integrons are a segment of dsDNA that play a major role in bacterial adaptation and evolution. These genetic determinants are known by the presence of three necessary apparatuses: an integrase (intI gene), Pc (a promoter) and attI (a recombination site). These elements are able to acquire gene cassettes, which can carry antibiotic resistance factors, via site-specific recombination mechanism. The most common types of resistance integrons are class I (Tn402 derivatives), followed by class II and III. In recent years, the role of integrons as an important factor in the transmission and spread of resistance factors has been considered. Therefore, the ongoing threats posed by integrons require an understanding of their origins and evolutionary history. This review examines the functions and activities of integrons. It shows how antibiotics use selected particular integrons from the environmental pool, so that integrons carrying resistance genes are now present in the majority of Gram-negative pathogens.

Resistance to antimicrobial agents is on the rise and this phenomenon not only leads to an increase in economic burden but may also cause serious therapeutic problems. Nowadays, it is known that horizontal transfer of resistance genes is a major cause for spreading antibiotic resistance genes in microbes. The previous studies have manifested that integrons play a significant role in horizontal transfer of antibiotic resistance. integrons are in fact natural cloning and expression systems which have the ability to spread multi drug resistance (MDR) in bacteria. They are normally motionless but can be transferred through mobile genetic elements, for example plasmids and transposons. integrons carry divergent gene cassettes that are rearranged under antibiotic selective pressure. It is based on the sequence of the integrase gene that various classes of integrons are known. Class 1 integron is the most prevalent type among bacteria. This review highlights the need for continuous surveillance to understand the dissemination of integron and multidrug resistance among different bacteria.

Background & Objective: Gastroenteritis is one of the most common Salmonella infections in human which is caused by Salmonella serotypes especially S. enteritidis and S. typhimurium. The spread of multi-drug resistant (MDR) Salmonella strains is a serious global issue. Obtaining integrons is considered as one of the most important factors in multidrug resistance among gram-negative microorganisms, particularly in intestinal bacteria. The aim of this study was to investigate the molecular level of class 1, 2 and 3 integrons which are the most important integrons in Salmonella enteritidis isolated from patients using Multiplex PCR.Methods: In this study, 567 stool and blood samples were collected from patients with acute gastroenteritis and Salmonella enteritidis were detected using culture method, standard biochemical test, and PCR. After DNA extraction, the presence of class 1, 2, and 3 of integrons was analyzed by multiplex PCR.Results: From 567 samples, 48 strains were identified as Salmonella enteritidis. Of all 48 strains, 45 strains (95%) had theintI gene, 7 strains (14.5%) had the intII gene, and 2 strains (4%) had theint III gene.Conclusion: In this study, high incidence of class 1, 2 and 3 integrons was detected. Screening integrons as a sign of obtaining and expansion of antibiotic resistance could be considered as an important mechanism to deal with antibiotic resistance in microorganisms.

Background: integrons are frequently detected in clinical isolates of Enterobacteriaceae. These elements are able to capture and express gene cassettes encoding antibiotic resistance. Numerous studies have examined the distribution of integrons in Escherichia coli. Despite this, there is a paucity of epidemiological data on the occurrence of integrons as well as extended spectrum b-lactamases (ESBLs) among enteropathogenic E. coli isolates.Objectives: The main aim of this study was to investigate the prevalence of integrons as well as ESBLs among enteropathogenic E. coli isolates obtained from children with diarrhea in Tehran, Iran.Patients and Methods: In total, 42 enteropathogenic E. coli strains were isolated from children with diarrhea and examined for the presence of class 1 and 2 integrons. The combined disk method was also performed to detect ESBL production. Statistical analysis was used for the comparison of the categorical data.Results: Class 1 integron was identified in 24 (57.1%) isolates, while only 2 (4.8%) isolates harbored class 2 integron. integrons were significantly associated with resistance to certain antibiotics, including, co-trimoxazole (P=0.016) and tetracycline (P=0.006). Of the 42 enteropathogenic E. coli isolates, 9 (21.4%) isolates were ESBL producers. However, no significant association was observed between the existence of integrons and ESBL production (P=0.26).Conclusions: Class 1 integrons are prevalent among enteropathogenic E. coli isolates, regardless of whether or not they produce ESBLs. This study emphasizes the alarming role of integrons in antibiotic resistance within diarrheagenic E. coli strains.