Molecular characterization of ESBL gene in Citrobacter spp. and antibacterial activity of omega-3 against resistant isolates

The study aimed to investigate the prevalence and resistance pattern of different Citrobacter spp., phenotypically and genotypically, to β-lactam antibiotics, then to evaluate the antibacterial activity of omega-3 extracted from flaxseed against isolates that harboring resistance genes. Herein, 19 Citrobacter isolates were isolated from 100 stool and urine samples taken from patients attended to AL-Sadar Hospital during June- December 2016. Clinical samples were then cultured on specific media, thereafter, isolates were identified depending on morphological, biochemical characteristics and VITK-2. The results showed that the Citrobacter spp. comprise 19/78 (24%) of positive bacterial growth on macConky agar, from which 14.1% were C. freundii, C. koseri represented 6.1% and C. farmeri were 3.8% of the total. The results of antibiotic susceptibility showed that all Citrobacter 100% isolates were resistant to ampicillin and cefoxitin, but were sensitive to imipinim. Moreover, the isolates initally showed different degrees of resistant to β-lactam antibiotics. Furthermore, by confirmatory test, the results observed that 17/19 (89.4%) of the isolated were extended-spectrum β-lactamase (ESBL - producers). Finally, using the PCR technique to detect bla_Genes, the results revealed that 14/17 (82.3) of potential ESBL producing Citrobacter harbored one or more ESBL genes. These included 10 isolates of C. freundii and 4 isolates of C. koseri. In related work, extracts of essential fatty acid semicarbazide - omega3 (EFASC) from Linum usitatissium (Flaxseed) were tested to evaluate their activity against resistant isolates. The results demonstrate the broad spectrum antibacterial property of EFASC compounds against resistant bacteria. In conclusion, this study found increase prevalence of multi-drug resistance MDR Citrobacter spp. as causative agents in clinical cases. Considering the antibacterial activity of EFASC that displayed high activity against resistant pathogens, deservedly, attention must be paid to developing their use as alternative antibiotics.