ABSTRACT Up to 70 clinical Escherichia coli samples were examined, with 30 identified as extended-spectrum β-lactamase (ESβL) isolates. These isolates were gathered from inpatients and outpatients at some Baghdad hospitals. Urine, pus, feces, and blood samples were obtained from government hospital patients of both genders and diverse age groups. Production of ESβL and the quick antibacterial diagnosis was checked using the VITEK2 for susceptibility experimentation and identification of the bacterial sample. The results showed that 30 isolates only in the current study were ESβL producers. Furthermore, all showed biofilm formation after 24 hours of incubation some of these isolates were the ability of biofilm formation decreased after 48 hours compared with negative control. The formation of biofilm has founded a vary from strong to weak. The variation in the bacterial study may depend on their antibiotic resistance and the sample’s source. Therefore, this study considers the need to focus in subsequent studies on the effect of biofilm formation and resistance of isolates, which produce beta-lactamase enzymes for many antibiotics, thus avoiding the occurrence of double health crises for infected patients. Keywords: Biofilm formation, Escherichia coli, ESβL, Multiple drug resistance. International Journal of Drug Delivery Technology (2022); DOI: 10.25258/ijddt.12.2.41 How to cite this article: Raoof MAJ, Fayidh MA. Investigation of Biofilm Formation Efficiency in ESβLs of Pathogenic Escherichia coli Isolates. International Journal of Drug Delivery Technology. 2022;12(2):695-700. Source of support: Nil. Conflict of interest: None Investigation of Biofilm Formation Efficiency in ESβLs of Pathogenic Escherichia coli Isolates May A. J. Raoof, Mohammed A. Fayidh* Department of Biology, College of Education for Pure Science Ibn Al-Haithum, University of Baghdad, Hillah, Iraq Received: 14th February, 2022; Revised: 24th April, 2022; Accepted: 05th May, 2022; Available Online: 25th June, 2022 INTRODUCTION Enterobacteriaceae is the most common group of pathogenic and non-pathogenic, gram-negative bacilli groups. 1 It is a symbiotic bacterium that colonizes the intestines naturally after birth. Escherichia coli is the most common pathogen in Enterobacteriaceae. It can potentially infect the human body (Opportunistic pathogen) opportunistically, 2 causing infection from diseases such as urinary tract infections (UTI), cystitis, and other pathogens such as meningitis, septicemia, gastritis, intestines among children, wound infection, and pneumonia. 3 These bacteria possess many virulence factors. 4 The most important of which are resistant to antibiotics and their ability to form biofilm. Characteristic of high and multiple antibiotic resistance. 5 ESβLs are a group of enzymes that lead to resistance increase in aztreonam, ceftazidime, cefotaxime related oxyimino-β-lactams, cephalosporins, and penicillins, but clavulanic acid inhibits them. 6 Until now, more than 400 ESβL variants have been identified. 7 Biofilms are a complex collection of bacteria with unique properties that facilitate their host avoidance, immune response, and penetration by Antagonists. 8 The resistance to antibiotics by the bacteria is higher when isolates can form biofilms. 9 The increase in levels of RESEARCH ARTICLE resistance leads to the fact that treatment options will be more difficult. The emergence of multiple resistance changes the infection from something simple to complex. Biofilm formation and extended spectrum beta-lactamase (ESBL) production synergistically contribute to the widespread dissemination of gram-negative bacilli antibiotic resistance (MDR) strains. These facts may be responsible for chronic and persistent injuries and relapses of infection, which subsequently lead to high rates of infection and death and thus the formation of a health crisis. 10 The present study aims to isolate and identify the ESBLs producing E. coli bacteria and to reveal the ability of these isolates to cause biofilm formation. MATERIALS AND METHODS Bacterial isolates Up to 70 clinical E. coli samples were examined, with 30 identified as ESβL isolates. These isolates were gathered from inpatients and outpatients at a few Baghdad hospitals. Urine, pus, faces, and blood samples were obtained from patients at government hospitals who came from both genders and diverse age groups between (9/10/2019 to 20/12/2019). Standard microbiological techniques were used for separation, and 11 and standard microbiological procedures *Author for Correspondence: mohammedcbt66@gmail.com