobial infection and β-lactamase in these bacterial species influenced indirectly to antimicrobial activity of CEPs. These results, the B. fragilis group and Prevotella spp. were direct and indirect pathogenicity of perforative peritonitis.
