Abstract:
This study was carried out to evaluate the efficacy of co-
trimoxazole against enterobacteria. Co-trimoxazole is a
combination of trimethoprim and sulfamethoxazole in a fixed 1 : 5
ratio.
Fifity clinical isolates from five different genera of
enterobacteria were isolated from patients suffering from
abdominal disturbances, respiratory tract infections, urinary tract
infections, typhoid fever and others. Ten strains from each genus
were isolated. The genera were: Salmonella, Shigella, Escherichia,
Proteus and Klebsiella. The species isolated were as follow: 2
species of Salmonella, 4 species of Shigella, 1 species of
Escherichia , 2 species of Proteus and 2 species of Klebsiella. Also
standard strains were obtained for comparison.
The different strains were purified on selective media and
identified by biochemical tests .All clinical isolates were subjected
to two types of tests: disc diffusion method and serial dilution
method in nutrient broth by using different concentrations of the
drug.
The results showed that: 10 strains of Salmonella were
susceptible to co-trimoxazole, 9 strains of Shigella from 4 species
were susceptible , while one strain of Shigella sonnei was
intermediate, 8 strains of E.coli were susceptible, one strain of
E.coli was intermediate and one strain was resistant. All strains of
Proteus were resistant, 6 strains of Klebsiella from 2 species were
susceptible, while 3 strains were intermediate and one strain of
Klebsiella pneumoniae was resistant. The same results obtained by
disc diffusion method were similar to those obtained by serial
dilution method.