Anotace:
Extended-spectrum β-lactamases (ESBL) are enzymes produced by Gram-negative microorganisms, which may be resistant to commonly used antibiotics. The purpose of this research was to estimate the bactericidal effects of cinnamon oil on ESBLproducing bacteria. In this study, 227 water samples were collected from wells in Hafr Al-Batin, Saudi Arabia. The samples were cultured on a cystine lactose electrolyte-deficient (CLED) medium. A MicroScan system was used to identify bacteria and also for antimicrobial susceptibility test. Activity of crud cinnamon oil and its fractions were detected by determining the minimum inhibitory concentration (MIC) against the ESBL-producing bacteria. Morphological changes of the treated bacteria were observed and oil compounds was investigated. The culture was positive on the CLED medium in 170 out of 227 water samples. In 170 CLED-positive isolates, E. coli was the most common organism, followed by K. pneumoniae. The results showed that 100% of K. pneumoniae isolates were completely resistant to ampicillin (100%), then by mezlocillin (92.5%), cefazolin, and cefuroxime (77.5%). Also, 86.9% of E. coli isolates were the most resistant to ampicillin, followed by mezlocillin (83%). 82% of K. pneumoniae and 89% of E. coli isolates were confirmed by phenotypic confirmatory disc diffusion test (PCDDT) as ESBL-producers. The cinnamon oil activity was only concentrated in the oxygenated fraction. The MICs of the oxygenated fraction were 80 and 20 µl/mL at 105 CFU of ESBL-producing E. coli and K. pneumoniae, respectively. This study indicated the antibacterial effects of cinnamon essential oil to eliminate some antibiotic-resistant bacteria from water.