Comparison of virulance gene ratios between quinolone-resistant and susceptible clinical escherichia coli strains

Introduction and Aim: Escherichia coli (E. coli) can cause morbidity and mortality by causing many extraintestinal infections such as urinary tract, bloodstream infections and neonatal meningitis as well as intestinal infections. In addition, increasing antibiotic resistance in recent years is a concern. For this reason, quinolone resistance, phylogenetic group, virulence gene characteristics and relations with each other of clinical E. coli strains isolated from extraintestinal samples obtained from ward and outpatient clinic patients were investigated. Materials and Methods: Antibiotic susceptibility tests of 91 E. coli strains isolated from urine, blood, respiratory samples and wound/tissue samples were performed by disc diffusion method. The virulence genes of hlyA, cnf1 and sfa/focDE were determined by PCR method. In addition, yjaA, chuA and TSPE4.C2 were examined by PCR method, and these strains were divided into 4 phylogenetic groups and their relationships with each other were analyzed statistically by Pearson chi-square or Fisher Exact tests. Results: The most common phylogenetic group was group D, which comprised 56 (61.5%) of 91 strains. Group D was also the most virulent group and its relationship with sfa/focDE was statistically significant (p=0.01). The most common virulence gene was sfa/focDE and it was positive in 12 strains (13.2%). The highest resistance was observed in ampicillin (41/55.4%) in strains obtained from urine samples, while piperacillin (14/82.4%) was observed in non-urine samples. Ciprofloxacin resistance was detected in 27 strains (36.5%) from urine samples and 9 strains (52.9%) from non-urine samples. Imipenem, meropenem and amikacin resistance was not observed in any of the strains. Discussion and Conclusion: It is a concern that the relatively high quinolone resistance may limit its use in the treatment of more serious infections. Although there is no carbapenem-resistant strain, irrational use of antibiotics may lead to the emergence of strains resistant to this antibiotic group. It is also of concern that the most common group is also the most virulent. The relationship between the virulence gene and the phylogenetic group gives different results in studies, and more studies are needed on this subject. Moreover, it is important to establish a database on this and similar issues by continuously conducting epidemiological studies. Keywords: E. coli, phylogenetic group, quinolone, virulence gene