Antimicrobial activity of garlic and cefotaxime against extended spectrum ß-lactamase (ESBL) - producing escherichia coli and its association with the molecular profile of ß-lactamase genes

Abstract

Since the first rise of extended spectrum beta lactamases (ESBL), ESBLproducing organisms have posed a remarkable threat to hospitalized patients due to their activity against cephalosporins, restricting available treatment option. This rapid emergence of ESBLs has been confronted by limited data regarding both phenotypic and genotypic profiles. This lack of information requires more exploration. The aim of this study was, in the first place, to investigate the effect of garlic (A ilium sativum) ethanolic plant extract against ESBL- producing Escherichia co/i and its effect in combination with cefotaxime, and secondly, to characterize the genotypic properties of ESBL-producing E. co/i and correlate it with the efficacy of the combinations of cefotaxime and garlic. The methods used included the agar-well diffusion method to determine the inhibition zone with the double disk synergy test, the microdilution method to determine minimum inhibitory concentration (MIC), the checkerboard technique to quantitatively determine the ameliorative effect, and the polymerase chain reaction method to detect genotypically ESBL genes. The results showed that 30 tg cefotaxime had inhibition zones ranging between 7 and 22mm against ESBL-producing E. co/i indicating that all isolates as resistant to cefotaxime. Using the checkerboard method, all the combinations of ethanolic garlic extract and CTX showed indifference except for some combinations that demonstrated an antagonistic activity with FIC>4. PCR analyses showed that the most common ESBL gene belonged to the CTX-M group. All isolates of E. co/i, except isolate 2, contain this allele according to the following proportions: 36.36% harbored CTX-M gene only, 36.36% harbored CTX-M and OXA genes, and 9.09% harbored CTX-M and TEM. TEM was found in 18.18% of the isolates. No correlation between the phenotype and the genotype of the bacteria was Fill found. A highly resistant isolate of ESBL-producing E. coil (isolate 2) to garlic ethanolic extract was discovered. Further research is needed in order to understand the mechanism of this resistance.