Investigation of the relationship between class-1 integrons and per-1 enzyme in ceftazidime resistant Pseudomonas aeruginosa. Ayşegül Opuş 1 , Tuba Yıldırım 2* , Asuman Birinci 3 , Belma Durupınar 3 1 Microbiology and Clinical Microbiology Laboratory, Konya Research and Education Hospital, Konya, Turkey 2 Department of Biology, Faculty of Arts and Sciences, Amasya University, Amasya, Turkey 3 Department of Medical Microbiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey Abstract Pseudomonas aeruginosa strains, especially multidrug resistant, have great of importance among nosocomial infection isolates. Production of beta lactamase is an important mechanism in gram-negative bacteria for resistance to beta-lactam antibiotics. PER-1 enzyme is derived from an extended spectrum beta-lactamase that is non-TEM, non-SHV-derived in class A and especially causes ceftazidime resistance. In this study, our aim was to investigate the relationship between CLASS-1 integrons and PER-1 enzyme in ceftazidime-resistance Pseudomonas aeruginosa. The PER-1 type beta lactamase enzyme that causes ceftazidime-resistance, determines the frequency, and detects the relationship between the enzyme and CLASS-1 integrons by PCR in 100 (one hundred) ceftazidime-resistant Pseudomonas aeruginosa (P. aeruginosa) isolated at Ondokuz Mayıs University Hospital (Turkey) between 2007 and 2008. In this study, blaPER-1 was detected in 40% (40/100) of the isolates. Four principal clones, which were detected in P. aeruginosa strains were responsible for high prevalence using Random Amplified Polymorphic DNA-PCR (RAPD-PCR) methods. CLASS-1 integron was detected in 62.5% (25/40) of the PER-1 enzyme bearing strains and association between blaPER-1 and CLASS-1 integrons were shown in 2 (two) Pseudomonas aeruginosa strain. Also resistance rates of PRL antibiotic in blaPER-1 negative group was found to be significantly higher against blaPER-1 positive group, resistance rates of other antibiotics were no different between these two groups. We concluded that PER-1 enzyme is common in our hospital and their clonal diversity indicates horizontal dissemination, the association between bla PER-1 and CLASS-1 integrons can accelerate dissemination of this gene. Keywords: Beta-lactamase, PER-1, Pseudomonas aeruginosa, Class-1 integron. Accepted on November 09, 2016 Introduction Pseudomonas aeruginosa is one of the most important nosocomial pathogens that causes nosocomial infections and frequently leads to mortality and morbidity [1,2]. P. aeruginosa infections are often difficult or impossible to eradicate. To some extent, this is due to high-level resistance to many antimicrobial and disinfectants as a result of both intrinsic and acquired mechanisms [3,4]. Several mechanisms can contribute to acquire beta-lactam resistance in P. aeruginosa, including beta-lactamase production, the upregulation of efflux systems, and decreased outer membrane permeability [5,6]. Beta- lactamases are the most common cause of bacterial resistance to beta-lactam antimicrobial agents [2]. Among the acquired enzymes, PER-1 is class A extended-spectrum beta-lactamase (ESBL) of notable clinical importance due to its high level of activity especially causes ceftazidime and to the broad diffusion achieved by it in some epidemiological settings [5,7-9]. Various classes of ESBLs (A, B and D) have been found recently in P. aeruginosa. Five types of class A ESBLs (PER, VEB, GES, IBC, TEM and SHV) were recently reported in P. aeruginosa; however, these were found in limited regions [10]. The PSE, OXA and PER types are the most common ESBLs found in P. aeruginosa isolates [10-13]. The PER-1 and VEB-1 types belong to class A enzymes and relate to a high level of resistance to cephems, monobactams and ceftazidime [12-14]. The resistance genes such as blaPER-1 can be transferred among bacteria by mobile genetic elements, such as integrons and even ESBL located on integron and facilitate these elements [15-17]. Integrons structure contains essential elements for insertion and mobilization of gene cassettes generally possess antimicrobial resistance genes [18,19]. In particular, much research effort has been devoted to integrons belonging to classes 1, 2 and 3, the classes most commonly associated with the spread of antibiotic resistance in pathogens [20]. Class 1 integron is composed of a 5'- conserved segment (5'CS) including the integrase gene intI and attI genes and Pant ISSN 0970-938X www.biomedres.info Biomed Res- India 2017 Volume 28 Issue 6 2689 Biomedical Research 2017; 28 (6): 2689-2695