Determination of the inhibitory ability of the metabolites of lactic acid bacteria against of Steptococcus pyogenes and Escherichia coli bacteria isolated from different infections from incoming and recumbent patients in Salah Al-Din General Hospital in Tikrit city

Abstract

This study aims to isolate and diagnose the bacterial species Streptococus. pyogenes and Escherichia. coli from different infections, and to study the inhibitory ability of the metabolic products of lactic acid bacteria against the isolated bacteria. The study was conducted on 50 samples from patients with tonsillitis, urinary tract infections, and wound infections, for both sexes and in different age groups, 32 isolates of Streptococus. pyogenes and 16 isolates of Escherichia. coli were obtained. In this study, certain types of lactic acid bacteria, including Lactobacillus. acidophilus and Bifidobacterium. bifidum collected from dairy products from local markets and homes in the city of Tikrit, where the filtrate of Lactobacillus. acidophilus and Bifidobacterium. bifidum bacteria was used separately, and the interaction of these two species with each other at certain concentrations (10, 20, 40) was used to determine the inhibitory ability against bacteria and E. coli using the well diffusion method. The results showed that the metabolites of Lactobacillus. acidophilus and Bifidobacterium. bifidum, both of which together possess a more efficient inhibitory capacity against isolates of Streptococus. pyogenes and Escherichia. coli when added to the holes at a concentration of 40 mg/ml compared to other concentrations of 10 and 20 mg/ml of These bacterial types, at a concentration of 40 mg/ml, led to the inhibition of Streptococus. pyogenes   bacteria with diameters of inhibition of 17.5, 18.6, and 22.0 mm. As for Escherichia. coli bacteria, the diameters of inhibition were as follows: 16.0, 17.5, and 20.5 mm for Lactobacillus. acidophilus, Bifidobacterium. bifidum, and both together respectively. In synergy, the effectiveness of L. acidophiles and B. bifidium was high against Streptococus. pyogenes and Escherichia. coli Compared each separately. The concentration 40mg/ml was the best concentration for producing the metabolites of lactic acid bacteria, and the effect of the metabolites of B. bifidium bacteria on the S. pyogenes and E. coli isolates was wider than the metabolites of L. acidophiles bacteria.