Phylogenetic Classification of Escherichia coli Isolated from Urinary Tract Infections in the Central Regions of Guilan Province

INTRODUCTIONEscherichia coli is the normal flora of the gastrointestinal tract of humans and warm-blooded animals.Most E. coli strains are not pathogenic, but several strains have gained disease-causing genes that have enabled them to cause diseases in humans and animals.They can cause a variety of intestinal and extra-intestinal diseases such as meningitis, neonatal, gastroenteritis, septicemia, wound infections and urinary tract infections (UTIs) [1][2][3].UTIs are the most common after the respiratory tract infections.Annually, approximately 150 million people suffer from UTIs around the world.Many bacteria are capable of causing UTIs, but among them, E. coli is known as the most common cause of UTI involving approximately 90% of these infections.Clinical signs of the infection are urinary frequency, dysuria, blood in the urine, and dirt in the urine [4].Data from gene library of E. coli showed that it comprised different phylogenetic groups and that specific bacteria genes or DNA fragments could be specific markers for phylogenetic classification of E. coli [5][6].Three selected markers, ChuA, YjaA, and TSPE4.C2 are used for phylogenetic classification of E. coli.The gene chuA is essential for transformation of E. coli O157: H7 EHEC, yjaA gene was the first identified in the full genome of E. coli K-12, but its function is still unknown, and TSPE4.C2 was obtained from the gene library of E. coli [5,7,8].More than fifty years have passed since antibiotics were used in the quick and efficient treatment of diseases.During this period, many bacteria have developed resistance to antibiotics, and new generations of antibiotics were introduced to the market.For this purpose, one of the most critical issues in the treatment of infectious diseases is the resistance of pathogenic bacteria to the antibiotics.The basis for appropriate treatment of UTIs is choosing high performance and inexpensive antibiotics.The indiscriminate use of antibiotics has resulted in high levels of antibiotic resistance of E. coli in many parts of the world.The objective of this study was to develop a phylogenetic classification of the E. coli isolates obtained from the individuals with UTIs and to evaluate the antibiotic resistance among them. MATERIAL AND METHODSThis cross-sectional study included 100 E. coli isolates from UTIs collected from the outpatients and hospitalized patients whom samples were sent to five laboratories, Al-Zahra Hospital, Dr. Ashtiyani, Razi, Afrah, and Dr. Afrayi in Rasht city during February 2015 through January 2016.To obtain single colonies, the samples were cultured on the EMB and Blood agar medium cultures and incubated for 24 h at 37°C.Introduction: Urinary tract infection (UTI) is one of the most common infectious diseases, and Escherichia coli is known as the most dominant causative agent of this infection in 90-80% of patients.There is not much information about the phylogenetic groups, types, and virulence factors of E. coli, causing UTIs from Iran.The objective of this study was to evaluate the antimicrobial susceptibility of E. coli strains isolated from patients with UTI and to determine the phylogenetic classification of the strains.Methods: In this cross-sectional study, 100 E. coli isolates were collected from patients with UTI from five laboratories in Rasht city.The isolates were confirmed by using morphological and biochemical common tests.The frequency of virulence genes and patterns of phylogenetic groups were performed using Multiplex PCR.Additionally, antimicrobial susceptibility of all isolates was evaluated by disk diffusion method.Results: Distribution of phylogenetic B2, D, A and B1 groups in the isolates were 64%, 24%, 12%, and 0%, respectively.The highest antibiotic resistance was reported to cefotaxime (84%), piperacillin, and cefixime (80%), and the lowest resistance was demonstrated to imipenem (8%), chloramphenicol and gentamicin (12%).Conclusion: Our findings showed that the B2 was the most prevalent phylogenetic group and the most resistant strain to generally used antibiotics among patients with UTI.